HomeMy WebLinkAboutBradley Lake Hydroelectric Project - Middle Fork Diversion Overland Access Assessment 1986MIDDLE FORK DIVERSION
OVERLAND ACCESS ASSESSI'lENT
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
FEDERAL ENERGY REGULATORY CO~lISSION
PROJECT NO. 8221-000
Prepared by
STONE &: WEBSTER ENGIriEERING CORPORATION
ANCHORAGE, ALASKA
DECm-1BER 1986
• 1
Steve Cowper, Governor.-"·_ .J
'> ~
Alaska Power Authority
State of Alaska
APA/OTHR/0272
December 31, 1986
Mr. Carl Yanagawa
Division of Habitat
Alaska Department of Fish & Game
333 Raspberry Road
Anchorage, Alaska 99502
Attn: Mr. Don McKay
MIDDLE FORK DIVERSION
OVERLAND ACCESS ASSESSMENT
BRADLEY LAKE HYDROELECTRIC PROJECT
Enclosed for your review and comment are two copies of the Middle Fork
Diversion Overland Access Assessment. This is the decision-making
document that has been prepared in response to the October 2.3, 1986
agency meeting. We would appreciate receiving your comments by January
30, 1987.
Should you have any questions, please contact Mr. Tom Arminski at
(907) 561-7877.
Very truly yours,
ALASKA POWER AUTHORITY
David R. Eberle ALASKA DEPT, OF
Project Manager FIS!-1 & C/IME
,.1 i'DRE/WDS/JJ l~~r§ r ...<JSKa .rtcs:,,~~[,::s '-'brOil)' & Inrormation Servicc~
UbmG' (Juilding, Suite In RECION IIEnclosure 3211 Providence Drive I-!A [) 'T J\ I ., '~;r\, 01\11<:;'0"Anchorage,AK 995084614 ' • 'VI :\
PO Box 190869 701 EastTudor Road Anchorage, Alaska 99519-0869 (907) 561-7877
2-1450-JJ
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MIDDLE FORK DIVERSION
OVERLAND ACCESS ASSESSMENT-
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BRADLEY LAKE HYDROELECTRIC PROJECT
• ALASKA POWER AUTHORITY
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FEDERAL ENERGY REGULATORY COMMISSION
PROJECT NO. 8221-000
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-Prepared by
STONE & WEBSTER ENGINEERING CORPORATION-ANCHORAGE, ALASKA
-DECEMBER 1986
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_4P~!S . -Alaska Resources Uhrary & Jn~ormation SeIVlCei
Uhr;,f\ Building, Suite 111
32 i f l'rovIDcncc Drive
~e.AK 99S084614 -
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TABLE OF CONTENTS-
-Section Section Title Page No.
LIST OF TABLES iii
LIST OF FIGURES iv
1.0 INTRODUCTION AND PURPOSE OF ACTION 1-1
-1.1 GENERAL DESCRIPTION 1-1
1.2 PURPOSE OF ACTION 1-1
1.3 ALTERNATIVES CONSIDERED 1-2•
2.0 PROPOSED ACTION AND ALTERNATIVES 2-1
2.1 OVERLAND ACCESS -PREFERRED ALTERNATIVE 2-1
• 2.1.1 Location 2-1
2.1.2 Overland Access 2-1
2.1.3 Construction Schedule 2-4
• 2.1.4 Work-Force Requirements 2-5
2.1.5 Required Permits 2-5
2.1.6 Coastal Consistency Compliance 2-5
2.2 AIR ACCESS ALTERNATIVE 2-6• 2.2.1 Location 2-6
2.2.2 Air Access 2-7
• 3.0 WATER USE AND QUALITY 3-1
3.1 BASELINE DESCRIPTION 3-1
3.2 PROJECT IMPACTS 3-1
• 3·3 MITIGATION MEASURES 3-2
4.0 BOTANICAL RESOURCES 4-1
4.1 BASELINE DESCRIPTION 4-1-4.2 PROJECT IMPACTS 4-2
4.3 MITIGATION MEASURES 4-4
4.3.1 Avoidance 4-4
• 4.3.2 Minimization 4-5
4.3.3 Rectification 4-5
• 5.0 WILDLIFE RESOURCES 5-1
5.1 BASELINE DESCRIPTION 5-1
5.1.1 Moose 5-1
5.1.2 Mountain Goat 5-1
-5.1.3 Brown Bear 5-2
5.1.4 Black Bear 5-2
5.2 PROJECT IMPACTS 5-2
-5.2.1 Moose 5-3
5.2.2 Mountain Goat 5-3
-5.2.3 Brown Bear 5-4
5.2.4 Black Bear 5-5
5.3 MITIGATION MEASURES 5-5
5.3.1 Habitat/Land Disturbance 5-5
5.3.2 Increased Access 5-6
5.3.3 Direct Disturbance 5-6
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... TABLE OF CONTENTS
(continued)
Section Section Title Page No.
6.0 HISTORIC AND ARCHAEOLOGICAL RESOURCES 6-1
6.1 BASELINE DESCRIPTION 6-1
6.2 PROJECT IMPACTS 6-1
6.3 MITIGATION MEASURES 6-1
• 7.0 VISUAL RESOURCES 7-1
7.1 BASELINE DESCRIPTION 7-1
7.1.1 Landscape Character and Existing
Visual Condition 7-1• 7.1.2 Visual Resource Importance 7-2
7.2 PROJECT IMPACTS AND MITIGATION MEASURES 7-2
• 8.0 LAND USE 8-1
9.0 ECONOMIC EVALUATION 9-1 • 10.0 RECOMMENDATIONS 10-1
11.0 BIBLIOGRAPHY 11-1•
12.0 AGENCY CONSULTATION 12 ... 1
12.1 DESCRIPTION 12-1
12.2 INDEX OF CORRESPONDENCE 12-1"
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LIST OF TABLES-
Subject -
Economic Evaluation of Overland Access
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LIST OF FIGURES•
Figure Subject -
1 Middle Fork Overland Access
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SECTION 1.0
INTRODUCTION AND
PURPOSE OF ACTION
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1.0 INTRODUCTION AND PURPOSE OF ACTION-
1.1 GENERAL DESCRIPTION•
The Bradley Lake Hydroelectric Project lies at the head of Kachemak
• Bay about 27 air miles northeast of Homer, Alaska. Most of the
Project will be built in the mountains and adjacent tidal flats
• bordering the eastern side of the Bay. Bradley Lake is located in the
Kenai Mountains about 5 air miles east of Kachemak Bay at an elevation
• of 1,080 feet. The surrounding area consists of steep-sided mountains
reaching 6,000 feet. Except for the alluvial delta at the head of
Bradley Lake where Kachemak Creek and the upper Bradley River flow•
into the lake, the land rises steeply from the lake surface level.
• The proposed development includes raising the existing Bradley Lake
level 100 feet by constructing a dam, spillway, and outlet facility at
• the lake outlet. To provide additional water for power generation, a
small rockfill diversion dam 20 feet high and 45 feet long will divert
• flows of the Middle Fork of the Bradley River (Middle Fork) into a
tributary of Bradley Lake. The diversion structure includes 1,050
• feet of open channel constructed in rock and glacial till and a low,
broad earthfill dam.
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Construction of the Middle Fork diversion will require heavy
construction equipment such as tracked bulldozers, air drills and-compressors, backhoes, and loaders. The License Application (Alaska
Power Authority 1984) and FERC Final Environmental Impact Statement-(CORPS 1982) proposed all equipment would be transported to the
diversion site by heavy-duty helicopter (e.g., Sikorsky Skycrane). -
1.2 PURPOSE OF ACTION -The Power Authority proposes to transport necessary construction
equipment to the Middle Fork diversion site by way of an overland•
access trail. Equipment would be barged from the Bradley Lake dam
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8i te to the head of Bradley Lake. The trail would extend from the
northeast shore of Bradley Lake to the diversion site.
1.3 ALTERNATIVES CONSIDERED
The only feasible al terna ti ve to the proposed action considered in
this assessment is air access. Because of the steep terrain type
found in the Project area, there is no feasible means to combine
overland access and air access for heavy equipment mobilization. A
commitment to mobilizing a barge for overland access or to lease of a
large helicopter for air access would preclude the utility of using
the alternate mode of access. However, construction personnel will be
using helicopter access. The size of helicopters used to normally
transport personnel limits the available lifting capactiy.
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SECTION 2.0
PROPOSED ACTION
AND ALTERNATIVES
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-2.0 PROPOSED ACTION AND ALTERNATIVES
2.1 OVERLAND ACCESS -PREFERRED ALTERNATIVE-
2.1 .1 Location -
The overland access trail would begin at the northeast shore of
Bradley Lake near Kachemak Creek and be routed up the steeply inc11ned-slopes north of the lake. The route would pass through patchy, tall
shrub vegetation on the slopes above the lake, eventually passing-through subalpine herbaceous vegetation at the higher elevations. The
lower slopes of the route are steep, ranging to 28 percent. Upper• slopes are on relatively flat ground between scattered rock knobs.
• 2.1.2 Overland Access
• A constructibility review was made of an approx1mately 3 mile long
overland access route from the head of Bradley Lake to the M1ddle Fork
diversion site during August and September 1986. The overland route•
-was inspected from the Middle Fork dam site to an accessible barge
landing site north of the Kachemak Creek delta on Bradley Lake. The
numbers in parentheses refer to points identified in Figure 1 •
• The access trail is envisioned as a approximately 30 feet wide
corridor within a 100 feet wide right-of-way (ROW). The ROW would be -flagged, and equipment would be required to stay within the 30 feet
initial corridor to minimize false startS. -
A barge landing can be made at the small beach at the mouth of the
second watercourse west of the Kachemak Creek delta (1). The beach-offers a reasonable slope for tracked equipment to ascend. At the
time of inspection, the lake level was very high and only a few feet• of the gravel shoreline was visible. The beach appeared to be stable,
with a gentle slope down to the water.-
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From the beach a bulldozer would be able to proceed uphill, bearing-toward the southeast along a ridge through low-growing shrubs mixed
-with scattered alders and willows. The average slope through this
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section is approximately 25 to 28 percent. It passes through
scattered patches of alders, but the soil is firm and dry. An
alternative access alignment follows the water course upstream for
approximately 300 -400 feet, then switches back to the south and
climbs out of the drainage (2). Approximately 1,600 feet up the slope
is a ridge of outcropping rock with scattered spruce trees (3). A
path was selected that follows the crown of this ridge top, which•
would result in little disturbance to the soil or vegetation •
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The overland access route continues uphill along the south side of the
drainage course, through 15 to 20 feet pa tches of 8 to 10 feet high-alder, into a clear area (4). The route then turns to the north for
300 feet until it reaches the drainage course, then turns to the
northeast and continues uphill along the drainage course toward the -
top of the drainage (5). Moderate amounts of bulldozer blade work
would be required to construct a path without excessive slope. The -
slope varies from 10 to 25 percent. The soil below the upper limit of
the alders is poorly drained, has a high organic content, and is of-undetermined depth.
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At the top of the drainage and prior to entering an area of dense
alders, the route turns to the north along the east side of a bare
rock knob and proceeds northward through a fairly open area (6).
Flowing water is encountered in this area and flotation track
equipment or mats will be required to cross these areas. -
Approximately 1,000 feet north of the rock knob, the route proceeds
500 feet northeast through alders (7), to the upper limit of the -
alders, then along a westerly-facing slope covered with subalpine
tundra and grass (8) ••
The route continues for approximately 1,000 feet through subalpine• tundra, following the upper limit of the alders. At this point a path
must be cut through a ~ection of alders approximately 500 feet across-
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(9). The soil in this area has a high organic content, and is wet and
poorly drained. The route then proceeds northwest up a 25 to 27
percent slope toward a natural bench between the lower and higher rock
knobs (10). This section will require cutting a path through another
500 to 700 feet of alders. This area is also wet and poorly drained
with a small drainage course running through it. The route then turns
east up a steep slope to the east side of a rock knob. This will
require sidehill cut and fill to prevent overturning of towed
equipment.
An alternate route is available east of the above described section
(11). This route would require at least two switchbacks, and
substantial cut and fill with a bulldozer. This area would be visible
from the lake surface. The route then would proceed north over rocky
ground through and along a natural drainage area and rock cuts (12).
This area is lightly vegetated, with generally less than 2 feet
overburden depths to bedrock. Fording of Marmot Creek approximately
2,000 feet above the downstream terminus of the Middle Fork diversion
channel would not pose a problem as the banks are low in this area
(13) •
The remaining 3,000 feet to the terminus at the Middle Fork diversion
dam site (15) travels over alpine tundra on relatively flat ground
between scattered rock knobs, with the exception of one 75 feet long
25 percent slope on which winching may be required (14).
Other optional routes leading from the beach up the first steep
incline may also be feasible. Depending on the equipment types to be
used, other more feasible routes may be identified. Identification
and flagging of a final access route will follow approval of the
overland access concept.
The route chosen will require hand cutting of alders in areas and cut
and fill in some areas. The proposed choice of routing was based on
using either a D-6 or D-8 size bulldozer with low ground pressure wide
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tracks and winch capability. The compressors and drills would need-winch capability. The compressors and drills would have to be skid or
track mounted, and be towed in after pioneering by two lead
bulldozers. -
-The minimum estimated equipment required for the Middle Fork diversion
construction would be an air track drill, 600 c.f.m. compressor, track -loader (similar to 955 Caterpillar), and a D-6 size bulldozer with
ripper and winch. Optional equipment would be an additional air track
drill and compressor, a backhoe on tracks, a tow-behind roller• compactor, and a larger bulldozer such as a D-8 or D-9.
• Small equipment, fuel, supplies, personnel, and personnel support
facilities will be transported by light helicopter.
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2.1.3 Construction Schedule
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The Middle Fork diversion will be constructed between May and October
1988. The construction schedule allows for a relatively narrow window•
within one summer for construction of the diversion. Deep snow drifts
and frozen ground conditions would limit equipment movements during• early spring. Severe winter weather conditions at the Middle Fork
site would preclude construction during late fall and winter.
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An estimated 6 to 1 days would be required for two bulldozers to
pioneer the access trail. Once pioneered, the estimated travel time
from the Bradley Lake beach to the Middle Fork dam site would be 5 to -12 hours. The majority of this time would be spent between the beach
and the midpoint of the trail, where occasional winching of equipment
would be necessary.-
Larger equipment can be moved overland than can be transported by-helicopter. Because of the larger eqUipment, less time to complete
construction of the Middle Fork diversion is expected with overland
access.
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2.1.4 Work-Force Requirements
Similar total work-force requirements would be needed for the overland
access as for air access. The capability for transporting larger
equipment by overland access than air access will favor an overall
shorter period for construction of the Middle Fork diversion.
2.1.5 Required Permits
Prior to construction of an overland access trail, the following state
and federal permits and authorizations would be required:
Federal
o Modify U.S. Army Corps of Engineers Section 10 and Section
404 Permit (071-04D-2-850502).
o Show consistency with Alaska Coastal Management Program.
2.1.6 Coastal Consistency Compliance
Alaska statutes require that projects conducted within the coastal
zones of Alaska be consistent with standards of the Alaska Coastal
Management Program (ACMP).
The proposed Middle Fork diversion overland access trail would provide
overland access for construction equipment between the northeast shore
of Bradley Lake and the Middle Fork diversion site. The temporary
access trail would be about 3 miles long and approximately 30 feet
wide. The access trail would be used on a one-time round trip basis
only. Winching of equipment would be required on steep slopes. The
access trail would be rehabilitated and artificially revegetated
foll owing use.
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-A review by the Alaska Power Authority of the proposed overland access
route found the activity consistent with the standards of ACMP as
established by 6 AAC 80, particularly standards for: 1) Energy• Facilities (6 AAC 80.070(b»; 2) Habitats (6 AAC 80.130); 3) Air,
Land, and Water Quality (6 AAC 80.140); and 4) Historic, Prehistoric, .. and Archaeological Resources (6 AAC 80.150).
.. Steps have been taken in planning for construction, use, and
rehabilitation of the overland trail to maximize conformance with the .. standards of the ACMP. Routing of the proposed overland access route
minimizes clearing of tall alder vegetation. The final route would be
selected based on the shortest length and width possible commensurate• with safety and environmental disturbance considerations. Winching
and floatation tracks would be used on equipment where necessary to
• minimize disturbance. Steep slopes and embankment cuts would be
avoided wherever practicable. Accidental petroleum spills could be
• readily contained and cleaned up. Dressing and cross-ditching of the
access trail would minimize water velocities and soil erosion, thus .. preserving water quality entering Bradley Lake. The access trail
would be seeded, fertilized, and protected from erosion by erosion
control blanket materials. Erodible slopes would be protected from•
erosion during the summer of construction by erosion control blanket
materials. Direct impacts to wildlife of construction and use of the • overland trail would be minimized. Should any historic, prehistoric,
or archaeological resources be discovered as a result of this
• activity, work which would disturb such resources would be stopped and
the State Historic Preservation Office contacted immediately. -
2.2 AIR ACCESS ALTERNATIVE
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2.2.1 Location
-Equipment would be air lifted by large helicopter (Sikorsky Skycrane)
from the Bradley Lake dam site to the Middle Fork diversion dam site,..
a distance of approximately 2.7 air miles.
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2.2.2 Air Access
Equipment transported to the Middle Fork diversion dam site by large
helicopter must be dismantled into component pieces and reassembled at
the work site. Individual pieces must weigh less than approximately
19, 000 pounds under optimum flying condi tions. A D-6 with blade
weighs 36,000 pounds, a D-7 weighs 51,410 pounds, a D-8 weighs 81,490
pounds, and a D-9 weighs 110,600 pounds. A tracked bulldozer of a
size comparable to a D-6 Caterpillar would be transported in three
trips composed of 1) blade, 2) tracks, and 3) main chassis. Depending
on the altitude and existing weather conditions (air temperature and
humidity), the engine and peripheral equipment (e.g., winches, track
rollers) may require removal from the main chassis to reduce weight.
A helicopter cannot lift an undismantled bulldozer chassis larger than
a D-6 or equivalent.
Smaller equipment, materials, and personnel would also be transported
to the Middle Fork diversion site by helicopter.
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SECTION 3.0
WATER USE AND QUALITY
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-3.0 WATER USE AND QUALITY
3.1 BASELINE DESCRIPTION-
Several small streams enter Bradley Lake on its northeast shoreline. -These clear-water streams are fed by surface runoff and groundwater,
and are likely intermittently flowing. No ice-rich permafrost has .. been identified. Marmot Creek is the only major stream crossed by the
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3.2 PROJECT IMPACTS -A pioneer trail would likely result in some localized erOSion,
particularly on steeper slopes where vegetation had been removed.• Most runoff from a pioneer trail would be diverted by cross-ditches
into the nearby dense vegetation. Spacing cross-ditches about 30 to
• 50 feet apart would limit runoff velocities and erosive capabilities,
thus sedimentation in streams would be minimized. Operation of
• equipment within stream channels would be avoided, except at specific
crossing points previously identified. If sedimentation were to occur
in any stream channels, it would enter Bradley Lake which does not•
support fish life. All runoff from the slopes affected by the
overland access trail would enter Bradley Lake, which is turbid• year-round. Fill fran borrow or quarrying operations would not be
used in oonstruction of the trail.
Accidental spillage and leakage of petroleum produots during
construction and use of the access trail could result in contamination -
of surface and ground water. It is believed that should a spill
occur, it can be contained using mitigation measures described below.-
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3.3 MITIGATION MEASURES
Erosion control measures as described in Section 4.3 will minimize or
prevent stream sedimentation. Any sedimentation in streams will
eventually reach Bradley Lake, which does not support fish life.
Residence time of water in Bradley Lake, and its capacity as a
settling basin, would also limit movement of sediment into the lower
Bradley River.
Impacts from accidental spillage or leakage of petroleum products will
be avoided by properly maintaining.equipment.
Fuel handling and oil spills would be addressed as described in the
Best Management Procedures Manuals Fuel and Hazardous Materials
(Alaska Power Authority 1985a) and Oil Spill Contingency Planning
(Alaska Power Authority 1985b), respectively. The Contractor would be
required to develop and implement a Spill Prevention Control and
Countermeasures (SPCC) Plan prior to mobilization of fuel on-site.
Bulk fuel can be transported to the Middle Fork diversion site by
helicopter.
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SECTION 4.0
BOTANICAL RESOURCES
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4.0 BOTANICAL RESOURCES-
-4. 1 BASELINE DESCRIPTION
The slopes surrounding Bradley Lake which are below approximately• 2,000 feet in elevation are dominated by tall alder shrubland
interspersed with tall grassland vegetation communities. -
The tall alder shrubland is a common vegetation community on sloping
• terrain from the upper boundary of closed coniferous forest to the
lower boundary of shrub tundra. Aspect does not appear to limit the
distribution of the alder community. On the steeply sloping terrain•
above Bradley Lake, the tall shrub layer consists of 10 feet tall
Sitka alder (Alnus sinuata). The low shrub layer extends to 3 feet•
and consists of salmonberry (Rubus speotabilis) and mountain ash
(Sorbus sitohensis). The tall herbaoeous layer extends to 3 feet and• consists of bluejoint (Calamagrostis oanadensis), horsetail (Eguisetum
spp.), shield fern (Dryopteris dilitata), fireweed (Epilobium
• angustifolium), twisted stalk (Streptopus amplexifolius), and false
hellebore (Veratrum viride). Ground vegetation oover generally
consists of nagoon berry (Rubus arcticus), primrose (Trientalis-
europaea), and sphagnum moss (Sphagnum spp.). Leaf litter is heavy
and extensive. Large deadfall is rare, but there are dead lower•
branches on the tall alders .
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Tall grassland is also a common vegetation community interspersed
among dense patches of tall alder shrubs on the slopes above Bradley-Lake. Shrubs reaching 3 feet tall are scattered throughout the
grassland and generally consist of raspberry (Rubus idaeus) and willow
(Salix spp.). The dominant vegetation is the 3 to 5 feet herbaceous -
layer that consists of bluejoint, other graminoids, fireweed,
horsetail, Jacob's ladder (Polemonium acutiflorum), marsh fivefinger-
(Potentilla palustris), yarrow (Achillea borealis), crowfoot (Caltha
palustris), and sedges. The ground layer vegetation is· moderately-abundant and oonsists of liverworts, moss, nagoon berry, and primrose.
There is an extensive layer of dead herbaceous material.-
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At elevations above approximately 2,000 feet the slopes above Bradley
Lake are dominated by the mesic herbaceous sedge-grass vegetation
community and exposed rock. Mesic herbaceous sedge-grass is a common
vegetation type in subalpine and alpine zones around Bradley Lake.
The meadows occur where a moderately well-drained, relatively deep
soil mantle has as supply of water fran deep snow accumulations,
runoff, or stored in the soil. The meadows occur on all aspects on
slopes up to 85 percent.
The dominant vegetation is the 1 to 1.5 feet layer of herbs that
consists of bluejoint, wormwood (Artemisia arctica), fescue grass
(Festuca altaica), yarrow, fireweed, cow parsnip (Heracleum lanatum),
burnet (Sanguisorba stipulata), and false hellebore. There are
scattered shrubs from 2 to 3 feet tall, consisting mostly of
salmonberry. The ground layer vegetation consists of bearberry
(Arctostaphylos spp.), crowberry (Empetrum nigrum) , Luetkea pectinata,
primrose, and marsh violet (Viola epipsila). There is an extensive
layer of dead grass. Large boulders and rock outcroppings occur
wi thin the meadows and provide a base for growth of crustose lichens,
crowberry, graminoids, and Alaska spiraea (Spiraea Beauverdiana).
