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Susitna-Watana Hydroelectric Project Document
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Title:
Susitna River ice processes study report
SuWa 40
Author(s) – Personal:
Author(s) – Corporate:
HDR Alaska, Inc.
AEA-identified category, if specified:
2012 Environmental Studies
AEA-identified series, if specified:
Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 40
Existing numbers on document:
Published by:
[Anchorage, Alaska : Alaska Energy Authority, 2013]
Date published:
March 2013
Published for:
Prepared for Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Final or Draft status, as indicated:
Document type:
Pagination:
x, 82, [1], 21 p.
Related work(s):
Pages added/changed by ARLIS:
Notes:
All reports in the Susitna-Watana Hydroelectric Project Document series include an ARLIS-
produced cover page and an ARLIS-assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna-watana/
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Susitna River Ice Processes Study Report
Prepared for
Alaska Energy Authority
Prepared by
HDR Alaska, Inc.
March 2013
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page i March 2013
TABLE OF CONTENTS
Summary .........................................................................................................................................x
1. Introduction ........................................................................................................................1
2. Study Objectives.................................................................................................................1
3. Study Area ..........................................................................................................................1
4. Methods ...............................................................................................................................2
4.1. Existing Information Review ...................................................................................2
4.2. Open Lead Mapping (March 2012) .........................................................................2
4.3. Time Lapse Camera Installation (March and April, 2012) ......................................2
4.4. Breakup Observations (April 2012 – May 2012) ....................................................2
4.5. Meteorological, Snow Depth, and Stream Temperature Data Compilation
(April 2012 - May 2012) ..........................................................................................3
4.6. Observations and Documentation of Freeze-up Progression (October 2012 –
December 31, 2012) .................................................................................................3
4.7. Deviations from Study Plan .....................................................................................4
5. Results .................................................................................................................................4
5.1. Existing Information Review ...................................................................................4
5.2. Open Lead Mapping ................................................................................................6
5.2.1. Lower River Open Leads .......................................................................... 6
5.2.2. Middle River Open Leads ........................................................................ 7
5.2.3. Upper River Open Leads .......................................................................... 7
5.3. Time Lapse Camera Installation and Maintenance ..................................................7
5.4. Breakup Observations ..............................................................................................7
5.4.1 Lower River Observations ........................................................................ 8
5.4.2 Middle River Observations ....................................................................... 9
5.4.3 Upper River Observations ...................................................................... 11
5.4.1. Ice Processes Effects on Other Resources .............................................. 11
5.5 Meteorological Data...............................................................................................12
5.6 Freeze-up Observations .........................................................................................12
6. Discussion..........................................................................................................................14
6.1. Open Leads ............................................................................................................14
6.2. Breakup ..................................................................................................................14
6.3. Freeze-up................................................................................................................15
ICE PROCESSES STUDY
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FERC Project No. 14241 Page ii March 2013
6.4. Ice Processes Effects on Other Resources .............................................................16
7. References .........................................................................................................................16
8. Tables ................................................................................................................................18
9. Figures ...............................................................................................................................50
LIST OF TABLES
Table 4.3-1. Location of time-lapse cameras installed for Ice Processes Study. ......................... 18
Table 5.1-1. Freeze up Observations from 1980-1985 ................................................................ 20
Table 5.1-2. Breakup observations from 1981-1985 .................................................................... 22
Table 5.1-3. Open leads mapped March 2, 1983 (Schoch, G.C. 1983) ........................................ 26
Table 5.1-4. Measurements taken on the Susitna River relevant to ice processes prior to
1986. ...................................................................................................................................... 29
Table 5.1-5. Documentation of Ice Processes Effects on Riparian Vegetation,
Geomorphology, and Aquatic Habitat .................................................................................. 44
LIST OF FIGURES
Figure 3-1. Map of Ice Processes Study Area............................... Error! Bookmark not defined.
Figure 3-2. Locations of Time-Lapse Cameras and Pressure Transducers. ................................. 51
Figure 5.2-1. Thermal lead in gravel bar near RM 32, March 20, 2012. Main channel is to
the left. View is looking upstream. ...................................................................................... 52
Figure 5.2-2. Tannic color of thermal lead at bank toe, near RM 15, March 20, 2012. .............. 53
Figure 5.2-3. Velocity leads near RM 97 March 20, 2012. Snowmachine tracks for scale. ...... 54
Figure 5.2-4. Thermal lead in Slough 8A, RM 126, March 21, 2012. .......................................... 55
Figure 5.2-5. Thermal lead in Slough 11, RM 136, March 21, 2012 .......................................... 56
Figure 5.2-6. Velocity lead in Devils Canyon, March 21, 2012. ................................................. 57
Figure 5.2-7. Close up view of velocity lead in Devils Canyon, March 22nd, 2012. Note
rapid and broken ice. ............................................................................................................. 58
Figure 5.2-8. Velocity lead in Vee Canyon, RM 222, March 22, 2012. ....................................... 58
Figure 5.2-9. Open leads in the Oshetna River (bottom of photo) and Susitna River (top of
photo), March 22, 2012. ........................................................................................................ 59
Figure 5.4-1. Ice jam near RM 62 on the Lower Susitna River, April 30, 2012. ......................... 60
Figure 5.4-2. Breakup near RM 9.5 on April 30, 2012 as recorded on a time-lapse camera. ...... 61
Figure 5.4-3. Stranded ice on banks near RM 59 after ice out on May 2, 2012. ......................... 62
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iii March 2013
Figure 5.4-4. Open water at the mouth of Portage Creek, April 11, 2012. Lead is about
4 feet wide. ............................................................................................................................ 63
Figure 5.4-5. A velocity lead in Devils Canyon, RM 151, widening on April 19, 2012. Ice is
slumping from the sides and accumulating in the lead. Note small avalanches from the
canyon walls. ......................................................................................................................... 64
Figure 5.4-6. Velocity lead opening near Gold Creek Bridge (RM 136) on April 19, 2012.
Broken ice is accumulating in the lead. ................................................................................ 65
Figure 5.4-7. Ice floes accumulated in open lead near RM 127 on April 23, 2012. Thermal
leads are opening up near the channel margin and overflow is appearing at the head of
Slough 8. ............................................................................................................................... 66
Figure 5.4-8. Ice jam near RM 136 on April 27, 2012. Slough 11 is in the upper left side of
the photo. ............................................................................................................................... 67
Figure 5.4-9. RM 136 and Slough 11 after the ice jam collapsed and moved downstream,
May 2, 2012. ......................................................................................................................... 68
Figure 5.4-10. Ice floes stranded on the bank near Slough 11 entrance (RM 135.6) on May 2,
2012. ...................................................................................................................................... 69
Figure 5.4-11. Ice jam forcing water into Slough 9, RM 128, May 2, 2012. ............................... 70
Figure 5.1-12. Ice jam in Vee Canyon (RM 221.5), April 27, 2012. ............................................ 71
Figure 5.4-13. Ice jam at RM 231, April 27, 2012. ...................................................................... 72
Figure 5.4-14. Ice jam at RM 207, mouth of Kosina Creek, April 27, 2012. ............................... 73
Figure 5.4-15. Remnant ice slabs downstream of Vee Canyon at RM 221, May 2, 2012. .......... 74
5.4-16. Ice jam remnants stranded on gravel island at RM 196, May 2, 2012. ............................ 75
Figure 5.4-17. Ice bulldozing head of island at RM 184, May 2, 2012. ....................................... 76
Figure 5.6-1. Frazil ice pans flowing past RM 100, October 16, 2012. ....................................... 77
Figure 5.6-2. Ice bridge in Devils Canyon, RM 151. Flow is from bottom to top.
October 22, 2012. .................................................................................................................. 78
Figure 5.6-3. Ice bridges at RM 2 in the west channel of the Lower River, October 26, 2012. .. 79
Figure 5.6-4. Pressure transducer readings from RM 10, showing a spike in pressure late on
October 23, 2012. .................................................................................................................. 79
Figure 5.6-5. Upstream end of ice cover, October 29, 2012 at RM 54. The thalweg is on the
lower part of the photo -- water is being pushed into side channels in the upper part of
the photo as the ice front progresses. .................................................................................... 80
Figure 5.6-6. Parks Highway bridge at RM 84 on November 1, 2012, prior to ice cover
progression. ........................................................................................................................... 81
Figure 5.6-7. Parks Highway Bridge at RM 84 on November 7, 2012, after ice cover
progression. Note flooded gravel bars on both sides of the river. ....................................... 82
ICE PROCESSES STUDY
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FERC Project No. 14241 Page iv March 2013
APPENDICES
Appendix A. Meteorological and Streamflow Data
Appendix A-1 Talkeetna Weather Station Data Tables
Appendix A-2 Freezing Degree Days Comparison
Appendix A-3 Surface Water Temperature for Susitna Basin Streams
Appendix A-4 Susitna Basin Snow Depth Measurements, 2011–2012
Appendix A-5 Stream Stage and Discharge Data
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LIST OF ACRONYMS AND SCIENTIFIC LABELS
Abbreviation Definition
Active floodplain The flat valley floor constructed by a river during lateral channel migration and
deposition of sediment under current climate conditions.
ADF&G Alaska Department of Fish and Game
AEA Alaska Energy Authority
AEIDC Arctic Environmental Information and Data Center
Anadromous Fishes that migrate as juveniles from freshwater to saltwater and then return as
adults to spawn in freshwater.
Anchor ice Submerged ice attached or anchored to the bottom, irrespective of the nature of its
formation. Often accumulates as frazil slush in open reaches.
APA Alaska Power Authority
Backwater
Off-channel habitat characterization feature found along channel margins and
generally within the influence of the active main channel with no independent
source of inflow. Water is not clear.
Bank
The sloping land bordering a stream channel that forms the usual boundaries of a
channel. The bank has a steeper slope than the bottom of the channel and is
usually steeper than the land surrounding the channel.
Baseline
Baseline (or Environmental Baseline): the environmental conditions that are the
starting point for analyzing the impacts of a proposed licensing action (such as
approval of a license application) and any alternative.
Border ice Ice sheet in the form of a long border attached to the bank or shore; shore ice.
Boulder Substrate particles greater than 12 inches in diameter. Larger than cobble.
Brash ice Accumulations of floating ice made up of fragments not more than about 2 meters
(6 feet) across; the wreckage of other forms of ice.
Break-up Disintegration of ice cover.
Break-up jam Ice jam that occurs as a result of the accumulation of broken ice pieces.
Break-up period Period of disintegration of an ice cover.
Calibration
In the context of hydrologic modeling, calibration is the process of adjusting input
variables to minimize the error between predicted and observed water surface
elevations or other hydrologic parameters.
Cfs cubic feet per second
Channel A natural or artificial watercourse that continuously or intermittently contains water,
with definite bed and banks that confine all but overbank stream flows.
Cobble Substrate particles between 3 and 12 inches in diameter. Larger than gravel and
smaller than boulder.
Confluence The junction of two or more rivers or streams.
Cross-section A plane across a river or stream channel perpendicular to the direction of water
flow.
CRREL U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, New
Hampshire.
Datum A geometric plane of known or arbitrary elevation used as a point of reference to
determine the elevation, or change of elevation, of another plane (see gage datum).
Degree-day Also termed freezing degree-day, a measure of the departure of the mean daily
temperature below a given standard, usually 0°C (32°F).
Depth Water depth at the measuring point (station).
Devils Canyon Located at approximately Susitna River Mile (RM) 150-161, Devils Canyon contains
four sets of turbulent rapids rated collectively as Class VI. This feature is a partial
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Abbreviation Definition
fish barrier because of high water velocity.
Discharge The rate of stream flow or the volume of water flowing at a location within a
specified time interval.
Duration of ice cover The time from freeze-up to break-up of an ice cover.
et al. “et alia”; and the rest
FERC Federal Energy Regulatory Commission
Flood Any flow that exceeds the bankfull capacity of a stream or channel and flows out on
the floodplain.
Floodplain
1. The area along waterways that is subject to periodic inundation by out-of-bank
flows. 2. The area adjoining a water body that becomes inundated during periods of
over-bank flooding and that is given rigorous legal definition in regulatory programs.
3. Land beyond a stream channel that forms the perimeter for the maximum
probability flood. 4. A relatively flat strip of land bordering a stream that is formed by
sediment deposition. 5. A deposit of alluvium that covers a valley flat from lateral
erosion of meandering streams and rivers.
Frazil Fine spicules, plates, or discoids of ice suspended in water. In rivers and lakes it is
formed in supercooled, turbulent waters.
Frazil pan A circular agglomerate of loosely packed frazil that floats.
Freeze-up jam Ice jam formed as frazil ice accumulates and thickens during the freeze-up period.
Freeze-up period Period of initial formation of an ice cover.
Ft feet
Gaging station A specific site on a stream where systematic observations of stream flow or other
hydrologic data are obtained.
Geomorphology The scientific study of landforms and the processes that shape them.
GIS
Geographic Information System. An integrated collection of computer software and
data used to view and manage information about geographic places, analyze
spatial relationships, and model spatial processes.
GPS global positioning system. A system of radio-emitting and -receiving satellites used
for determining positions on the earth.
Gradient The rate of change of any characteristic, expressed per unit of length (see Slope).
May also apply to longitudinal succession of biological communities.
Gravel Substrate particles between 0.1 and 3.0 inches in size, larger than sand and
smaller than cobble.
Grounded ice Ice that has run aground or is in contact with the ground underneath it.
Groundwater (GW) In the broadest sense, all subsurface water; more commonly that part of the
subsurface water in the saturated zone.
Habitat
The environment in which the fish live, including everything that surrounds and
affects its life, e.g. water quality, bottom, vegetation, associated species (including
food supplies). The locality, site and particular type of local environment occupied
by an organism.
Hummocked ice Ice piled haphazardly, one piece over another, to form an uneven surface.
Ice bridge A continuous ice cover of limited size extending from shore to shore like a bridge.
Ice concentration
The ratio (in eighths or tenths) of the water surface actually covered by ice to the
total area of surface, both ice-covered and ice-free, at a specific location or over a
defined area.
Ice cover A significant expanse of ice of any form on the surface of a body of water.
Ice floe Free-floating piece of ice greater than about 1 meter (3 feet) in extent.
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Abbreviation Definition
Ice jam A stationary accumulation of fragmented ice or frazil that restricts or blocks a
stream channel.
Ice run Flow of ice in a river. An ice run may be light or heavy, and may consist of frazil or
broken sheet ice.
Ice-free No floating ice present.
In Inch
Instream flow The rate of flow in a river or stream channel at any time of year.
Intergravel Intergravel refers to the subsurface environment within the riverbed.
Leading edge of ice cover The upstream extent of a continuous ice cover that is progressing upstream via
juxtaposition (accumulation) of frazil ice pans.
Lower segment Susitna The Susitna River from Cook Inlet (RM 0) to the confluence of the Chulitna River at
RM 98.
Main channel For habitat classification system: a single dominant main channel. Also, the primary
downstream segment of a river, as contrasted to its tributaries.
Mainstem
Mainstem refers to the primary river corridor, as contrasted to its tributaries.
Mainstem habitats include the main channel, split main channels, side channels,
tributary mouths, and off-channel habitats.
Middle segment Susitna The Susitna River from the confluence of the Chulitna River at RM 98 to the
proposed Watana Dam Site at RM 184.
ºF degrees Fahrenheit
NRCS National Resources Conservation Services
Off-channel Those bodies of water adjacent to the main channel that have surface water
connections to the main river at some discharge levels.
Off-channel habitat Habitat within those bodies of water adjacent to the main channel that have surface
water connections to the main river at some discharge levels.
Open lead Elongated opening in the ice cover caused by water current (velocity lead) or warm
water (thermal lead).
Overbank flow Flow that exceeds the level of a river’s banks and extends into the floodplain. Also
overflow.
Period of record The length of time for which data for an environmental variable has been collected
on a regular and continuous basis.
Porosity The ratio of the volume of voids in ice, rock or soil to the total volume.
Project Susitna-Watana Hydroelectric Project
Q Hydrological abbreviation for discharge, usually presented as cfs (cubic feet per
second) or cms (cubic meters per second). Flow (discharge at a cross-section).
Rapid
Swift, turbulent flow including small chutes and some hydraulic jumps swirling
around boulders. Exposed substrate composed of individual boulders, boulder
clusters, and partial bars. Lower gradient and less dense concentration of boulders
and white water than Cascade. Moderate gradient; usually 2.0-4.0% slope.
Reservoir A body of water, either natural or artificial, that is used to manipulate flow or store
water for future use.
Riffle
A fast water habitat with turbulent, shallow flow over submerged or partially
submerged gravel and cobble substrates. Generally broad, uniform cross-section.
Low gradient; usually 0.5-2.0% slope.
Riparian Pertaining to anything connected with or adjacent to the bank of a stream or other
body of water.
Riparian vegetation Vegetation that is dependent upon an excess of moisture during a portion of the
growing season on a site that is perceptively more moist than the surrounding area.