Small bogs have formed in localized depressions at higher elevations.
Bogs are daninated by sphagnum moss, andromeda (Andromeda polifolia),
sedges, horsetail, crowberry, cotton grass (Eriophorum spp.), and
labrador tea (Ledum palustre). Wet fringes of bogs support dwarf
birch (Betula glandulosa), willow, shrubby cinquefoil (Potentilla
fruticosa), cloudberry (Rubus chamaemorus), and bog blueberry
(Vaccinium uliginosum).
4.2 PROJECT IMPACTS
Beginning at Bradley Lake, the initial approximately 1.4 miles of the
access trail below 2,000 feet elevation traverse tall alder shrub land
and tall grassland vegetation communities. The proposed route (Figure
1) avoids dense alders, where practicable. Approximately 60 percent
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of the final route within this 1.4 mile section is considered to pass-through alder stands. Alders wi thin the 30 feet wide right-of-way
would be hand-cut to ground level. The alder root masses would be• left intact since clearing and grubbing is not proposed. Alders would
only be cleared where necessary to allow passage of equipment. The
cleared width would range from 10 to 30 feet wide. However, for -
estimation of acreages of distrubance, a maximum 30 feet wide cleared
• corridor will be assumed. Based on a 30 feet wide cleared
right-of-way and a 0.8 mile length (60 percent of 1.4 miles), about
2.9 acres of tall alder shrubland would be cleared.•
Length Width Disturbance•
Vegetation Canmunity ~Miles~ ill.L (Acres)
Tall alder shrubland 0.8 30 2.9• Tall grassland 0.6 30 2.2
Mesic herbaceous sedge-grass 1.6 30 5.8
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Total 3.0 30 10.9
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About 2.2 acres of tall grassland wi thin this 1.4 mile section of
access trail would also be disturbed. About 5.8 acres of mesic•
herbaceous sedge-grass vegetation type would be disturbed in the final
1 .6 miles of access trail. A total of nearly 11 acres would be• disturbed along the 3 mile long access trail.
• Virtually all vegetation within a 10 to 30 feet wide corridor will be
disturbed or removed by the passing equipment. Winching of equipment
up and down steep inclines will be used to minimize spinning of -
tracks, but it would be unlikely that vegetation would survive intact.
The access route was selected to minimize erosion by ascending the
-least steep route and to follow contours where the topography was too
steep for equipment to negotiate. Sane cuts would be required when
side slopes become too steep and threaten to overturn equipment.-Disturbance or removal of vegetation would result where pioneering
equipment would use blades to cut embankments.
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Most cuts would occur on the steep section of the access trail below
approximately 2,000 feet elevation. Little or no cuts would be
required along the 1.6 miles of access trail above 2,000 feet
elevation. Cuts would be avoided in wet soils or bogs, which would be
skirted wherever practical.
Sheet and rill erosion will occur on disturbed slopes, particularly on
sections of the access trail oriented perpendicular to the contour of
the slope. Tracks left by ascending equipment will be natural
channels for collection of runoff. Disturbed vegetation and detritus
will impede surface erosion, but will not prevent it.
Vegetation would have little opportunity for permanent
re-establishment during the same summer following movement of the
equipment into the Middle Fork diversion site. Movement of equipment
back to Bradley Lake in late summer or fall would again disturb any
plant growth having occurred during that summer. Slopes disturbed
during the late summer or fall would be vulnerable to erosion the
following spring if left unprotected during fall and winter.
4.3 MITIGATION MEASURES
Mi tigation for impacts on botanical resources resul ting from
establishment and use of an overland access trail to the Middle Fork
diversion site would be addressed primarily through avoidance,
minimization, and rectification.
4.3. 1 Avoidance
Streams, bogs, and wet soils would be avoided wherever practicable in
final siting of the overland access trail. Negotia tion of steep
slopes requiring embankment cuts or blasting would also be avoided, if
possible. The access route would be flagged to avoid false starts of
equipment.
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-4.3.2 Minimization
Impacts on vegetation will be minimized by 1) establishing the-narrowest corridor width commensurate with safe construction
requirements, 2) hand-cutting and clearing alders only where necessary-to insure passage of equipment, 3) routing the access trail to
minimize size and extents of cuts in embankments, and 4) by winching
• where necessary to minimize spinning of tracks. Floatation or extra
wide tracks may be used on equipment taken over the access trail. Cut
alders would be laid across the trail to provide support and minimize •
disturbance to the underlying substrate. Intact root systems of cut
alders would also provide support and traction to passing equipment.•
Mats would be used for support of equipment when crossing wet soils.
• Disturbance of vegetation caused by erosion would be minimized by
implementing erosion control measures. Erosion control blankets of a
• construction suitable to the specific need would be placed on erodible
slopes. Erosion control blankets or cross-ditching would be used on
• slopes with severe erosion potential following movement of all
equipment into the site. These erosion control measures would remain
in place throughout the summer until the equipment was demobilized•
back to Bradley Lake. Erosion control blankets and other site
rehabilitation measures would be implemented following removal of the• construction equipment.
-4.3.3 Rectification
The access trail would be dressed by the final pieces of equipment -
caning out on the access trail. Dressing would entail smoothing to
eliminate ruts, and cross-ditching every 30 to 50 feet to control•
runoff velocities. Cross-ditching would create 15 inch deep ditches
on the uphill side side of 8 inch angled berms. Cross-ditches limit•
runoff velocities and divert it from the trail into the surrounding
intact vegetation.•
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A grass-forb mixture of native plants would be broadcast seeded and
then fertilized over the entire area of disturbance. Erosion control
blankets, straw, or other erosion-arresting material would be placed
over the seed, as appropriate. The particular type of erosion control
blanket or other material would be matched to the specific requirement
(e.g., slope, soil type, water volume). The erosion control materials
would hold the seed in place through the winter and into the following
growing season.
Alders vigorously sprout from intact root systems, and from damaged or
partially buried but attached limbs. Natural revegetation would be
expected to be rapid within the alder zone. Through revegetation is
slower at subalpine and alpine elevations, artificial seeding of forbs
and graminoids would be expected to also rapidly revegetate the access
trail.
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SECTION 5.0
WILDLIFE RESOURCES
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5.0 WILDLIFE RESOURCES
• 5.1 BASELINE DESCRIPTION
Major large mammal species that occur in the mountains surrounding-Bradley Lake include moose, mountain goat, black bear, and brown bear.
These species are also hunted for sport.•
5.1.1 Moose-
The nearest population concentration of moose is a herd of 5 to 15
• animals residing in the Kachemak Creek area at the west end of Bradley
Lake. Sane movements of individual moose occurs between Kachemak
• Creek and the Fox River valley (Woodward-Clyde 1984).
5.1.2 Mountain Goat •
A relatively stable mountain goat population of approximately 65• animals has been recorded in the Project area (USFWS 1982). Within
the Project area, mountain goats are widely dispersed during the
• summer and concentrated on a smaller range during winter. Goats
reportedly move to summer range in late Mayor early June and return
• to winter range in late October to early November (Hjeljord 1973).
-Winter surveys conducted by ADF&G within the Project area from 1979 to
1982 have shown that mountain goats were concentrated in the vicinity
-of the Bradley River wi thin a 2.5 mile radius of the late outlet
(Holdermann 1983). The largest number of goats observed was 27 in
late March 1980 in the Bradley River canyon. Of these animals, 19-were 1.5 miles fran the lake outlet and 1.5 miles east of the Bradley
River, and eight goats were on the west side of the river at the lake
outlet. Goats move fran one side of the Bradley River canyon to the -
other on a trail and shallow crossing at the lake outlet (Holdermann
• 1983).
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The summer range of mountain goats in the Bradley Lake area
encompasses the area from Sheep Creek, through the mountains around
Bradley Lake to the Nuka Glacier. During summer surveys conducted by
ADF&G from 1979 to 1981, goats occurred in groups ranging from 1 to 17
animals.
5.1.3 Brown Bear
Brown bears occur in limited numbers in the Project area around
Bradley Lake. Occasional sightings of brown bears have been made by
Project personnel. One adult female was killed near Bradley Lake
during the September 1981 hunting season (Holdermann 1983).
5.1.4 Black Bear
Black bear sightings are common in the Project area (Rappoport et al.
1981), and Bradley Lake vicinity is a popular hunting area for local
residents (Holdermann 1983). Black bears are generalists that can be
found in most habitats during any season, but their distributions are
governed by food availability (Schwartz and Franzmann 1980) and by
proximity to cover. Black bear sign was evident in all Project areas
sampled, except at the subalpine Middle Fork diversion area (Rappoport
et al. 1981).
5.2 PROJECT IMPACTS
The overland access trail would be constructed during an approximately
2 week period in Mayor early June. Equipment movement to the Middle
Fork diversion would take place over an approximately 5 to 10 day
period following construction. Explosives would not be used in
construction of the access route. Transport of equipment back to
Bradley Lake would take place in late summer or early fall.
Rehabili tation and revegetation of the access trail would be
accomplished following removal of the equipment.
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5.2.1 Moose-
Construction and use of the overland access route may displace...
resident moose from the immediate vicinity of the operating equipment.
Spring migrations of moose that are believed to occur between the Fox• River valley and Kachemak Creek may be disrupted. However, potential
for disruptions would be short-term in duration and minor in extent.
• Moose are known to tolerate man-caused disturbance without adverse
impacts. Impacts to moose from construction and use of an overland
., access trail would not be expected to be significant •
5.2.2 Mountain Goat •
A migration corridor used by mountain goats between summer and winter• range may cross the proposed access route. Mountain goats are known
to use the higher elevation subalpine zones near the Middle Fork• diversion site during summer (June through October). As discussed in
Section 5.2.1 -Moose, direct disturbance or displacement of mountain
• goats resulting from construction and use of the overland access route
would not be expected to cause significant impacts to the population.
No blasting would be used in construction, and noise from passing-machinery would be short-term in duration.
•
Construction of an access trail from Bradley Lake through the
alder-covered slopes to the higher elevation subalpine zone could
result in higher success rates for mountain goat hunters. The area
lies within the Alaska Department of Fish and Game (ADF&G) Game
• Management Unit (GMU) 859 •. Hunters would be able to take advantage of
the increased aecessfb.:llity to increase their probabilities for
• success.
Before 1984, th~ GMU 859mOJ,.intain goat hunt was regulated by a drawing •
permit system (n:~irnldermann 1986, pers. comm.). Since 1984, a
combination of drawing and registration permits has resulted in up to
28 permitees per year. The actual number of hunters is a subset of
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the permitees. Total hunter success has ranged to 60 percent for
years of available data (D. Holdermann 1986, pel's. comm.) • In 1983,
116 goats were counted in GMU 859. Niney-four mountain goats were
counted in GMU 859 in 1986.
No. Goats No. No.
Counted Permit Permits No. Goats
Year GMU 859 ~ Issued Hunters Harvested
1983 116 a Draw b 15 3
Regis. c 1
1984 116 a Draw b 16 8 3
Regis. c 12 8 6
14 5 31985 116 a Regis. d
1986 94 Regis. d (data in processing)
a All based on 1983 counts
b Early season hunt
c Late season hunt
d Entire season hunt
ADF&G management objectives for goats target approximately 5 percent
of the population as the harvestable surplus. It is likely that,
through time, the number of hunters exercising their permit to use the
Bradley Lake area would increase to a point that the number of drawing
permits would need to be decreased to maintain the harvest objective.
Number of permits would probably not be decreased until a need had
been demonstrated.
5.2.3 Brown Bear
Brown bears are infrequent in the area traversed by the overland
access trail. Temporary avoidance of the access trail during movement
of equipment would be expected, but permanent direct impacts upon the
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anticipated. Increased access for hunters may increase brown bear -mortality.
5.2.4 Black Bear •
As discussed for brown bears (Section 5.2.3), direct impacts on black
• bears other than temporary avoidance of the access trail would not be
expected. Increased access for hunters may increase black bear
• mortality.
• 5.3 MITIGATION MEASURES
The major impact issues affecting wildlife resources associated with•
the overland access trail are three-fold:
• 1) habitat/land disturbance;
increased access; and
• direct disturbance.
Mitigation measures to address these impact issues are discussed
below •
•
5.3.1 Habitat/Land Disturbance
• Vegetation and surface land disturbance would be avoided wherever
possible. Where disturbance would be unavoidable or necessary for ..
safe operation of equipment, minimum disturbance practices would be
followed. Wet or boggy areas and streams would be avoided wherever
• practicable. Mats or floatation tracks would be used to support
equipment where crossing of wet soils could not be avoided. Minimum -clearing widths of tall alder vegetation would be used. Winching of
equipment would be used where necessary to minimize spinning of tracks
and other surface disturbance. Rehabilitation and revegetation of the
access trail would be accomplished following movement of the equipment
-back to Bradley Lake (see Section 4.3 -Mitigation Measures).
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5.3.2 Increased Access
Impacts of increased access on harvest of mountain goat populations
could not be fully avoided by the Alaska Power Authority. Natural
revegetation of alders would eventually impede foot travel by hunters
using the access trail, but it would be many years before alder
re-growth would approach its original height and density. Natural and
artificial revegetation of the access trail would be the only feasible
means of impeding foot traffic on the trail. Negative impacts on the
mountain goat population could be avoided by changes to the number of
hunting permits issued, but this would require action by the Alaska
Board of Game. A decrease in number of permits issued resulting from
increased hunter access over the access trail would be a small
percentage of the total number of goat permits issued on the southern
Kenai Peninsula. However, any decrease in permits issued would
represent a loss of opportunity for goat hunting.
5.3.3 Direct Disturbance
The impact of noise disturbance would be short-term during spring and
late summer. Equipment would be maintained to minimize engine noise.
Project personnel would not be permit ted to hunt or harass wildlife.
Noise and direct disturbance created by equipment would be much more
localized and of shorter overall duration than noise levels generated
by a heavy-duty helicopter such as a Sikorsky Skycrane. A helicopter
of this caliber, operating under maximum loads and flying the
ci rcui tous route it must travel to gain al ti tude from the main dam
site to the Middle Fork diversion site, would emit a high level of
noise which would reach to all parts of the hillsides around Bradley
Lake.
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SECTION 6.0
HISTORIC AND
ARCHAEOLOGICAL RESOURCES
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-6.0 HISTORIC AND ARCHAEOLOGICAL RESOURCES
6. 1 BASELINE DESCRIPTION•
The License Application described cultural pedestrian surveys of the
• Project area. No cultural resources were discovered during the
surveys conducted for the project around Bradley Lake or the Middle
• Fork diversion site.
6.2 PROJECT IMPACTS-
Cultural resources are not known to exist at or around Bradley Lake.
No impacts of the overland access route would be anticipated.
• 6.3 MITIGATION MEASURES
• Discussions would be initiated with the State Historic Preservation
Office regarding the necessity tor a cultural resources survey of the
• overland
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access route.
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SECTION 7.0
VISUAL RESOURCES
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.. 7.0 VISUAL RESOURCES
-7.1 BASELINE DESCRIPTION
7.1.1 Landscape Character And Existing Visual Condition•
The License Application described the landscape character and existing
• visual condition of the Bradley Lake basin (Alaska Power Authority
1984) •
•
Peaks from 5,000 to 6, 000 feet in elevation surround Bradley Lake,
which lies in a basin at 1, 080 feet. Compared to other mountains•
wi thin the area, the Kenai Range is not high, but it is extremely
rugged and the Nuka and Kachemak Glaciers are scenic. A massive rock • shoreline dips steeply to the waters edge around much of the lake
surface, with only the upper end of the lake having a gentle,• accessible shore.
• The patterns of vegetation in and around the Bradley Lake basin are
subtle. At the higher elevations, low-growing shrub tundra gives way
• to rocky, uneven ridges or to glaciers and ice fields. Alder stands
with a low shrub and grass understory occur on lower, south-facing
slopes. North and south of the Bradley River canyon, vegetation is a•
mosaic of tall alder, herbaceous sedge-grass, shrub tundra and open
coniferous forest. In the lower Kachemak Creek valley there are low•
willows mixed with herbaceous sedge-grass.
-Streams are generally inconspicuous, glacier-fed, and meandering as
they cross outwash plains. Suspended solids from glacial action
impart a milky cast to streams and lake waters. -
Apart from one USGS structure at the head of Bradley Lake, there were-no visually evident features which had been introduced by man into the
Bradley Lake basin prior to the Project.
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7.1.2 Visual Resource Importance
The Bradley Lake basin is enclosed by the watershed divide, forming a
discrete visual experience dominated by terrain and water forms.
Peaks surrounding the basin are moderately to highly defined, craggy
and penetrated by glacial troughs. Few distinct geologic features are
present (prominent escarpments, large rock outcrops and bOUlder
accumulations, spires, etc.). The notable exception is the maSSive,
steep-walled shoreline near the lake outlet. The Kachemak and Nuka
Glaciers are scenic but not impressive when compared to others in the
region, especially those within Kachemak Bay State Park (Grewingk,
Portlock, and Dixon Glaciers). The muted vegetation patterns have a
more or less uniform appearance, except in the local drainages where
willow and alder occur. The waters of the lake and its tributaries
have a milky hue diminishing their attractiveness. Compared to other
lake basins within the character type, the scenic features are not
among the most distinctive, and yet are moderately scenic. Based upon
rating standards and photographic examples of scenic quality classes
for the Kenai-Chugach Mountains, the Bradley Lake basin is judged to
be a Class B area.
7.2 PROJECT IMPACTS AND MITIGATION MEASURES
An access trail cannot be pioneered without leaving visual evidence,
particularly in the subalpine and alpine vegetation types. The
overland access route would not be visible from the Bradley Lake dam
si te, which is the closest point an observer could obtain without
leaving the permanent Project access roads. The lower 1 mile of the
access trail could be viewed from the south shore of the Bradley Lake.
The remaining 2 miles of the route would be hidden from view of an
observer at the elevation of Bradley Lake by the natural screening of
tall elders and hillside contours. From an elevated observer position
on the hillside or ridgetop on the south side of Bradley Lake,
portions of approximately 2 miles of the access route would be
visible. The entire route would be visible from an aircraft.
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Visibility of the temporary overland access trail would decrease over
time as vegetation encroaches into the disturbed area. Natural colors
would return with growth of grass, but linear features crossing alder
clones would present obvious textural contrasts to the observer.
Artificial revegetation of native graminoids and forbs would return
the natural green colors to the trail within the second growing
season •
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The overland access route to the Middle Fork diversion site would have
negligible visual effects. These Project facilities would be designed
and constructed to minimize disturbance in space, and would be
temporary in time. The access route would not be visible from areas
and routes
basin. Few• Lake area.
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receiving the majority of use within the Bradley Lake
visitors would be expected to access the upper Bradley
7-3
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SECTION 8.0
LAND USE
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8.0 LAND USE-
-The current status of land ownership affected by the overland access
route was determined by the Alaska Department of Natural Resources on
June 20, 1986. The portion of the access trail below 1,300 feet in
elevation would be within Powersite Classification No. 436. the
remainder of the access trail above 1,300 feet in elevation would be
within Public Land Order (PLO) 3953 Withdrawal for the Bradley Lake -
Hydroelectric Project. The State of Alaska made a land selection on
• the entire Township 5 South,
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4-225-LM•
Range 9 West on May 16, 1986.
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SECTION 9.0
ECONOMIC EVALUATION
•
9.0 ECONOMIC EVALUATION-
-Access to the Middle Fork diversion site was proposed in the License
Application (Alaska Power Authority 1984) to be entirely by
helicopter. Large equipment, fuel, and supplies would be transported
• by heavy-duty helicopter (e.g., Sikorsky Skycrane), while small
equipment and personnel would be by light helicopter.-
Cost estimates for overland access to the Middle Fork diversion site
• were developed assuming larger equipment would be transported
overland rather than by air. A light helicopter would be used to
support construction and use of the overland access route, and for
transport of small equipment, fuel, supplies, and personnel.
• Cost estimates for rehabilitation and revegetation of the overland
access route are described in Table 1.
•
The potential cost savings of construction and use of an overland
• access
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trail over air access would be about $413,000.
4-225-LM 9-1
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TABLE 1-ECONOMIC EVALUATION OF OVERLAND ACCESS
-
Overland Air-Description Access Access
Equipment, fuel, supplies $430,000 $960,000
personnel-
Rehabilitation/Revegetation
Seedbed Preparation and Seeding
• ,0 Dressing and Cross-Ditching
11 acres incl. w/labor
o Seed 11 acres @ 25 Ibs/acre
• -material 500
o Fertilizer 11 acres @
500 Ibs/acre 16-30-12
-material 1,200• o Packing 11 acres incl. w/labor
o Labor 150 manhours 11,250
• Erosion Control Blankets.
o Blanket -Type N.A.G. SC-150
1,380 rolls @ $50.40/1'011 69,550• o Staples -125 cases @
$42.00/case 5,250
o Staplers - 3 @ $275.00 825
o Transportation from Homer• to site 6,000
o Labor -345 manhours @ 4
rolls/manhour 22,425•
TOTAL $960,000...
-Assumes 3 mile long by 30 feet wide corridor wi th 1 foot
overlap of 6.5-feet wide blankets. Also assumes an extra 1
mile of blanket material to cover steep sections of access
road during first summer • ..
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SECTION 10.0
RECOMMENDATIONS
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10.0 RECOMMENDATIONS
The Alaska Power Authority recommends the overland access trail be-adopted for the mode of transporting construction equipment from
Bradley Lake to the Middle Fork diversion site. Measures to minimize
• disturbance and promote revegetation can be implemented and yet
maintain the economic advantage of the overland route.
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4-225-LM 10-1-
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SECTION 11.0
BIBLIOGRAPHY
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.. 11.0 BIBLIOGRAPHY
-Alaska Power Authority. 1984. Application for license for major
unconstructed project, Bradley Lake Hydroelectric Project. Before
the Federal Energy Regulatory Commission. April. Vol. 1-10.-
Alaska Power Authority. 1985a. Best management practices manual
• Fuel and hazardous materials. Prepared by Frank Moolin and
Associates under contract to Harza-Ebasco Susitna Joint Venture.
•
Alaska Power Authority. 1985b. Best management practices manual
Oil spill contingency planning. Prepared by Frank Moolin and•
Associates under contract to Harza-Ebasco Susitna Joint Venture.
Hjeljord, O. 1971. Feeding ecology and habitat preference of the
mountain goat in Alaska. M. S. Thesis, U. of Alaska, Fairbanks.
• 65 pp.
• Holderman, D.A. 1983. An assessment of the impact of the Bradley
Lake Hydroelectric Project on selected wildlife populations.
Unpub. Rep. Alaska Dep. of Fish &Game. Homer, AX. 78 pp.•
Holderman, D.A. 1986. Game management biologist, Alaska Dep. Fish &•
Game, personal communication December 1, 1986 •
..
Rappoport, A., L. Shea, and L. Halpin. 1981. Application of the U.S.
Fish and Wildlife Service's Habitat Evaluation Procedures to the .. proposed Bradley Lake Project, Alaska. USFWS WEstern Alaska
Ecological Services. Anchorage, AX 31 pp. + appendices. -
Schwartz, C.C., and A.W. Franzmann. 1980. Population ecology of the .. Kenai Peninsula black bear. Alaska Dep. of Fish & Game. Fed •
Aid Wildl. Rest. Proj. Prog. Rep. W-17-11 .
•
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U.S. Army Corps of Engineers (CORPS). 1982. Bradley Lake Hydro
electric Project, Alaska. Final Environmental Impact Statement.
Alaska District, U.S. Army Corps of Engineers, Anchorage, Alaska.
U.S. Fish and Wildlife Service (USFWS). 1919. Visual character
types. U.S.D.A. Forest Service, Alaska Region, Division of
Recreation, Soils and Watersheds.
U.S. Fish and Wildlife Service (USFWS). 1982. Appendix B: Bradley
Lake Hydroelectric Project. Homer, Alaska. Final Coordination
Report. USFWS Western Alaska Ecological Services. Anchorage,
AK. 131 pp. In: U.S. Army Corps of Engineers. 1982. Bradley
Lake Hydrolectric Project, Alaska. Final Environmental Impact
Statement. Alaska District, U.S. Army Corps of Engineers,
Anchorage, Alaska.
Woodward-Clyde Consultants. 1984. Moose survey report. Under
Contract to Stone & Webster Engineering Corporation. Prepared
for Alaska Power Authority Bradley Lake Hydroelectric Proje.:lt.
November.
4-225-LM 11-2
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SECTION 12.0
AGENCY CONSULTATION
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12.0 AGENCY CONSULTATION
12.1 DESCRIPTION
As required by the Federal Energy Regulatory Commission Licence, the
Middle Fork Diversion Overland Access Assessment was prepared in
consultation with local, state, and federal agencies that have
management authority over the resources that may be affected by the
Bradley Lake Hydroelectric Project. Prior to the preparation of this
assessment, agencies were provided a site visit and comments were
solicited. The comments and concerns expressed by the agencies were
included, as applicable, in the assessment.
An index of agency and related correspondence documenting agency
consultation is presented in chronological order.
12.2 INDEX OF CORRESPONDENCE
CHRONOLOGICAL INDEX OF CORRESPONDENCE
December 1, 1986
October 23, 1986
October 7, 1986
October 2, 1986
September 26, 1986
July 25, 1986
July 25, 1986
July 25, 1986
July 25, 1986
4-225-LM
Source of Correspondence
Notes of Telephone Conversation, Stone &
Webster Engineering Corporation
Notes of Conference,
Engineering Corporation
Stone & Webster
Alaska Power Authority
Trip Report,
Corporation
Stone & Webster Engineering
Alaska Power Authority
Alaska Power Authority
Alaska Power Authority
Alaska Power Authority
Alaska Power Authority
12-1
July 25, 1986
June 20, 1986
June 19, 1986
June 19, 1986
June 19, 1986
June 9, 1986
June 5, 1986
June 4, 1986
May 28, 1986
Source of Correspondence
Alaska Power Authority
Alaska Department of Natural Resources,
Division of Land and Water Management
U.S. Environmental Protection Agency,
Region 10
Department of the Army, U. S. Army Engineer
District, Alaska
Alaska Department of Fish and Game, Division
of Habitat
U.S. Department of the Interior, Fish and
Wildlife Service, Western Alaska Ecological
Services
Notes of Conference, Stone & Webster
Engineering Corporation
Alaska Power Authority
Alaska Power Authority
4-225-LM 12-2
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J.O. No. 15500 NOTES OF TELEPHONE CONVERSATION Sheet 1 of 2
& 15800 BRADLEY LAKE HYDROELECTRIC PROJECT
Alaska Power Authority
.. File No. 15800.12 (98A)
SUBJECT Mountain Goat Harvest Near Bradley Lake, Alaska
..
INSTRUCTIONS: Summarize your phone
discussion, noting participants,
date & time of call. Indicate• desired distribution at right. Call
reporter must insert File Number(S)
and Subject(s) in file box above. • Clerk takes care of Chrono file copy
and distribution. ..
B. Steisers 2
E. Puch 1
M. Fisk 1• J. Finnimore 1
..
DISTRIBUT ION:
JJMPlante/DLMatchett DOC GF ____1~_
JJGarrity/Chron Files 1
T Critikos JBK TK .1f. WP 98A _--=-1_
DPRyan
NABishop
LCDuncan
CLClark
JHron
GEEng
MMiddaugh
WCSherman
JSYale
RKrohn
JNowak
T1.4
• Call Date _---=1..::;;2_-..:...1-.....:8:..,:6:....-_ Time _1;..-1:.....;;:"'""'1..;:;.0.....:A;,;;:M~_ Incoming ___ Outgoing
Between ____________ SWEC &_______________ APA - __~B=il=I~S~t~e~i~ge~r~s______ SWEC & Dave Holdermann (ADF&G)
(907) 235-8191
&_----------( )•
Originated by: Bill Steigers
•
DISCUSSION:
Dave Holdermann, Alaska Department of Fish and Game (ADF&G) Management• Biologist in Homer, was called to request information on the harvest system
and hunter success for mountain goats near Bradley Lake. Bradley Lake is
within Game Management Unit (GMU) 859. GMU 859 has been on a combination of-drawing and registration permit system since 1984, with the number of
permits ranging up to 28 issued each year. The subsistence issue affected
the type and number of permits issued in 1984 and 1985. Dave provided the.. following information on permits issued and goat harvest for Gl~ 859:
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NOTES OF TELEPHONE CONVERSATION Sheet 2 of 2
No. Goats No.
Counted Permit Permits No. No. Goats
Year Gr1U 852 T:lEe Issued Hunters Harvested
1983 116 a Draw. b
Regis. c 15 3
1
1984 116 a bDraw.
Regis. c 16
12
3
6
8
8
1985 116 a Regis. d 14 3 5
1986 94 Regis. d (data in processing)
a
b
c
d
A based on 1983 counts
Early season hunt
Late season hunt
Entire season hunt
For GMU 859, the count area is the same as the game management area.
Permits are allocated based on the assumption that some percentage of the
permittees will not hunt, and that only a certain percentage of hunters will
be successful.
The allowable harvest from a goat population (or count area) is based on the
most recent counts for the area. Counts have been typically conducted about
every 3 years. Generally, about 5 to 8 percent of the goat population based
on the most recent count is considered the allowable harvest. In actuality,
the allowable harvest may be only about 5 percent because it is assumed that
not all animals are counted.
rlhenever access is increased into an area such as would happen around
Bradley Lake if the overland access trail were constructed, either:
1) fewer permits must be issued by ADF&G to counter increased harvest; or
2) intensive localized harvest would cause a reduction in the local
population. In the case of the Bradley Lake goat population, the management
option to reduce the number of the permits would probably not be exercised
until there was a demonstrated need.
ACTION REQUIRED:
Include information in Middle Fork Diversion Overland Access Assessment.
3-433-RW 2
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NOTES OF CONFERENCE
AGENCY REVIEW MEETING
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
J.O. No. 15800.12
WP 98D-6
Held in the Conference Room Present for:
Stone & Webster Engineering • Corporation Agencies:
800 nAn Street
Anchorage, Alaska 99501 Patty Bielawski, OMB/DGC
• October 23, 1986 Don McKay, ADF&G/Habitat
9:00 AM Mark Kuwada, ADF&G/Habitat
Pat Beckley, ADNR
Deborah Heebner, ADNR• Keith Harding, ADNR
Hank Hosking, USFWS
Scott Hansen, COE•
Alaska Power Authority CAPA)
• Tom Arrninski
Dave Trudgen
Bechtel Civil, Inc. (Bechtel)•
John Smith
Jim Daly •
Dames & Moore, Inc. (D&M)
• Jim Hemming
Stone &Webster Engineering
Corporation (SWEC)•
Norm Bishop ..
Bill Steigers
PURPOSE-The meeting was held to discuss 1) construction of overland access to
the Middle Fork diversion site, 2) the Rehabilitation and Recreation-Facilities Contract, 3) tunnel muck disposal, and 4) Project Update.
The meeting also served as a bimonthly agency update. Attachment 1 is
the meeting agenda. Attachment 2 is the sign-in attendance sheet. -DISCUSSION
-Following an introduction by T. Arminski of the general purpose for the
meeting, each partiCipant introduced themselves and their affiliation.
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2-1173-JJ 1
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1. Middle Fork Diversion Overland Access Route
J. Smith presented a public relations video tape depicting Bechtel's
capability to manage contractors for both large and small projects.
Following the video tape, J. Smith discussed Bechtel's methods and
capabili ties with respect to holding contractors to specific contract
requiranents.
Following this presentation the meeting was opened to discussion
relative to the Middle Fork diversion overland access route. H.
Hosking requested affirmation that no foreign materials such as gravel
would be hauled in during the construction of the Middle Fork overland
access, and that no blasting was currently anticipated in construction
of the access route. J. Smith confirmed that, at this time, no foreign
materials or blasting is anticipated. H. Hosking also inquired how
water erosion would be controlled. J. Smith indicated that several
measures could be taken to control erosion including grading and
dressing the access trail as the equipment was transported back down to
Bradley Lake, and cross ditching where necessary to control and divert
water that may drain down the trail.
When asked of the type of equipment that would be used in construction
of the Middle Fork diversion, J. Smith replied that each contractor has
different types of equipment. It would be difficult to make an
assumption at this time of the exact types and sizes of equipment that
would be used. N. Bishop indicated that smaller equipment would be
required if helicopters were used to transport equipment. J. Smith
also stated that construction of the Middle Fork diversion would
require a longer time period if equipment were flown in because of the
reduced capabilities of smaller equipment. When asked if any equipment
types would be excluded, J. Smith replied that such equipment as
wheeled fuel tanker trucks would probably be excluded, but there would
be no normal construction equipment that would be expected to be
excluded. A Nodwell 240 or equivalent equipped with a fuel tank would
probably not be excluded if it were considered that safe passage on the
trail was possible for that equipment.
A 100 feet wide right-of-way, with a 30 feet wide pathway for the
actual trail, was envisioned by J. Smith to be adequate for the
overland access route. If the overland access route were adopted, the
100 feet wide right-of-way would be delineated and flagged prior to
letting the bid for the Middle Fork diversion. J. Daly stated the two
things a contractor wishes to avoid are 1) blasting rock and 2) flowing
water because they require extra work which costs extra money. All
contractors would visit the site before bidding as a requirement for
submitting a bid. Because of a 6 to 8 month period between letting the
bid and initiation of construction, the successful bidder would
potentially have opportunity to have input on finalization of the
route. The contractor may have at his disposal certain equipment that
would make a certain access route preferable over an alternate access
route. The restricted 100 feet wide right-of-way would eliminate
arbitrary starts selected by the contractor. Within the 100 feet wide
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corridor, the contractor could select his own route to the Middle Fork -diversion site. Once that route were selected, the contractor would be
required to stay within the 30 feet wide initial pathway created by the -leading equipment. The contractor will be required to utilize the
route according to restrictive specifications. The Alaska Power
Authority EFO and Bechtel would be jointly responsible for enforcing
the contractor's compliance with environmental and contract
specifica tions.-
In responding to a question from P. Beckley in reference to the
differences in ground pressure between a D6 and DB tractors, J. Smith-indicated that there was no real differences in effective ground
pressures between the two tractors but the DB had a wider thread width
and could be equipped with a wider blade. A DB with a narrow blade• would probably be an advantage during construction of the actual Middle
Fork diversion.
• When asked about the expected number of days that would be required to
complete the ac cess route and move eq uipmen t to the site, J. Smith
replied that it was difficult to estimate, but probably would be
completed within a 7 day period. N. Bishop suggested that a limitation• in the size of barge that could be brought up the project access road
to the dam site would be a factor limiting the size and number of
pieces of equipment that could be moved from the dam site across• Bradley Lake to the beginning point of the access trail. Workers would
be flown in daily from the project construction camp to the Middle Fork
diversion site. A spring or early summer construction start would be
• essential because of weather limitations during late fall and winter.
It was stated that a known migration corridor of mountain goats between
summer and winter range crossed the proposed access route. This was• discussed, but generally concluded that the level of disturbance
created by passing traffic on a one time travel in and out would
generally not cause significant disturbance to migrating mountain• goats. It is expected the contractor will have completed the Middle
Fork diversion construction and demobilized from the Bradley Lake area
by the em of the sllDmer prior to goat migration to winter range. A
mid to late summer initiation of construction would probably not give
the contractor sufficient time to complete the construction in one
summer. Severe winter and snow conditions at the Middle Fork site
would probably preclude construction during late fall and winter.- Weather conditions necessitate early summer start-up of construction.
N. Bishop indicated the hillsides above Bradley Lake were dominated by
colluvial gravels and exposed rock in most areas, making them a rather• stable substrate for equipment in early summer.
When questioned about the probable approach that equipment operators
• would take when encountering wet or boggy areas, J. Smith indica ted
that deep, wet layers would not be pushed out but rather mats or
geotextiles would be laid down and the equipment walked over those
materials. It is expensive to move materials, and the contractor will• take all reasonable measures available to him rather than moving large
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quantities of material. There was some discussion about the nature of
wet or boggy soils that might be encountered along the access route.
Crawler tractors can sidehill effectively, and in many cases could
skirt wet or boggy areas. The project access road from Kachemak Bay to
the Bradley Lake dam site is strong evidence that a pioneer trail from
Bradley Lake to the Middle Fork diversion site can be engineered to
address environmental concerns and minimize disturbance.
Where the access trail passes through alders, they would probably be
hand cut to ground level where necessary. D. Heebner stated that
alders revegetate quickly when cut at ground level. Alders naturally
re-sprout from remaining root systems. The presence of roots would
also assist equipment traveling over those areas. S. Hansen stated
that it would be difficult or nearly impossible to prevent tracks of
equipment from spinning. He also stated the growing season was short
and because revegetation could not proceed until the following year,
erosion would occur in the interim. T. Arm inski indicated that erosion
control matting would be used in steep areas and diversion berms or
di version logs placed every 30 feet may be used to control erosion
until the following year. When asked of the number of pieces of
equipment that would be moved to the diversion site, J. Smith stated
that up to 20 pieces of equipment on tracks, wheels, or skids would be
moved along the access trail in each direction.
B. Steigers discussed opportunities for rehabilitation and revegetation
of the access trail. The trail would be dressed by the final pieces of
. equipment coming out on the access trail. Dressing would entail
smoothing to eliminate ruts and cross ditching every 30 to 50 feet to
control runoff down the trail. Cross ditching would entail an angled 8
inch berm, which would create a ditch 15 inches deep on the uphill side
of the berm. Revegetation would include broadcast seeding of a
grass-forb mixture on slopes of shallow-to-moderate slope. On steeper
slopes, erosion control blankets would be used. Bundle planting of
rooted shrubs on slopes may also be used in areas of high erosion
potential.
Samples of erosion control blankets were distributed and a discussion
followed on how erosion control blankets could be laid down on steep
areas following movement of the equipment into the site. These
blankets would remain in place when the equipment came back out, and
other blankets again laid down after the equipment had passed. S.
Hansen stated that the methods used to control erosion and promote
revegetation would be very important to the resource agencies.
Resource agenCies were assured the Power Authority would take all
necessary precautions and measures required to minimize erosion and to
promote rapid revegetation. When asked if erosion control blankets
would be used over the entire route, B. Steigers replied that erosion
control blankets would be placed where necessary on steeper slopes and
that other methods such as scattering of straw or contouring and
seeding would also be used. Several types of erosion control blankets
are available, and the particular type of blanket used would be matched·
2-1173-JJ 4
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to the specific requirement. If seeding is undertaken prior to-placement of the erosion control blankets, the blankets will hold the
seed in place through the winter until the following growing season.
N. Bishop reiterated that approximately $500,000 would be saved by -establishing an overland access trail to the Middle Fork diversion
si teo The greater safety of overland access over helicopter transport
of equipment, and decreased time for construction because of the larger-equipment that can be taken overland than by helicopter transport are
also considerations.
• s. Hansen stated that this area is above headwaters. Normally, if no
cut and fill resulting in changes to contour lines were required this
work would fall under the Nationwide Corps Permit. If significant cut• and fill which would change contours were needed, an individual permit
would be required under normal circumstances. However, because this
activity is part of the Bradley Lake project, it will need to be
• addressed in the individual permit which already exists for the
project. N. Bishop indicated that following the route survey and
probes to determine soil types and depth, the quantities and locations
of disturbance would be better known.•
Agency representatives were then asked to provide their general
impressions of the overland access concept. D. McKay indicated that• surface disturbance could not be avoided and rehabilitation measures
would be necessary if the overland access were established. Creation
of roads generally caused management problems for ADF&G' or secondary
impacts on animal populations. An unknown number of hunting permits• are issued for mountain goat in this area. Construction of an overland
access trail to the higher elevation areas from Bradley Lake would
result in some impact on success rates of mountain goat hunters in this• unit, and ADF&G would potentially have to revise the number of permits
issued or adjust other management options to account for increased
access. B. Steigers commented that minimal impacts would be realized• by ADF&G managers of area goat populations because of the small Dl.lllber
of animals under consideration. B. Steigers felt management
implications of reducing number of permits from approximately 8 to 6
' .• should be kept in perspective.
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P. Beckley thought the overland access to be feasible, but suggested
the Power Authority look at alternate beaching sites along Bradley
Lake. He suggested the contractor avoid all wet and boggy areas to the
extent feasible. There was a discussion of the advantages of the
various equipment and equipment sizes. P. Beckley felt the D6 was more
maneuverable than the D8. N. Bishop stated that the larger tractors
were more suitable for ripping. The difference in track width between
a D6 and D10 was said to be approximately 1 foot. J. Daly stated that -larger pieces of equipment were more economical to operate, and that
blade sizes could be limited on the larger equipment to narrow their
effective width over the overland trail. Wider tracks could be
required for travel on the overland trail, even though the contractor-may elect to use narrower tracks while ripping. When asked of the
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types of equipment that would be transported over the trail, J. Smith
listed a backhoe, loader, D8 or D9 for ripping, drills, compressors on
skids or wheels, and miscellaneous equipment that would be transported
in sane type of container. Other types of equipment and supplies
required at the Middle Fork diversion site would be crew survival
sheds, small generators, and a fuel facility. N. Bishop reiterated
that it is the Power Authority's desire to keep construction costs of
the Middle Fork diversion as low as possible. However, the Power
Authority is willing and is canmitted to minimizing environmental
impacts wherever practicable and will mitigate for unavoidable impacts.
T. Ammski summarized this portion of the meeting by stating that a
decision-making document would be prepared which would describe the
proposed action and alternatives and would address those concerns
brought up by agency representatives at this meeting. This document
would be sent out for review and canment by the agenCies and would be
the basis for deciding on how to proceed with the overland access
alterna tive. It was agreed that this document would also address
methods and costs for rehabilitation, erosion control, and
revegetation. This document would contain as an attachment the notes
of conference for this meeting. All feasible routes of access would
also be explored. This document would be distributed during December
1986.
2. Rehabilitation and Recreational Facilities Contract
The Power Authority is considering the expansion of its present 10
contract scenario for the development of the Bradley Lake Hydroelectric
Project to include a rehabilitation and recreational facilities
contract as an 11th contract. The reasons for this expansion are to:
1) provide further opportunity for local contractor participation;
2) minimize potential construction contractor conflicts; 3) achieve a
better rehabilitation end product; and 4) reduce potential risk for
construction claims. N. Bishop discussed the scope of work for the new
rehabilitation and recreational facility contract.
1. Rehabilitation of the Martin River borrow areas
2. Rehabilita tion of and/or removal of the Martin River borrow
access road.
3. Construction of the waterfowl nesting islands.
4. Construction of recreation facilities.
5. Rehabilitation of miscellaneous areas, including fertili
zation and revegetation of:
a. Staging and laydown
b. Disposal areas
c. Concrete batching areas
d. Quarry sites
e. Disturbed areas adjacent to access roads
f. Culvert and road maintenance
6. Rehabilitation of the construction camps.
7. Revegetation activities.
8. Other undefined miscellaneous items.
2-1173-JJ 6
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-This contract is expected to conclude one year (1 spring) after
completion of the General Civil Contract. Following completion of this
contract, the operations and maintenance of the Bradley Lake project
would be turned over to the managing entity. The bid document would -prepared during 1988 and the bid let during mid-1989. Agency
representatives had no comment on the rehabilitation and recreational
facility contract. -3. Tunnel Muck Disposal
N. Bishop discussed the need for identifying a tunnel muck disposal-area as a result of relocating the permanent project airstrip. Tunnel
muck is described as angular clean, poorly graded rock material ranging
in size fran sand to rock 1 to 3 feet in diameter. Rock produced by.. blasting is usually larger than that produced by the tunnel boring
machine (TBM). J. Daly described tunnel muck produced by older TBMt s
as angular rock ranging in size from sand particles to 2 1/2 inches.
Tunnel muck from newer TBM's usually ranges in size from sand particles• to 1 1/2 inches in diameter. If the rock is sound, the tunnel muck
produced by a TBM usually makes a good road surfacing material. If the
rock is not sound or has an affinity for water and does not drain• easily, the resulting product is very fluid until the water has been
drained. If drained, sane of this material could be stockpiled for
road maintenance purposes. J. Hemming suggested that some of the• tunnel muck could be offered for sale and barged to Homer to be used
for road surfacing or gravel.
• On site investigations have resulted in identification of several
possible disposal sites for the tunnel muck. The possible disposal
sites are:
• 1. Adjacent to the marshalling yard;
2. In the waterfowl nesting area adjacent to the access road;
3. In the lower concrete batching area and clean fill disposal• sites;
4. Northwest portion of the lower oonstruotion oamp staging
area;
.' 5 • Martin River borrow pit; and
6. Other unidentified areas.
The advantages and disadvantages of each potential disposal site were-discussed.
1. Adjacent to Marshalling Yard.-
An area approximately 160 feet wide and 320 feet long (about
1.2 acres) between the marshalling yard and the shoreline - north of the permanent camp could be used as a disposal site
for tunnel mUCk. Approximately 23,000 cubic yards of tunnel
muck could be depOSited in this area if it was brought to the
elevation of the marshalling yard at elevation 18 feet.
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Alternatively, up to 65,000 cubic yards could be deposited if
both the marshalling yard and adjacent area were filled to
elevation 30 feet. The latter fill depth would bring the
fill to the elevation of the adjacent permanent camp area,
but would infringe upon use of the marshalling yard for its
intended purpose as a service area for the tunnel portal.
This area will be used as a settling pond, with a small dike
constructed between the northwest corner of the marshalling
yard and the adjacent embankment.
2. Waterfowl Nesting Area Adjacent to Access Road
Widening by an additional 47 feet the 3,600 feet long access
road adjacent to the waterfowl nesting area would provide
disposal for approximately 88,000 cubic yards of tunnel muck.
Widening of the access road would require lengthening of ten
48 inch diameter culverts by 47 feet and relocation of 10
concrete drop boxes. This scheme would reduce the size of
the waterfowl nesting area by about 4 acres and bring the
northern nesting islands in closer proximity to the access
road. If a larger area were desired the western or eastern
corners would provide additional storage area for tunnel
muck.
3. Lower Concrete Batching Area and Clean Fill Disposal Sites
These areas are expected to be filled prior to initiation of
power tunnel construction.
4. Northwest Portion of Lower Construction Camp
The northwest portion of the lower construction camp is
presently being used as a log storage area. Ultimately this
area will be used for contractor staging and laydown. The
presen t design calls for the 10 acre northwest staging area
to be brought up to grade at elevation 12 feet with Martin
River fill to raise it above the maximum high tide elevation
of 11.4 feet. This area has excellent potential as a
disposal site for tunnel muck. The area within the clearing
limits of the lower construction camp boundary in the
northwest staging area could contain 193,000 cubic yards of
tunnel muck at elevation 22 feet. Elevation 22 feet is the
design elevation of the adjacent access road. Deposition of
tunnel muck in this area would require coordination with the
needs of the various construction contractors who would
potentially use it as a staging area. A gravel berm could be
maintained at the northern clearing limits to contain tunnel
muck within the designated spoil area.