River A large stream that serves as the natural drainage channel for a relatively large
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FERC Project No. 14241 Page viii March 2013
Abbreviation Definition
catchment or drainage basin.
River mile The distance of a point on a river measured in miles from the river's mouth along
the low-water channel.
RM
River Mile(s) referencing those of the 1980s APA Project. These were the distance
of a point on a river measured in miles from the river's mouth along the low-water
channel.
Sediment Solid material, both mineral and organic, that is in suspension in the current or
deposited on the streambed.
Sediment transport
The movement of solid particles (sediment), typically due to a combination of the
force of gravity acting on the sediment, and/or the movement of the fluid in which
the sediment is entrained.
Side channel
Lateral channel with an axis of flow roughly parallel to the mainstem, which is fed by
water from the mainstem; a braid of a river with flow appreciably lower than the
main channel. Side channel habitat may exist either in well-defined secondary
(overflow) channels, or in poorly-defined watercourses flowing through partially
submerged gravel bars and islands along the margins of the mainstem.
Side slough Off-channel habitat characterization of an Overflow channel contained in the
floodplain, but disconnected from the main channel. Has clear water,
Slough
A widely used term for wetland environment in a channel or series of shallow lakes
where water is stagnant or may flow slowly on a seasonal basis. Also known as a
stream distributary or anabranch.
Slush ice An agglomerate of loosely packed frazil floating on the water surface or adhered to
the bed or underside of the ice cover.
Stage The distance of the water surface in a river above a known datum.
Stage-discharge relationship The relation between the water-surface elevation, termed stage (gage height), and
the volume of water flowing in a channel per unit time.
Staging Increase in water levels upstream of the leading edge of ice cover caused by the
partial blockage of the channel by ice.
Supercooled water Water with a temperature slightly below the freezing point (0°C or 32°F).
Thalweg A continuous line that defines the deepest channel of a watercourse.
Thermal break-up Melting in place. Also called in situ break-up.
Thermal ice Solid ice formed in place in low-velocity areas.
Three Rivers Confluence
The confluence of the Susitna, Chulitna, and Talkeetna rivers at Susitna River Mile
(RM) 98.5 represents the downstream end of the Middle River and the upstream
end of the Upper River.
Tributary A stream feeding, joining, or flowing into a larger stream (at any point along its
course or into a lake). Synonyms: feeder stream, side stream.
Upper segment Susitna The Susitna River upstream of the proposed Watana Dam Site at RM 184.
Upwelling
The movement of groundwater into rivers, stream, sloughs and other surface water
features. This is also called groundwater discharge and may be associated with a
gaining reach of a river or stream.
USGS DOI, Geological Survey
Watana Dam
The dam proposed by the Susitna-Watana Hydroelectric project. The approximately
750-foot-high Watana Dam (as measured from sound bedrock) would be located at
river mile (RM) 184 on the Susitna River. The dam would block the upstream
passage of Chinook salmon, possibly other salmon species, and resident fish that
migrate through and otherwise use the proposed Watana Dam site and upstream
habitat in the Susitna River and tributaries.
Water slope Change in water surface elevation per unit distance.
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Abbreviation Definition
Water stage The water surface elevation above the bottom of the river channel or above some
arbitrary datum.
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SUMMARY
The purpose of the 2012 Ice Processes Study was to document baseline winter ice conditions on
the Susitna River between Cook Inlet and the Oshetna River confluence near river mile (RM)
234. The specific information sought included the location of open leads in the ice cover in late
winter, the progression of breakup, including the locations and effects of ice jams, the
progression of freeze-up, and the interaction between river ice processes and riparian vegetation
and fish habitat. This baseline data will help identify the river reaches most likely to experience
changes in river ice formation as a result of Project construction and operation.
The following data were collected in 2012:
Open leads were mapped between Cook Inlet and RM 234.
The progression of breakup was documented using aerial reconnaissance, aerial videos,
and stationary time-lapse cameras.
Meteorological data were compiled.
Post-breakup reconnaissance documented interactions between ice, vegetation, and
sediment.
The progression of freeze-up was documented using aerial reconnaissance, videos,
stationary time-lapse cameras, and pressure transducers.
The documentation of breakup and freeze-up will be used to supplement ice observations from
the 1980s to further our understanding of the natural timing and duration of ice cover on the
Susitna River. This will provide a baseline against which to evaluate the potential effects of the
Project. The 2012 season also provided an opportunity to view an unusually slow and mild
breakup, and unusually high flows during freeze-up. The map of open leads will be used by the
Instream Flow and Groundwater studies to identify upwelling habitats and areas of potential
surface/groundwater interaction. Observations of ice interactions with riparian vegetation and
fish habitat areas (especially side sloughs) will be used by Riparian and Instream Flow Habitat
studies to define the effects of freeze-up, ice cover, and breakup on riparian and aquatic
resources.
Many open leads documented in 2012 were also documented in the 1980s, indicating that
upwelling habitats are likely to be in largely the same areas. Breakup in 2012 was mild, with
few large ice jams. The largest jams occurred in the Middle River. There were three ice jams
large enough to inundate riparian vegetation and flood sloughs in 2012. Freeze-up in 2012 began
with high water levels, as mid-October flows at USGS gages along the river were about twice as
high as the long-term average. The ice cover on the Lower River progressed upstream from a
bridge formed near the mouth of the river, and followed the same pattern as ice cover
progression documented during the 1980s. Water level increases as recorded by pressure
transducers in the Lower River reached 2-4 feet.
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1. INTRODUCTION
The Alaska Energy Authority (AEA) is preparing a License Application that will be submitted to
the Federal Energy Regulatory Commission (FERC) for the Susitna-Watana Hydroelectric
Project (Project) using the Integrated Licensing Process (ILP). The Project is located on the
Susitna River, an approximately 300-mile long river in the Southcentral Region of Alaska. The
Project’s dam site will be located at River Mile (RM) 184. The Project has the potential to affect
ice processes, including the timing and extent of ice formation, severity of breakup, ice
thickness, and winter water levels on the Susitna River downstream of the dam site.
This report provides the results of the 2012 Susitna River Ice Processes Study from March, 2012
to December, 2012. The primary purpose of the 2012 Ice Processes Study is to document ice
cover conditions in the Susitna River from Cook Inlet to the Oshetna River confluence at RM
234. Field activities included aerial breakup and freeze-up reconnaissance, open-lead mapping,
and time-lapse camera installation and maintenance. Office activities included meteorological
data compilation and georeferencing of observations from the 1980s Susitna River ice studies.
This study provided data to inform the 2013–2014 licensing study program, Exhibit E of the
License Application, and FERC’s National Environmental Policy Act (NEPA) analysis for the
Project license.
2. STUDY OBJECTIVES
The overall objective of the 2012 ice processes study is to document baseline ice conditions and
initiate assessment of potential Project effects on downstream river ice processes. The specific
objectives are as follows:
Document the timing and progression of breakup and freeze-up on the Susitna River
between Cook Inlet and RM 234 (Oshetna River confluence).
Document open leads between Cook Inlet and RM 234 throughout the winter.
Document the interaction between river ice processes and channel morphology,
vegetation, and aquatic habitats.
Provide baseline data to help identify the river reaches most likely to experience changes
in river ice formation as a result of Project construction and operation.
3. STUDY AREA
Observations were taken between the mouth at Cook Inlet and the Oshetna River confluence
(RM 234) (Figure 3-1). Time-lapse cameras were installed in eleven locations prior to breakup
in 2012 and in three additional locations prior to freeze-up (Figure 3-2). Telemetered time-lapse
cameras associated with the Open-Water HEC-RAS Flow Routing Model Study (R2 et al. 2013)
and pressure transducers were installed in 13 additional locations prior to freeze-up in 2012
(Figure 3-2).
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4. METHODS
4.1. Existing Information Review
The 1980s river ice studies were reviewed and synthesized for use in developing the 2012-2014
study plans. Observations of the timing and location of ice formation and break up, ice
thickness, ice elevation with respect to discharge, and ice process effects on geomorphology,
riparian vegetation, and aquatic habitat were compiled in a geospatial format for comparison
with present day observations.
4.2. Open Lead Mapping (March 2012)
In March 2012, open leads from Cook Inlet to RM 234 were mapped aerially and documented
using GPS-enabled cameras. Leads were classified by location (main channel, side channel,
slough, tributary mouth) and type (thermal or velocity, where identifiable). The upstream and
downstream limits of each open lead were located using an Archer handheld mapping GPS, and
the width of each lead was estimated visually as a percentage of river width. Open leads in the
Middle River were compared with the location of open leads documented in 1983 in the Middle
River.
4.3. Time Lapse Camera Installation (March and April, 2012)
Fourteen time lapse-cameras were installed in 11 locations between RM 9 and RM 184 for the
purpose of observing ice breakup and ice-cover formation (Table 4.3-1). The cameras were
programmed to record one still image per hour. Data cards were retrieved following ice-out
(May 8 or 9) and photos downloaded. Break-up progression as documented by the time-lapse
photos was summarized in text and video form.
4.4. Breakup Observations (April 2012 – May 2012)
General breakup progression was documented between Cook Inlet and RM 234 from April 2012
through May 2012 during eight aerial reconnaissance flights. Conditions that were documented
included the following:
Locations and width of open leads;
Locations and floe size in ice runs;
Locations and general observations of ice jams; and
General observations of condition of remaining ice cover, including overflow, and
evidence of deterioration.
On aerial missions, observers also documented interaction between breakup processes and
geomorphology, fish habitat (especially slough/side channel habitats) and riparian vegetation.
The specific documentation requested by the Riparian study included locations were ice directly
contacted vegetation, locations where ice-induced flooding contacted vegetation, and locations
where ice or ice-induced flooding disturbed soils. Specific direction was not provided by other
studies as to documenting geomorphic or fish habitat effects. Geomorphic observations
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consisted of noting differences among open leads, breakup, and freeze-up processes in different
channel forms, including wide braided, confined with floodplain, and steep confined cascades.
Sloughs and side channels in the Middle River were identified in the 1980s as important salmon
habitat, especially those sloughs given names/numbers. For these sloughs, the following were
documented: late winter open leads, any overflow or flooding during breakup, any ice runs
during breakup, any ice-induced scour during breakup, and any flooding during freeze-up.
Observations were documented using GPS-enabled still cameras and a helicopter-mounted video
camera.
4.5. Meteorological, Snow Depth, and Stream Temperature Data
Compilation (April 2012 - May 2012)
All meteorological and surface water measurements described below for 2011-2012 are included
in Appendix A.
Meteorological data were obtained daily starting April 1 from the National Weather Service
(NWS) station in Talkeetna. A tabulation of freezing degree-days was kept, along with water
temperature data from Willow Creek, Talkeetna River, and Montana Creek, which were the only
real-time water temperature monitoring stations in the Susitna Basin in spring of 2012.
River stage data from the NWS observer at Sunshine Station (Parks Highway Bridge), and the
Gold Creek gage (USGS) were obtained daily, along with any pilot reports or other observations
taken for the Susitna River by the NWS.
SNOTEL data for Tokositna Valley, Bentalit Lodge, Point Mackenzie, and Susitna Valley High
(Talkeetna) were downloaded daily. Snow course data for an additional 28 sites in the Susitna
Basin were downloaded monthly, as updated by the National Resources Conservation Services
(NRCS).
USGS winter gaging records were obtained and included in the documentation.
4.6. Observations and Documentation of Freeze-up Progression
(October 2012 – December 31, 2012)
Freeze-up was documented during twelve reconnaissance flights between the onset of frazil
accumulation in October and December 31, 2012. The following routine observations were
documented with GPS, and GPS-enabled still photographs and video:
Presence of frazil by location (main channel, side channel, slough, tributary) and type
(frazil ice, anchor ice, pans)
Ice bridges, including downstream and upstream extents
Ice cover, including type (hummocky accumulation, overflow ice, shore ice)
Snow cover
In addition to aerial observations, the progression of freeze-up at 13 sites was documented using
the time-lapse cameras described above, although the processing of the freeze-up time-lapse data
is not included in this report. Where pressure transducers are located, the staging elevation
associated with ice-front progression was estimated. On aerial missions, observers also
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documented interaction between freeze-up ice processes and geomorphology, fish habitat
(especially slough/side channel habitats) and riparian vegetation. The specific documentation
requested by the Riparian study included locations where ice directly contacted vegetation,
locations where ice-induced flooding contacted vegetation, and locations where ice or ice-
induced flooding disturbed soils. Of these, only the flooding of sloughs and side channels and
minor ice encroachment into vegetation were actually observed during freeze-up of 2012.
4.7. Deviations from Study Plan
The following deviations from the 2012 study plan were made:
The 2012 study plan included in the existing information review a summary of studies of
northern regions hydroelectric projects. This was not completed in 2012, and instead has
been incorporated into the 2013-2014 Revised Study Plan as part of a more thorough
literature review.
Several of the 14 time-lapse cameras installed during breakup were moved for the 2012
freeze-up period, and additional cameras were installed as a result of consultation with
the instream flow study team (Table 3-1). Thirteen additional telemetered time-lapse
cameras associated with the Open-Water HEC-RAS Flow Routing Model Study (R2 et
al. 2013) were installed prior to the 2012 freeze-up event at pressure transducer locations.
It was found to be impractical to install readable staff gages in view of the time-lapse
cameras as they were placed as high as possible in trees in order to have a wide view of
the river. Staging during breakup was instead estimated using records from pressure
transducers. Two time-lapse cameras were destroyed during summer flooding and bank
erosion and were replaced in October. One camera (Slough 9A) malfunctioned during
the breakup season and did not record images. One camera (Curry Slough)
malfunctioned during freeze-up and did not record images.
USGS field measurement records were obtained, but did not contain information on ice
thickness or frazil ice.
Freeze-up reconnaissance required twelve aerial missions as of December 31, 2012 as
opposed to the six anticipated.
During the freeze-up period, air and water temperature data and meteorological data were
collected by the water quality and instream flow hydrology teams, rather than compiled
from stations further from the river such as were available during breakup.
Ice thickness and elevation measurements were postponed from spring of 2012 because
of ice safety concerns.
5. RESULTS
5.1. Existing Information Review
Eight studies from the 1980s were used to identify historic river miles, location names, river ice
observations, and data collected to place them into a geodatabase (Keklak and Quane, 1984;
LaBelle, 1984; R&M Consultants Inc. 1981, 1982, and 1986; Schoch 1983, 1984, and 1985).
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Freeze-up was observed from 1980-1985 (Table 5.1-1), and breakup from 1981-1985 (Table 5.1-
2). Open leads were mapped in 1983 (Table 5.1-3). Other measurements, such as ice thickness,
frazil concentration, frazil ice porosity, staging, and winter conditions at selected fish habitats
varied between study years (Table 5.1-4). Historical observations were compared to
observations from 2012 where they occurred on the same reach of river, and the comparisons are
discussed in the results for open lead mapping, breakup observations, and freeze-up observations
below. Historical observations of ice processes interactions with riparian vegetation,
geomorphology, and fish habitat varied each year by study plan objectives and actual conditions.
Table 5.1-5 lists specific locations where these interactions were observed.
No systematic attempt was made by ice observers to document effects on riparian vegetation,
although removal and scarring of vegetation during breakup were noted in some study years.
The most systematic discussion is included in the Riparian Vegetation Succession Report (AFES
1985), which divides the river into Middle (Oshetna confluence to Chulitna confluence), and
Lower (below Chulitna confluence). The study authors found that downstream of the Oshetna
confluence, vegetation showed signs of frequent scraping and bending by ice. The riparian
vegetation line in ice jam affected reaches appeared to be determined by the elevation of the ice
jams and subsequent flooding. Ice jams also scarred or removed vegetation from the heads of
islands, toppled trees, and scarred trees in the middle of stands on islands. The wide braided
morphology and weaker breakup drive on the Lower River appeared to reduce the occurrence of
ice-induced overbank flooding, and consequently, effects of ice on vegetation. No ice jam scars
were reported for this reach.
Observations of ice effects on geomorphology of the river channel and floodplain are primarily
bank erosion and scour from the breakup periods and located in the Middle River, between
Talkeetna and Gold Creek (Table 5.1-5). Additional documentation of the interaction between
ice and geomorphology was reported in the 1982-1983 Ice Study Report (Schoch, G.C. 1983):
Scour holes in the Middle River are often indicators of ice jam locations
Ice jams in the Middle River generally occur in shallow channels with a narrow confined
thalweg along one bank.
Ice jams in the Middle River commonly occur adjacent to side channels and sloughs,
which act as bypass channels during extreme ice jam flood events in the main channel.
Ice jam flooding probably formed the majority of sloughs between Curry and Gold
Creek.
The wide, braided morphology and low winter discharges in the Lower River seem to
limit the extent of flooding during freeze-up and jamming during breakup. Open water
floods during summer storms seem to have a greater effect on channel form in the Lower
River than ice processes.
Sediment transport is affected by both freeze-up and breakup processes.
o During freeze-up, frazil ice nucleates around suspended sediment, buoying it up to the
surface in frazil pans. This silt may remain entrained in the ice cover until it melts
out in the spring.
o Anchor ice adheres to bed sediment, and if it gains enough mass will rise to the
surface, bringing gravel with it.