2-1173-JJ 8
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The construction camp spoil area could be extended north of
the clearing limits into a 4.6 acre saltwater herbaceous
sedge-grass vegetation type behind the access road. This
area is presently under tidal influence provided by double-culverts on the access road. This approximately 200 feet by
1000 feet area is bordered to the south by the lower
construction camp clearing limits. If brought to grade of -the access road at elevation 22 feet from about 7 feet
elevation, the 4.6 acre area could hold 111,000 cubic yards
of tunnel muck. Drainage for the watershed would be
re-routed to parallel and abut the steep hillside face on the• north side of the sedge-grass lowland. D. Trudgen stated
that juvenile salmon had been observed in this drainage
slough. H. Hosking indicated his opposition to encroachment• beyond the clearing limits into this wetland and further
re-routing of this slough channel.
• 5. Martin River Borrow Pit
All tunnel rock could potentially be placed in anyone of the
borrow pits. Deposition of tunnel muck in the Martin River
borrow pits would impact mitigation plans designed to create
rearing and over-wintering habitat for juvenile salmonids.
The degree of impact would depend on the quantity of tunnel
muck that would be spoiled in the pits. D. Trudgen
recommended that if tunnel muck were placed in the Martin
River pits, that it be placed in a corner of one of the• downstream pits. Tunnel muck would be covered by Martin
River spoils following completion of hauling. It was stated
that trucks hauling muck could not backhaul Martin River
gravels to the concrete batching plants because the concrete• aggregate would be contaminated. Additionally, sequencing of
the contracts would not provide an opportunity for
backhauling.•
6. Other Unidentified Areas
Agency representati ves did not have any further
recommendations for additional tunnel muck disposal areas.
.... When asked for responses to the suggested alternative disposal Sites,
H. Hosking recommended investigation of barging some of the tunnel muck
to Homer. D. McKay indicated his opposition to spoiling tunnel muck in
the Waterfowl Nesting Area. H. Hosking stated his opposition to- storage or placement of tunnel muck on the tidelands. There was some
discussion of extending the dock area to the east or west but this was
opposed by ADF&G and USFWS. P. Beckley stated his preference for use
of the area beside the marshalling yard, but it was stated that this-
was a relatively small area and would preferably be used as a settling
basin for tunnel water.
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2-1173-JJ 9 ..
It was agreed that up to 65,000 cubic yards (or the required amount) of
tunnel muck could be stored in the Waterfowl Nesting Area for use in
construction of the nesting islands. The tunnel muck would be placed
by end dumping in a series of roads within the Waterfowl Nesting Area
or in one corner of the nesting area in preparation for construction of
the nesting islands.
It was agreed that tunnel muck would be disposed of as follows:
1. In the construction of dikes adjacent to the marshalling yard
to create settling ponds for tunnel water.
2. Up to 65,000 cubic yards in the Waterfowl Nesting Area for
construction of nesting islands.
3. The lower construction camp staging area within the clearing
limits.
4. Project Update.
The Power Authority will apply for a NPDES permit for the tunnel water.
Preparation of the 1986 fisheries monitoring study report by Dames &
Moore will be complete by the end of October. A report on the 1986
Bald Eagle Program will be prepared and distributed by mid-November.
The well drilling equipment on the project site has been demobilized.
It is believed that enough water is now available fran the wells and
other sources for the permanent camp facilities. The Power Authority
is investigating utilizing water fran Powerhouse Creek for the concrete
batching water to facilitate other water sources available for that
purpose.
ACTION
A decision-making docl.lllent for the Middle Fork overland access route
and an assessment of tunnel muck disposal areas will be prepared and
distributed to resource agencies for their review and comment.
B. Steigers
WDS/JJ
2-1173-JJ 10
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AGENDA
• AGENCY REVIEW MEETING
OCTOBER 23, 1986-
• Held at
Stone &Webster Engineering Corporation
800 "A" Street• Anchorage, Alaska
•
Introduction -Tom Arm1nski•
Middle Fork OVerland-Access
Construction Access -John Smith
• Revegetation/Rehabilitation -Bill Steigers
Economic Benefits -Norm Bishop•
... Rehabilitation Contract -Norm Bishop
Tunnel Muck Disposal -Norm Bishop
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2-1155-JJ
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Bill Sheffield. Governor
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A~skaPowerAu~or"y
State of Alaska
AP A/OTHR/O 195
October 1, 1986
Mr. Robert Bowker
Western Alaska Ecological Services
U.S. Fish & Wildlife Service
411 W. Fourth Avenue, Suite 2B
Anchorage, Alaska 99501
Attn: Mr. Hank Hosking
AGENCY REVIEW MEETING
MIDDLE FORIC OVERLAND ACCESS
BRADLEY LAIE HIDROELECTRIC PROJ.ECT
You are invited to attend an agency review meeting to discuss the
Middle Fork overland access site visit of October 2, 1986. Tbe meeting
is scheduled for Thursday, October 23, 1986 at 9 :00 AM in the Stone &
Webster Engineering Corporation conference room.
ConstruCtiOD specialists from Bechtel Civil, Ino. will discuss
contractor equipment requirements, and the type ot overland access that
would be needed to meet those requirements. Subsequent to the meeting,
agenCies will be requested to submit their written cCllUDents on the
overland access alternative by November 1, 1986.
Should you have any questions, please contact Mr. Tom Arminski at (901)
561-1811 •
Very truly yours,
ALASKA POWER AUTHORITY
David R. Eberle
Project Hanager
DRE/WDS/JJ
PO. Box 190869 701 East Tudor Road AnChorage. Alaska 99519'()869 (907) 561·7877
2-1014-JJ
APA/OTHRl0195
Same Letter sent to:
Mr. Robert Bowker
Western Alaska Ecological Services
U.S. Fish &Wildlite Service
411 W. Fourth Avenue, Suite 2B
Anchorage, Alaska 99501
Attn: Mr. Hank Hosking
Mr. Dan Robison
U.S. Environmental Protection Agency
701 ·Cft Street, Box 19
Anchorage, Alaska 99513
Mr. Brad Smith
National Marine Fisheries Service
Department ot Caamerce
701 ftC· Street, Box 43
Anchorage, Alaska 99513
Colonel Wilbur T. Gregory
District Engineer
U.S. Army Engineer District, Alaska
Department ot the Army
P.O. Box 898
Anchorage, Alaska ~9506-0898
Attn: Mr. Scott Hansen
Ms. Patty Bielawski
Oftice ot the Governor
Ottice ot Management &Budget
Division ot Governmental Coordination
2600 Denali Street, Suite 700
Anchorage, Alaska 99503
Number of Copies
1
1
1
1
1
2-1074-JJ 1
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APA/OTHR/0195
Same Letter sent to:
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Mr. Bill Lamoreaux• Alaska Department of Environmental Conservation
437 "E" street, Suite 200
Anchorage, Alaska 99501•
Attn:' Mr. Dan Wilkerson
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• Ms. Margaret J. Hayes, Manager
Division of Land and Water Management
Alaska Department of Batural Resouroes
• 3601 "C" Street, Frontier Building
Pouch 7-005
Anchorage, Alaska 99510
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Mr. Carl Yanagawa
Division of Habitat• Alaska Department of Fish &Game
333 Raspberry Road
Anchorage, Alaska 99502
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A.ttn: Hr. Don MoKay
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-Ms. Marcia G. Lagerloef, Chief
EnviroDJllental Evaluation Branch
Region 10
Environmental Protection Agenoy
1200 Sixth Avenue
Seattle, Washington 98101 -
Attn: Mr. Brian Ross-
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Humber of Copies
1
2
2
1
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-TRIP REPORT
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
J .0. No. 15800. 1 2
WP 98D-6
-Bradley Lake Projeot Site Present for:
Ootober 2, 1986
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Alaska Power Authority (APA)
Tom Arminski
Dave Trudgen
U.S. Army Engineers District,
Alaska (CORPS)
Scott Hansen
U.S. Fish and Wildlife Servioe
(USFWS)
Hank Hosking
Office of Management and
Budget, Division of
Governmental Coordination
(OMB-DGC)
Patty Bielawski
Alaska Department of Environ
mental Conservation (ADEC)
Paul Horwath
Alaska Department of Fish and
Game, Division of Habitat
(ADF&G)
Don McKay
Carl Yanagawa
Alaska Department of Natural
Resources, Division of Land
and Water Management (ADNR)
Pat Beckley
Deborah Heebner
Dames & Moore, Inc. (D&M)
Dave Erikson
Stone & Webster Engineering
Corporation (SWEC)
- Myrl Fisk
Bill Steigers
2-1087-JJ 1-
PURPOSE
The purpose of the site visit was to acquaint resource agency
representatives with the proposed Middle Fork diversion overland access
route.
DISCUSSION
All representatives met at Maritime Helicopters at 9:00 AM for a flight
by helicopter to the lower construction camp area for staging. After
arriving at camp and while waiting for the cloud ceiling to lift,
Dave Trudgen and Dave Erikson provided representatives a tour of the
lower construction camp area, the access road between the camp and the
powerhouse, the powerhouse and permanent camp facilities, and the lower
access road between the camp and the Main Dam site.
All representatives, excluding Carl Yanagawa (ADF&G) and Dave Erikson
(D&M), were transported by helicopter between 11:30 AM and 12:15 PM to
Stop #1 (Figure 1) along a lower elevation section of the overland
access route. Upon arrival of the third group of 3 to 4 persons to
stop #1, the groups in sequence moved to Stops 12 and '3 (Figure 1).
Limited time was available for most representatives to ask questions at
each stop. The general route was flown between stops and described
from the vantage point at each stop.
Helicopter refueling, lowering cloud ceilings, and airline flight
departure requirements necessitated transportation of the first group
of representatives to Homer by 2:45 PM. The remaining representatives
climbed several hundred feet higher on the hillside above Stop #3 where
they awaited helicopter pickup. Representatives of ADNR, ADEC,
OMB-DGC, and SWEC stopped at the Main Dam site for approximately 45
minutes before departing for Homer. All representatives were returned
to Homer by 4:00 PM.
BSteigers b ~
WDS/JJ
2-1087-JJ 2
( ') I ""~I "I'J / ~ I ~ nl I "I,'<:) "'tJ ( 'l; ~ ~ Jr'\l'-t () -\ ~ ~') ;;-.,r,l 'I, '''t rt --, " '\
;:.:;.;.....-.....
.: Bill Sheffield. Governor
.~ r Alaska Power Authority
State o(Alaska -
APA/OTHR/0186
- September 26, 1986
-Mr. Robert Bowker
Western Alaska Ecological Services
U.S. Fish &Wildlife Service
411 W. Fourth Avenue, Suite 2B
• Anchorage, Alaska 99501
Attn: Mr. Hank Hosking•
PROPOSED MIDDLE FORK OVERLAND
ACCESS ROAD
BRADLEY LAKE HYDROELECTRIC PROJECT
•
Attached is a site reconnaissance report by Stone &Webster Engineering
Corporation about the overland access route to the Middle Fork• Diversion. The study team visited the site August 25, 1986 and again
on September 3, 1986 to determine if equipment movement is feasible on
the proposed overland access route.
The report concludes that a temporary overland access road is feasible.
The access route will require cut and fills along the route alignment.
• The proposed route will cross over and follow along flowing drainages.
Host areas along the route soils are rock, but some sections have soft,
poorly drained soils.
• An agency site inspection of the proposed access road is being
scheduled on October 2, 1986. We would like to make helicopter
arrangements for this site visit. Tentatively the logistics would be
to leave for the site from Maritime Helicopters at 9 :00 AM and return
to Homer at about 3:00 PM.
Please confirm your availability for this site visit with Mr. Thomas J.-Arminski at (907) 561-7frl'7 or Ms. Myrl Fisk of Stone & Webster
Engineering Corporation at (907) 277-2427. -Very truly yours,
ALASKA POWER AUTHORITY-fJ---Y-'<UL
David R. Eberle-
",( Project Manager
-DRE/MF/JJ
Enclosure
2-1 O~~~190869 701 East Tudor Rood Anchorage. Alaska 99519-0869 (907) 561-7~77-
AP~/oTHR/0186
Same Letter sent ~o:
Mr. Robert Bowker
Western Alaska Ecological Services
U.S. Fish &Wildlite Service
411 W. Fourth Avenue, Suite 2B
Anchorage, Alaska 99501
Attn: Mr. Hank Hosking
Mr. Dan Robison
U.S. Environmental Protection Agency
701 ·C" Street, Box 19
Anchorage, Alaska 99513·
Mr. Brad Smith
Nation@l-Harine Fisheries Service
Department ot Commerce
701 "C" Street, Box 43
Anchorage, Alaska 99513
Colonel Wilbur T. Gregory
District Engineer
U.S. Army Engineer District, Alaska
Department ot the Army
P.O. Box 898
Anohorage, Alaska 99506-0898
Attn: Mr. Scott Hansen
Ms. Patty Bielawski
Ottioe ot the Governor
Ottioe ot Management &Budget
Division ot Governmental Coordination
2600 Denali Street, Suite 700
Anohorage, Alaska 99503
2-1045-JJ 1
Number ot Copies
1
1
1
1
1
II
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APAlOTBRlO 195
Same Letter aent to:
•
• Mr. B11l Lamoreaux
Alaska Department ot BDvirol'llllental Conserva tion
1137 "E" Street, Suite 200• Anchorage, Alaska 99501
Attn: .. Mr. DaD Wilkerson
•
•
Ms. Margaret J. H818a, HaDager
Division ot Land and Water Management • Alaska Department ot latural leaources
3601 "C" street, Frontier Building
Pouch 7-005
• Anchorage, Alaska 99510
•
Mr. Carl lanagawa• Divisicn ot Habitat
Alaska Department ot F1ah & Game
333 laspberr.y load
• Anchorage, Alaska 99502
Attn: Mr. Don Hc.['81
-Ms. Marcia G. Lagerloet, Cbiet
EDviroamental Bvaltat!on Branch
legton 10
EDvirol'llll8ntal Proteotion Agency
1200 Sixth A98Due
-Seattle, Wash1Dgtcn 98101
Attn: Mr. Brian Roaa-
•
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Number ot Copiea
1
2
2
1
2-1011J-JJ 2
J.O. ORINTEROFFICE MEMORANDUM W.O. NO • 15800.12 WP 980-6
• CUO.U
SUBJECT MIDDLE FORK ACCESS ROAD DATE September 16, 1986
(-FROM LMcDaniels
-TO T. Critikos CC T. Beck
(
On August 25 and September 3, 1986 a constructibility review was made
of an overland access route from the head of Bradley Lake to the
Middle Fork Diversion Structure. Tom Beck, geologist, and I walked
an overland route from the Middle Fork to an accessible barge landing
site north of the Kachemak Creek delta on Bradley Lake. The
following are our findings. (The numbers in brackets refer to select
pOints identified in fig. 1.)
A barge landing can be made at the small beach at the mouth of the
second watercourse west of the delta.(1) The beach offers a
reasonable slope for tracked equipment to ascend. At the time of our
inspection, the lake level was very high and only a few feet of the
gravel shoreline was visible. Tbe beach appeared to be stable, with
a gentle slope down to the water.
From the beach a dozer would be able to proceed uphill, bearing to
ward the southeast along a ridge through minor low growing brush
mixed with a small amount of alders and willows. The average slope
is apprOximately 25% to 28%, with scattered patches at alders, but
the soil is firm and dry. An alternative access alignment follows
the water course upstream for approximately 300' -400' then switches
back to the south and climbs out of the drainage.(2) ApprOximately
1600 ft. up the slope is a ridge of outcropping rock with scattered
spruce trees.(3) A path was selected that follows the trend of this
ridge top, which would result in little disturbance to the soil or
vegetation.
The proposed access route continues uphill along the south side of
the drainage course, through 15-20 foot patches of 8-10 foot high
willow and alder patches, into a clear area.(4) The route then turns
to the north for 300' until it reaches the drainage course, then
turns to the North-east and continues uphill along the drainage
course toward the top of the drainage. Moderate amounts of bulldozer
blade work would be required to construct a path without excessive
side slope. Tbe slope varies from 10% to 25%. The soil below the
upper limit of the alders is very poorly drained, has a high organiC
content and is of undetermined depth.
At the top of the drainage and prior to entering an area of dense
alders, the route turns to the north along the east side of a bare
rock knob and proceeds northward through a fairly open area. (6)
Flowing water is encountered in this area and flotation track
4-212-DB 1
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eq~pment will be required. Approximately -1000 teet ~ortb ot tbe
rook knob, tbe ~oute prooeeds 500' nortbeast tbrough alders,(1) to
tbe upper limit ot tbe alders,· tben along a westerly .taoing slope
oov~red witb alpine tundra and grass.(8)
Tbe route continues tor approximately 1,000 tt. through alpine,
beatber and tundra, tollowing tbe upper limit ot tbe alders. At tbis
point a patb must be cut tbrough a seotion ot alders approximately
500 teet across. (9) The so11 in tbis area bas a very bigh organic
content and is also wet and poorly drained. The route tben proceeds
nortb-west up a 25 to 271$ slope toward a natural bench between tbe
lower and bigher rock knobs. (10) Tbis section will require cutting a
patb tbrough anotber 500 to 100 tt. ot alders. This area is also wet
and poorly drained witb a small drainage course running tbrougb it.
The route tben turns east up a steep slope to tbe east side ot a rock
knob. This will require sidehill out and t11l to prevent overturning
ot towed equipment.
An alternate route is available east ot tbe above described
section.(ll) This route would require at least two switcbbacks, and
signitioant out and t11l witb a dozer. This area would be visible
trom tbe lake surt~ce. The route then would proceed nortb over rocky
ground tbrough and along a natural drainage area and rock cuts.(12)
This area is lightly vegetated generally witb less tban 2 toot depths
to bedrock. A crossing ot Marmot Creek approximately 2,000' above
tbe downstream terminus ot tbe Middle Fork Diversion would pose no
real problem as tbe banks are low in tbis area.(13)
The remaining 3,000' to tbe terminus at tbe Middle Fork Diversion
struoture (15) goes over alpine tundra on relatively tlat ground
between scattered rock knobs, witb tbe exception ot one 15' long 25%
slope on wbicb winobing may be required.(14)
The route ohosen will require band cutting ot alders in areas and out
and till in some areas. We based our choioe or routing on using
eitber a D-6 or D-8 dozer with low ground pressure and winch
capability. The compressors and drills would bave to be skid or
traok mounted and be towed in atter pioneering by two lead dozers.
Tbe estimated equipment required for tbe Middle Fork Construction
would be air track, drill 600 o.t.m. compressor track loader (similar
to 955 oat), a D-6 dozer witb ripper and wincb. Optional equipment
would be an additional air track and compressor, a backhoe on tracks,
a tow behind roller oompactor and a larger dozer such as a D-8 or
D-9 •
It would take an estimated 6-1 days witb two dozers to pioneer tbe
route. Once the route is pioneered, tbe estimated travel time trom
tbe beaob to Middle Fork would be 5 to 12 bours. Most of this time
will be taken trom beach to midpoint, where stop-and-go winching of
towed equipment will be necessary.
In conclusion, wbile it is very feasible trom a construction stand
point to const~ot an aocess trom Bradley Lake to tbe Middle Fork, it
4-212-DB
is not a task which can be performed without selected cut and fill( along the?Oad alignment, much cutting of brush, (alders and willow)
crossing ·of soft, poorly drained areas, and travel along and through
flowing-drainages. An access cannot be ...pioneered without leaving
visual evidence, espe-e-ially in the slow growing alpine t~a and
heather. Visual impact as viewed from the lake is 11m!ted to the
first 6000 L.F. The remainder is over ridges or behind brush which
hides the route from view. The entire route is visible from
low-flying aircraft. It is expected that most of the route will be
viSible from the hillside and ridgetop that lies along the south side
of Bradley Lake.
If you have additional questions or comments, contact the undersigned
or Tom Beck.
L. McDaniel
Construction SpeCialist
Attachment
LHIDB
4-212-DB 3
\~ ~\ \l1 l-l,j ( -J '.J ''1 ~-ld ~ " r~(,I) ~ ~ ~ " n\I t,l C r\ -w L{ \~-"( '0 ~ \J \, ~ t..u -" \l t -1 V) ~ I')(J !1;} (,l.. r-
• Bill Sheffield. Governor
~ - Alaska Power Authority
State of Alaska -
-APA/OTHR/0121
July 25, 1986
•
Mr. Robert Bowker• Western Alaska Ecological Services
U.S. Fish and Wildlife Service
411 W. Fourth Avenue, Suite 2B
• Anchorage, Alaska 99501
• MIDDLE FORK DIVERSION STUDY
BRADLEY LAKE HYDROELECTRIC PROJECT
• Enclosed are responses to the U.S. Fish and Wildlife Service comments
on the Preliminary Assessment of t~e Middle Fork Diversion. Comments
on the open channel diversion have been addressed, and, unless for• reasons discussed in our responses, have been included in the final
assessment.
• Further studies are required should the Alaska Power Authority wish to
consider the overland route to the Middle Fork diversion site. The
Alaska Power Authority is proceeding with limited field studies to
confirm whether further consideration is worthwhile.•
If you. have any questions please contact Mr. Tom Arminski at 561-7677 • ..
Very truly yours,
-ALASKA POWER AUTHORITY
-David R. Eberle
Project Manager
-DRE/WDS/DB
.. Enclosure
•
701 East Tudor Road Anchorage. Alaska 99519-0869 (907) 561·7877 4-o~.;.~i 190869
•
U.S. FISH AND WILDLIFE SERVICE
WESTERN ALASKA ECOLOGICAL SERVICES COMMENTS
U.S. DEPARTMENT OF THE INTERIOR
JUNE 9, 1986 LETTER FROM HR. ROBERT BOWKER
MIDDLE FORK DIVERSION STUDY -PRELIMINARY ASSESSMENT AND
JUNE 5, 1986 NOTES OF CONFERENCE
BRADLEY LAKE HYDROELECTRIC PROJECT
USFWS -2 Proposed Overland Access Route
U.S. Fish and Wildlife Service -WAES Comment
We recommend additional assessment of the proposed overland access from
the vicinity of Kachemak Creek to the si te of the Middle Fork Creek
diversion. We do not support the construction of an access road to the
site, but the establishment of a double-pass trail (in and out) may be
acceptable. Prior to use, any trail should be field flagged to assess
the potential for adverse impacts as false starts on other projects
have caused avoidable disruptions to terrestrial habitats.
Alaska Power Authority Response
Your comment is noted, and will be considered in the decision whether
to pursue the overland access alternative.
1-341-JW 2
U.S. FISH AND WILDLIFE SERVICE• WESTERN ALASKA ECOLOGICAL SERVICES COMMENTS
U.S. DEPARTMENT OF THE INTERIOR
JUNE 9, 1986 LETTER FROM MR. ROBERT BOWKER
MIDDLE FORK DIVERSION STUDY -PRELIMINARY ASSESSMENT AND -JUNE 5, 1986 NOTES OF CONFERENCE
BRADLEY LAKE HYDROELECTRIC PROJECT
USFWS - 3 Proposed Overland AcCess Route
U.S. Fish and Wildlife Service -WAES Comment..
It would be appropriate to address the proposed impact of overland
access in an addendum to the project Visual Resources Mitigation Plan,
• Section 3.3.2 Middle Fork Diversion.
..
Alaska Power Authority Response:
..
If the Alaska Power Authority elects to proceed further with the
overland access alternative, it will be addressed in an addendum to the
Visual Resources Mitigation Plan.
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1-341-JW 3
•
Bill Sheffield, Governor • ~ -Alaska Power Authority
State of Alaska -
APA/OTHR/0121•
July 25, 1986
•
Mr. Carl Yanagawa• Alaska Department of Fish &Game
Division of Habitat
333 Raspberry Road
• Anchorage, Alaska 99502
Attn: Mr. Don MacKay•
MIDDLE FORK DIVERSION STUDY
BRADLEY LAKE HYDROELECTRIC PROJECT•
Enclosed are responses to the Alaska Department of Fish and Game• comments on the Preliminary Assessment of the Middle Fork Diversion.
Comments on the open channel diversion have been addressed, and,
unless for reasons discussed in our responses, have been included in• the final assessment.
Further studies are required should the Alaska Power Authority wish to
consider the overland route to the Middle Fork diversion site. The• Alaska Power Authority is proceeding with limited field studies to
confirm whether further consideration is worthwhile •
.,.
If you have any questions please contact Mr. Tom Arminski at 561-7877.
Very truly yours,•
ALASKA POWER AUTHORITY
•
David R. Eberle• Project Manager
DRE/WDS/DB•
Enclosure -
4-0~~Si 190869 701 EastTudor Rood Anchorage, Alaska 99519-0869 (907) 561-7877
•
DIVISION OF HABITAT
ALASKA DEP ARTMENT OF FISH AND GAME
JUNE 19t 1986 LETTER FROM CARL YANAGAWA
MIDDLE FORK DIVERSION STUDY -PRELIMINARY ASSESSMENT AND
JUNE 5 t 1986 NOTES OF CONFERENCE
BRADLEY LAKE HYDROELECTRIC PROJECT
ADF&G -3 Proposed OVerland Access Route
Alaska Department of Fish & Game Comment
The Middle Fork Diversion Study recommends that an access road to the
diversion site be considered for further study. The department opposes
development of any road access to the diversion from the Bradley Lake
dam site. Such access would only create further disturbance into
mountain goat winter range habitat and increase hunter access and
potential poaching problems.
Alaska Power Authority Response
Your comment is noted, and will be considered in the decision whether
to adopt the overland access alternative.
1-339-JW 3
• Bill Sheffield, Governor
~ - Alaska Power Authority
State of Alaska -
APA/OTHR/0121•
July 25, 1986
•
Mr. Gene V. Augustine
Acting Chief, Special Actions Section
• Regulatory Branch
Department of the Army
U.S. Army Engineer District, Alaska• P.O. Box 898
Anchorage, Alaska 99506-0898
• Attn: Mr. Scott Hansen
MIDDLE FORK DIVERSION STUDY• BRADLEY LAKE HYDROELECTRIC PROJECT
• Enclosed are responses to the Department of the Army comments on the
Preliminary Assessment of the Middle Fork Diversion. Comments on the
open channel diversion have been addressed, and, unless for reasons• discussed in our responses, have been included in the final
assessment.
Further studies are required should the Alaska Power Authority wish to• consider the over land route to the Middle Fork diversion site. The
Alaska. Power Authority is proceeding with limited field studies to
confirm whether further consideration is worthwhile • ..
If you have any questions please contact Mr. Tom Arminski at 561-7877 .
•• Very truly yours,
ALASKA POWER AUTHORITY-
-David R. Eberle
Project Manager
DRE/WDS/DB -
Enclosure-
4-09~B13X 190869 701 East Tudor Rood Anchorage, Alaska 99519-0869 (907) 561-7877
•
U • S. ARMY ENGINEER DISTRI CT, ALASKA
REGULATORY BRANCH
DEPARTMENT OF THE ARMY
JUNE 19, 1986 LETTER FROM MR. GENE V. AUGUSTINE
MIDDLE FORK DIVERSION STUDY -PRELIMINARY ASSESSEMENT AND
JUNE 5, 1986 NOTES OF ·CONFERENCE
BRADLEY LAKE HYDROELECTRIC PROJECT
DOA - 2 Preferred Open Channel Alternative and/or Proposed Overland
Access Route
Department of the Army
The proposed revision would require a modification of the original
permit. This modification would undergo the public interest review and
teat for compliance with the 404(b)(t) guidelines just like the
original proposal. However, if the scope of the modification is minor
compared to the overall project, then a 15 day letter soliciting
comments from the State and Federal agencies would be used instead of
the standard 30 day public notice.
Alaska Power Authority Response:
The scope of the modification is minor compared to the overall project.
1-340-JW 2
• Bill Sheffield, Governor
.. ~
Alaska Power Authority.
State of Alaska
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APA/OTHR/0121
July 25, 1986
Ms. Marcia G. Lagerloef, Chief
Environmental Evaluation Branch
Environmental Protection Agency
1200 Sixth Avenue
Seattle, Washington 98101
Attn: Mr. Brian Ross
MIDDLE FORK DIVERSION STUDY
BRADLEY LAKE HYDROELECTRIC PROJECT
Enclosed are responses to the Environmental Protection Agency comments
on the Preliminary Assessment of the Middle Fork Diversion. Comments
on the open channel diversion have been addressed, and, unless for
reasons discussed in our responses, have been included in the final
assessment.
Further studies are required should the Alaska Power Authority wish to
consider the overland route to the Middle Fork diversion site. The
Alaska Power Authority is proceeding with limited field studies to
confirm whether further consideration is worthwhile.
If you have any questions please contact Mr. Tom Arminski at 561-7877 •
Very truly yours,
ALASKA POWER AUTHORITY
David R. Eberle
Project Manager
DRE/WDS/DB
Enclosure
1t-o~Bw: 190869 701 EastTudor Road Anchorage, Alaska 99519-0869 (907) 561-7877
•
REGION 10 ENVIRONMENTAL EVALUATION BRANCH
U.S. ENVIRONMENTAL PROTECTION AGENCY
JUNE 19, 1966 LETTER FROM MS. MARCIA G. LAGERLOEF
MIDDLE FORK DIVERSION STUDY -PRELIMINARY ASSESSMENT AND
JUNE 5, 1986 NOTES OF CONFERENCE
BRADLEY LAKE HYDROELECTRIC PROJECT
EPA - 3 Proposed Overland Access Route
Environmental Protection Agency Comment
At the same time, the proposal to move heavy equipment to the site via
an overland route as opposed to sky crane is of concern to us. As the
meeting notes point out, the land disturbance that would be unavoidable
with the overland route could not be mitigated. Although cost savings
could be realized by the overland route, the skycrane alternative is
practicable. Also, the cost savings associated with construction of an
open channel versus a pipeline for the Middle Fork diversion
overshadows the higher cost of skycrane versus overland access to the
site. Therefore, we do not support the overland proposal; we recommend
access to the site remain via skycrane as originally proposed.
Alaska Power Authority Response:
Your comment is noted, and will be considered in the deCision whether
to pursue the overland access alternative.
1-343-JW 3
Bill Sheffield, Governor • r.1-
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Alaska Power Authority
State of Alaska
APA/OTHR/0121
July 25, 1986
Mr. Leroy K. Latta, Jr.
Division of Land and Water Mgmt.
Alaska Department of Natural Resources
3601 "C" Street, Frontier Building
Pouch 7-005
Anchorage, Alaska 99510
MIDDLE FORK DIVERSION STUDY
BRADLEY LAKE HYDROELECTRIC PROJECT
Enclosed are responses to the Alaska Department of Natural Resources
comments on the Preliminary Assessment of the Middle Fork Diversion.
Comments on the open channel diversion have been addressed, and,
unless for reasons discussed in our responses, have been included in
the final assessment.
Further studies are required should the Alaska Power Authority wish to
consider the overland route to the Middle Fork diversion site. The
Alaska Power Authority is proceeding with limited field studies to
confirm whether further consideration is worthwhile.
If you ,have any questions please contact Mr. Tom Arminski at 561-7877 •
Very truly yours,
ALASKA POWER AUTHORITY
David R. Eberle
Project Manager
DRE/WDS/DB
Enclosure
4-09f2?;~x 190869 701 EastTudor Road Anchorage, Alaska 99519·0869 (907) 561·7877 -
DEPARTMENT OF NATURAL RESOURCES
DIVISION OF LAND AND WATER MANAGEMENT
SOUTHCENTRAL REGION -STATE OF ALASKA
JUNE 20, 1986 LETTER FROM MS. DEBORAH K. HEEBNER
MIDDLE FORK DIVERSIONS STUDY -PRELIMINARY ASSESSMENT
JUNE 5, 1986 NOTES OF CONFERENCE
BRADLEY LAKE HYDROELECTRIC PROJECT
AND
ADNR -4 Proposed Overland Access Route
Alaska Department of Natural Resources Comment
If the proposed overland concept is approved, the State
Preservation Officer requests discussion be initiated as
Historic
to the
applicability of a cultural resource survey of the proposed access
route.
Alaska Power Authority Response
The Alaska Power Authority will initiate discussions with the State
Historic Preservation Officer regarding a cultural resource survey if
the overland access route alternative is adopted.
1-342-JW 4
DEPARTMENT OF NATURAL RESOURCES• DIVISION OF LAND AND WATER MANAGEMENT
SOUTHCENTRAL REGION -STATE OF ALASKA
JUNE 20, 1986 LETTER FROM MS. DEBORAH K. HEEBNER
.. MIDDLE FORK DIVERSIONS STUDY -PRELIMINARY ASSESSMENT AND
JUNE 5, 1986 NOTES OF CONFERENCE
BRADLEY LAKE HYDROELECTRIC PROJECT
ADNR -5 Proposed Overland Access Route
..
Alaska Department of Natural Resources Comment
We also suggest the proposed impact of overland access be addressed in
an addendum to the Visual Resources Mitigation Plan • ..
• Alaska Power Authority Response:
If the Alaska Power Authority elects to proceed further with the
overland access alternative, it will be addressed in an addendum to the• Visual Resources Mitigation Plan.
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1-342-JW 5
•
DEPARTMENT OF NATURAL RESOURCES
DIVISION OF LAND AND WATER MANAGEMENT
SOUTHCENTRAL REGION -STATE OF ALASKA
JUNE 20, 1986 LETTER FROM MS. DEBORAH K. HEEBNER
MIDDLE FORK DIVERSIONS STUDY -PRELIMINARY ASSESSMENT AND
JUNE 5, 1986 NOTES OF CONFERENCE
BRADLEY LAKE HYDROELECTRIC PROJECT
ADNR - 6 Proposed Overland Access
Alaska Department of Natural Resources Comment
The current status of the ownership of the land on which the proposed
access road is located is Powersite Classifications No. 436 and PLO
3953. The access road adjacent to Bradley Lake at an elevation of less
than 1300 feet above mean sea level is within Powersite Classification
No. 436. The remainder of the access road is within PLO 3953
Withdrawal Hydro Project. The state did make a land selection on the
entire township on May 16, 1986.
Alaska Power Authority Response:
Thank you for providing us with the current status of land ownership
along the proposed overland access route.
1-342-JW 6
III
•
DEPARTMENT OF NATURAL RESOURCES
DIVISION OF LAND AND WATER MANAGEMENT
SOUTHCENTRAL REGION -STATE OF ALASKA-JUNE 20, 1986 LETTER FROM MS. DEBORAH K. HEEBNER
MIDDLE FORK DIVERSIONS STUDY -PRELIMINARY ASSESSMENT AND
JUNE 5, 1986 NOTES OF CONFERENCE-BRADLEY LAKE HYDROELECTRIC PROJECT
ADNR -9 Proposed Overland Access Route
•
Alaska Department of Natural Resources Comment
What is an estimate of the amount of area and vegetation mat disturbed• by equipment with blades down to maintain stability. Discuss the
efforts to be made in controlling erosion,
rehabilitating the access road.•
• Alaska Power Authority Response:
Your comment is noted, and will be considered in
revegetating and
the decision whether
to pursue the overland•
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access alternative.
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1-342-JW 9•
• MEMORANDUM State of Alaska
DEPT. CF NA ruRAL RE~CES, DIV. CF LAND & WATER MGMT., SOUTHCENTRAL REGION- Rf Cf I V ED DATE: .lJne 20, 1986TO: David R. Eberle
Project Manager, APA
FILE NO: Bradley Lake Hydro-TI-RU: Leroy K. latta, Jr. UN 2 3 1986
APA Unit, Project Manager TELEPHONE NO: 762-2274
SWEC-A ."\ ~I" . NCHORAGE •• FROM: Deborah K. Heebner l:i'IJ SUBJECT: Middle Fork Diversion
Natural Resource Officer Study -Agency Comments -We appreciate the opportunity to review the Middle Fork Diversion Study for
the Bradley Lake Hydroelectric Project.
• There are several points in the Diversion Study that merit further discussion.
Section 2.3.1 Flood Analysis •
Six years of hydrologic data are generally considered inadequate to evaluate
flood characteristics. However, in this case, regional regression equations • (U.S.F.S. Water Resources Atlas, 1979, rev. 1984; Parks and Madison, 1985)
yield comparable values for Q2, Q5, QIO, and QlOO to those calculated
in the study.
• Section 3.3 Open Channel -Partial Year Operation
On page 3-1 the rockfill dam in the gorge is described as being 50 feet long• and earthfill dam in the depression is described as being 25 feet high and 175
feet long.
• On page 4-6 the rockfill dam in the gorge is inconsistently described as being
45 feet long and on page 4-7 the earthfill dam in the depression is
inconsistently described as being 20 feet high and 170 feet long.
• On page 6-5 the earthfill dam in the depression is inconsistently described as
being 25 feet high and 170 feet long.
• Section 4.2.2 Preferred Open Channel Development
On page 4-8, it is stated, "the channel route is favorably located in rock to• maintain water tightness or, when in till, away from permeable zones that may
drain the diverted water back into the Middle Fork System. What type of
bedrock is along the proposed channel alignment? What are the fracture- characteristics? Are the joints open or closed? What will the transition
section from the trapezoidal to the V-cut channel look like?
Section 5.2 Site Access-
If the proposed overland concept is approved, the State Historic Preservation
Officer requests discussions be initiated as to the applicability of a
cultural resource survey of the proposed access road.-
We also suggest the proposed impact of overland access be addressed in an -addendum to the Visual Resources Mitigation Plan.
•
Mr. Eberle
.l..Jne 20, 1986
Page 2
The current status of the ownership of the land on which the proposed access
road is located is Powersite Classifications No. 436 and PlO 3953. The access
road adjacent to Bradley Lake at an elevation of less than 1300 feet above
mean sea level is within Powersite Classification No. 436. The remainder of
the access road is within PlO 3953 Withdrawal Hydro Project. The state did
make a land selection on the entire township on May 16, 1986.
Section 6.4 Erosion and Sediment Control
More information is needed regarding the amount of scour to be expected in the
V-cut portion of'the open channel. Velocities of 11 fps may produce
~onsiderable degradation in an unarmored channel. How will infilling of the
small pool affect the hydraulics of the channel system?
Cutting a deep V-cut trench into overburden may result in lowering the water
table in the vicinity of the cut, thus harming or killing vegetation along the
channel alignment. This, in turn, could lead to increased erosion rates along
the channel.
Section 6.6 Access Road
What is an estimate of the amount of area and vegetation mat disturbed by
equipment with blades down to maintain stability. Discuss the efforts to be
made in controlling erosion, revegetating and rehabilitating the access road.
DKH:bsp/0201p
-CORRESPONDENCE DISTRI8l1T1ON
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U.S. ENVIRONMENTAL PROTECTION AGENCY -REGION 10
1200 SIXTH AVENUE
SEATTLE, WASHINGTON 98101
-RECEIVED
JUN 2 3 1986-
=-EPLY TO MIS 443 ... a~ 01< SWEC-ANCHORAGE
David R. Eberle
Alaska Power Authority
P.O. Box 190869-101 East Tudor Road
Anchorage, Alaska 99519-0869
Subject: Middle Fork Dfversion and Overl~nd Atcess Route Proposals -Bradley Lake Hydroelectric Project
Dear Mr. Eberle:•
Thank you for sending us the Middle Fork Diversion preliminary assessment
and the notes of the June 5. 1986, inter4gency review meeting at which the• assessment was presented. I regret that we were unabl e to have a
representative at the meeting.
• We have no objections to the open channel proposal for the H1ddle Fork
diversion. We are pleased that, along with more fe4s1b1e winter operation and
Significant potential cost savings, construction of the open channel wo~ld
disturb only one third the land area of pipeline-construction.
At the same time, the proposal to move heavy equipment to the site via an
overland route as opposed to skycrane is of concern to us. As the meeting • notes point out, the land dfsturbance that would be un4vofaable with the
overland route could not be mitigated. Although cost savings could be
realized by the overland route, the skycrane alternatfve is practltable.
Also, the cost saving associated with construction of an open channel versus a
pipeline for the Mfddle Fork diversion overshadows the hfgher cost of skycrane
versus overland access to the site. Therefore, we do not support the overland -proposal; we recommend access to the site remain via skycrane as originally
proposed.
Thank you for the opportunfty to provide these comments. If there are-any Questions. please contact Brian Ross of -mY staff at (206) 442-8516.
Sfncerely.-CORRESPONDENCE DISTRIBUTION f :~;':"lN...l \ .:.,.,:..-/ ~<---ACTION: COPIES;
Marcia G. Lagerloef, Ch1ef• S .-J:-C-Environmental Evaluation Branch
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cc: FERC I
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• DEPARTMENT OF THE ARMY
u.s. ARMY ENGINEER DISTRICT. ALASKA - P.o. BOX 898
ANCHORAGE. ALASKA 99506-0898 RECE\'lED
.......,. TO
JUN19 {got:.ATTCNT.O.. 0 .... JUN 2 u 1986-Regulatory Branch
Special Actions Section SWEC_~NCHOAAGE -
David R. Eberle, Project Manager pt".-cl': .~ r:'J• Alaska Power Authority t.t!<·li,: .
Post Office Box 190869
701 East Tudor Road '86 JUr, 23 P12 :02Anchorage, Alaska 99519-0869•
Dear Mr. Eberle:
• This is in response to your June 10, 1986, request for comments on the
proposed design alternatives for the Middle Fork Di~ersion, Bradley Lake
Hydroelectric Project. •
A Oepartment of the Army (DA) permit for the Bradley Lake
Hydroe1ectroc Project was issued on April 11, 1986, (permit No.
• 071-0YU-2-850502, Bradley Lake 1). It involved construction of a pipeline
to convey and regulate Middle Fork Bradley River water flow into Marmot
Creek and Braoley Lake. The proposed revision would involve construction
of an open channel to convey the same flow on a full time basis. Material• excavdted from the channel would be side-cast. An overland route is
proposed for the equipment needed to do the job. The original proposal
would have utilized a sky crane to transport this equipment.•
The proposea revision would require a modification of the original
permit. This modification would undergo the public interest review and
• test for compliance with the 404(b)(1) guidelines just like the original
proposal. However, if the scope of the modification is minor compared to
the overall project~ then a 15 day letter soliciting comments from State
and Federal agencies would be used instead of the standard 30 day public•
notice.
If you have any questions regarding this matter,• Hansen at (907) 753-27l4 •
. . ~0n;·H:.5p01-.jDENcci CISTp.16u·r·I~::T~-:. .. .. . .. ,
f\~TION:
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Gene V. Augustine
contact Mr. Scott
Acting Chief, Special Actions Section i..#t:. ~Hrt!1: Regulatory Branch- I....._---
•
•
RECElvt:U
• JlJj\j ? ".t 1986 RECEIVED
BILL SHEFFIELD. GOVERNOR(. . ASKA POWER AlIllfORIn
~. JUN 2 ~ 1986
DEPARTMENT OF FISII::ArlfID:lQ&ME -333 RASPBERRY ROAD
ANCHORAGE. AlASKA 99518-1599
June 19~ 1986
• RECEIVED
Mr. Thomas Arminski
Alaska Power Authority JUN 241986 -P.O. Box 190869 '86 JJN 23 Pl2 :02Anchorage, Alaska 99519-0869
•
Dear Mr. Arminski:
Re: Bradley lake Hydroelectric Project f4iddle Fork Diversion Study•
The Alaska Department of Fish and Game (ADF&G) has reviewed the Middle Fork
Diversion Study prepared by Stone and Webster Engineering Corporation for • the Alaska Power Authority. The department finds the recommendation for the
Middle Fork diversion to be designed as an open channel, as opposed to the
originally designed buried pipeline, to be acceptable. However, the • department is concerned that the steep side slopes of the open channel
section that passes through rock (.25 to 1 slope) could pose a hazard and
physical barrier to mountain goat that utilize this area as a migration
corridor from summer to winter range. The department recommends that the
side slopes in the section of the open channel that passes through rock be
designed with either a more gradual (1.5 to 1 slope) or the slope be
designed to include sufficient roughness or terraces for goats footing. •
The middle fork Diversion Study recommends that an access road to the
diversion site be considered for further study. The department opposes• development of any road access to the diversion from the Bradley lake dam
site. Such access would only create further disturbance into mountain goat
winter range habitat and increase hunter access and potential poaching ,. problems.
Thank Y9U for the opportunity to comment on the Middle Fork Diversion Study. ... Should you have any questions on our comments, please contact either myself
or Don McKay at 267-2285.
i_
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cc: G. Bos, ADF&G ID. Holdermann, ADF&G• : .: !.i'3-G-at-e:-~-'I-7-Tl. latta, ADNR
D. Wilkerson, ADEC
H. Hosking, USFWS•
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•
•
United States Department of the Interior
Wesrern AI~ska Ecologi~al Services R E eEl VED
Sunshme Plaza. Suite 28
411 W. 4th Ave.
Anchorage. Alaska 99501 JUN 23 1986
IN REPL V REFER TO:
WAES SWEC-ANCHORAGE -9 I!B)
Mr. David Eberle, Manager
Bradley Lake Hydroelectric Projecr• P.O. Box 190869 ~:"":".t:·-. -'.
Al.~ c.' ,
701 East Tudor Road
Anchorage, Alaska 99519-0869•
Re: '81 Ait~ 1~8~~~6cy Meeting
Middle Fork Diversion
•
Dear Mr. Eberle:
The U.S. Fish and Wildlife Service (FWS) has reviewed the Middle Fork• Diversion Study -Preliminary Assessment, which was presented at the subject
meeting. We have no objection to the diversion design of delivering 800 cubic
feet per second of water at peak flow, year-round flows with no low level• by-pass into lower Middle Fork Creek, and an open channel design for
,conveyance of flows into Marmot Creek.
• We recommend additional assessment of the proposed overland access from the
vicinity of Kachemak Creek to the site of the Middle Fork creek diversion.
We do not support the construction of an access road_to the site, but the
establishment of a double-pass trail (in and out) may be acceptable. Prior to• use, any trail should be field flagged to assess the potential for adverse
impacts as false starts on other projects have caused avoidable disruptions to
terrestrial habitats. It would be appropriate to address the proposed impact
of overland access in an addendum to the project Visual Resources Mitigation -Plan, Section 3.3.2 Middle Fork Diversion.