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o During breakup, shore-fast ice can be lifted and shoved laterally, moving sediment up
to boulder sized and creating ridges of floodplain material.
o During breakup, ice jam releases can scour the channel bed and erode many feet of
bank quickly.
Observations of ice effects on fish habitat included documentation of sloughs and side channels
that were overtopped during freeze-up as water levels increased, open water in sloughs and side
channels during winter that may have resulted from ice driving water laterally into the
floodplains, and scouring or flooding of sloughs and side channels during breakup. The
locations of these observations are listed in Table 5.1-5.
5.2. Open Lead Mapping
Open leads were documented throughout the lower 234 miles of the Susitna River in March of
2012, before temperatures rose above freezing. Observers classified the leads as thermal,
velocity, or unknown. Leads classified as thermal in origin were generally shallow, located in
marginal areas (sloughs, side channels, or bank toes), and did not appear from the air to have
strong current. Velocity leads were located in the main channel or substantial side channels and
had visible current. Velocity leads often had broken or jumbled ice along the margins or
accumulated at the downstream end. It is likely that many leads in the main channel exist
because of a combination of thermal input and rapid current. R&M mapped open leads on
March 2, 1983, between RM 85 and RM 151 (Schoch 1983b). R&M recorded river mile at
upstream end, length, width, location (main channel, side channel, or slough) and type (thermal
or velocity). However, the criteria for establishing the origin of the lead as thermal or velocity
were not documented in the study report. Because the majority of the 1983 leads were classified
as velocity leads, including sloughs, it appears that different criteria were used in 1983 than that
applied in 2012.
5.2.1. Lower River Open Leads
Most of the open leads documented in the Lower River (Cook Inlet to the Three Rivers
Confluence) appeared to be thermal leads associated with upwelling through gravel bar
complexes and bank toes. They were small compared with the width of the channel (less than
5%), and were shallow trickles emerging from gravel bars (Figure 5.2-1). Some open leads had
a distinct rust color, suggesting that they drained peat or other tannic material (Figure 5.2-2).
There were approximately the same concentration of open leads in side channels and sloughs as
there were in the main channel. The longest main channel open leads occurred near the town of
Talkeetna, around RM 97.
Observations in 1983 of open leads covered the section of the Lower River upstream of RM 84.
Main channel open leads were generally not comparable as the channel has shifted eastward
since 1983 in this reach. However, the Birch Creek Slough complex at RM 87 was documented
as open in 1983 and in 2012. In both 1983 and 2012, persistent velocity leads were documented
near the town of Talkeetna between RM 96 and 97 (Figure 5.2-3).
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5.2.2. Middle River Open Leads
Open leads were more frequent in the Middle River (Three Rivers Confluence to the proposed
dam site at RM 184) than the Lower River, both in the main channel and in sloughs. Thermal
leads were concentrated around sloughs, including Slough 1 (RM 99), Whiskers
Slough/Whiskers Creek entrance (RM 103), Slough 6A (RM 112), Slough 7 (RM 122), Slough 8
(RM 125) (Figure 5.2-4), Slough 8A (RM 127), Slough 9 (RM 129), Slough 11 (RM 135)
(Figure 5.2-5), Slough 16 (RM 138), Slough 20 (RM 141), and Slough 21 (RM 142). All of
these except for Whiskers Slough and Slough 1 were also documented in 1983, although a
number of them were classified as velocity leads. Downstream of RM 130, the 2012 mainstem
open leads were generally classified as thermal, while the 1983 mainstem open leads were
classified as velocity. Upstream of RM 130, most mainstem open leads were classified as
velocity leads in both studies, corresponding to an increase in river gradient. Numerous velocity
leads were documented in both studies near the Portage Creek confluence and throughout the
Devils Canyon reach (Figure 5.2-6 and 5.2-7), although the exact locations of the leads likely
differ from year to year. The 1983 survey ended at RM 151. In 2012, velocity leads continued
up to the confluence of Devil Creek at RM 163. Upstream of this confluence, the river gradient
decreases, and the open leads were a mix of thermal and velocity-derived. Thermal leads
occurred more often in side channels and along gravel bar complexes, while velocity leads
occurred near bedrock outcrops and sharp bends.
5.2.3. Upper River Open Leads
The Upper River, from the proposed dam site at RM 184 upstream to the Oshetna River
confluence had fewer open leads in general than the Middle and Lower Rivers. Short thermal
leads were documented in side channels and gravel bar complexes, and velocity leads were
documented between Vee Canyon (RM 221) (Figure 5.2-8) and the Oshetna River (RM 234).
Open leads were also documented at tributary mouths, including the mouths of Watana Creek,
Kosina Creek, Jay Creek, and the Oshetna River (Figure 5.2-9).
5.3. Time Lapse Camera Installation and Maintenance
Fourteen time-lapse cameras were installed prior to breakup in April 2012 (Table 4.3-1). The
cameras were installed in trees facing either the mainstem of the river or side channels or side
sloughs of interest. The cameras were installed April 9-11, 2012, and pictures retrieved May 9,
2012 after breakup. The breakup summaries are included in the breakup observations below.
Freeze-up camera installation included the replacement of two cameras (at RM 9.5 and RM 184)
lost to bank erosion, probably during the September 2012 floods. One camera at RM 59 was
moved to face the main channel, and one camera was removed from this location. Additional
cameras were placed at RM 102 on the left bank across from Whisker Slough, and on the right
bank adjacent to Whisker Slough, at Slough 8A, and at Slough 11. Other cameras were
maintained by swapping out batteries and memory cards, and clearing of brush where needed.
5.4. Breakup Observations
Breakup observations included aerial reconnaissance flights, time-lapse camera observations,
and post-breakup ground reconnaissance at time-lapse camera locations. Breakup on the Susitna
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River was slow and uneventful in 2012. Snowpack was 138% of normal in the Susitna Basin on
April 1, 2012 but intermittent above-freezing temperatures in April and cool temperatures in
May caused the snowpack to melt slowly. Because of the slow melt, the river ice weakened and
decayed in place before river discharges increased enough to mechanically break up the ice
cover. When break up did occur, the remaining ice was too weak to form large jams. Ice and
water stayed within the channel except in a few places in the Middle River.
5.4.1 Lower River Observations
Between April 11 and April 19, 2012, open leads on the Lower River gradually widened. Ice
began to break off of the edges of open leads and accumulate against the solid ice cover on April
19 between RM 97 and RM 53. Leads continued to widen until ice runs began on April 25.
Intermittent ice runs continued until May 6, when the Lower River was generally ice free.
The largest ice jam occurred near RM 62 (Figure 5.4-1). Much of the main channel was
jammed, forcing water overbank and into a short side channel on the left bank. This was the
largest instance of overbank flooding seen in the Lower River during the 2012 breakup.
Four time lapse camera installations recorded breakup on the Lower River at Alexander (RM
9.5), Susitna Station (RM 26), Rustic Wilderness Side Channel (RM 59) and Birch Creek Slough
(RM 88).
RM 9.5, Alexander
This camera views the main river looking upstream from the right bank. Overflow was visible in
tracks in the snow from the beginning of the image sequence (April 5, 2012). The overflow went
through daily freeze/thaw cycles until April 19 when a lead opened completely (though
continuing to freeze at night until April 23). The near-shore ice began to break up April 23 at
16:00. Ice in the near-shore channel alternately jammed up/flowed from April 24 until April 30.
At this time ice from the main channel was pushed to the near shore, which is on the outside of a
sweeping bend (Figure 5.4-2). The ice went out completely on April 30, with runs of broken ice
on May 1, 2, and 5.
RM 26, near Susitna Station
Viewed from the left bank looking upstream, this image sequence ran from April 11 to May 9.
The river was completely ice covered on April 11. Water was visible in the snow/ice near the left
bank beginning on April 15. A lead opened in the mid-channel on April 23 and flowed freely on
April 28. Overflow near the left bank opened up to a lead on April 29. The ice broke up
completely on May 1 at approximately 16:00. Broken ice flowed downstream freely by May 5.
Only stranded ice was left to melt when the sequence ended on May 9.
RM 60, near Rustic Wilderness Side Channel
One camera at this site recorded images of two side channels near the right bank. This sequence
includes images from April 5 through May 9. Snow melt was fairly continuous and consistent
from the beginning of the sequence. In the image there are two channels visible, a small gut in
the foreground and a more sizable channel in the background. Overflow on top of the ice was
first visible on the foreground channel on April 24, with overflow increasing during daily
freeze/thaw cycles until a lead opened on April 29. Flow continued (and diminished) until the
channel was dry on May 3, 2012.
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The larger channel in the background was open on April 5, and the channel widened until the
water level began to recede on May 3. The channel was first ice free on April 28 until an ice run
on May 2 left large ice chunks stranded in the channel (Figure 5.4-3). The channel was almost
dry by May 6, 2012.
A second camera at this site recorded images of the main channel. The main channel was
completely ice covered on April 5. Overflow in the snow was first visible in the afternoon of
April 7 and increased until open water was visible beginning April 22. Daily freeze/thaw cycles
closed the lead at night and opened it during the day until on April 25 the lead remained open.
Ice began to break up and flow on April 27 in the evening. The water level dropped on May 2,
stranding ice on the banks. The water level rose and ice began to flow again on May 5. The
channel was ice-free and flowing freely May 6.
RM 88, near Birch Creek
This camera recorded images facing the mouth of a slough and side channel from April 5
through May 9. There was an open lead in the side channel all winter. The lead began to widen
on April 13. The last of the ice went out on April 22. Occasional chunks of ice flowed by on
April 26; otherwise the channel was ice-free after April 22. By April 28 dry ground was
appearing on the bank and by May 9 all that was left was some snow on the bank.
The second camera in this location recorded images of the main channel across two side
channels from the left bank. Open water was visible in a hole in the foreground from the start of
the images on April 9. The channel continued to grow until it opened into a freely flowing
channel on April 12. A second channel opened up and joined the first channel on April 24.
Bank ice receded or broke off and the channel grew continuously until it was ice-free on April
27. Ice chunks could be seen flowing out in the main channel April 25, 2012.
5.4.2 Middle River Observations
Ice began moving and jamming in the Middle River between April 11 and April 19. On April 11,
observers noted that open leads were widening and open water began appearing in Fog Creek
(RM 162) and Portage Creek (RM 148) (Figure 5.4-4). On April 19, numerous small jams were
observed from RM 159 to RM 134 (Figures 5.4-5-6). Upstream of RM 159, the open leads had
widened. Downstream of RM 134, open leads remained narrow but lengthened.
By April 23, snow had melted from the banks and bars, and open sections of river had increased.
Small ice jams within open leads were observed between the mouth of Devils Canyon (RM 150)
and Slough 8 (RM 127) (Figures 5-4.7).
From April 27 to May 4, most of the ice jam activity occurred in the mainstem and side sloughs
in the Middle River between RM 136 and RM 121. Below RM 121, the river opened up
gradually as open leads widened, but few jams were observed. By May 9, the Middle River was
largely ice-free.
The largest jams with the greatest potential to affect vegetation, geomorphology, and fish habitat
were near Sloughs 11, 8 and 9. Near RM 134-136, a large ice jam occupied the main channel
and right bank side channel from April 27 to May 2 (Figure 5.4-8). While the jam held, water
was forced overbank into Slough 11 (Figure 5.4-9). After the jam released, ice was observed
overbank and in the riparian vegetation at RM 135.8 on May 2, 2012 (Figure 5.4-10). Neither
scouring of the banks nor scarring of vegetation was observed following the jam release.
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A large jam was also documented in the mainstem, Slough 9, and Slough 8 from RM 130.2 to
RM 126.4 on May 2 that collapsed by May 4 to span from RM 130.1 to RM 128.2 (Figure 5.4 -
11). Following the release of this jam, ice floes were observed in the trees lining Slough 8A from
RM 127.8 to RM 126.6. The build-up and release of this jam is also documented on the Slough
9 time-lapse camera. Again, post-breakup reconnaissance did not document significant scour or
vegetation scars resulting from this jam release, possibly because the ice was relatively weak.
Six time-lapse camera installations monitored breakup on the Middle River:
RM 99, Slough 1
The image sequence ran from April 6 through May 24. Open water was visible from the
beginning of the sequence in Slough 1 near the camera. A lead opened in the main channel on
April 19. Ice began to break up and move on April 27. During the night of April 27 the water
level rose by several feet, covering gravel bars that had been visible earlier in the day. The water
level began dropping by the afternoon of April 28. The remaining river ice went out early
morning May 1. The water level dropped continuously until May 7 and then rose continuously
until the sequence ended May 24.
RM 103, Talkeetna Station
The camera is on the left bank facing across the main channel and upstream. A small lead on the
left bank is visible from the beginning (April 6). Water was visible on the ice mid-channel on
April 12. A lead in the mid-channel opened and closed daily from April 17 until April 21, when
it opened for good. Ice jammed the center lead on April 25 and the near-shore lead on April 28.
Both jams broke sometime after 22:00 on April 30. A small jam formed on the side channel
upstream of the camera on May 1. The jam broke May 3. The river flowed freely from this
point on, with stranded ice melting by May 18.
RM 120, Curry Slough
This camera views the main channel from the left bank looking upstream across a side channel.
The snow melt is continuous and consistent throughout this sequence. On April 9, an open lead
is visible against the left bank of the side channel. The lead widened and lengthened into a
continuous channel on April 13, 2012. A snow storm on May 1obscured the camera’s view.
Broken ice can be seen flowing on May 6. The channel was open and ice free (except for bank
and bar snow) when the sequence ended May 9.
RM 129, Slough 9
Viewed from the left bank looking downstream, this sequence runs from April 9 through May 9.
Meltwater/overflow in a depression in the ice closest to the camera melted through to running
water on April 17. Ice jammed downstream on April 19, and at 16:00 on April 22 the channel
jammed completely with ice. The jam broke on April 25 at 16:00. A second jam occurred on
April 26 and released on April 28. A snow storm passed through May 1. The largest jam
occurred on May 2 and released on May 3, sending ice floes up onto the banks. Broken ice ran
through on the morning of May 5 and when the sequence ended on May 9 the river was flowing
freely with stranded ice from the jams on the banks.
RM 141, Slough 20
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An open lead is visible from the beginning of this image sequence, April 10. The lead widened
consistently from the beginning with no visible broken ice flowing. As snow melted and receded
from the gravel bar, the surrounding brush sprang up and increasingly obscured the view until
the sequence ended May 9, 2012.
RM 148, Portage Creek
This camera looks upstream across the mouth of Portage Creek. Small leads and depressions in
the snow can be seen from the beginning of the image sequence in both Portage Creek and the
Susitna River (April 11). Water was visible in the snow/ice beginning April 13. A lead in the
Susitna River opened April 14 and went through daily freeze/thaw cycles until April 25, when
Portage Creek opened up. Broken ice runs occurred in the main channel April 26 to April 28.
Ice in the channel was gone April 29. A snow storm moved through on May 1. The channel was
ice-free (excepting bank ice) through May 9.
5.4.3 Upper River Observations
Breakup commenced on the Upper River between April 11 and April 19. On April 19, two small
ice jams were observed near RM 221. By April 27, larger jams had formed at RM 221.5, RM
231, and RM 207 (Figures 5.4-12, 5.4-13, 5.4-14). Ice jam activity had subsided by May 4, and
the Upper River main channel was ice free with stranded ice on the banks and bars by May 9.
Especially large slabs of stranded ice were observed downstream of Vee Canyon at RM 221
(Figure 5.4-15), and at RM 196 (Figure 5.4-16).
Despite the presence of ice jams, both ice and water generally remained below the vegetated
bank throughout the breakup observation period. Exceptions to this were found at RM 184,
where water and ice flows severely undercut an island, uprooting several trees, and an ice slab
bulldozed the elevated point of the island (Figure 5.4-17). There were no other observed ice-
vegetation interactions or recent ice scouring.
One time-lapse camera recorded breakup in the Upper River:
RM 184, Proposed Watana Dam site
In this image sequence (viewed upstream from the right bank), a large puddle of melt water went
through a daily freeze/thaw cycle, first opening to the river on April 16. A lead opened upstream
of the site on April 22. The freeze/thaw cycle near-shore continued until April 23 when a lead
opened completely. On April 30 an ice jam formed in the main channel upstream and a lead
opened from the main channel to the right side. The ice jam upstream broke on May 2 and ice
ran through May 3. The main drive of the jam occurred after dark on May 2, thus the floes that
impacted the island were missed by the camera.
5.4.1. Ice Processes Effects on Other Resources
5.4.1.1. Riparian Vegetation and LWD
The mild breakup in 2012 resulted in less out-of-channel flow than reported for other years, and
consequently little apparent effect on floodplain vegetation and large woody debris. Flooding
(primarily backwater) associated with ice jams reached the vegetation line in the Lower River
near RM 62. In the Middle River, water and ice inundated the vegetated floodplains adjacent to
Sloughs 11, 9, and 8, but no scarring or removal of vegetation was noted following breakup. The
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only damaged vegetation documented were trees at the upstream end of the island near RM 184.
These toppled trees are also the only potential contribution of breakup to large woody debris in
2012.
5.4.1.2. Geomorphology
The only documented geomorphic impact caused by breakup in 2012 was scour to the island at
RM 184.
5.4.1.3. Aquatic Habitat
The presence of open water and increases in stage in side channels and sloughs were the only
documented interactions between ice processes and aquatic habitat. Some Lower River sloughs
and side channels and most sloughs between Talkeetna and Indian River had open water in them
in March prior to snowmelt, indicating upwelling. During breakup, Sloughs 11, 9, and 8 were
flooded by ice jams, although the events were relatively mild and did not appear to scour the
beds. Time-lapse cameras indicated that Slough 1 flooded during breakup with water, but not
ice. Time-lapse cameras on the Lower River documented similar brief rises in water level in side
channels during breakup.
5.5 Meteorological Data
The compiled meteorological data (Appendix A) indicated that several factors likely contributed
to the mild breakup in 2012. The April 1 snowpack was 38% above normal in the Susitna Basin.
April was slightly warmer than normal at Talkeetna, however May was cooler than normal, so
that melting occurred over a long period of time rather than rapidly. The warmer temperatures in
April also likely allowed the ice cover to weaken prior to a rise in flow. Tributary temperatures
at Willow Creek, Montana Creek, and Talkeetna River increased above freezing prior to the
Susitna River because they opened up earlier. River stage data from the Talkeetna River, Denali
gage, Gold Creek gage, and Sunshine gage are considered invalid for estimating discharge
during ice-affected periods, but the graphs indicate when ice-out occurred and when the largest
ice jams occurred at Gold Creek.
5.6 Freeze-up Observations
Freeze-up commenced in the Project Area around October 12, 2012. This was the date upon
which frazil ice was first recorded at the ESS80 camera at RM 223. By October 16, 2012, frazil
ice was flowing past Talkeetna (Figure 5.6-1). Between October 17 and October 22, two long ice
bridges formed in Devils Canyon, with one short bridge in between (Figure 5.6-2). A short ice
bridge also formed just upstream of the proposed dam site at RM 186.5. More detailed timing of
the bridge formation is unknown. None of these bridges were captured on cameras, and they
were far enough removed from pressure transducers that any staging associated with their
formation was not recorded. Frazil concentrations did not appear to drop at ESS70 (RM 184.1)
or ESS55 (RM 148) during this period, which would have indicated the timing of the upper river
ice bridge formation, or Devils Canyon ice bridge formations, respectively. This indicates that
the total volume of frazil removed from the river by these bridges was negligible compared to the
volume generated between the bridges and flowing downstream underneath them.
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On October 23, two bridges formed near the mouth of the river and the ice cover began
progressing upstream via juxtaposition (frazil pans flowed downstream, hit the upstream edge of
the bridge, and froze into place) (Figure 5.6-3). Observers at RM 9.5 noted that ice was still
flowing out to Cook Inlet in the afternoon, but had slowed greatly and ice pans were pushing
against each other. The tide began rising after 17:30, and the bridges likely formed as
accumulating frazil pans flowing into the mouth were halted by the rising tide. Late in the
evening, the pressure transducer at RM 10 (ESS10) recorded a sharp increase in stage of about
2.5 feet, which was likely caused by the advancing ice front (Figure 5.6-4). Soon thereafter, the
pressure transducer at RM 15 followed suit. By the October 26 reconnaissance flight, the ice
cover had progressed up to RM 33, at a rate of nearly 12 miles per day. The rapid progression
was likely aided by contributions of frazil from the Yenta River, which supplied ice to the reach
below RM 27. By October 29, the ice cover had extended to RM 54, a rate of 7 miles per day
(Figure 5.5-5). By November 1, it had reach RM 68, also about 7 miles per day. On November
7, ice cover reached RM 90; the rate had slowed to about 4 miles per day.
The slowing of the ice cover progression between November 1 and November 7 does not appear
to have been caused by either warmer weather or blockage of frazil upstream, but by factors
related to the geometry of the river channel. Talkeetna weather indicates steady temperatures.
Time-lapse photos from ESS30 (Susitna River at Twister Creek, below the Three Rivers
Confluence) show fairly steady frazil concentrations between November 1 and November 7. The
bridges in Devils Canyon did not appear to increase in size, although a few additional short
bridges formed. The slowing of the ice front was most likely due to the increased gradient of the
river, which increases the hydraulic thickening of the ice cover, and thus the volume of ice
necessary to allow the ice cover to progress upstream.
Staging associated with ice cover advance through RM 90 was indicated by progressive flooding
of gravel bars and side channels. Figures 5.6-6 and 5.6-7 show the Parks Highway Bridge area
near RM 84 before and after ice cover advance.
A short summary of freeze-up through November 7 is below:
October 12: Frazil ice appeared in the river between ESS80 (RM 223) and Portage Creek (RM
148). Little frazil ice was seen at Curry Station (RM 121).
October 13: Frazil ice appeared between Curry Station and Twister Creek (RM 128 and RM 96).
October 14: Frazil ice appeared at Susitna Station (RM 26).
October 15: Too much frazil ice near Deshka Landing (RM 44) to operate a jet boat.
October 16 and 17: Frazil ice concentrations of 5-40% were observed at Talkeetna. No bridges
were visible from RM 184 downstream.
October 17: Frazil ice appeared at ESS10 below Flathorn Lake (RM 10).
October 22: One short bridge formed in the Upper River just upstream of the proposed Watana
Dam site (RM 186.5). In the Middle River, a short bridge formed at RM 154.9, and two longer
bridges formed over segments of Devils Canyon rapids. These bridges extended from RM 150.2
- 151, and from RM 159.5 - 161. No bridges were visible in the main channel downstream of
Devils Canyon on October 22. Anchor ice observed upstream of Devils Canyon.
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FERC Project No. 14241 Page 14 March 2013
October 23: Bridging appeared imminent at RM 9 in afternoon. Pressure transducer readings at
RM 10 indicate ice cover progressed past in the late evening. Pressure transducer reading at
Susitna Station indicated ice cover progressed past on October 25.
October 26: Ice bridges were visible in west and east side channels at Big Island near Susitna
mouth. The first ice bridge extended from RM 1 to RM 5, and a second ice bridge extended
from RM 6 upstream. Open water was visible between the two bridges. An ice cover progressed
upstream from the second ice bridge to RM 20. A third ice bridge extended from RM 21.5 past
the Yentna confluence to RM 33. On the Yenta, the ice cover extended about three miles
upstream from the confluence.
Short ice bridges had formed in Devils Canyon at RM 154, 155, and 156, while the two longer
bridges seen on October 22 were unchanged. The same short bridge was seen in the Upper River
at RM 186.5.
October 29: Ice cover extended from the mouth up to RM 54. One additional ice bridge had
formed in the Devils Canyon area.
November 1: Ice cover extended up to RM 68. Nine short ice bridges had formed in Devils
Canyon and upstream. Devils Canyon ice cover was otherwise the same. A short bridge formed
at RM 223.
November 7: Ice cover extended up to RM 90. An ice cover formed in the south channel of
Chulitna River, but two other channels of the Chulitna remained open. Two additional ice
bridges formed just upstream of Portage Creek mouth. The ice bridge at RM 223 had broken.
6. DISCUSSION
The 2012 ice processes observations provide baseline data useful for extending the observations
from the 1980s. In particular, the 2012 year provided the first open lead observations below RM
85 and upstream of RM 161, and the first breakup and freeze-up observations in the Upper River.
6.1. Open Leads
Open leads followed the same general pattern in 2012 as 1983, despite using different criteria for
establishing the origin of the lead. Side channels and sloughs in the Middle River were mapped
as open or partially open during both surveys, while velocity leads were common in the steep
reach upstream of Indian River in both surveys. Lower River open leads were difficult to
compare because the main channel appears to have shifted eastward since 1983. After watching
open leads form and evolve over the 2012 freeze-up season, observers have determined that
many velocity leads slowly grow in over time while thermal leads tend to remain open or even
erode further. Therefore the photos obtained during freeze-up 2012 will also be used to
determine the origin of open leads where differentiation is not clear.
6.2. Breakup
Compared to earlier reports, breakup in 2012 was exceptionally mild, with few large jams and
little observed flooding. It is likely the mildest breakup that has been systematically observed.
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The Lower River was subject to relatively uneventful breakups in the 1980s as well as 2012.
Breakup does not appear to frequently cause extensive damage as it does in the Middle River.
The 1981 breakup study observed an ice jam at the Deshka River (RM 40.5) and Montana Creek
(RM 77) confluences. In 1982, two large ice jams (RM 85.5 and RM 89) released with a high
enough stage to entrain logs stranded from summertime flooding (R&M 1981, R&M 1983).
During the 1985 breakup, jams were observed at RM 78 and RM 86 (R&M 1986).
The Middle River experienced severe ice jams during breakup in the 1980s and earlier, although
the 2012 breakup did little or no damage. Ice floes accumulated in the same general reaches as
those reported previously in the Middle River. The majority of ice-jam observations in the
Middle River during the 1981-1985 breakup studies were within the same 15-mile section of the
river from RM 136 to RM 121 as in the 2012 breakup observations, although ice jams were more
frequent, extensive, and severe in 1981-1985. The following locations were subject to ice jam
activity and flooding in 2012 and in the 1980s:
Slough 11 (RM 134 - 136): Major ice jams and ice-jam flooding were documented near
Slough 11 (RM 136) in 1983 and 1985 (LaBelle 1984; R&M 1985). Previous observers
documented that Slough 11 was in fact created by an extensive ice jam breakout in May
of 1976 (R&M, 1983).
Slough 8 and Slough 9 (RM 126.4-RM 130.2): Historically, RM 129 (Slough 9 area) was
a very active breakup location with many observations of ice jams and side channel and
slough ice-induced flooding (LaBelle 1984, R&M 1983). In 1985, a breakup jam released
from the same location and caused ice to flow through and possibly scour Slough 8A
(R&M 1986).
RM 121-123: In May of 1983 and 1985, a 1-mile long major ice jam was observed at RM
122 (R&M 1983). A smaller jam was documented here in 2012.
Breakup was not systematically documented in the Upper River prior to 2012, with the exception
of the Watana Dam site area, where jams were reported in May of 1983. Large stranded chunks
and damaged vegetation observed in 2012 indicated that more recent jams had inundated the
floodplain.
6.3. Freeze-up
Only the initial freeze-up period is covered in this report. However, 2012 provided an
opportunity to observe freeze-up during relatively high flows (discharges at Gold Creek were
about 15,000 cfs on October 12, compared to a mean of 7,600 cfs, and at Sunshine were about
42,000 cfs on October 12, compared to a mean of 19,600 cfs). The high flows prevented
intermediate bridges and ice cover from forming between tidewater and Devils Canyon, and
likely somewhat delayed the initial ice bridge formation at tidewater, although the timing of ice
bridge formation was similar to previous reports. The following aspects of freeze-up were
consistent with R&M’s observations between 1980 and 1985:
Frazil flow begins in the Upper Susitna in October.
The greatest frazil concentrations are in the Susitna and Yentna Rivers, with minor frazil
contribution from the Chulitna or Talkeetna Rivers to the lower Susitna River.
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Earliest ice bridges are short, thick frazil ice bridges in Devils Canyon, which do not
progress upstream.
Ice cover is initiated by bridging in the lower five miles of the Susitna River.
Ice cover advances rapidly to the Yentna confluence, and gradually slows as it advances
upstream.
Staging associated with ice cover advance in the Lower River is between 1-4 feet.
An ice cover had not yet formed on the Middle River by November 7, 2012. Shore ice was
gradually widening, and frazil ice was thick enough to clog constrictions in the main channel,
giving the appearance of imminent bridging. Similar observations were documented in 1981 and
1982 in the Middle River. The early appearance of anchor ice in shallow riffles upstream of
Devils Canyon is also consistent among study years.
In the Upper River, an ice cover had not yet formed by November 7, 2012. Although ice
observations did not extend to the Upper River in the 1980s, it was speculated that reductions in
frazil concentrations at Gold Creek were associated with an ice cover forming upstream of
Devils Canyon. The formation of the intermittent Devils Canyon ice cover on October 22 did
not have a noticeable effect on frazil concentrations at Portage Creek in a preliminary evaluation
of telemetered camera images. When the time-lapse camera images are available from above
and below Devils Canyon for the freeze-up period, a more detailed evaluation of frazil
concentrations during the Devils Canyon ice bridge formation will be undertaken.
6.4. Ice Processes Effects on Other Resources
As described in Section 5.1, river ice processes locally have had significant effects on riparian
vegetation, geomorphology, and fish habitat, especially in the Middle River between Indian
River and Talkeetna. In 2012, very minor effects to vegetation and geomorphology were
documented because of the mild breakup. The influence of a river ice cover on stage and flow in
lateral habitats was indicated by open water in sloughs and side channels in April of 2012.
Flooding during breakup inundated many sloughs and side channels in the Middle River, but did
not appear to change the channels. The progression of the ice cover during freeze-up in 2012
caused stage to increase several feet in the Lower River, flooding side channels and sloughs.
The high initial discharges may have resulted in a greater total extent of ice cover compared to
previous years. The final processing of 2012 freeze-up data may indicate whether these higher
discharges resulted in more inundation than seen in previous years.
7. REFERENCES
Keklak, T. and T. Quane. 1984. Report No. 5 - Winter Aquatic Investigations (September 1983-
May 1984) Volume 2: Appendix F Winter Temperature Data. Prepared by Alaska
Department of Fish and Game Susitna Hydro Aquatic Studies for Alaska Power
Authority. Anchorage, Alaska.
LaBelle, L.J. 1984. Assessment of the effects of with-project instream temperatures on Susitna
River ice processes in the Devils Canyon to Talkeetna reach. Prepared by Arctic
Environmental Information and Data Center, University of Alaska on behalf of
Harza/Ebasco Joint Venture for Alaska Power Authority. Anchorage, Alaska.
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 17 March 2013
NWS Alaska Pacific River Forecast Center Ice Thickness Database.
http://aprfc.arh.noaa.gov/php/icedb/getice.php. Accessed 4/12/2012.
R&M Consultants, Inc. 1981. Alaska Power Authority Susitna Hydroelectric Project Task 3 -
Hydrology: Ice Observations 1980-1981. Prepared on behalf of Acres American
Incorporated for Alaska Power Authority. Anchorage, Alaska.
R&M Consultants, Inc. 1982. Alaska Power Authority Susitna Hydroelectric Project Task 3 -
Hydrology: Hydraulic and Ice Studies. Prepared on behalf of Acres American
Incorporated for Alaska Power Authority. Anchorage, Alaska.
R&M Consultants, Inc. 1986. Susitna Hydroelectric Project Technical Memorandum: 1985
Susitna River Freeze-Up. Prepared on behalf of Harza/Ebasco Joint Venture for Alaska
Power Authority. Anchorage, Alaska.
R2 Resource Consultants, Inc, GW Scientific, Brailey Hydrologic, and Geovera. 2013. Susitna-
Watana Hydroelectric Project (FERC No. 14241). Open Water HEC-RAS Flow Routing
Model. Prepared for Alaska Energy Authority. Anchorage, Alaska.
Schoch, G.C. 1983a. Susitna River Ice Study 1981-1982. Prepared by R&M Consultants, Inc. on
behalf of Harza/Ebasco Joint Venture for Alaska Power Authority. Anchorage, Alaska.
Schoch, G.C. 1983b. Susitna Hydroelectric Project Susitna River Ice Study 1982-1983. Prepared
by R&M Consultants, Inc. on behalf of Harza/Ebasco Joint Venture for Alaska Power
Authority. Anchorage, Alaska.
Schoch, G.C. 1985. Susitna Hydroelectric Project Susitna River Ice Study 1984-1985. Prepared
by R&M Consultants, Inc. on behalf of Harza/Ebasco Joint Venture for Alaska Power
Authority. Anchorage, Alaska.
USGS Surface Water Data Collection Program. Streamflow data for the Susitna Basin.
http://waterdata.usgs.gov/ak/nwis/dv/?site_no=15291000&agency_cd=USGS&refer
red_momodu=sw. and
http://waterdata.usgs.gov/ak/nwis/dv/?site_no=15291500&agency_cd=USGS&refer
red_momodu=sw. Accessed 4/12/2012.
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8. TABLES
Table 4.3-1. Location of time-lapse cameras installed for Ice Processes Study.
Historic
River
Mile
Location
Bank View Location Name Time Period Recording
9.5 Right Main channel
upstream Alexander
April – May, 2012; October -
December, 2012. Camera replaced in
October 2012 in a different tree.
26 Left Main channel
upstream Susitna Station April – December 2012
60 Island
Camera 1 facing side
channel toward right
bank,
Rustic Wilderness Side
Channel April – October, 2012.
60 Island
Camera 2 facing
main channel
downstream across
a side channel.