The construction of the rock-filled and earth-filled dams, as proposed, should
not result in significant environmental impacts. The FWS would not object to
a modification of the Corps of Engineers permit reflecting these changes. Any ... required mitigation resulting from:an increase in adverse environmental
impacts associated with this proposed modification would automatically be
addressed in the as-built Terrestrial Impact Assessment Report. -Thank you for the opportunity to comment.
Sincerely,-~~,:,':::':!:.~,,, DiS-TRim.. , - Field Supervisor I ACTION: .I (;O?IE~.
cc: CE, ADF&G, DGC, ADNR, ADEC, NHFS. EPA -Anchorage f (F/l. t!: ) __ , __ "L./I'C<.IO"~ -.•
FERC -Portland, OR __, l:-,$""<.-J6C
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J. o. 15800. 12-
-NOTES OF CONFERENCE
MIDDLE FORK DIVERSION
AGENCY REVIEW MEETING
BRADLEY LAKE HYDROELECTRIC PROJECT
• ALASKA POWER AUTHORITY
Held in the Conference Room
Stone & Webster Engineering Corp.
• 800 A Street
Anchorage, AK 99501
June 5, 1986•
•
•
•
•
•
• PURroSE
UP 98D-6
Present for:
Agencies:
Don HcKay, ADF&G/Habitat
Mark Kuwada, ADF&G/Habitat
Bob Cutler, ADNR
~~chael Granata, ADNR
Deborah Heebner, ADNR
Leroy Latta, ADNR
Hank Hosking, USFl..IS
Scott Hansen, COE
Patty Bielawski, DGC/ACHP
Alaska Power Authority (APA):
Tom Arminski
Stone & Webster Engineering
Corporation (SWEC)
Norm Bishop
Nyrl Fisk
Bill Steigers
The meeting was held to discuss a preliminary assessment of the
technical, economic, and environmental considerations of alternatives
for the Middle Fork Diversion. Two distinct alternatives to the FERC
License Application were discussed: (1) an open channel-diversion; and (2) overland construction access to the Middle Fork
diversion site. Attachment 1 is the meeting agenda. Attachment 2 is
the sign-in attendance sheet. Attachment 3 is a preliminary
assessment of the proposed alternate open channel diversion and-construction access for the Middle Fork Diversion.
DISCUSSION-T. Arminski presented a short introduction to the Middle Fork
Di version.
•
•
1-303-Jly•
1.0 Old Business
N. Bishop presented the results of a May, 1986 assessment by SWEC of
the height of transmission lines over the tidal flats near the Hilmer
Olsen Fox Farm. It has been determined that the 50 feet minimum
conductor heights can be maintained as recommended by ADF&G/Habitat
without major tower modifications.
o The minimum height of the transmission line conductors above the
mud flats under "normal" loading conditions will be approximately
67 feet. This condition is taken with a temperature of 40 0 F
which represents the prevailing condition when waterfowl are
present during spring and fall.
o When the temperature increases on the conductors from 40 o to
60 0 F, the minimum height of the conductors will be about 65 feet.
o A 30 foot minimum sag height could occur under the extreme design
case when 1.7 radial inches of wet snow occurs on the conductors.
This has a probability of occurring once in 50 years based on our
meteorologist's report.
o The proba bility of waterfowl being in the area at the time when
the extreme design case will occur is low. This design case will
occur during the winter when the birds are not present.
T. Arm in ski reported that no settlement with the U. S. Department of
Interior (USDI) and the National Park Service (NPS) has been reached
related to the resolution of water rights from the Nuka Glacier,
although APA is continuing to discuss the matter with them. All FERC
Article Compliance plans have been approved, and APA is prepared to
begin construction of the Bradley Lake Project. However, the APA
Board of Directors has, at this time, decided to delay proceeding with
the Project until an agreement is reached.
Responding to a question by P. Bielawski on whether an amendment to
the FERC License Application would be needed if final resolution of
the matter resulted in less water being diverted froI:l the Nuka
Glacier, T. Arminski indicated that APA might have to go back to FERC
if water quantities differed substantially from those stated in the
License Application. N. Bishop stated that total diversion of the
Nuka Glacier flows contributed about 13% of the average annual energy
output of the Project. Existing flows from the Nuka Glacier would
contribute about 7% of the average annual energy. Up to 30% of the
average annual energy of the Project could be derived during short
periods of time from the Nuka Glacier flows, depending on localized
summer precipitation anomalies in the basin.
2.0 New Business
N. Bishop introduced B. Steigers as a new addition to the staff at
SWEC. With this staff addition, SWEC will be in a position to conduct
revisions of terrestrial impact assessments and mitigation plans for
1-303-JW 2
•
-design changes to the Project (e. g. , re-aligned transmission line
corridor and Middle Fork Diversion) in a timely and expeditious
manner.
2.1 Middle Fork Diversion Alternatives -
SWEC presented a year around open channel alternative to the partial-year pipeline concept found in the FERC License Application.
2.1.1 Technical Considerations -M. Fisk presented the pipeline concept found in the PERC License
Application and design modifications made since its submittal (see
Attachment 3 for details). The buried pipeline, as originally• proposed, would transport water during the period May through October
from the Middle Fork drainage approximately 1,860 feet through a 6
feet diameter pipe into Marmot Creek, which drains directly into
• Bradley Lake. The pipeline diversion includes a 20 feet high and 140
feet long rockfill dam on the Middle Fork. Water would pass through a
lower pipe bypass in the dam during the period November through April.
-
.. Design modifications since submittal of the License Application
include an 8 feet instead of 6 feet pipe to accommodate flows up to
800 cfs instead of the original 450 cfs captured from the Middle Fork.
Winter flows are estimated to range from 15 to 2 cfs during winter.
M. Fisk expressed concern that the low level pipe in the dam might
freeze closed during winter.
• The open channel diversion alternative would be located in a narrow
gorge about 200 feet downstream from the damsite location of the
proposed pipeline. The open channel diversion would consist of: a
smaller 20 feet high and 45 feet long rockfill dam; a spillway over• the dam; an intake structure to the open channel that restricts flow
to the peak flood operating level i a 700 feet long open channel; a
low, broad earthfill dam and shallow pool at the terminus of the 700• feet long open channel; and a 350 feet long open channel leading to
the Marmot Creek drainage. The intake structure to the open channel
would allow a maximum flow of 800 cfs to be diverted. Flow peaks.. above this level would pass over the rockfill dam.
The open channel would be built in two sections. The section adjacent
• to the rockfill dam would be 700 feet long. About 250 feet of this
length would be entirely in rock while the remainder of the channel
would be an unlined vee trench in glacial till. The section in rock
would be a modified trapezoidal section and range from 15 to 20 feet• in depth. There would be a 2 feet deep vee-channel in the center of
the flat bottom section in rock to improve the winter flow hydraulics.
The 700 feet open channel would be built with a slope of 2% to.. maintain velocities and use existing topography to an advantage,
thereby reducing excavation quantities. The channel section in till
would range from 0 to 20 feet deep.
•
..
The initial 700 feet channel bottom elevation would reach undisturbed
ground elevation near a small depression in a relict channel. The
diverted water would flow across this mesic grassy depression and form
1-303-JW 3•
a small pool. A 20 feet high and 170 feet long earthfill dam would be
required at one end of the pool to retain the water in the channel so
it does not return to the Middle Fork drainage system. The earthfill
dam would have a crest height which would allow for ice and flood
staging. The size of the pool would vary up to about 1.7 acres,
depending on flow rates.
The pool would be drained by a 350 feet long outlet trench into a
steep natural channel that is part of the Marmot Creek drainage, which
then drains into Bradley Lake. This open channel is expected to be
constructed entirely in till with a bottom slope of 2%.
The open channel constructed in rock requires drill and blast
excavation techniques. The overburden and till would be removed with
conventional earthmoving techniques. Blasted rock would be placed in
the rockfill dam, while the excavated till would be used in
construction of the earthfill dam. The completed trench bottom would
require no additional construction. The channel route is favorably
located in rock to maintain water tightness or, when in till, away
fran permeable zones that may drain the diverted water back into the
~~ddle Fork system.
The open channel has been designed to accommodate flow velocities of
11.5 fps during summer and 2 to 3 fps during winter. The USGS gaging
station on the upper Middle Fork has recorded flows during winter for
each year of record, thus these flO'.-ls would be diverted into Bradley
Lake. Receding flow levels during winter that may freeze a pipe
closed would not block the open channel.
2.1.2 Economic Considerations
N. Bishop presented the economic benefits to the Project of the open
channel over the pipeline alternatives. The capital costs for the
pipeline and open channel al ternati ves are listed below. All costs
assume helicopter transportation of all equipment, materials, and
personnel to the site. Cost estimates for the open channel are for
year around diversion of the flow and do not include bypass flow
controls.
Pipeline Alternative $3,290,000
(FERC License Application Proposal)
Open Channel Alternative $1.450.000
Potential Cost Savings of
Open Channel Alternative $1,840,000
Additionally, operation and maintenance costs would be lower with the
open channel year around alternative, which is a passive structure
requiring low maintenance.
1-303-J\-1 4
•
The helicopter trips in May to open flow gates and in October to close-flow gates to the pipeline would not be required for the year around
diversion of the open channel.
The Bradley Lake dam will maintain minimum flow requirements to the -lower Bradley River salmon spawning areas.
There was some discussion of dam construction materials, particularly• ti:x:>se used to seal the dams against leakage. Final geotechnical
engineering has not yet been conducted. But whether a face slab, face
membrane, or other materials were used, provisions would be made to• sling construction materials to the site by helicopter. These costs
have already been included in the presented cost estimates.
• Flows from the Middle Fork and Bradley Rivers would continue to be
monitored after construction of the Middle Fork diversion.
• 2.1.3 Environmental Considerations
B. Steigers presented a preliminary environmental evaluation and
comparison of the open channel and pipeline alternatives. The Middle- Fork diversion site occurs in the alpine tundra vegetation zone at
approximate Elevation 2,200 ft. Vegetation cover is dominated by
dwarf ericaceous shrubs, herbaceous sedges and grasses, and lichens on• rock outcrops. Substrate is hard-packed glacial till over bedrock.
The entire route of both diversion alternatives occurs above the
winter snow line. High winds and drifting snow are very common during
• winter, with 7 to 10 feet drifts accumulating. Both diversion routes
are in close general proximity to each other.
Positive environmental attributes of the open channel alternative-over the pipeline alternative include: (1) shorter length of
excavated trench (1,050 feet versus 1,860 feet long) j (2) use of
excava ted material for dam construction rather than excavation from• material sites; (3) narrower disturbed zone along channel route (about.
1 acre versus about 3 acres); and (4) potential erosion control
contained within open channel, settling out in the small pool or in ., Bradley Lake.
The potential barrier effects of an open channel were discussed. In
the 250 feet open channel section in rock, animals (primarily mountain• goats) may be prevented from crossing. However, the 5 feet bench
above the channel in rock would facilitate movements along the channel
section to a more sui table crossing location. Densities of moose,• black bears, and oountain goats are low in this area.
2.2 Site Access Alternatives-In the FERC License Application, access to the Middle Fork Diversion
s.i:te was recanmended to be by helicopter, with heavy equipment to be
transported by skycrane.•
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1-303-JW 5•
SrlEC presented an overland access alternative to move heavy earth
moving equipment to the site. Light equipment, materials, and
personnel would continue to be transported to the site by light
helicopter.
2.2. 1 Technical Considerations
M. Fisk presented the proposed approximate overland route (see
Figure 6 of Attachmen t 3). The route has not been ground surveyed.
The climb away from Bradley Lake would entail 20% to 30% slopes. H.
Fisk expressed reservations about the degree of difficulty that might
be encountered in negotiating the slopes surrounding Bradley Lake, and
whether the route could be safely utilized by crawler tractors. There
was sane discussion on whether additional DNR permits might be
required for the trail or pioneer "road" that would be established.
Land ownership of some sections of the proposed route were also
questioned. Approximately 3 crawler tractors would be taken to the
diversion site and back out again. D-6 Caterpillar (or equivalent) or
larger could be taken in over the overland route, while the skycrane
is limited to D-6 or smaller sized equipment. Total length of the
proposed route is 2 to 3 miles.
2.2.2 Economic Considerations
N. Bishop presented the cost savings of the overland route over use of
a skycrane.
Skycrane transportation of fuel, supplies and
equipment during construction $ 960,000
Overland route equipment transportation
costs $ 130,000
Bell 206B helicopter support required
for small equipment, fuel and supplies $ 300.000
$ 430,000
Potential Cost Savings of Access
Road Alternative
$ 430,000
$ 530,000
2.2.3 Environmental Considerations
B. Steigers presented
impacts of the proposed
a preliminary
overland route alternative.
evaluation of environmental
The proposed route climbs from the north edge of Bradley Lake
predominantly through a tall-growing alder zone for about 1 mile. The
route then ascends out of the alder zone and into the alpine
environment for the remaining approximately 2 miles.
1-303-Jl,i 6
Natural revegetation of cuts made by equipment would be relatively-slow, especially in the alpine areas. Cuts made on dense, tall alder
slopes above Bradley lake would be noticeable linear corridors, but
would likely be partially hidden from view by adjacent alder shrubs.
Within 10 years the alder should be firmly re-established in those -cuts. Crossings in scree would, over time, become less obvious
because of the dynamic nature of rock on those slopes.-The vegetation would be completely disturbed in the tracks of the
equipment across alpine tundra (2 passes of 3 pieces of equipment)
when blades are up. Where blades are lowered to maintain stability on-steep slopes, the vegetation mat ~lOuld be completely disturbed or
removed across the full width of the blade. Trenches would probably
be created by the lowered blades when the equipment descends steep• slopes. On the alpine tundra, natural revegetation on the disturbed
areas would be very slow. Erosion would likely be prevalent in cuts
made perpendicular to the slope contour. It would not be feasible to
attempt artificial revegetation. Erosion control procedures outlined -in the BMP Manuals would be followed.
The overland route would present no physical barrier effects to• animals.
3.0 Agency Comments •
Agency representatives \Olere then asked for their first impressions of
the proposed alternatives to site access and diversion.-D. McKay expressed reservations about the overland access concept.
There would be a substantial level of surface disturbance, which may
be unacceptable to ADF&G. In addition, he felt ADF&G would be opposed-to establishing a route frem Bradley lake to the alpine environment.
This route would give mountain goat hunters a much easier path to the
high elevations, and would probably alter the way the hunt is managed.• D. McKay estima.ted that 6 to 7 goans \Olere currently harvested
annually, from 8 to 15 permits issued for that subunit.
There was seme discussion whether DNR would be required to open the -trail to public access after construction.
-P. Bielawski concurred with D. McKay that there were too many unknowns
related to false starts of the lead piece of equipment' in the train.
Safety factors of steep slopes and false starts were also discussed. -N. Bishop suggested that surveys may be able to route the trail to
r.1aintain maximum slopes to 20% instead of 30%.
-A~ncy representatives were concerned about the overland site access.
N. Bishop solicited written agency responses to the presentation and
accompanying written materials within 2 weeks (by June 19, 1986). The-agencies were in concurrence with that schedule.
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1-303-J\>1 7•
The question of additional permit requirements was raised by P.
Bielawski. N. Bishop stated no additional wetlands permits were
required. S. Hansen stated that a permit for the additional earthfill
dam would be needed, and that COE would need a drawing to process a
permit amendment. There was some discussion between P. Bielawski and
S. Hansen over period of public notice for the COE permit.
M. Granata believed that an additional ADNR water rights permit would
be required to capture the increased flow of the Hiddle Fork. It was
concurred that the application for permit would request the maximum
average annual flow to be expected as diverted outflow from the Middle
Fork, which is in addition to the amount requested on the original
ADNR permit. M. Granata indicated he would review that requirement
for the permit with the ADNR staff after the meeting. P. Bielawski
recommended that the COE permit be applied for at the same time as the
AONR permit to expedite its processing.
N. Bishop stated that every ac-ft of water diverted would be
equivalent to approximately $45 to $55 in power output by the project,
based on a bus-bar energy cost of 4.5 cents/kw hr to 5.5 cents/kw hr.
Over the life of the project, additional diverted flow from the Middle
Fork would add to a substantial amount. APA would like to submit
revisions to the License Application to FERC concerning the Middle
Fork diversion as soon as possible following receipt of written agency
comments. There was sane discussion of the action FERC might take
regarding the approval of the recommended changes.
ACTION REQUIRED:
Agencies are requested to respond with written comments to
Mr. D. Eberle, APA, by June 19, 1986.
B. Steigers
Attachments
1-303-JW 8
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AGENDA
AGENCY MEETING
JUNE 5, 1986
Held at
Stone &Webster Engineering Corporation
800 "A" Street
Anchorage, Alaska
I. INTRODUCTION -Tom Arminski
II. OLD BUSINESS
1. Transmission Line -Norm Bishop
2. Nuka River -Tom Arminski
III. NEW BUSINESS
1. Middle Fork Diversion
A. Technical -Myrl Fisk
B. Economic -Norm Bishop
C. Environmental -Bill Steigers
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BRADLEY LAKE HYDROELECTRIC PROJECT
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MIDDLE
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FORK DIVERSION STUDY
Prepared by
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Stone & Webster Engineering Corporation
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Prepared for
Alaska Power Authority
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Preliminary Assessment
June 1986-
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1.0
Section
2.0
11.0
5.0
1.1
1.2
2.1
2.2
2.3
2.3. 1
2.3.2
2·3.3
3.2
3.3
3.4
4. 1
4. 1 • 1
4. 1 .2
4.1.3
11.1.11
4.1.5
4.2
4.2.1
4.2.2
5. 1
5.2
5.3
5.4
5.5
5.6
5.7
MIDDLE FORK DIVERSION STUDY
TABLE OF CONTENTS
Section Title
INTRODUCTION
Description and Location of Middle Fork
Diversion
Background and Objectives
FIELD STUDIES
Surveys
Geotechnical Investigation
Hydraulic Investigation
Flood Analysis
Water Quality
Winter Considerations
ALTERNATIVES CONSIDERED
Pipeline -Partial Year Operation (FERC
License Application Proposal)
Pipeline -Year Around Operation
Open Channel -Partial Year Operation
Open Channel -Year Around Operation
DESCRIPTION OF ALTERNATIVES
Pipeline Alternate -FERC License
Application Proposal
General
Pipeline Development
Technical Details
Dam, Gates and Conduit
Modifications to the FERC License
Application Proposal
Open Channel Alternate
General
Preferred Open Channel Development
TECHNICAL CONSIDERATIONS
General
Site Access
Construction Methods
Maintenance
Flood Operation
Breakup Operation
Winter Operation
Page No,
1-1
1-1
1-1
2-1
2-1
2-1
2-2
2-2
2-3
2-3
3-1
3-1
3-1
3-1
3-2
11-1
11-1
11-1
11-1
11-3
11-4
11-5
11-6
11-6
11-6
5-1
5-1
5-1
5-2
5-2
5-3
5-4
5-5
1-209-JW
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TABLE OF CONTENTS
(Cont.)
Section Section Title Page No, -
6.0 ENVIRONMENTAL ASSESSMENT 6-1
6, 1 Hydrology 6-1• 6,2 \Olinter Flow 6-2
6,3 Water Quality 6-3
6,4 Erosion and Sediment Control 6-4• 6,5 Physical Barrier Effects 6-6
6,6 Access Road 6-6
• 7,0 COST ESTIMATES 7-1
7.1 Construction Costs 7-1
7,2 Access Costs 7-1• 7,3 Maintenance Costs 7-2
7,3, 1 Pipeline 7-2
7,3,2 Open Channel 7-3
7,3,3 Dam Cutoffs 7-3
• 7,3,4 Diversion Structures -Partial Year
Opera tion 7-4
• 8,0 RECOMMENDATIONS 8-1
8,1 Peak Flow Level 8-1
8,2 Diversion Operation 8-1
• 8,3 Conveyance Method 8-1
8,4 Access Road 8-2
8,5 Environmental Considerations 8-2
• 9,0 BIBLIOGRAPHY 9-1
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LIST OF TABLES
Table Subject
Middle Fork Flow Conditions
2 USGS Winter Discharge Measurements on
the Middle Fork During 1979-1986.
All Discharges were Measured Downstream
of the Middle Fork Gaging Station.
3 Monthly Average Flows (cfs) for the
Bradley River System During Three
Water Years.
4 Water Quality of the Bradley River System
Sampled on May 1, 1980.
1-209-JW
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Figure
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LIST OF FIGURES
Subject
Middle Fork Location
Middle Fork Diversion -Pipeline
Alternate Route
Middle Fork Diversion -Pipeline
Alternative -Elevation and Details
Middle Fork Diversion -Open Channel
Alternative Layout
Middle Fork Diversion -Open Channel
Alternative -Channel Section
Proposed Overland Access Route Alternative
1-209-JW
1.0 INTRODUCTION
1.1 DESCRIPTION AND LOCATION OF THE MIDDLE FORK DIVERSION
The Middle Fork Diversion was originally proposed by the Corps of
Engineers and later adopted by the Alaska Power Authority to divert
stream flows from the upper Middle Fork of the Bradley River into
Bradley Lake to increase power production from the Bradley Lake
Hydroelectric Project. The flow from the Middle Fork Diversion into
Bradley Lake will contribute about 31 GWh of average annual energy to
the Bradley Lake Hydroelectric Project. The Middle Fork Diversion is
located 1 mile north of Bradley Lake and Marmot Creek in Seward
Heridian, T. 5S R. 9W, Sections 3 and 10 (Figure 1).
1.2 BACKGROUND AND OBJECTIVES
As part of the Phase II detailed design effort, Stone & Webster
Engineering Corporation (SWEC) has examined the alternatives for the
Middle Fork Diversion. This report summarizes that work effort.
The Corps of Engineers selected a buried pipeline as the preferred
method to deli vel" water from the upper Middle Fork of the Bradley
River to Bradley Lake. This method of diversion was reviewed by SWEC
during the Feasibility Study conducted in 1983 and found to be
technically adequate. This was the only alternative considered at
that time,
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In March through May, 1986, SWEC examined an open channel concept for
technical, environmental, and economic viability as an alternate to-the buried pipeline arrangement. Several channel route alternatives
have been considered and are discussed in this report.-
• The original concept of diverting flows during May through October
from the Middle Fork has also been reconsidered in this report. An•
examination of year around diversion of Middle Fork flows and
resulting hydraulic and environmental impacts upon the Bradley River•
system was also undertaken. Additionally, the peak flood level
• capacity of the Middle Fork diversion has been re-evaluated.
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2.0 FIELD STUDIES
2.1 SURVEYS
In 1979 the Corps of Engineers prepared a detailed alignment of the
proposed buried pipeline centerline. Field cross section surveys were
conducted and a series of topographic maps were prepared for the
alignment. These maps depicted the Middle Fork upstream and
downstream from the proposed diversion damsite location.
In 1985, R&M Consultants, Inc. relocated the Corps of Engineers
horizontal and vertical control monuments in the Middle Fork diversion
area and conducted a pipeline centerline profile and cross section
survey. In 1986, cross section surveys were conducted to provide
additional coverage outside the area in the previous Corps surveys.
The 1986 topographic maps of the area were prepared with 2 feet
contours. This topographic coverage was necessary to study open
channel diversion alternatives.
2.2 GEOTECHNICAL INVESTIGATION
Seismic refraction surveys were conducted by R&M Consultants, Inc. in
both 1984 and 1985 in both the diversion pipeline and channel route
areas. The 1984 surveys were performed in the damsite location and a
few cross sections were obtained along the pipeline channel route
location. The 1985 surveys added additional seismic lines between the
less frequent 1984 survey lines. The 1985 seismic surveys showed two
1-209-JW 2-1
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layers of till were present over the bedrock. This finding required
some of the 1984 surveys to be reinterpreted. Test bores were drilled-near the damsite and cores were obtained for rock fracture analysis.