Rustic Wilderness Side
Channel
April – December, 2012. Camera
moved to face main channel better in
October, 2012
88 Island
Camera 1 looking
upstream at head of
Birch Creek Slough.
Birch Creek Slough April – October, 2012
88 Island
Camera 2 looking
downstream at main
channel.
Birch Creek Slough April – December, 2012
99 Left Upstream across
Slough 1 Slough 1 April – September, 2012. Camera
moved in October, 2012.
103 Left Upstream across
main channel Talkeetna Station April – December, 2012
120 Left Upstream across
main channel Curry Slough April – December, 2012
126 Left
Upstream across
entrance to Slough
8A toward main
channel.
Slough 8A October – December, 2012
129 Left
Camera 1 looking
downstream at left
bank and slough
mouth
Slough 9 April –October, 2012
129 Left
Camera 2 looking
downstream at right
bank and main
channel
Slough 9 April – October, 2012
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Historic
River
Mile
Location
Bank View Location Name Time Period Recording
135 Left Upstream across
side channel Slough 11 October – December, 2012
141 Left Upstream toward
slough mouth Slough 21 April – December, 2012
148 Right
Upstream towards
the bottom of Devils
Canyon and the
confluence with
Portage Creek
Portage Creek April – December, 2012
184 Right
Main channel
upstream toward
dam site
Watana Dam
April – May, 2012; October -
December, 2012. Camera replaced in
October 2012 in a different tree.
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Table 5.1-1. Freeze up Observations from 1980-1985
River
Mile Location Information Observations Made Date of
Observation
Reference
Document
1.9 Ice bridge 23 Oct 1985
R&M
Consultants, Inc
1986
5 Ice bridge 27 Oct 1984 Schoch 1985
8 Ice bridge 23 Oct 1985
R&M
Consultants, Inc
1986
9 Ice bridge Winter 1982 LaBelle 1984
24
Ice bridges - intermediate (through
RM 26) Winter 1984 Schoch 1985
26 Ice bridge 30 Oct 1984 Schoch 1985
35.2 Hooligan Side
Channel no winter flow from main channel Winter 1984 Schoch 1985
36.2 Eagles Nest Side
Channel Flooded snow during freeze-up Winter 1984 Schoch 1985
36.3 Kroto Slough, head no winter flow from main channel Winter 1984 Schoch 1985
39 Rolly Creek, mouth no winter flow from main channel Winter 1984 Schoch 1985
43 Bear Bait Side
Channel
Ice bridges - intermediate (West
channel through RM 46) Winter 1984 Schoch 1985
43 Bear Bait Side
Channel no winter flow from main channel Winter 1984 Schoch 1985
45.4 Last Chance Side
Channel no winter flow from main channel Winter 1984 Schoch 1985
49
Ice bridges - intermediate (East
channel through RM 52) Winter 1984 Schoch 1985
52 Ice bridge 30 Oct 1984 Schoch 1985
59.5 Rustic Wilderness
Side Channel
overflow into side channel during
freeze-up Winter 1984 Schoch 1985
63 Caswell Creek,
mouth no winter flow from main channel Winter 1984 Schoch 1985
63.2 Island Side Channel Flooded snow during freeze-up Winter 1984 Schoch 1985
74.4 Mainstem West Bank Flooded snow during freeze-up Winter 1984 Schoch 1985
74.8 Goose 2 Side
Channel
overflow into side channel during
freeze-up Winter 1984 Schoch 1985
75.3 Circular Side
Channel no winter flow from main channel Winter 1984 Schoch 1985
79.8 Sauna Side Channel no winter flow from main channel Winter 1984 Schoch 1985
84.5 Sucker Side Channel no winter flow from main channel Winter 1984 Schoch 1985
86.3 Beaver Dam Slough no winter flow from main channel Winter 1984 Schoch 1985
86.9 Sunset Side Channel no winter flow from main channel Winter 1984 Schoch 1985
87 Sunrise Side
Channel no winter flow from main channel Winter 1984 Schoch 1985
88.4 Birch Creek Slough no winter flow from main channel Winter 1984 Schoch 1985
91.6 Trapper Creek Side
Channel no winter flow from main channel Winter 1984 Schoch 1985
92
Ice bridges - intermediate (through
RM 105) Winter 1984 Schoch 1985
ICE PROCESSES STUDY
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FERC Project No. 14241 Page 21 March 2013
River
Mile Location Information Observations Made Date of
Observation
Reference
Document
98.6 Freeze-up ice bridge Winter 1982 LaBelle 1984
98.6 Staging during ice cover formation Winter 1980
R&M
Consultants, Inc
1982
105 Freeze-up ice bridge 03 Nov 1984 Schoch 1985
130.9
open water - intermediate ice bridges
through RM 135 Dec 1984 Schoch 1985
136.9
open water - intermediate ice bridges
through RM 147 Dec 1984 Schoch 1985
149 Portage Creek Freeze-up ice bridge Winter 1982 Schoch 1983a
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Table 5.1-2. Breakup observations from 1981-1985
River
Mile
Location
Information Observations Made Date of
Observation
Reference
Document
25.5 Susitna Station Breakup 01 Apr - 12
May 1983 Schoch 1985
40.5 Deshka River Breakup 01 Apr - 15
May 1983 Schoch 1985
40.5 Deshka River Ice jam at Deshka confluence May 1980
R&M
Consultants, Inc
1981
77 Montana Creek
confluence
Ice jam - flooded Montana Creek
confluence 03 May 1983 Schoch 1983b
85.5 Ice jam - flood released logs stranded
from summertime flooding 04 May 1983 Schoch 1983b
89 Ice jam - flood released logs stranded
from summertime flooding 04 May 1983 Schoch 1983b
95 severe bank erosion from breakup 5/27/1982
R&M
Consultants, Inc
1983
97 10-15 feet of bank erosion on left bank
from breakup 5/27/1982
R&M
Consultants, Inc
1983
98 2-3 feet bank erosion from breakup 5/27/1982
R&M
Consultants, Inc
1983
99 large stranded jam, ice blocks 20-30 ft
long 5/27/1982
R&M
Consultants, Inc
1983
100 large stranded jam, ice blocks 20-30 ft
long 5/27/1982
R&M
Consultants, Inc
1983
101.5 Ice jam May 1983 Schoch 1983b
102 4-5 feet bank erosion from breakup 5/27/1982 Schoch 1983a
103.3 Historical flood damage during breakup
R&M
Consultants, Inc
1981
103.5 ice jam 5/10/1982
R&M
Consultants, Inc
1983
106 ice jam 5/10/1982
R&M
Consultants, Inc
1983
107 3-day ice jam over one mile in length Winter 1981 Schoch 1983a
107 ice jam with 10-15 of water level rise 5/12/1982
R&M
Consultants, Inc
1983
109 ice jam and railroad damage 5/12/1982
R&M
Consultants, Inc
1983
110 erosion and vegetation damage from
ice in mid-river islands 5/27/1982
R&M
Consultants, Inc
1983
ICE PROCESSES STUDY
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FERC Project No. 14241 Page 23 March 2013
River
Mile
Location
Information Observations Made Date of
Observation
Reference
Document
110.4 Historical flood damage during breakup
R&M
Consultants, Inc
1981
110.4 Significant ice scouring (through RM
113) May 1976
R&M
Consultants, Inc
1981
112.5 Slough 6A Major ice jam during breakup 07 May 1983 Schoch 1983b
113 Breakup ice jam Spring 1985 Schoch 1985
113 Major ice jam during breakup 06 May 1983 Schoch 1983b
113.2 Breakup ice jam 04 May 1983 LaBelle 1984
113.5 Grounded ice jam Spring 1983 Schoch 1983b
115 ice jam 5/10/1982
R&M
Consultants, Inc
1983
116 ice jam 5/10/1982
R&M
Consultants, Inc
1983
117 ice jam 5/10/1982
R&M
Consultants, Inc
1983
117 ice jam and railroad damage 5/12/1982
R&M
Consultants, Inc
1983
117.2 Historical flood damage during breakup
R&M
Consultants, Inc
1981
118 ice jam and railroad damage 5/12/1982
R&M
Consultants, Inc
1983
118.4 Ice jam (through RM 123) May 1976
R&M
Consultants, Inc
1981
118.8 Historical flood damage during breakup
R&M
Consultants, Inc
1981
118.9 Breakup ice jam Spring 1985 Schoch 1985
119.4 Breakup ice jam (through RM 120.5) Spring 1983 LaBelle 1984
119.5 Breakup ice jam 04 May 1983 Schoch 1983b
120 Extensive channel enlargements and
small ice jams 27 Apr 1983 Schoch 1983b
120.5 Breakup ice jam 04 May 1983 Schoch 1983b
120.5 Breakup ice jam Spring 1985 Schoch 1985
120.5 Major ice jam during breakup 06 May 1983 Schoch 1983b
120.9 Deadhorse Creek mile-long ice jam 5/17/1982
R&M
Consultants, Inc
1983
121.9 Breakup ice jam Spring 1985 Schoch 1985
122 Breakup ice jam 04 May 1983 Schoch 1983b
ICE PROCESSES STUDY
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FERC Project No. 14241 Page 24 March 2013
River
Mile
Location
Information Observations Made Date of
Observation
Reference
Document
122 Major ice jam during breakup 06 May 1983 Schoch 1983b
122 Major ice jam during breakup (1 mile
long) 07 May 1983 Schoch 1983b
122.5 ice jam and railroad damage 5/15/1982
R&M
Consultants, Inc
1983
123 Slough 7 sloughs regularly flooded during
breakup Spring 1983 LaBelle 1984
124.5 Major ice jam during breakup 06 May 1983 Schoch 1983b
125 severe ice jam redirecting flow into
Slough 8 5/15/1982
R&M
Consultants, Inc
1983
126 Breakup ice jam 06 May 1983 Schoch 1983b
126.4 Breakup ice jam 23 May 1985 Schoch 1985
127 Slough 8, 8A slough regularly flooded during breakup Spring 1983 LaBelle 1984
127.5 Historical flood damage during breakup
R&M
Consultants, Inc
1981
128 Breakup dry jam - diverted flows to side
channel Winter 1982 Schoch 1983b
128 Slough 9 scour and deposition from breakup
floods in Slough 9 5/27/1982
R&M
Consultants, Inc
1983
128.9 Breakup ice jam Spring 1983 LaBelle 1984
129 Breakup ice jam 04 May 1983 Schoch 1983b
129 ice jam 5/10/1982
R&M
Consultants, Inc
1983
129 Major ice jam during breakup 06 May 1983 Schoch 1983b
129 severe ice jam redirected flow into
Slough 9, breaching slough berm 5/15/1982
R&M
Consultants, Inc
1983
129 Slough 9 sloughs regularly flooded during
breakup Spring 1983 LaBelle 1984
129.4 Slough 9 Side channel regularly flooded during
breakup Spring 1983 LaBelle 1984
130 ice jam 5/10/1982
R&M
Consultants, Inc
1983
131 Sherman -
Slough 9 Breakup ice jam Spring 1985 Schoch 1985
131 Sherman -
Slough 9
Extensive channel enlargements and
small ice jams 27 Apr 1983 Schoch 1983b
131.3 Breakup ice jam Spring 1983 LaBelle 1984
131.4 Breakup ice jam 04 May 1983 Schoch 1983b
131.4 Side channel regularly flooded during
breakup Spring 1983 LaBelle 1984
131.5 Sherman Creek Major ice jam during breakup 06 May 1983 Schoch 1983b
ICE PROCESSES STUDY
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FERC Project No. 14241 Page 25 March 2013
River
Mile
Location
Information Observations Made Date of
Observation
Reference
Document
131.5 Sherman Creek Major ice jam during breakup (3.5 miles
long) 07 May 1983 Schoch 1983b
134.4
Side channel
upstream of
Slough 10
Breakup ice jam Spring 1983 LaBelle 1984
134.5 Breakup ice jam 04 May 1983 Schoch 1983b
134.5 Side channel regularly flooded during
breakup Spring 1983 LaBelle 1984
134.9 Breakup ice jam Spring 1985 Schoch 1985
135.9 Slough 11 Extensive channel enlargements and
small ice jams 27 Apr 1983 Schoch 1983b
135.9 Slough 11 Extreme ice jam created Slough 11 May 1976 Schoch 1983b
136 Slough 11 ice jam flood breached Slough 11 5/12/1982
R&M
Consultants, Inc
1983
136.5 Slough 11 Breakup observations 11 Apr - 11
May 1983 Schoch 1983b
139 Breakup ice jam Spring 1985 Schoch 1985
140.9 Side channel regularly flooded during
breakup Spring 1983 LaBelle 1984
141.7 Breakup ice jam Spring 1983 LaBelle 1984
141.8 Breakup ice jam 04 May 1983 Schoch 1983b
141.8 Ice jam Spring 1983 Schoch 1983b
142 Extensive channel enlargements and
small ice jams 27 Apr 1983 Schoch 1983b
142 Extensive channel enlargements and
small ice jams 27 Apr 1983 Schoch 1983b
143.9 Breakup ice jam Spring 1985 Schoch 1985
144.4 Slough 22 Slough regularly flooded during breakup Spring 1983 LaBelle 1984
144.9 Slough 22 Breakup ice jam Spring 1985 Schoch 1985
145.5 Extensive channel enlargements and
small ice jams 27 Apr 1983 Schoch 1983b
147.9 Mouth of
Portage Creek Breakup ice jam Spring 1985 Schoch 1985
148.8 Extensive channel enlargements and
small ice jams 27 Apr 1983 Schoch 1985
153 ice jam 5/12/1982
R&M
Consultants, Inc
1983
184 Major ice jam during breakup 06 May 1983 Schoch 1985
184 Major ice jam during breakup 07 May 1983 Schoch 1985
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Table 5.1-3. Open leads mapped March 2, 1983 (Schoch, G.C. 1983)
River
Mile
Channel Location Origin of
Lead
Length Widest
Point
Continuous or
Discontinuous
85.0 Mainstem Velocity 550 80 Continuous
87.1 Slough Velocity 4,500 50 Discontinuous
87.6 Mainstem Velocity 700 100 Continuous
89.0 Mainstem Velocity 1,200 100 Continuous
89.3 Side Channel Velocity 2,500 40 Continuous
89.5 Mainstem Velocity 1,400 60 Discontinuous
91.0 Mainstem Velocity 1,700 80 Discontinuous
92.3 Mainstem Velocity 1,300 110 Discontinuous
93.7 Mainstem Velocity 3.5 110 Continuous
94.0 Mainstem Thermal 3,500 20 Discontinuous
95.2 Side Channel Velocity 2,400 100 Continuous
96.9 Side Channel Velocity 5,600 150 Discontinuous
97.0 Mainstem Velocity 1,100 30 Continuous
102.0 Mainstem Velocity 2,400 100 Discontinuous
102.9 Mainstem Velocity 600 100 Continuous
103.5 Mainstem Velocity 1,850 100 Discontinuous
104.1 Mainstem Velocity 280 70 Continuous
104.5 Mainstem Velocity 1,700 110 Continuous
104.9 Mainstem Velocity 900 150 Continuous
105.9 Mainstem Velocity 1,050 100 Continuous
106.1 Mainstem Velocity 200 60 Continuous
106.4 Mainstem Velocity 370 50 Continuous
106.6 Mainstem Velocity 350 50 Discontinuous
107.4 Mainstem Velocity 200 50 Continuous
109.1 Mainstem Velocity 550 100 Discontinuous
110.3 Mainstem Velocity 150 100 Discontinuous
110.4 Mainstem Velocity 290 50 Continuous
110.9 Mainstem Velocity 450 50 Discontinuous
111.5 Mainstem Velocity 1,600 100 Continuous
111.7 Mainstem Velocity 500 90 Continuous
111.9 Mainstem Velocity 900 150 Continuous
112.5 Mainstem Velocity 700 100 Discontinuous
112.9 Mainstem Velocity 500 110 Continuous
113.8 Mainstem Velocity 600 110 Continuous
117.4 Mainstem Thermal 780 60 Continuous
117.9 Side Channel Thermal 1,260 120 Discontinuous
119.6 Side Channel Thermal 550 50 Continuous
119.7 Mainstem Velocity 350 50 Continuous
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 27 March 2013
River
Mile
Channel Location Origin of
Lead
Length Widest
Point
Continuous or
Discontinuous
120.3 Mainstem Velocity 800 100 Continuous
121.1 Mainstem Velocity 550 100 Continuous
121.8 Side Channel Thermal 1,450 30 Discontinuous
122.4 Slough (7) Thermal 1,850 60 Discontinuous
122.5 Slough (7) Thermal 380 50 Continuous
122.9 Slough (7) Thermal 1,950 80 Discontinuous
123.1 Mainstem Velocity 1,000 80 Continuous
123.9 Side Channel Thermal 200 50 Continuous
124.4 Side Channel Velocity 270 40 Continuous
124.9 Mainstem Thermal 600 90 Continuous
125.3 Slough (8) Thermal 3,500 50 Discontinuous
125.5 Mainstem Velocity 2,140 100 Continuous
125.5 Slough (8) Thermal 800 500 Continuous
125.6 Mainstem Velocity 350 60 Continuous
125.9 Slough (8) Thermal 580 50 Continuous
126.1 Slough (8) Thermal 500 30 Continuous
126.3 Slough (8) Thermal 250 50 Continuous
126.8 Slough (8) Thermal 1,500 80 Discontinuous
127.2 Side Channel Thermal 2,450 50 Continuous
127.5 Mainstem Velocity 700 80 Continuous
128.5 Side Channel Thermal 1,210 30 Discontinuous
128.8 Side Channel Thermal 380 20 Continuous
128.9 Slough (9) Thermal 5,060 100 Continuous
129.2 Slough Thermal 4,000 30 Discontinuous
130.0 Mainstem Velocity 600 90 Continuous
130.7 Mainstem Velocity 150 50 Continuous
130.8 Side Channel Thermal 5,000 50 Discontinuous
131.1 Mainstem Velocity 490 90 Continuous
131.3 Mainstem Velocity 800 100 Continuous
131.4 Side Channel Thermal 900 90 Discontinuous
131.5 Side Channel Thermal 5,000 80 Discontinuous
132.0 Mainstem Velocity 150 20 Continuous
132.1 Mainstem Velocity 500 20 Discontinuous
132.3 Mainstem Velocity 400 80 Continuous
132.6 Mainstem Velocity 1,350 80 Continuous
133.1 Slough Thermal 6,000 60 Continuous
133.7 Mainstem Velocity 1,110 100 Continuous
134.0 Side Channel Thermal 1,200 50 Continuous
134.3 Slough (10) Thermal 4,500 40 Continuous
ICE PROCESSES STUDY
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FERC Project No. 14241 Page 28 March 2013
River
Mile
Channel Location Origin of
Lead
Length Widest
Point
Continuous or
Discontinuous
134.5 Side Channel Thermal 850 100 Continuous
135.2 Mainstem Velocity 1,580 90 Discontinuous
135.4 Slough (11) Thermal 5,500 80 Continuous
136.0 Mainstem Velocity 230 80 Continuous
136.3 Side Channel Thermal 2,050 40 Continuous
136.7 Mainstem Thermal 1,620 80 Continuous
137.1 Mainstem Velocity 750 60 Continuous
137.4 Side Channel Thermal 2,500 20 Discontinuous
137.8 Slough (16) Thermal 1,400 30 Discontinuous
138.2 Mainstem Velocity 2,000 150 Continuous
138.9 Mainstem Thermal 2,100 150 Continuous
139.0 Mainstem Velocity 780 20 Continuous
139.1 Mainstem Velocity 500 30 Continuous
139.4 Mainstem Velocity 600 30 Continuous
140.6 Side Channel Thermal 1,900 100 Discontinuous
141.0 Slough (20) Thermal 1,100 20 Continuous
141.5 Mainstem Velocity 850 40 Continuous
142.0 Mainstem Velocity 950 50 Continuous
142.0 Slough (21) Thermal 3,850 40 Discontinuous
142.6 Mainstem Velocity 1,600 150 Discontinuous
142.8 Mainstem Velocity 850 150 Continuous
143.6 Mainstem Velocity 550 20 Discontinuous
143.7 Mainstem Velocity 280 20 Continuous
143.8 Mainstem Velocity 780 100 Continuous
143.9 Mainstem Velocity 500 30 Continuous
144.5 Mainstem Velocity 900 100 Discontinuous
144.6 Slough (22) Thermal 250 20 Continuous
144.7 Slough (22) Thermal 300 20 Continuous
145.5 Mainstem Velocity 1,150 100 Continuous
146.9 Mainstem Velocity 700 100 Continuous
147.1 Mainstem Velocity 850 80 Discontinuous
147.7 Mainstem Velocity 150 40 Continuous
148.1 Mainstem Velocity 420 50 Oiscontinuous
148.5 Mainstem Velocity 680 140 Continuous
149.0 Mainstem Velocity 400 60 Continuous
149.5 Mainstem Velocity 500 80 Continuous
150.0 Mainstem Velocity 350 20 Discontinuous
150.2 Mainstem Velocity 750 100 Continuous
151.2 Mainstem Velocity 2,800 100 Discontinuous
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
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Table 5.1-4. Measurements taken on the Susitna River relevant to ice processes prior to 1986.
River
Mile Location Information Data Collected Date of Measurement Reference Document
9 Frazil ice porosity 19 Oct 1984 Schoch 1985
9 Frazil ice porosity 26 Oct 1984 Schoch 1985
10 Alexander Ice thickness Jan, Mar, May
1972
NWS Alaska-Pacific River
Forecast Center
10 Alexander Ice thickness Jan-Apr , Dec
1971
NWS Alaska-Pacific River
Forecast Center
10 Alexander Ice thickness Oct-Nov 1970 NWS Alaska-Pacific River
Forecast Center
10 Alexander Snow depth Jan, Mar, May
1972
NWS Alaska-Pacific River
Forecast Center
10 Alexander Snow depth Jan-Apr , Dec
1971
NWS Alaska-Pacific River
Forecast Center
10 Alexander Snow depth Oct-Nov 1970 NWS Alaska-Pacific River
Forecast Center
28 Yentna River Frazil ice porosity 19 Oct 1984 Schoch 1985
28 Yentna River Frazil ice porosity 26 Oct 1984 Schoch 1985
29.5 Water
temperature Sep - Oct 1982 Schoch 1983a
40 Freeze-up water
level 11 Oct 1985 Schoch 1985
40 Freeze-up water
level 29 Oct 1985 Schoch 1985
40 Ice thickness Feb 1985 Schoch 1985
40 River cross-
section Sep 1984 Schoch 1985
40 Stage and
discharge Oct 1984 Schoch 1985
40 Stage and
discharge Sep 1984 Schoch 1985
40 Water
temperature Oct 1984 Schoch 1985
40 Water
temperature Sep 1984 Schoch 1985
47.8 Freeze-up water
level 11 Oct 1985 R&M Consultants, Inc 1986
47.8 Freeze-up water
level 29 Oct 1985 R&M Consultants, Inc 1986
47.8 River cross-
section Sep 1984 Schoch 1985
47.9 Both East and West Air temperature Oct -Dec 1984 Schoch 1985
47.9 Both East and West Air temperature Oct -Dec 1985 Schoch 1985
47.9 Both East and West Freezing degree
days Oct -Dec 1984 Schoch 1985
47.9 Both East and West Freezing degree
days Oct -Dec 1985 Schoch 1985
47.9 Both East and West Stage and
discharge Sep - Nov 1984 Schoch 1985
47.9 Both East and West Water
temperature Sep - Nov 1984 Schoch 1985
ICE PROCESSES STUDY
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River
Mile Location Information Data Collected Date of Measurement Reference Document
48 Delta Islands Ice thickness Feb 1985 Schoch 1985
59.7 Rustic Wilderness
Side Channel
Freeze-up water
level 29 Oct 1985 R&M Consultants, Inc 1986
59.7 Rustic Wilderness
Side Channel
Freeze-up water
level 11 Oct 1985 R&M Consultants, Inc 1986
59.7 Rustic Wilderness
Side Channel
River cross-
section Sep 1984 Schoch 1985
59.7 Rustic Wilderness
Side Channel
Stage and
discharge Sep - Nov 1984 Schoch 1985
59.7 Rustic Wilderness
Side Channel
Water
temperature Sep - Nov 1984 Schoch 1985
60 Ice thickness Feb 1985 Schoch 1985
60 Frazil ice porosity 03 Nov 1984 Schoch 1985
76.8 Freeze-up water
level 11 Oct 1985 R&M Consultants, Inc 1986
76.8 Freeze-up water
level 29 Oct 1985 R&M Consultants, Inc 1986
76.8 River cross-
section Sep 1984 Schoch 1985
76.8 Stage and
discharge Sep - Nov 1984 Schoch 1985
76.8 Water
temperature Sep - Nov 1984 Schoch 1985
77 Ice thickness Feb 1985 Schoch 1985
78 Frazil ice porosity 03 Nov 1984 Schoch 1985
83.9 Water
temperature Sep - Oct 1982 Schoch 1983a
84 Freeze-up water
level 06 Nov 1985 R&M Consultants, Inc 1986
84 Freeze-up water
level 11 Oct 1985 R&M Consultants, Inc 1986
84 Freeze-up water
level 21 Nov 1985 R&M Consultants, Inc 1986
84 Freeze-up water
level 29 Oct 1985 R&M Consultants, Inc 1986
84.6 River cross-
section Sep 1984 Schoch 1985
84.6 Stage and
discharge Jun-Oct 1984 Schoch 1985
84.6 Water
temperature Jun-Oct 1984 Schoch 1985
86.3 River cross-
section Sep 1984 Schoch 1985
86.3 Stage and
discharge Jun-Nov 1984 Schoch 1985
86.3 Water
temperature Jun-Nov 1984 Schoch 1985
87.8 River cross-
section Sep 1984 Schoch 1985
87.8 Stage and
discharge Jun-Oct 1984 Schoch 1985
ICE PROCESSES STUDY
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River
Mile Location Information Data Collected Date of Measurement Reference Document
87.8 Water
temperature Jun-Oct 1984 Schoch 1985
90 River cross-
section Sep 1984 Schoch 1985
90 Stage and
discharge
Jun, Aug-Nov
1984 Schoch 1985
90 Water
temperature
Jun, Aug-Nov
1984 Schoch 1985
91.6 Ice thickness 1967-1971 LaBelle 1984
91.7 River cross-
section Sep 1984 Schoch 1985
91.7 Stage and
discharge Jun-Nov 1984 Schoch 1985
91.7 Water
temperature Jun-Nov 1984 Schoch 1985
93.1 Freeze-up water
level 06 Nov 1985 R&M Consultants, Inc 1986
93.1 Freeze-up water
level 11 Oct 1985 R&M Consultants, Inc 1986
93.1 Freeze-up water
level 29 Oct 1985 R&M Consultants, Inc 1986
93.3 Both East and West River cross-
section Sep 1984 Schoch 1985
93.3 Both East and West Stage and
discharge Jun-Nov 1984 Schoch 1985
93.3 Both East and West Water
temperature Jun-Nov 1984 Schoch 1985
95.9 River cross-
section Sep 1984 Schoch 1985
95.9 Stage and
discharge Sep-Oct 1984 Schoch 1985
95.9 Water
temperature Sep-Oct 1984 Schoch 1985
97 Air temperature Oct - Dec 1984 Schoch 1985
97 Air temperature Sep - Oct, Dec
1985 Schoch 1985
97 Freezing degree
days Oct - Dec 1984 Schoch 1985
97 Freezing degree
days
Sep - Oct, Dec
1985 Schoch 1985
97 Freezing degree
days
Sep-May 1980-
1983 Schoch 1985
97 Ice thickness 1961-1966 LaBelle 1984
97 Frazil ice porosity 19 Oct 1984 Schoch 1985
97 Frazil ice porosity 26 Oct 1984 Schoch 1985
97.1 River cross-
section Sep 1984 Schoch 1985
97.1 Stage and
discharge Sep-Oct 1984 Schoch 1985
97.1 Water
temperature Sep-Oct 1984 Schoch 1985
ICE PROCESSES STUDY
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River
Mile Location Information Data Collected Date of Measurement Reference Document
98 River cross-
section Sep 1984 Schoch 1985
98 Stage and
discharge Sep-Oct 1984 Schoch 1985
98 Water
temperature Sep-Oct 1984 Schoch 1985
98.5 Ice thickness 04 Feb 1983 Schoch 1983b
98.5 Ice thickness 12 Apr 1983 Schoch 1983b
98.5 Freeze-up water
level Winter 1982 Schoch 1983
98.5 Frazil ice porosity 03 Nov 1984 Schoch 1985
98.5 Frazil ice porosity 19 Oct 1984 Schoch 1985
98.5 Frazil ice porosity 26 Oct 1984 Schoch 1985
98.6 Breakup ice
thickness 28 Apr 1983 Schoch 1983b
98.6 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
98.6 Freeze-up water
level Winter 1982 LaBelle 1984
98.6 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
99.6 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
99.6 Rating curves Winter 1981 R&M Consultants, Inc 1982
99.6 Crest gage Winter 1980 R&M Consultants, Inc 1982
99.6 Crest gage Winter 1981 R&M Consultants, Inc 1982
99.6 Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
100.4 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
100.4 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
101 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
101 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
101.5 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
102.4 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
102.4 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
103 Surface water
temperature Sep - Oct 1982 Schoch 1983a
103.2 Talkeetna Fish Camp Intragravel water
temperature Winter 1983 Keklak and Quane 1984
103.2 Talkeetna Fish Camp Surface water
temperature Winter 1983 Keklak and Quane 1984
103.3 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
ICE PROCESSES STUDY
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River
Mile Location Information Data Collected Date of Measurement Reference Document
103.3 Breakup ice
thickness 28-30 Apr 1983 Schoch 1983b
103.3 Ice thickness 05 Mar 1981 R&M Consultants, Inc 1981
103.3 Ice thickness Winter 1982 LaBelle 1984
103.3 Rating curves Winter 1981 R&M Consultants, Inc 1982
103.3 Freeze-up water
level 1980, 1982, 1983 R&M Consultants, Inc 1986
103.3 Crest gage Winter 1980 R&M Consultants, Inc 1982
103.3 Crest gage Winter 1981 R&M Consultants, Inc 1982
103.3 Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
104.8 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
104.8 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
104.8 Freeze-up water
level 07 Oct 1980 R&M Consultants, Inc 1981
106.2 Freeze-up water
level Winter 1982 Schoch 1983a
106.2 Freeze-up water
level Winter 1982 LaBelle 1984
106.2 Freeze-up water
level Winter 1983 LaBelle 1984
106.7 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
106.7 Breakup ice
thickness 28-30 Apr 1983 R&M Consultants, Inc 1982
106.7 Breakup water
level 28-30 Apr 1983 R&M Consultants, Inc 1982
106.7 Freeze-up water
level 02 Dec 1980 R&M Consultants, Inc 1981
106.7 Freeze-up water
level 07 Oct 1980 R&M Consultants, Inc 1981
108 Ice thickness Winter 1980 LaBelle 1984
108.4 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
108.4 Freeze-up water
level 02-03 Dec 1980 R&M Consultants, Inc 1981
108.4 Freeze-up water
level 07 Oct 1980 R&M Consultants, Inc 1981
110.4 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
110.4 Freeze-up water
level 02-03 Dec 1980 R&M Consultants, Inc 1981
110.4 Freeze-up water
level 07 Oct 1980 R&M Consultants, Inc 1981
110.9 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
111.8 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
ICE PROCESSES STUDY
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River
Mile Location Information Data Collected Date of Measurement Reference Document
112.3 Bed material
distribution Winter 1981 LaBelle 1984
112.3 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
112.3 Freeze-up water
level 03 Dec 1980 R&M Consultants, Inc 1981
112.3 Freeze-up water
level 07 Oct 1980 R&M Consultants, Inc 1981
112.7 Freeze-up water
level 03 Dec 1980 R&M Consultants, Inc 1982
112.7 Freeze-up water
level 07 Oct 1980 R&M Consultants, Inc 1981
113 Freeze-up water
level 06 Nov 1985 R&M Consultants, Inc 1986
113 Freeze-up water
level 21 Nov 1985 R&M Consultants, Inc 1986
113 Ice thickness Winter 1983 LaBelle 1984
113 Freeze-up water
level Winter 1980 LaBelle 1984
113 Freeze-up water
level Winter 1983 LaBelle 1984
113 Freeze-up water
level 03 Dec 1980 R&M Consultants, Inc 1981
113 Freeze-up water
level 07 Oct 1980 R&M Consultants, Inc 1981
113.2 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
113.2 Freeze-up water
level 03 Dec 1980 R&M Consultants, Inc 1981
113.2 Freeze-up water
level 07 Oct 1980 R&M Consultants, Inc 1982
113.7 Breakup ice
thickness
28 Apr - 02 May
1983 Schoch 1983b
113.7 Freeze-up water
level 06 Nov 1985 R&M Consultants, Inc 1986
113.7 Freeze-up water
level 21 Nov 1985 R&M Consultants, Inc 1986
113.7 Freeze-up water
level Winter 1982 Schoch 1983b
113.7 Freeze-up water
level Winter 1982 LaBelle 1984
116.4 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
116.4 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
116.7 Freeze-up water
level Winter 1982 Schoch 1983b
117.2 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
119.3 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
ICE PROCESSES STUDY
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River
Mile Location Information Data Collected Date of Measurement Reference Document
119.4 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
120.3 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
120.4 Breakup ice
thickness
28 Apr - 01 May
1983 Schoch 1983b
120.4 Breakup water
level
28 Apr - 01 May
1983 Schoch 1983b
120.4 Freeze-up water
level Winter 1982 LaBelle 1984
120.4 Freeze-up water
level Winter 1983 LaBelle 1984
120.5 Ice thickness Winter 1980 LaBelle 1984
120.5 Ice thickness Winter 1981 LaBelle 1984
120.5 Ice thickness Winter 1982 LaBelle 1984
120.5 Ice thickness Winter 1983 LaBelle 1984
120.7 Ice thickness 04 Feb 1983 Schoch 1983b
120.7 Ice thickness 12 Apr 1983 Schoch 1983b
120.7 Rating curves Winter 1981 R&M Consultants, Inc 1982
120.7 Freeze-up water
level Winter 1982 Schoch 1983a
120.7 Surface water
temperature Sep - Oct 1982 Schoch 1983a
120.7 Crest gage Winter 1980 R&M Consultants, Inc 1982
120.7 Crest gage Winter 1981 R&M Consultants, Inc 1982
120.7 Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
120.9 Frazil ice porosity 14 Nov 1984 Schoch 1985
120.9 Surface water
temperature Winter 1983 Schoch 1983b
120.9 Water quality data Winter 1983 Keklak and Quane 1984
122.6 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
123.2 Freeze-up water
level Winter 1980 LaBelle 1984
123.2 Freeze-up water
level Winter 1983 LaBelle 1984
123.3 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
123.3 Freeze-up water
level 05 Dec 1985 R&M Consultants, Inc 1986
123.3 Ice thickness Winter 1983 LaBelle 1984
123.3 Freeze-up water
level 06 Nov 1980 R&M Consultants, Inc 1981
123.3 Freeze-up water
level 07 Nov 1980 R&M Consultants, Inc 1981
123.3 Freeze-up water
level 08 Dec 1980 R&M Consultants, Inc 1981
ICE PROCESSES STUDY
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River
Mile Location Information Data Collected Date of Measurement Reference Document
124.4 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
124.4 Breakup ice
thickness 28-30 Apr 1983 Schoch 1983b
124.4 Breakup ice
thickness Winter 1981 R&M Consultants, Inc 1982
124.4 Freeze-up water
level 06 - 07 Nov 1980 R&M Consultants, Inc 1981
124.4 Crest gage Winter 1980 R&M Consultants, Inc 1982
124.4 Crest gage Winter 1981 R&M Consultants, Inc 1982
124.4 Freeze-up water
level Winter 1980 LaBelle 1984
124.4 Freeze-up water
level Winter 1982 LaBelle 1984
124.4 Freeze-up water
level 06 Nov 1980 R&M Consultants, Inc 1981
124.4 Freeze-up water
level 07 Nov 1980 R&M Consultants, Inc 1981
124.4 Freeze-up water
level 08 Dec 1980 R&M Consultants, Inc 1981
124.4 Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
124.5 Frazil ice porosity 14 Nov 1984 Schoch 1985
125.5 Freeze-up water
level Winter 1982 Schoch 1983a
125.6 Intragravel water
temperature Winter 1983 Keklak. and Quane 1984
125.6 Surface water
temperature Winter 1983 Keklak and Quane 1984
126 Freeze-up water
level Winter 1980 LaBelle 1984
126 Freeze-up water
level Winter 1983 LaBelle 1984
126.1 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
126.1 Freeze-up water
level 06 Nov 1985 R&M Consultants, Inc 1986
126.1 Freeze-up water
level 21 Nov 1985 Schoch 1985
126.1 Ice thickness Winter 1983 LaBelle 1984
126.1 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
126.1 Surface water
temperature Winter 1983 Keklak and Quane 1984
126.1 Surface water
temperature Sep-Oct 1982 Schoch 1983b
126.1 Freeze-up water
level 06 Nov 1980 R&M Consultants, Inc 1981
126.1 Freeze-up water
level 07 Nov 1980 R&M Consultants, Inc 1981
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River
Mile Location Information Data Collected Date of Measurement Reference Document
126.1 Freeze-up water
level 08 Dec 1980 R&M Consultants, Inc 1981
126.6 Slough 8A Intragravel water
temperature Winter 1983 Keklak and Quane 1984
126.6 Slough 8A Surface water
temperature Winter 1983 Keklak and Quane 1984
126.9 Breakup ice
thickness
28 Apr - 04 May
1983 Schoch 1983b
126.9 Breakup ice
thickness Winter 1982 LaBelle 1984
126.9 Breakup water
level
28 Apr - 04 May
1983 Schoch 1983b
127 Freeze-up water
level Winter 1982 Schoch 1983b
127.5 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