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A top of rock calculation was made from the available seismic
information. This rock location determination has been used, as the -
basis for the conceptual layout of the open channel alternatives. The •
soil and rock depths developed by the calculation were used to draw
cross sections that showed both till and rock. These were used for•
developing excavation quantities of overburden and rock for the cost
• estimate for the open channel alternative and additionally for
locating the channel in an orientation that would not lose water.•
• 2.3 HYDRAULIC INVESTIGATION
• 2.3.1 Flood Analysis
The USGS has six years of stream flow records available for the Middle•
Fork drainage near the proposed diversion location. Based upon this
• USGS stream flow data, a flood frequency analysis using a Log Pearson
III distribution, and regional skew factors from USGS was developed to - obtain the 2, 5, 10, and 100 year flood flows for design purposes
(Table 1). Mean average annual flow is 50 cfs, or 36,200 ac-ft, per-
year.
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A 1979 flood peak hydrograph was obtained from USGS. The Corps of
Engineers Probable Maximum Precipitation (PMP) for the Bradley Lake
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Project and a uni t hydrograph prepared from the USGS 1979 peak flood
were used to predict the Probable Maximum Flood (PMF) for the Middle
Fork. The PMP occurs over a three day period and the PMF over a six
day period. The PMF for the Middle Fork was calculated to be 5800
cfs. An analysis of the 25 year reservoir operation levels prepared
for the FERC License Application was examined for the Main Dam
Spillway flood routing calculation. Based on a computer simulation of
the reservoir levels for power production, the Main Dam spillway
passes water about once every five years. A five year flood for the
Middle Fork is estimated to be 860 cfs. On this basis a diversion
channel capacity of 800 cfs was selected.
2.3.2 Water Quality
The 1980 Bradley Lake Water Quality Report presented water quality
measurements on the Middle Fork. Water quality measurements from the
1980 report are summarized in Chapter 6 of this report.
2.3.3 Winter Considerations
The USGS has maintained a continuous stage recording gage upstream of
the proposed Middle Fork diversion site since 1979. Their published
average daily flow, stage discharge relationship, maximum
instantaneous flow levels, and winter flow discharge measurement notes
have been incorporated in this analysis. During periods of snow
cover, the USGS gage site freezes with a solid cover of ice. Snow
frequently drifts into the river channel and drifts of 10 feet are not
uncommon (L. Lavene, USGS, Anchorage, pers. comm.). However, stream
1-209-JW . 2-3
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discharge measurements have been collected every winter with a
frequency of every 6 to 8 weeks. During the winter an open channel
exists through the ice and snow in the gorge section downstream from
the gage site. Wading measurements are obtained at this cross•
section. Average velocities and channel characteristics at each
downstream location are
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shown in Table 2.
2-4
3.0 ALTERNATIVES CONSIPERED
3.1 PIPELINE -PARTIAL YEAR OPERATION (FERC LICENSE APPLICATION
PROPOSAL)
The original FERC License Application proposal includes a 20 feet high
and 160 feet long rockfill dam; a low level bypass structure; and a
6 feet diameter penstock pipe buried from the Middle Fork to Marmot
Creek, a distance of about 1,860 feet. The original proposal is for
partial year operation, with the Middle Fork diverted into the Bradley
Lake drainage from May through October.
3.2 PIPELINE -YEAR AROUND OPERATION
This alternative is a buried pipeline with a geometry identical to the
FERC License Application proposal, but with year around diversion.
3.3 OPEN CHANNEL -PARTIAL YEAR OPERATION
This alternative includes a 20 feet high and 50 feet long rockfill
dam in a gorge about 200 feet downstream from the FERC License
Application Middle Fork dam location; a channel 700 feet long draining
into a local depression near Marmot Creek; a 25 feet high and 175 feet
long earthfill dam in the depression; and a 350 feet long open channel
draining into Marmot Creek and Bradley Lake. The rockfilled dam would
include a bypass pipe and gate for low level winter flow maintenance
in the Middle Fork tributary.
1-209-JW 3-1
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.. 3.4 OPEN CHANNEL -YEAR AROUND OPERATION
-This alternative is an open channel with geometry and dams identical
to the open channel with partial year operation previously described.
Under th is alterna ti ve, the open channel would di vert water from .. Middle Fork into
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Bradley Lake year around and no bypass structure
3-2
4.0 DESCRIPTION OF ALTERNATIVES
4.1 PIPELINE ALTERNATE -FERC LICENSE APPLICATION PROPOSAL
4.1.1 General
The pipeline alternative would be located approximately one mile north
of Bradley Lake in an adjacent drainage at elevation 2,200 on the
Middle Fork stream. The pipeline alternate includes a small dam,
spill way, and two diversion lines. One line would be provided for
initial construction efforts to bypass natural streamflows, and
subsequently to serve as a permanent outlet for downstream releases.
The other main diversion line conveys water to Marmot Creek, a
tributary to Bradley Lake. Figure 2 shows this pipeline layout. The
in terbasin diversion facility, which would be operational from May
through October, provides additional water to the Bradley Lake
reservoir.
4.1.2 Pipeline Development
The Middle Fork Diversion pipeline development includes a small
20 feet high rockfill dam with a central sheet pile cutoff wall and an
excavated channel spillway in the right abutment. Both the main
diversion line and low level outlet line intake works would be
integral with the dam. The low level outlet serves as a temporary
diversion during construction of the dam, spillway, and main diversion
flow line intake. Both the main diversion line and low level outlet
would be 6 feet diameter steel pipes with face mounted manually
operated intake sluice gates.
1-209-JW 4-1
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The main diversion line would be approximately 1,900 feet long and
would be buried along its entire length with a slope of 0.6 percent.-The terrain along the proposed alignment is typically exposed bedrock,
-and "drill and shoot" excavation techniques are anticipated. The
pipeline bedding and covel' material would be shot rock from the
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The low level outlet would be located in an excavated rock trench on
• the left bank. The low level outlet pipe invert would be located
approximately 3 feet below the natural stream channel bottom elevation
• to permit streamflow diversion during the dam and spillway
construction, and allow the reservoir to be lowered for intake sluice•
gate inspection. It would also serve as a permanent outlet for
• downstream releases during the November through April period.
• The proposed intake for the main diversion line and the low level
outlet would be a reinforced concrete structure with a platform for•
the manual operators at elevation 2,212. The intake works would
encase the 6 feet diameter pipes and provide anchorage for the intake
sluice gates and operators •
The spillway would be a 30 feet wide channel located in the right-
abutment. The material excavated for the spillway would be used for
the dam rockfill. A 30 feet wide, 4 feet high ungated concrete
overflow weir with crest at elevation 2,204 would be located in the
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spillway channel at the dam axis. The spillway channel would be
excavated in bedrock and is proposed as unlined. The pipeline Middle
Fork Diversion concept is shown on Figures 2 and 3.
4.1.3 Technical Details
The proposed main diversion line would have the capacity to pass
450 cfs into Marmot Creek without spillway discharges occurring at the
diversion dam. The spillway could pass about 1,600 cfs at pool
elevation 2,210 which exceeds the 100 year design flood discharge with
no flow in the main diversion line and 2 feet of freeboard on the dam
crest. The main diversion line would be able to pass an additional
670 cfs if operational with the pool at elevation 2,210. Should
streamflows exceed 1,600 cfs (or 2,300 cfs if the line is
operational), the water level would continue to rise until the dam is
overtopped at pool elevation 2,212 which corresponds to a spillway
flow of 2,600 cfs. The combined capacity of the spillway and main
diversion pipe at pool elevation 2,212 is approximately 3,400 cfs.
This represents about 60 percent of the PMF peak flow. Should the
diversion dam be overtopped, little damage is anticipated to either
the dam, flow lines, or the downstream river section. It is
uneconomical to design the structures for larger and less probable
flood design flows. The main diversion line and low level outlet
would be vented downstream of the intake sluice gates.
Field observations indicate that the Middle Fork and Marmot Creek
streambeds are cut into rock. The spillway channel is proposed to be
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excavated in rock and direct the discharge into the natural streambed
downstream of the dam toe. The low level outlet would discharge water-onto a concrete apron and into the natural streambed downstream of the
dam toe.-
4.1.4 Dam, Gates and Conduit
• The proposed rockfill dam would be approximately 140 feet long and 20
feet high with a central sheet pile cutoff wall embedded in concrete•
in a rock key along the dam axis. A 15 feet deep grout curtain would
seal the foundation rock below the concrete key. The sheet pile would•
be embedded in the encasement surrounding the 6 feet diameter
• di version pipes. At each end of the dam the sheet pile would be
embedded in concrete keyed into the abutment rock.•
• The 4 feet high and 30 feet long concrete spillway weir would also be
keyed into the foundation rock, and the 15 feet deep grout curtain
• along the dam axis would be continued under the weir and into the
right abutment. The spillway weir crest is proposed 8 feet below the•
top of the dam. -
The proposed main diversion line would consist of a common intake
• structure with the low level outlet, a 6 feet entrance slUice gate
-with manual operator, a 3/8 inch thick steel pipe 1,900 feet long and
6 feet in diameter buried throughout its length to preclude snow creep
• damage, and a screened outlet to prevent entry of animals. The low
level outlet would consist of an intake structure common with the main-
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diversion line, a 6 feet entrance sluice gate with a manual operator,
a 6 feet diameter 3/8 inch thick steel pipe embedded in the dam, a
screened outlet, and a concrete apron downstream of the outlet.
4.1.5 Modifications to the PERC License Application Proposal
The buried pipeline alternative as previously described has been
modified to provide for transport of 800 cfs maximum flow instead of
the original proposal of 450 cfs maximum flow. An 8 feet diameter
pipeline would be required to accommodate the 800 cfs rather than the
6 foot diameter previously proposed in the FERC License Application.
The peak capacity has been increased to 800 efs to capture the average
5 year flood. Additionally, the peak flood level captured has a
statistical recurrence interval equal to the projected frequency that
the Main Dam spillway passes water according to a 25 year operation
simulation. This linking of peak delivery levels of the Middle Fork
flows to the Main Dam operation ensures that the maximum amount of
water from the Middle Fork diversion would be retained for power
generation and not released over the spillway. The energy benefits
of the project are increased approximately 1,000 kWh for every acre-ft
diverted.
1-209-JW 4-5
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4.2 OPEN CHANNEL ALTERNATE
-4.2.1 General
• The open channel diversion would be located about 200 feet downstream
from the damsite location of the proposed pipeline alternative. The
• dam would be built in a narrow gorge with a crest elevation of about
2,180 feet. The open channel diversion would consist of: a small..
rockfill dam; a spillway over the dam; an intake structure to the open
channel that restricts flow to the peak flood operating level; a 700-
feet long open channel; a low, broad earthfill dam; and a 350 feet
• long open channel. The intake structure to the open channel would
allow a maximum flow of 800 cfs to be diverted. Flow peaks above this•
level would pass over the rockfill dam. The open channel concept can
• be deSigned to accommoda te year around diversion or partial year
diversion. If a facility is selected to provide partial year
• diverSions, a flow bypass structure consisting of a single sluice gate
and pipe placed through the rockfill dam would also be required.•
4.2.2 Preferred Open Channel Development -
The preferred open channel alternative requires a 20 feet high and 45 -feet long rockfill dam in the Middle Fork gorge area. This year
around diversion would require no bypass structures in the dam. The
open channel, which would be constructed first, would become
-operational as soon as construction began on the rockfill dam. The
downstream face of the dam would be deSigned so the entire dam-functions as a brC?ad-crested weir and spillway. The 100 year design
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flood can be accommodated with the open channel flowing at 800 cfs
capacity and the spillway passing 1,100 cfs of water. This flow level
would result in 4 feet of water depth passing over the dam crest.
The open channel would be builtin two sections (Figure 4). The
section adjacent to the rockfill dam would be 700 feet long. About
250 feet of this length would be entirely in rock while the remainder
of the channel would be an unlined vee trench in glacial till
(Figure 5). The section in rock would be a modified trapezoidal
section. There would be a 2 feet deep vee-channel in the center of
the flat bottom section to improve the winter flow hydraulics. The
700 feet open channel would be built with a slope of 2% to maintain
velocities and use existing topography to an advantage. thereby
reducing excavation quantities.
The initial 700 feet channel bottom elevation would reach undisturbed
ground elevation near a small depression in a relict channel
(Figure 4). The diverted water would flow across this mesic grassy
depression and form a small pool with a peak water surface level of
eleva tion 2. 148. A 20 feet high and 170 feet 10 ng earthfilled dam
would be required at one end of the pool to retain the water in the
channel so it does not return to the Middle Fork drainage system. The
earthfilled dam would have a crest at elevation 2.156 which would
allow for ice and flood staging.
1-209-JW 14-7
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The pool would be drained by a 350 feet long outlet trench into Marmot
-Creek, which drains into Bradley Lake. This open channel is expected
to be constructed entirely in till with a bottom slope of 2%. The 350
feet open channel would drain into a steep natural channel that is -
part of the Marmot Creek drainage. The water diverted past this point-would flow in relict channels and reach Marmot Creek without any
additional diversion construction.•
• The open channel constructed in rock requires drill and blast
excavation techniques. The overburden and till would be removed with
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conventional earthmoving techniques. Blasted rock would be placed in
the rockfill dam, while the excavated till would be used in•
construction of the earthfill dam. The completed trench bottom would
• require no additional construction. The channel route is favorably
located in rock to maintain water tightness or, when in till, away
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from permeable zones
Middle Fork system.•
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that may drain the diverted water back into the
4-8
5.0 IECHNICAL CONSIDERATIONS
5.1 GENERAL
Both delivery methods (a buried pipe or an open channel) use
conventional construction techniques. The following considerations
are addressed below:
1. Access to the site.
2. Construction methods, materials, and necessary equipment.
3. Maintenance.
4. Flood operation.
5. Breakup operation.
6. Winter operation.
5.2 SITE ACCESS
The construction of the Middle Fork diversion would require the use of
conventional blasting and earth moving equipment. Also, an excavator,
rigging, and small equipment and tools would be required. Equipment
and personnel have to be mobilized from the Bradley Lake dam site to
the remote Middle Fork Diversion location. Site access is possible
by overland and helicopter transport.
The overland concept would require equipment to be barged from the
Bradley Lake damsite to the head of Bradley Lake, offloaded and moved
overland from Kachemak Creek up the relatively steep slopes near
1-209-JW 5-1
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• Marmot Creek to the Middle Fork damsite. The proposed overland route
is shown on Figure 6. Equipment that moves overland would be limited
to crawler type equipment due to the terrain and steep slopes (20$
- grades) •
-Helicopter support could also be used for personnel transportation and
equipment mobilization. A skycrane would be required to transport•
equipment if the overland route were not developed.
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5.3 CONSTRUCTION METHODS
•
All alternatives considered for the Middle Fork diversion use•
conventional construction equipment and methods. The excavation would
• be drill and blast in rock, while the overburden and loosened rock
would be excavated with earth moving equipment.-
The pipe trench would be a steep side slope trapezoidal flat bottom•
trench. Cribbing would be required to align and level the pipe. Once
the pipe assembly was welded, the pipe trench would be backfilled and
compacted.-
5.4 MAINTENANCE-
-If the Middle Fork Diversion was required to operate between May and
October each year, a minimum of two trips would be required to the-site each year. Control structures must be constructed to redirect -
• 1-209-J\i 5-2
flow from the diversion back into the stream channel from November
until May. Servicing the control structures would be required each
year to remove ice prior to gate operation, and to replace and repair
diversion gate components. Ice removal may require several days to
completely free the control structures.
Year around diversion methods would also require annual inspection.
However, since there would be no operating gates or equipment, the
maintenance would be minimal.
5.5 FLOOD OPERATION
The maximum diversion flow has been selected to be 800 cfs. Middle
Fork stream flows exceeding 800 cfs would pass over the spillway.
The buried pipeline option has been designated to operate with an open
channel flow condition. The buried pipeline was increased in size
from a 6 feet to an 8 feet diameter pipe. Depth of flow within the
pipe at 800 cfs with a bottom slope of .006 ft/ft would be 5.8 feet
with an average velocity of 11.5 fps.
The open channel alignment has an 8 feet water depth and an average
velocity of 11 fps at a flow of 800 efs.
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5.6 BREAKUP OPERATION
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A buried pipeline with partial
operational problems during the ice
year operation
breakup period.
should have no
Icing may occur
•
in the pipe prior to the spring melt event, but it should not be
significant since the pipe would be dry during the winter. The sluice
.. gate may be frozen at the early May opening date; however, ice can be
•
removed or melted and the gates made operational.
The buried pipeline with year round operation would remain ice laden
through the spring breakup. Eventually internal ice will melt,
•
•
al though this may occur aft er the high flow period of June and July.
Also, the pipe would require annual internal inspection and main
tenance to determine if ice had damaged the water tightness of the
.. pipe. Due to potential ice
considered technically feasible •
problems, this alternative is not
•
An open channel with partial year diversion would require a sluice
gate or other control structure as does the partial year pipeline
..
-
alternati ve. Again,
and spring operation
open channel would
the control works would experience ice buildup
would require removal of ice. The partial year
fill with drifting snow, but water should
-eventually wash the channel free in spring.
..
..
An open channel with year around diversion of the Middle Fork would
overflow the ice buildup layers from winter operation. USGS records
indicate spring ice staging events are generally higher in stage by 2
• 1-209-JW 5-4
feet than flood stage in summer. The open channel option has both the
channel depth and dam heights designed to prevent water from leaving
either the channel system or the river system. The channel bottom has
been set to encourage high velocities and water flows would flush out
accumulated snow and ice in a short period of time.
5.7 WINTER OPERATION
Winter operation has been considered for only the year around
alternative. The open channel with complete diversion of winter flows
would experience receding flow levels as the temperatures fall below
freezing. The open channels have sufficient room for flow to pass
over the ice and snow formations that are expected to occur. The open
channel would experience snow drifting, but the water would continue
to flow within the channel banks. Even though local damming or flow
restriction may occur, the open channel should not experience any
stoppages. The natural Hiddle Fork river channel is narrow, has a
deep central channel, and is affected by snow drifts, yet it flows
continuously throughout the winter. Flow through the pond area would
continue beneath the ice.
1-209-JIl 5-5
-
-
6.0 ENVIRONMENTAL ASSESSMENT
-
6.1 HYDROLOGY -
A year around diversion of the Middle Fork of the Bradley River would
• additionally modify the natural flow regime from December to May. The
area of the Middle Fork drainage basin at the diversion is 10.2 square•
miles. The area of the North Fork and Middle Fork basins at the
• confluence with the Bradley River is 25.8 square miles. Thus, with
year around diversion of the Middle Fork the contribution of the
• unregulated basin area to the Bradley River at the confluence is 15.6
square miles.•
• Average monthly flows at the Middle Fork diversion range from 8 cfs to
2.8 cfs during the winter diversion period. During the period
• November 30 to May 1, water would be released through the diversion
tunnel to maintain 40 efs flow at the lower Bradley River stream gage.•
The unregulated basin (i.e., the 15.6 square miles) contributes 12 to
100$ of the flow at this gage. Currently, the Middle Fork and North
Fork basins contribute from 22 to 100% of the flow recorded at the -lower Bradley River gage.
-
Discharge data collected on the North Fork during the winter months in
the 1985 water year (WY) (Alaska Power Authority 1986) indicated the -
Middle Fork drainage at the diversion site contributed only slightly
•
to the runoff of the North Fork-Middle Fork basin. Contribution of
-
• 1-209-JW 6-1
the Middle Fork drainage at the diversion site ranged from 12% to 30%
of flow quantity that flows into the lower Bradley River. All of the
Middle Fork drainage at the diversion (elevation 2160) is above the
snowline elevation in winter. Most precipitation falling in the
Middle Fork drainage in the winter months contributes to the snowpack,
and only slightly to winter runoff. Diverting the small discharge
quantities to Bradley Lake in winter should have little effect on the
stream hydraulics of the Middle Fork. The unregulated portion of the
basin contributes most of the runoff, and this area would not be
modified.
USGS has gages at three locations in the lower Bradley River system:
one near the Middle Fork diversion, one on the Bradley River at the
lake outlet, and one on the Bradley River just below the hydraulic
block near tidewater. Using published data for monthly averages,
Table 3 was developed to show average flows at the three sites and the
unregulated basin flow, assuming total diversion of the Middle Fork.
6.2 WINTER FLOW
The Middle Fork is covered with ice and snow during most of the winter
period. Due to the velocity barrier in the Bradley River mainstem
downstream from the mouth of the North Fork, fish are not believed to
inhabit the river. Studies between 1980 and the present have failed
to loca te any fish in the Middle Fork. The Middle Fork has rather
steep gradients and a series of small falls that limit or exclude use
1-209-JW 6-2
•
-
by fish. Ground water flow and surface runoff during short melting
-events during winter contribute inflow to the Middle FOI'k downstream
from the proposed diversion. These flows would maintain nearly the
• same level of flows as occurred in the river prior to the diversion •
Released water from the Bradley Lake dam would supplement natural
• drainage and maintain a minimum of 40 cfs at the lower Bradley River
salmon spawning areas. Instream flows in the lower Middle Fork and•
North Fork will continue to maintain benthic invertebrates below the
di version as precipitation and the unregulated basin contribute to
stream runoff.
•
6.3 WATER QUALITY•
• The unregulated basin contributing flow to the Bradley River is the
only nonglaciated water source in the system. Winter flows of the-Middle Fork at the diversion are low in turbidity and suspended
sediment because glacial melt is not occurring. The water quality of•
the Middle Fork at the diversion has similar pH, dissolved oxygen, and -suspended sediments as the lower Bradley River during winter
conditions (Table 4). The Middle Fork has slightly more alkalinity
•
expressed as calcium carbonate (CaC0 ), and slightly more magnesium3
(Mg) and calcium (Ca) than the lower Bradley River above the Middle•
Fork. The Bradley River contains twice the chemical oxygen demand
(COD) of the Middle Fork. The winter flow quality is basically -
analogous between the Bradley Lake outflow and the Middle Fork flows.-The few apparent water quality differences are due to base flow
conditions on the Middle Fork, while the Bradley River has its base-
flow diluted by preCipitation runoff.
•
Released flows from the Bradley Lake Dam would maintain the ~O cfs
minimum at the downstream fish spawning beds. This water may be of
slightly higher quality than the diverted Middle Fork water.
6.4 EROSION AND SEDIMENT CONTROL
The open channel would be excavated in rock or till. The excavated
rock would be reused in building the dam at the gorge Site, while the
excavated gravels and overburden would be available for constructing
the earthfill dam in the depression into which the channel empties.
The initial channel section would be 700 feet long.
The open channel would end near the small depression, and would
develop its own flowline through the small pool that would be formed.
This may cause localized erosion, but it would be contained within the
watercourse itself. The scoured material from the unlined sections of
channel and the flow pa th eroded by the water would set t Ie in the
small pool area. The pool would be shallow in depth, have an area of
1 to 2 acres, and have relatively slow velocities in comparison to the
channel section. The pool would retain any upstream sedimention.