127.5 Freeze-up water
level 06 Nov 1980 R&M Consultants, Inc 1981
127.5 Freeze-up water
level 07 Nov 1980 R&M Consultants, Inc 1981
127.5 Freeze-up water
level 08 Dec 1980 R&M Consultants, Inc 1981
128.2 Breakup ice
thickness 27-30 Apr 1983 Schoch 1983b
128.2 Breakup ice
thickness Winter 1982 LaBelle 1984
128.2 Breakup water
level 27-30 Apr 1983 Schoch 1983b
128.3 Freeze-up water
level Winter 1982 Schoch 1983b
128.4 Slough 9 mouth Ice thickness Winter 1983 LaBelle 1984
128.5 Surface water
temperature Winter 1983 Keklak and Quane 1984
128.6 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
128.6 Freeze-up water
level Winter 1980 LaBelle 1984
128.6 Freeze-up water
level Winter 1983 LaBelle 1984
128.6 Surface water
temperature Winter 1983 Keklak and Quane 1984
128.7 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
128.7 Freeze-up water
level 06 Nov 1985 R&M Consultants, Inc 1986
128.7 Freeze-up water
level 21 Nov 1985 R&M Consultants, Inc 1986
128.7 Freeze-up water
level 06 Nov 1980 R&M Consultants, Inc 1981
128.7 Freeze-up water
level 07 Nov 1980 R&M Consultants, Inc 1981
ICE PROCESSES STUDY
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River
Mile Location Information Data Collected Date of Measurement Reference Document
128.7 Freeze-up water
level 08 Dec 1980 R&M Consultants, Inc 1981
129.7 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
130.8 Breakup ice
thickness 27-30 Apr 1983 Schoch 1983b
130.8 Breakup ice
thickness Winter 1982 LaBelle 1984
130.8 Breakup water
level 27-30 Apr 1983 Schoch 1983b
130.8 Ice thickness 05 Mar 1981 R&M Consultants, Inc 1981
130.8 Ice thickness 05 May 1983 Schoch 1983b
130.8 Freeze-up water
level Winter 1983 LaBelle 1984
130.8 Freeze-up water
level 05 May 1983 Schoch 1983b
130.9 Ice thickness Winter 1984 Schoch 1985
130.9 Stage and
discharge Jul - Nov 1980 R&M Consultants, Inc 1982
130.9 Rating curves Winter 1981 R&M Consultants, Inc 1982
130.9 Freeze-up water
level Winter 1982 Schoch 1983b
130.9 Freeze-up water
level Winter 1980 LaBelle 1984
130.9 Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
131 Sherman - Slough 9 Freezing degree
days Sep-May 1982 Schoch 1985
131 Sherman - Slough 9 Freezing degree
days Sep-May 1983 Schoch 1985
131 Sherman - Slough 9 Freezing degree
days Sep-May 1984 Schoch 1985
131 Sherman - Slough 9 Frazil ice porosity 14 Nov 1984 Schoch 1985
131 Sherman - Slough 9 Crest gage Winter 1980 R&M Consultants, Inc 1982
131 Sherman - Slough 9 Crest gage Winter 1981 R&M Consultants, Inc 1982
131.1 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
131.1 Surface water
temperature Winter 1983 Keklak and Quane 1984
134 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
134 Surface water
temperature Winter 1983 Keklak and Quane 1984
134.1 Freeze-up water
level Winter 1983 LaBelle 1984
134.2 Side Channel 10 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
134.2 Side Channel 10 Freeze-up water
level 05 Dec 1985 R&M Consultants, Inc 1986
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River
Mile Location Information Data Collected Date of Measurement Reference Document
135.3 Freeze-up water
level Winter 1982 Schoch 1983a
135.4
Side channel
downstream of Slough
11
Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
135.5 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
135.7 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
135.7 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
135.7 Surface water
temperature Winter 1983 Keklak and Quane 1984
135.7 Freeze-up water
level 12 Dec 1980 R&M Consultants, Inc 1981
135.7 Freeze-up water
level Oct 1980 R&M Consultants, Inc 1981
136.1 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
136.1 Surface water
temperature Winter 1983 Keklak and Quane 1984
136.3 Breakup ice
thickness
27 Apr - 03 May
1983 Schoch 1983b
136.3 Breakup ice
thickness Winter 1983 Keklak and Quane 1984
136.3 Breakup water
level
27 Apr - 03 May
1983 Schoch 1983
136.3 Surface water
temperature Winter 1983 Keklak and Quane 1984
136.5 Slough 11 Bed material
distribution Winter 1983 Schoch 1985
136.5 Slough 11 Breakup ice
thickness
27 Apr - 10 May
1983 Schoch 1983b
136.5 Slough 11 Breakup ice
thickness 27 Feb 1981 R&M Consultants, Inc 1981
136.5 Slough 11 Breakup water
level
27 Apr - 10 May
1983 Schoch 1983b
136.5 Slough 11 Freeze-up water
level 06 Nov 1985 R&M Consultants, Inc 1986
136.5 Slough 11 Freeze-up water
level 11 Oct 1985 R&M Consultants, Inc 1986
136.5 Slough 11 Freeze-up water
level 21 Nov 1985 R&M Consultants, Inc 1986
136.5 Slough 11 Freeze-up water
level 29 Oct 1985 R&M Consultants, Inc 1986
136.5 Slough 11 General met
observations
01 Oct - 02 Dec
1985 R&M Consultants, Inc 1986
136.5 Slough 11 Ice thickness 04 Feb 1983 Schoch 1983b
136.5 Slough 11 Ice thickness 12 Apr 1983 Schoch 1983b
136.5 Slough 11 Ice thickness 12 Dec 1980 R&M Consultants, Inc 1981
136.5 Slough 11 Ice thickness 14 Jan 1981 R&M Consultants, Inc 1981
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 40 March 2013
River
Mile Location Information Data Collected Date of Measurement Reference Document
136.5 Slough 11 Ice thickness 1950-1956 R&M Consultants, Inc 1981
136.5 Slough 11 Ice thickness 1963-1967 R&M Consultants, Inc 1981
136.5 Slough 11 Ice thickness 1969-1970 R&M Consultants, Inc 1981
136.5 Slough 11 Ice thickness Winter 1961 R&M Consultants, Inc 1981
136.5 Slough 11 Ice thickness Winter 1970 R&M Consultants, Inc 1981
136.5 Slough 11 Ice thickness Winter 1980 LaBelle 1984
136.5 Slough 11 Ice thickness Winter 1981 LaBelle 1984
136.5 Slough 11 Ice thickness Winter 1982 LaBelle 1984
136.5 Slough 11 Ice thickness Winter 1983 LaBelle 1984
136.5 Slough 11 Frazil ice porosity 19 Oct 1984 Schoch 1985
136.5 Slough 11 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
136.5 Slough 11 Freeze-up water
level Winter 1982 R&M Consultants, Inc 1982
136.5 Slough 11 Freeze-up water
level Winter 1983 R&M Consultants, Inc 1982
136.5 Slough 11 Stream flow
measurements
Sep 1980 - May
1981 (no Dec) R&M Consultants, Inc 1981
136.5 Slough 11 Freeze-up water
level 12 Dec 1980 R&M Consultants, Inc 1981
136.5 Slough 11 Freeze-up water
level Oct 1980 R&M Consultants, Inc 1981
136.6 Freeze-up water
level Winter 1982 Schoch 1983b
136.7 Gold Creek Rating curves Winter 1981 R&M Consultants, Inc 1982
136.7 Gold Creek Discharge Winter 1980 R&M Consultants, Inc 1982
136.7 Gold Creek Discharge Winter 1981 R&M Consultants, Inc 1982
136.7 Gold Creek Freeze-up water
level 12 Dec 1980 R&M Consultants, Inc 1981
136.7 Gold Creek Freeze-up water
level Oct 1980 R&M Consultants, Inc 1981
136.7 Gold Creek Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
137 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
137 Freeze-up water
level 12 Dec 1980 R&M Consultants, Inc 1981
137 Freeze-up water
level Oct 1980 R&M Consultants, Inc 1981
137.2 Freeze-up water
level 12 Dec 1980 R&M Consultants, Inc 1981
137.2 Freeze-up water
level Oct 1980 R&M Consultants, Inc 1981
137.4 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
137.4 Freeze-up water
level 12 Dec 1980 R&M Consultants, Inc 1981
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 41 March 2013
River
Mile Location Information Data Collected Date of Measurement Reference Document
137.4 Freeze-up water
level Oct 1980 R&M Consultants, Inc 1981
138.2 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
138.5 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
138.6 Indian River Intragravel water
temperature Winter 1983 Keklak and Quane 1984
138.6 Indian River Surface water
temperature Winter 1983 Keklak and Quane 1984
138.9 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
140.2 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
140.8 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
140.8 Breakup ice
thickness
27 Apr - 03 May
1983 Schoch 1983b
140.8 Breakup ice
thickness Winter 1982 Schoch 1983b
140.8 Breakup water
level
27 Apr - 03 May
1983 Schoch 1983b
141 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
141 Surface water
temperature Winter 1983 Keklak and Quane 1984
141.5 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
141.8 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
141.8 Surface water
temperature Winter 1983 Keklak and Quane 1984
142 Intragravel water
temperature Winter 1983 Keklak and Quane 1984
142 Surface water
temperature Winter 1983 Keklak and Quane 1984
142.1 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
142.3 Slough 21 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
142.3 Slough 21 Breakup ice
thickness
27 Apr - 02 May
1983 Schoch 1983b
142.3 Slough 21 Breakup ice
thickness Winter 1983 Keklak and Quane 1984
142.3 Slough 21 Breakup water
level
27 Apr - 02 May
1983 Schoch 1983b
142.3 Slough 21 Freeze-up water
level Winter 1982 Schoch 1983b
142.3 Slough 21 Surface water
temperature Winter 1983 Keklak and Quane 1984
143.2 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 42 March 2013
River
Mile Location Information Data Collected Date of Measurement Reference Document
144.8 Bed material
distribution Winter 1981 R&M Consultants, Inc 1982
148.8 Breakup ice
thickness
27 Apr - 02 May
1983 Schoch 1983b
148.8 Breakup ice
thickness Winter 1982 LaBelle 1984
148.8 Breakup water
level
27 Apr - 02 May
1983 Schoch 1983b
148.8 Ice thickness 05 Mar 1981 R&M Consultants, Inc 1981
148.8 Freeze-up water
level Winter 1982 LaBelle 1984
148.9 Ice thickness 04 Feb 1983 Schoch 1983b
148.9 Ice thickness 12 Apr 1983 Schoch 1983b
148.9 Rating curves Winter 1981 R&M Consultants, Inc 1982
148.9 Freeze-up water
level Winter 1982 Schoch 1983b
148.9 Crest gage Winter 1980 R&M Consultants, Inc 1982
148.9 Crest gage Winter 1981 R&M Consultants, Inc 1982
148.9 Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
149.7 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
149.9 Freezing degree
days Winter 1980 Schoch 1983a
149.9 Freezing degree
days Winter 1981 Schoch 1983a
149.9 Freezing degree
days Winter 1982 Schoch 1985
149.9 Ice thickness 13 Apr 1981 R&M Consultants, Inc 1981
150.1 Devils Canyon, mouth Surface water
temperature Winter 1982 Schoch 1983a
150.2 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
150.2 Rating curves Winter 1981 R&M Consultants, Inc 1982
150.2 Staff gage Installed Apr 1981 R&M Consultants, Inc 1982
150.2 Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
151 Freeze-up water
level Winter 1980 R&M Consultants, Inc 1982
162.1 Ice thickness 13 Mar 1981 R&M Consultants, Inc 1981
162.1 Rating curves Winter 1981 R&M Consultants, Inc 1982
162.1 Crest gage Winter 1980 R&M Consultants, Inc 1982
162.1 Crest gage Winter 1981 R&M Consultants, Inc 1982
162.1 Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
167 Ice thickness 12 Mar 1981 R&M Consultants, Inc 1981
173.1 Ice thickness 12 Mar 1981 R&M Consultants, Inc 1981
ICE PROCESSES STUDY
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FERC Project No. 14241 Page 43 March 2013
River
Mile Location Information Data Collected Date of Measurement Reference Document
174 Ice thickness 11 Mar 1981 R&M Consultants, Inc 1981
176 Ice thickness 11 Mar 1981 R&M Consultants, Inc 1981
176.7 Ice thickness 11 Mar 1981 R&M Consultants, Inc 1981
178.8 Ice thickness 10 Mar 1981 R&M Consultants, Inc 1981
180.1 Ice thickness 09 Mar 1981 R&M Consultants, Inc 1981
181 Ice thickness 09 Mar 1981 R&M Consultants, Inc 1981
181.8 Ice thickness 08 Mar 1981 R&M Consultants, Inc 1981
182.1 Air temperature Oct - Dec 1984 Schoch 1985
182.1 Air temperature Sep - Dec 1985 R&M Consultants, Inc 1982
182.1 Freezing degree
days Oct - Dec 1984 Schoch 1985
182.1 Freezing degree
days Sep - Dec 1985 R&M Consultants, Inc 1982
182.1 Ice thickness 01 Apr 1981 R&M Consultants, Inc 1981
182.1 Rating curves Winter 1981 R&M Consultants, Inc 1982
182.1 Discharge Winter 1980 R&M Consultants, Inc 1982
182.1 Discharge Winter 1981 R&M Consultants, Inc 1982
182.1 Freeze-up water
level Winter 1981 R&M Consultants, Inc 1982
182.5 Ice thickness 08 Mar 1981 R&M Consultants, Inc 1981
182.8 Ice thickness 07 Mar 1981 R&M Consultants, Inc 1981
183.5 Ice thickness 07 Mar 1981 R&M Consultants, Inc 1981
183.8 Ice thickness 07 Mar 1981 R&M Consultants, Inc 1981
184 Air temperature Oct - Dec 1984 Schoch 1985
184 Air temperature Sep - Dec 1985 R&M Consultants, Inc 1982
184 Freezing degree
days Oct - Dec 1984 Schoch 1985
184 Freezing degree
days Sep - Dec 1985 R&M Consultants, Inc 1982
184 Freezing degree
days Winter 1980 Schoch 1985
184 Freezing degree
days Winter 1981 Schoch 1985
184 Freezing degree
days Winter 1982 Schoch 1985
184 Ice thickness 04 Feb 1983 Schoch 1983b
184 Ice thickness 12 Apr 1983 Schoch 1983b
184 Ice thickness 27 Feb 1981 R&M Consultants, Inc 1981
184 Frazil ice porosity 19 Oct 1984 Schoch 1985
184.2 Watana Dam Site Ice thickness 06 Apr 1981 R&M Consultants, Inc 1981
184.4 Ice thickness 06 Apr 1981 R&M Consultants, Inc 1981
184.4 Rating curves Winter 1981 R&M Consultants, Inc 1982
184.4 Crest gage Winter 1980 R&M Consultants, Inc 1982
ICE PROCESSES STUDY
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FERC Project No. 14241 Page 44 March 2013
River
Mile Location Information Data Collected Date of Measurement Reference Document
184.4 Crest gage Winter 1981 R&M Consultants, Inc 1982
184.4 Water surface
elevations Winter 1981 R&M Consultants, Inc 1982
184.8 Ice thickness 05 Apr 1981 R&M Consultants, Inc 1981
185.4 Ice thickness 05 Apr 1981 R&M Consultants, Inc 1981
185.9 Ice thickness 04 Apr 1981 R&M Consultants, Inc 1981
186.5 Ice thickness 04 Apr 1981 R&M Consultants, Inc 1981
186.8 Ice thickness 04 Apr 1981 R&M Consultants, Inc 1981
186.8 Rating curves Winter 1981 R&M Consultants, Inc 1982
186.8 Crest gage Winter 1980 R&M Consultants, Inc 1982
186.8 Crest gage Winter 1981 R&M Consultants, Inc 1982
186.8 Water surface
elevations Winter 1981 R&M Consultants, Inc 1982
223 Vee Canyon Stage and
Discharge
1961-1972, 1980-
1986
USGS Surface Water Data
Collection Program
281 Denali Highway Stage and
Discharge 1956-1986 USGS Surface Water Data
Collection Program
281 Denali Highway Frazil ice Porosity 10/19/1984 Schoch, G.C. 1985
Table 5.1-5. Documentation of Ice Processes Effects on Riparian Vegetation, Geomorphology, and Aquatic Habitat
River
Mile
Location
Information Observations Made
Date of
Observa
tion
Reference
Document
Ice Effects on Vegetation and LWD Recruitment
85.5
Ice jam - flood released logs stranded from
summertime flooding
04 May
1983
Schoch
1984
89
Ice jam - flood released logs stranded from
summertime flooding
04 May
1983
Schoch
1984
101.5 Ice scarring on trees following ice jam release
May,
1981
R&M
Consultant
s, Inc 1981
103 Flooded vegetation during ice jam
5/5/198
1
R&M
Consultant
s, Inc 1981
110
erosion and vegetation removed by ice in mid-river
islands. 15-20" cottonwood and birch damaged.