Another small open channel about 350 feet long would be excavated to
drain the small pool into an existing stream that empties into the
Marmot Creek drainage. The unlined channels would scour for one or
two years during peak floods until an equilibrium was reached in the
flow path. Marmot Creek has a stream gradient of 20%, thus,
transported sediment would be carried into Bradley Lake.
1-209-JW 6-4
•
-
The earthfill dam at the small pool would be 25 feet high and 170 feet
-long with the crest placed 11 feet above the design flow level. The
pool side of the dam would be armored with riprap to prevent scour
• from ice or high summer flows.
• The buried pipe concept would use an excavation and backfill
construction method. The quantity backfilled would be about 2,000•
cubic yards greater than the excavation because the entire pipe must
• be buried. Thus, excavation of areas other than the pipe trench to
obtain cover material (e.g., dam material site) would impact a wider
•
area than the pipeline trench itself.
•
The buried pipeline would require excavating a trench 1,860 feet long
• and then backfilling the pipe. The pipeline would directly connect
the Middle Fork to Marmot Creek. This excavated and backfilled area
•
would be a minimum of 40 feet wide and work limits would be another 50
feet beyond the excavation limits. The entire work area would be•
susceptible to erosion, as revegetation is rela ti vely slOW in the
I"" alpine environment. The area affected by pipeline construction would
be about 3 acres, while the open channel would affect less than 1
•
acre. Excavation for the open channel would be contained within the
channel, thus also containing any potential for erosion. A backfilled•
trench would present a bare scar subject to surface erosion. The open
-
-channel would present a more natural appearing visual impact than the
pipeline alternative.
-
• 1-209-JW 6-5
6.5 PHYSICAL BARRIER EFFECTS
Because the open channel section in rock is only about 250 feet long,
and the remainder of the channel is an unlined vee trench in
overburden, the open channel would not present physical barriers to
movements of crossing animals (e.g., mountain goats). Animals would
be able to negotiate crOSSings in all channel sections constructed as
a vee trench and in all but the deepest sections constructed in rock.
The 5 feet bench overlooking channel sections in rock would facilitate
movements of animals along the trench to more suitable crossing
points.
6.6 ACCESS ROAD
An alternative to helicopter transportation of earthmoving equipment
is an overland route from Bradley Lake near Kachemak Creek, across
Marmot Creek, and into the Middle Fork Diversion area. The
preliminary assessment of this route indicates it is 2 to 3 miles in
length. Before this route becomes a viable alternative to helicopter
transport, it will have to be surveyed by helicopter, the slopes
checked for steepness, and field assessed for potential site-specific
environmental damage.
The proposed route climbs from the shore of Bradley Lake near Kachemak
Creek onto the alder covered slopes along the mountain rim adjacent to
Bradley Lake (Figure 6). Approximately 200 feet of the initial climb
from the access point would be within the reservoir inundation area.
1-209-JW 6-6
-
-
Beyond the inundation area, the initial approximately mile of
vegetation crossed would be in a ta11 alder shrub/mesic herbaceous
sedge grass zone (Alaska Power Authority 1985) intermixed with
scattered Sitka spruce. The remainding 1-2 miles of the access road-
would cross scree slopes and shrub tundra plant communities.
•
Photogrammetric stereo models were set up for the initial route•
selection. The route was aligned in the least environmentally
sensitive areas (Le., on the least steep alder and scree slopes)•
which are dynamic graveled areas on the mountain slopes. The route
• was selected to minimize erosion by climbing the least steep routes
and to follow contours where the topography is too steep for equipment•
to negotiate. Most of the contour paralleling would require the
• equipment to travel with the blade down as the side slopes vary from
20 to 100%. The equipment blades should be up when climbing; however,
• when the equipment travels downhill on the return trip the blade would
have to be down to prevent ro11ing or runaways. Disturbance or•
removal of the vegetation mat would result in areas where equipment
• will use blades to maintain stability. The pioneer access road would
not be installed as a permanent project feature. It would be traveled
• only twice (one round trip) by the necessary earthmoving equipment
(estimated to be 3 dozers). About 20 feet of fi11 appears to be-
required to build a crossing area at Marmot Creek. A culvert would be
necessary to bridge the Marmot Creek, which would be removed upon -
completion of the project.-
-
• 1-209-JW 6-1
The road would leave a noticable scar on the tundra where crossed by
the tracked equipment, particularly where blades were required to be
down. Unvegetated scree slopes would "heal" relatively quickly as the
bottom of these steep slopes are in a dynamic state with boulders and
gravel constantly rolling downslope. The shrub and alder plant
communities, if not scraped and removed by a blade, should regain
their erect stature if not broken. However, much of this area is
shallow vegetative cover overlying rock. These vegetation types have
slow healing rates and conceivably would leave a visibly noticable
scar. The degree of scarring will depend on level of disturbance and
use of equipment blades. However, much of the climbing along the
route would be located in flash flood flow channels. These areas
support less vegetation and are less sensitive than are vegetated
hillsides.
If sedimentation occurs in the runoff channels it would not enter any
anadromous fish streams. Due to the steepness of this area and the
lack of vegetative cover, most rainfall/runoff events leading to
sedimentation would be confined to these flash flood channels.
The geotechnical surveys in this area, primarily around the Middle
Fork diversion area, indicate that soils are gravel or bedrock
outcroppings. No ice-rich permafrost has been identified. Thus, a
pioneer road would cause some increase in sedimentation; however,
thermo-kars ting should not occur. Any roadway scars tha t would be
produced would not be spreading scars, which often take 10 to 20 years
to stabilize.
1-209-JW 6-8
•
-
7.0 COST ESTIMATES
7.1 CONSTRUCTION COSTS
-
The capital costs for the pipeline and open channel alternatives are
• listed below. All costs assume helicopter transportation of all
equipment, materials, and personnel to the site. The open channel•
scheme is for year around diversion of the flow and do not include
bypass flow controls.
• Pipeline Alternative
(FERC License Application Proposal)•
Open Channel Alternative•
• Potential Cost Savings of Open Channel
Alternative•
7.2 ACCESS COSTS
• The previous construction costs assumed access
materials, and personnel to the site would be•
Alternately, an overland pioneer road about 3 miles
-
$3,290,000
$1.450.000
$1,840,000
of equipment,
by helicopter.
in total le ngth
could be developed to transport construction equipment to the site.
The estimate for the overland road access indicates that development
• of this route would have cost benefits over use of a skycrane.
-
• 1-209-JW 7-1
Skycrane transportation of equipment, fuel and
supplies during construction $ 960,000
Overland route equipment
transportation costs $ 130,000
Bell 206B helicopter support
required for small equipment,
fuel and supplies $ 300,QQO
$ 430,000
$ 430.000
Potential Cost Savings of Access Road Alternative $ 530,000
7.3 MAINTENANCE COSTS
7.3.1 Pipeline
The pipeline alternative would require, at a minimum, annual visual
surveys of the pipeline route to assure watertightness. Summer flood
flow velocities are fas t (11 fps) in the pipeline and the bedload in
the Middle Fork system may be movable. Normal streams in mountainous
terrain have boulders rolling during peak floods. These rolling
boulders may collect in bends in the channel system, presenting
hazards for the pipeline.
Winter flow conditions may cause frost heave under the pipe if water
seeps under the pipe and along the pipeline corridor. This frost
1-209-JW 7-2
-
-
heave would only occur if the material under the pipe is frost
susceptible. Two feet of bedding material (round or granular-
-
aggregate) placed under the pipe would help prevent this. But, if the
original ground has frost susceptible material, heaving would be
transmitted up through the 2 feet of bedding.
•
Field repair of the pipeline may involve patching small holes or
•
cracked welds. These repairs should be completed by travel through
the pipeline with appropriate equipment. The pipeline cannot be-
economically unburied for repair.
•
7.3.2 Open Channel •
No annual maintenance would be anticipated on the open channel. The
• 5 feet benches on top of the bedrock should prevent overburden from
unraveling into the channel. If the channel scours deeper the channel - would not be hydraulically harmed. The 700 feet upper channel would
be self-cleaning of sediment during high flow periods, with the pool-acting as the sedimentation pond. The 350 feet lower channel would
• also be self-cleaning, with Marmot Creek and eventually Bradley Lake
receiving any sediment . ..
7.3.3 Dam Cutoffs-
The Geotechnical Division would be designing the dam face membrane or
-other means of cutoff. A membrane may have a useful life of 20 years,
while steel plate may last 50 years •
•
-
• 1-209-JW 7-3
Annual inspections of the riprap face protection of the earthfill dam
in the pond area would be required. Some leakage through this dam
could be tolerated, but the structure would need inspection for
seepage. Riprap protection replacement would need to be by hand, as
equipment would be unavailable at the site.
The gorge rockfill dam may be designed with either a metal or membrane
cutoff. Both metal and membrane cutoff cores would not be available
for future inspection.
7.3.4 Diversion Structures -Partial Year Operation
As discussed in Chapter 3, the diversion structures require two visits
per year to open and close the two gates. The bypass pipe would
deliver average daily flows ranging from 8 to 4 cfs per day during the
winter flow period (See Chapter 7). The cost of this diversion
structure would be approximately $250,000.
At the Bradley Lake Dam a diversion tunnel to maintain minimum flows
for fish would be operational. If the low winter level flows from the
Middle Fork were diverted into Bradley Lake, the water necessary to
maintain 40 cfs on the downstream salmon beds would be released at a
marginal increase in cost. The cost of releasing water directly from
the Middle Fork would be higher than the cost of increasing the
release of water from Bradley Lake.
1-209-JW 7-4
-
-
The open channel would cost nothing to operate in winter, while the
diversion structure would increase the cost both of construction and-operation/maintenance. -
•
•
•
•
•
-
•
•
-
-
-
-
-
• 1-209-JW 7-5
8.0 RECOMMENDATIONS
8.1 PEAK FLOW LEVEL
It is recommended that the Middle Fork diversion be designed to
deliver 800 cfs at peak flow. This flow level corresponds in a flood
frequency analysis to the Main Dam Spillway frequency analysis of
discharge over the spillway.
8.2 DIVERSION OPERATION
It is recommended that the Middle Fork diversion be designed for year
around flow with no low level bypass. The technical, environmental
and economic analysis indicates that this would be both feasible and
cost effective. The cost of the project increases when seasonal
diversion is planned; the additional water required by the lower
Bradley River would be released by equipment already in place in the
bypass system at the Main Dam.
8.3 CONVEYANCE HETHOD
It is recommended that the diversion be designed as an open channel.
Economic analysis indicates that this method would be cost effective.
1-209-JW 8-1
•
-
8.4 ACCESS HOAD
It is recommended that the access road be considered for further
-study. Ground surveys of the route, erosion potential of slopes,
vegetation impacts, and location of stream crossing sites would be
• tasks indicated for the 1986 field season. Preliminary cost estimates
• indicate the road route could save about $530,000 in helicopter
transportation costs. This potential cost savings should be
• considered sufficient to warrant further field studies. Agency review
and comment will ultimately determine the feasibility of an overland
• route.
-8.5 ENVIHONMENTAL CONSIDERATIONS
-
The open channel alternative and access road have not been discussed
• with the Resource Agencies. We recommend that preliminary discussion
• with the Resource Agencies be initiated so the need for environmental
studies and licensihg impacts can be fully identified. -
•
•
•
-
• 1-209-JW 8-2
9.0 BIBLIOGRAPHY
Alaska Power Authority. 1985. Bradley Lake Hydroelectric Proiect,
Terres trial Impact Assessment Report. Prepared by Entrix, Inc.
and Stone &Webster Engineering Corporation. November.
Alaska Power Authority. 1986. Bradley Lake Hydroelectric Proiect.
Bradley River Water Quality Report. Prepared by Woodward-Clyde
Consultants, Entrix, Inc. and Stone & Webster Engineering
Corporation. February.
1-209-JW 9-1
..
Table 1. Middle Fork Flow Conditions. -
Flood Flow
PMF flood Q 6100 efs• =
100 year flood Q = 1900 efs
• 10 year flood Q = 1100 efs
5 year flood Q 860 efs= •
2 year flood Q 570 efs=
•
•
•
•
•
...
-
-
-
1-209-JW•
Table 2. USGS Winter Discharge Measurements on the Middle Fork during
1979-1986. All Discharges were Measured Downstream of the
Middle Fork Gaging Station.
Average
Width Are~ Velocity Q-Discharge
Date (ft) (ft ) (fps) (cfs)
Feb. 4, 1986 8.5 3.61 1.22 4.40
Apr. 24, 1986 13.5 5.61 0.49 2.77
Dec. 4, 1985 22.6 10.30 0.57 5.87
Feb. 20, 1985 16.0 7. 14 0.52 3.70
Jan. 9, 1985 19.7 10.80 0.37 4.01
Nov. 7, 1984 15.5 14.20 0.38 5.38
Feb. 15, 1984 19.0 8.23 0.46 3.82
Dec. 13, 1983 22.0 12.60 0.57 7.21
Mar. 15, 1983 12.5 4. 11 0.70 2.88
Jan. 27, 1983 14.5 4.34 0.95 4.13
Dec. 12, 1982 15.7 9.58 0.23 2.24
Mar. 18, 1982 8.6 4.03 0.92 3.70
Jan. 14, 1982 13.0 5.54 1.00 5.53
Mar. 25, 1981 13.0 7.84 0.52 4.11
Feb. 18, 1981 17.0 8. 11 0.60 4.89
Mar. 11 , 1980 15.0 4.00 1.00 4.00
Jan. 8, 1979 14.0 5.32 1. 10 5.86
1-209-JW
• • • • • • • • • • • • • • I
I II I
Table 3. Monthly Average Flows (efs) for the Bradley River System During Three Water' Years.
1983 WY Oct Nov Dec Jan Feb Mar Apr Hay June July Aug Sept
Bradley River near
Tide Water by USGS
480 1028 1153 907 470
Bradley River at
Lake Outlet by USGS
256 117 146 123 67.9 47.0 47.9 337 777 892 730 402
t1iddle Fork near
Diversion by USGS
23.9 9.8 8.4 4.7 3.5 2.9 3.2 15.8 91.0 128 113 48.1
1984 WY Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept
Bradley River near
Tide Water by USGS
363 481 249 95.0 66.2 163 95.5 354 970 1193 1393 735
Bradley River at
Lake Outlet by USGS
310 305 192 77.0 57.6 141 73.3 254 683 861 1013 567
Middle Fork near
Diversion by USGS
30.1 19.5 7.6 6.0 3.9 4.4 3.9 11. 3 84.5 139 168 76.8
Unregulated Basin
Flow by U&SGS
23 155 50 12 4 18 18 89 203 193 186 91
1-209-JW
Table 3 (Cont.)
1985 WY Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept
Bradley River near
Tidewater by USGS
554 128 127 223 115 43.6 42.5 282 891 1455 1004 796
Bradley River at
Lake Outlet by USGS
416 91.7 94.4 184 93.1 34. 1 31.1 190 614 977 796 651
Middle Fork near
Diversion by USGS
42.5 5.3 4.4 4. 1 3.8 3.3 2.8 10.7 44.7 150 118 88.7
North Fork, below
Middle Fork, near
Bradley River by WCC
36.3 23.5 26.6 13.0 9.6
Unregulated Basin Flow
from USGS
95 31 28 34 18 6 9 82 232 328 91 56
Estimated Average
Monthly Flow
Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept
Bradley River
Tide Water
near 560 258 131 116 94 76 85 390 1043 1324 1379 1081
Bradley River at
Lake Outlet
478 196 99 79 65 52 57 283 869 1222 1326 1021
Middle Fork near
Diversion by USGS
46 19 8 7 6 4 4 12 83 162 162 101
Lower Bradley River
Unregulated Portion
82 62 32 37 29 211 28 107 17lJ 102 53 60
1-209-JW
•
-Table 4. Water Quality of the Bradley River System Sampled on May 1,
1980.
-pH
D.O. % Conductivity
Saturated in micromhos
Alkalinity Suspended
as CaC0 3 Solids
(mgll)(mg/l)
• Middle
Fork 7.8 73% 117 43.6 6.3
•
•
Bradley
River
above
Confluence
of Middle
Fork
8.2 84% 60 31.4 9.9
• Dissolved
Solids
(mg/l)
Turbidity
(NTU)
COD
(mg/l)
Mg
(mg/l)
Na
(mg/l)
Ca
(mg/l )
•
-
•
Middle
Fork
Bradley
River
above
Confluen~e
of !-tiddle
Fork
2.1 1.4 40.5 10.0 0.09 33.7
22.4 23 94.5 5.5 0.09 24. 1
•
I.
1-209-JW-
•
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•
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•
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•
L-.__________ ~
jz
Middle Fork
Tributary ) Marmot
Creek
,,~~ . ~¥ W\r· CJd'
'> \~\'~~)\t!;.L,./.~i ~ 'I'Y-'"
\J ) j\V\ )
Bradley
River ..,-",
Scale 1-: 2000'
o 1000 2000
, I
BRADLEY LAKE
MIDDLE FORK LOCATION
FIGURE 1
•
• • • • • • • • • • • • • • I I & I I
."
C)
c:
:0
m
I\)
-T I I
I I I 1-- GROUND SURFACE _ _
SPILLWAY ':!E~ -. ---!---APPROX.--~-d-:;-:-~~O;:t~1 aN ''0 ;. . gm ""w,
I ----t--, I LINE
HYCRAULIC GRADE ---ril~j-
~ z l_-t-+-+~1-TI
~ ~,
~ Ai ~-,---,
---1--
--+---+·--I----lI-~I______1
VERTICAL SCALE' 1'1, IS' • _+__+ __--tI..:.HOP=.::IZ:..:,O~T~-SCALE: "',300______1· _____ ·_1" r.--_ ...t--
--~!. !!II
DEVELOPED F'RO'"ILE
CHANNEL"\
WIER INTAKE
SHEET PILE CUT-OFT
CENTER LINE
NATURAL FL()N
MAIN OM,RSlON
FtON LlNE
6' 1/1 STEEL PIPE
1-1 ..
I
\
'L 2 DfE" KEY CUT
INTO SOL,Q ROC~
VIEW lOOKING DONNSTREAM
AT SHEET PilE CUT-CFF WALL . ..' ,....*~
r
pZ 38 CAULKED INTERLOCKS
SI-lEET PILE CUT--QFF WALL .,
;!:i-Q'
NX DI'<ILL HOLES
,5 DE:£P GIl 10' OC
FOR GROUT CURTAIN
•
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•
•
•
•
•
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-
•
•
-
-
-
-
•
SPILLWAY
SPlLL_Y
CO'CRETE APRON
IXJWNSTREAM or:
tON LEVEL OUTLET~'
72'" 72' S<.UICE
WITH
WALL
PlAN-MUX)LE FffiK DIVERSION
SECTION THROUGH DAM
MIDDLE FORK DIVERSION -PIPEUNE
ALTERNATIVE-ELEVATION AND DETAILS
FIGURE 3-----1
CIRCULAR
THIMBLE--___..I1
SELECT BEDDING
MATERIAL BEL()N
PIPE SPRING LINE
•
Middle Fork..
Rock-filled Dam
Trapezoidel Section
Rock Excavation
pen Ch,imnel
; I ;
I i
~ -~hannel
Ove,burden
i:X98vption
0//((
I I
i II ,
I '
Tributary
-
•
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•
•
•
•
•
•
•
...
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MIDDLE FORK DIVERSION -OPEN CHANNEL
ALTERNATIVE LAYOUT -
'-------------------FIGURE 4•
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Varies from
7' to 21'
Varies from
0' to 30'
Channel Section in Rock
Varies from
0' to 21'
Channel Section in Overburden
MIDDLE FORK DIVERSION -OPEN CHANNEL
ALTERNATIVE -CHANNEL SECTION
FIGURE 5
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Alaska Power Authority-State of Alaska
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APA/OTHR/0060
-June 4, 1986
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Mr. Brian Ross
Region X
Environmental Protection Agency -1200 6th Avenue
Seattle, WA 98101-PRELIMINARY ASSESSMENT
OPEN CHANNEL DIVERSION -MIDDLE FORK DIVERSION
BRADLEY LAKE HYDROELECTRIC
• Enclosed is a preliminary
PROJECT
assessment of a proposed alternate open
channel diversion and construction access for the Middle Fork Diversion
of the Bradley Lake Hydroelectric Project. This document was provided
to attendees of the June 5, 1986 Agency Meeting at the offices of Stone-&Webster in Anchorage.
We request that you provide initial comments
• time. Should you have any questions or
Mr. Thomas J. Arminski at (907) 561-7877.
Very truly yours,
ALASKA POWER AUTHORITY
•
David R. Eberle• Project Manager
DRE/WS/JJ
• Enclosure
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and consultation at this
comments please contaat
PO Box 190869 701 East Tudor Rood Anchorage, Alaska 99519-0869 (907) 561-7877
2-708-JJ•
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Alaska Power Authority
State of Alaska
APA/OTHR/0051
May 28, 1986
Mr. Hank Hosking
U.S. Fish &Wildlife Service
WAES
411 W. Fourth Avenue, Suite 2B
Anchorage, AK 99501
JUNE 5, 1986 AGENCY MEETING
MIDDLE FORK DIVERSION
BRADLEY LAKE HYDROELECTRIC PROJECT
There will be a Bradley Lake Hydroelectric Project agency meeting on
June 5, 1986 at 9:00 AM at the offices of Stone &Webster Engineering
Corporation, 800 "An Street, Anchorage, Alaska to discuss the Middle
Fork Diversion. The original Federal Energy Regulatory Commission
License Application for the Bradley Project involved a buried pipeline
for the diversion of the Middle Fork water from the river into Bradley
Lake. We wish to discuss a change in the buried pipeline concept for
your review and comments.
Should you have any questions on the above, please contact
Mr. Thomas J. Arminski at (907) 561-7877.
Very truly yours,
ALASKA POWER AUTHORITY
~R~
David R. Eberle
Project Manager
DRE/NAB/JJ
/
PO Box 190869 701 EastT~dor Road Af"Chorage. Alaska 99519·0869 (907) 561.7877
2-676-JJ
APA/OTHR/0051
Same Letter sent to:
Mr. Hank Hosking
U.S. Fish & Wildlife Service
WAES
411 W. Fourth Avenue, Suite 2B
Anchorage, AK 99501
Mr. Dan Robison
U.S. Environmental Protection Agency
701 "C" Street, Box 19
Anchorage, AK 99513
Mr. Brad Smith
National Marine Fisheries Service
Department of Commerce
701 "cn Street, Box 43
Anchorage, AK 99513
Colonel Wilbur T. Gregory
District Engineer
Alaska District
Corps of Engineers
Building 21710
P.O. Box 898
Anchorage, AK 99506-0898
Attn: Mr. Scott Hansen
Ms. Patty Bielawski
Office of the Governor
Office of Management & Budget
Division of Governmental Coordination
2600 Denali Street, Suite 700
Anchorage, AK 99503
2-676-JJ 1
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APA/OTHR/0051
Same Letter sent to:
.. Mr. Bob Martin
Alaska Department of Environmental Conservation
437 "E" Street, Suite 200
Anchorage, AK 99501
Attn: Mr. Dan Wilkerson
•
M~. Robet~ Cutl~r• Division of Land and Water
Alaska Department of Natural Resources
3601 ftC" Street, Frontier Building
• Pouch 1-005
Anchorage, AK 99510
•
Mr. Don MacKay
Alaska Department of Fish &Game• 333 Raspberry Road
Anchorage, AK 99502
Mr. Brian Ross
Region X
• Environmental Proteotion Agenoy
1200 6th Avenue
Seattle, WA 98101
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2-616-JJ• 2