5/27/19
82
R&M
Consultant
s, Inc 1983
141
Ice scarred mature cottonwoods 5 ft above ground
along Slough 21
5/27/19
82
R&M
Consultant
s, Inc 1983
Ice Effects on Geomorphology
95
severe bank erosion from breakup at outside of
bends and cut banks
5/27/19
82
R&M
Consultant
s, Inc 1983
97 10-15 feet of bank erosion on left bank from breakup
5/27/19
82
R&M
Consultant
s, Inc 1983
ICE PROCESSES STUDY
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FERC Project No. 14241 Page 45 March 2013
River
Mile
Location
Information Observations Made
Date of
Observa
tion
Reference
Document
98 2-3 feet bank erosion from breakup
5/27/19
82
R&M
Consultant
s, Inc 1983
102 4-5 feet bank erosion from breakup
5/27/19
82
R&M
Consultant
s, Inc 1983
107 ice jam scour on east bank
May
12-15,
1982
R&M
Consultant
s, Inc 1983
110
erosion and vegetation damage from ice in mid-river
islands
5/27/19
82
R&M
Consultant
s, Inc 1983
110.4 Significant ice scouring (through RM 113)
May
1976
R&M
Consultant
s, Inc 1981
120 Extensive channel enlargements and small ice jams
27 Apr
1983
Schoch
1984
126.1 Slough 8 Slough breached at freezeup
Fall
1982
LaBelle
1984
128 Slough 9
scour and deposition from breakup floods in Slough
9
5/27/19
82
R&M
Consultant
s, Inc 1983
131
Sherman -
Slough 9 Extensive channel enlargements and small ice jams
27 Apr
1983
Schoch
1984
135.9 Slough 11 Extensive channel enlargements and small ice jams
27 Apr
1983
Schoch
1984
135.9 Slough 11 Extreme ice jam created Slough 11
May
1976
Schoch
1984
136 Slough 11 ice jam flood breached Slough 11
5/12/19
82
R&M
Consultant
s, Inc 1983
142 Slough 21 Extensive channel enlargements and small ice jams
27 Apr
1983
Schoch
1984
145.5 Extensive channel enlargements and small ice jams
27 Apr
1983
Schoch
1984
148.8 Extensive channel enlargements and small ice jams
27 Apr
1983
Schoch
1984
Ice Effects on Fish Habitat
19
Alexander
Slough (Upper) Minimal winter flow from main channel
Octobe
r, 1982
Schoch
1984
35.2
Hooligan Side
Channel
no winter flow from main channel Winter
1984
Schoch
1985
36.2
Eagles Nest Side
Channel
Flooded snow during freezeup Winter
1984
Schoch
1985
36.3
Kroto Slough,
head
no winter flow from main channel Winter
1984
Schoch
1985
39
Rolly Creek,
mouth
no winter flow from main channel Winter
1984
Schoch
1985
40.5 Deshka River Ice jam at Deshka confluence
May
1980
R&M
Consultant
s, Inc 1981
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 46 March 2013
River
Mile
Location
Information Observations Made
Date of
Observa
tion
Reference
Document
43
Bear Bait Side
Channel
no winter flow from main channel Winter
1984
Schoch
1985
45.4
Last Chance
Side Channel
no winter flow from main channel Winter
1984
Schoch
1985
59.5
Rustic
Wilderness Side
Channel
overflow into side channel during freeze-up
Winter
1984
Schoch
1985
63
Caswell Creek,
mouth
no winter flow from main channel Winter
1984
Schoch
1985
63.2
Island Side
Channel
Flooded snow during freezeup Winter
1984
Schoch
1985
72
Goose Creek
Slough
no winter flow from main channel Octobe
r, 1982
Schoch
1984
74.4
Mainstem West
Bank Flooded snow during freezeup
Winter
1984
Schoch
1985
74.8
Goose 2 Side
Channel
overflow into side channel during freeze-up Winter
1984
Schoch
1985
75.3
Circular Side
Channel
no winter flow from main channel Winter
1984
Schoch
1985
77
Montana Creek
confluence Ice jam - flooded Montana Creek confluence
03 May
1983
Schoch
1984
79.8
Sauna Side
Channel
no winter flow from main channel Winter
1984
Schoch
1985
83
Rabideaux
Slough Minimal winter flow from main channel
Octobe
r, 1982
Schoch
1984
84
Sunshine Slough
Minimal winter flow from main channel
Octobe
r, 1982
Schoch
1984
84.5
Sucker Side
Channel
no winter flow from main channel Winter
1984
Schoch
1985
86.3
Beaver Dam
Slough
no winter flow from main channel Winter
1984
Schoch
1985
86.9
Sunset Side
Channel
no winter flow from main channel Winter
1984
Schoch
1985
87
Sunrise Side
Channel
no winter flow from main channel Winter
1984
Schoch
1985
88.4
Birch Creek
Slough
no winter flow from main channel Winter
1984
Schoch
1985
88.4
Birch Creek
Slough Minimal winter flow from main channel
Octobe
r, 1982
Schoch
1984
91.6
Trapper Creek
Side Channel
no winter flow from main channel Winter
1984
Schoch
1985
112.5 Slough 6A Major ice jam during breakup
07 May
1983
Schoch
1984
112.5 Slough 6A Open slough
Winter
1982-
1983
Schoch
1984
112.5 Slough 6A Open slough
Winter
1983-
1984
Schoch
1985
ICE PROCESSES STUDY
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River
Mile
Location
Information Observations Made
Date of
Observa
tion
Reference
Document
122.9 Slough 7 Open slough
Winter
1982-
1983
Schoch
1984
125 Slough 8 severe ice jam redirecting flow into Slough 8
5/15/19
82
R&M
Consultant
s, Inc 1983
126.1 Slough 8 Slough breached at freezeup
Fall
1982
LaBelle
1984
126.2 Slough 8A Open slough
Winter
1982-
1983
Schoch
1984
126.2
Slough 8A, West
Channel Open slough
Winter
1983-
1984
Schoch
1985
127 Slough 8 Open slough -- groundwater upwelling
Winter
1982
LaBelle
1984
127 Slough 8
Side channels and sloughs regularly influenced by
ice-induced flooding during breakup (Slough 8 and
8A)
Spring
1983
LaBelle
1984
127.1 Slough 8 Open slough
Winter
1982-
1983
Schoch
1984
127.1 Slough 8 Open slough
Winter
1983-
1984
Schoch
1985
128 Slough 9
scour and deposition from breakup floods in Slough
9
5/27/19
82
R&M
Consultant
s, Inc 1983
129 Slough 9
severe ice jam redirecting flow into Slough 9,
breaching slough berm
5/15/19
82
R&M
Consultant
s, Inc 1983
129 Slough 9
Side channels and sloughs regularly influenced by
ice-induced flooding during breakup (Slough 9)
Spring
1983
LaBelle
1984
129.2 Slough 9 Open slough
Winter
1982-
1983
LaBelle
1984
129.4 Slough 9
Side channels and sloughs regularly influenced by
ice-induced flooding during breakup (through RM
130.5 - side channel)
Spring
1983
LaBelle
1984
130.7
Side channel
upstream of
Slough 9 Open leads
Winter
1982
Schoch
1984
130.7
Side channel
upstream of
Slough 9 Open leads
Winter
1983
Schoch
1985
130.9 Slough 9
Late December open water - some intermediate ice
bridges (through RM 135)
Dec
1984
Schoch
1985
131
Sherman -
Slough 9 Extensive channel enlargements and small ice jams
27 Apr
1983
Schoch
1984
131
Sherman -
Slough 9 Breakup ice jam
Spring
1985
Schoch
1985
ICE PROCESSES STUDY
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River
Mile
Location
Information Observations Made
Date of
Observa
tion
Reference
Document
131
Sherman -
Slough 9 Open leads
Winter
1983
Schoch
1985
131.5 Sherman Creek Major ice jam during breakup (3.5 miles long)
07 May
1983
Schoch
1984
131.5 Sherman Creek Open leads
Winter
1982
Schoch
1984
131.5 Sherman Creek Open leads
Winter
1983
Schoch
1985
131.9
Side channel
upstream from
4th of July Creek Open leads
Winter
1982
Schoch
1984
131.9
Side channel
upstream from
4th of July Creek Open leads
Winter
1983
Schoch
1985
134.2 Slough 10 Open slough -- groundwater upwelling
Winter
1982-
1983
LaBelle
1984
134.4
Side channel
upstream of
Slough 10 Breakup ice jam
Spring
1983
LaBelle
1984
134.5 Side Channel 10
Side channels and sloughs regularly influenced by
ice-induced flooding during breakup
Spring
1983
LaBelle
1984
135.9 Slough 11 Extensive channel enlargements and small ice jams
27 Apr
1983
Schoch
1984
135.9 Slough 11 Extreme ice jam created Slough 11
May
1976
Schoch
1984
136 Slough 11 ice jam flood breached Slough 11
5/12/19
82
R&M
Consultant
s, Inc 1983
136.3 Slough 11 Open slough -- groundwater upwelling
Winter
1982-
1983
Schoch
1984
UNK Slough 16 Open slough -- groundwater upwelling
Winter
1982-
1983
Schoch
1984
140.4 Slough 20 Open slough -- groundwater upwelling
Winter
1982-
1983
Schoch
1984
141 Slough 21
Side channels and sloughs regularly influenced by
ice-induced flooding during breakup
Spring
1983
LaBelle
1984
141.9 Slough 21 Open slough
Winter
1983-
1984
Schoch
1985
142 Slough 21 Extensive channel enlargements and small ice jams
27 Apr
1983
Schoch
1984
142.1 Slough 21 Open slough -- groundwater upwelling
Winter
1982-
1983
Schoch
1984
144.4 Slough 21
Side channels and sloughs regularly influenced by
ice-induced flooding during breakup (Slough 22)
Spring
1983
LaBelle
1984
144.9 Slough 22 Breakup ice jam
Spring
1985
Schoch
1985
ICE PROCESSES STUDY
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River
Mile
Location
Information Observations Made
Date of
Observa
tion
Reference
Document
144.5 Slough 22 Open slough -- groundwater upwelling
Winter
1982-
1983
Schoch
1984
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9. FIGURES
ICE PROCESSES STUDY
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Figure 3-1. Map of Study Area
Figure 3-2. Locations of Time-Lapse Cameras and Pressure Transducers.
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Figure 5.2-1. Thermal lead in gravel bar near RM 32, March 20, 2012. Main channel is to the left. View is looking
upstream.
ICE PROCESSES STUDY
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Figure 5.2-2. Tannic color of thermal lead at bank toe, near RM 15, March 20, 2012.
ICE PROCESSES STUDY
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Figure 5.2-3. Velocity leads near RM 97 March 20, 2012. Snowmachine tracks for scale.
ICE PROCESSES STUDY
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Figure 5.2-4. Thermal lead in Slough 8A, RM 126, March 21, 2012.
ICE PROCESSES STUDY
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Figure 5.2-5. Thermal lead in Slough 11, RM 136, March 21, 2012
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Figure 5.2-6. Velocity lead in Devils Canyon, March 21, 2012.
ICE PROCESSES STUDY
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Figure 5.2-7. Close up view of velocity lead in Devils Canyon, March 22nd, 2012. Note rapid and broken ice.
Figure 5.2-8. Velocity lead in Vee Canyon, RM 222, March 22, 2012.
ICE PROCESSES STUDY
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Figure 5.2-9. Open leads in the Oshetna River (bottom of photo) and Susitna River (top of photo), March 22, 2012.
ICE PROCESSES STUDY
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Figure 5.4-1. Ice jam near RM 62 on the Lower Susitna River, April 30, 2012.
ICE PROCESSES STUDY
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Figure 5.4-2. Breakup near RM 9.5 on April 30, 2012 as recorded on a time-lapse camera.
ICE PROCESSES STUDY
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Figure 5.4-3. Stranded ice on banks near RM 59 after ice out on May 2, 2012.
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Figure 5.4-4. Open water at the mouth of Portage Creek, April 11, 2012. Lead is about 4 feet wide.
ICE PROCESSES STUDY
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Figure 5.4-5. A velocity lead in Devils Canyon, RM 151, widening on April 19, 2012. Ice is slumping from the sides and
accumulating in the lead. Note small avalanches from the canyon walls.
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Figure 5.4-6. Velocity lead opening near Gold Creek Bridge (RM 136) on April 19, 2012. Broken ice is accumulating in
the lead.
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Figure 5.4-7. Ice floes accumulated in open lead near RM 127 on April 23, 2012. Thermal leads are opening up near the
channel margin and overflow is appearing at the head of Slough 8.
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Figure 5.4-8. Ice jam near RM 136 on April 27, 2012. Slough 11 is in the upper left side of the photo.
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Figure 5.4-9. RM 136 and Slough 11 after the ice jam collapsed and moved downstream, May 2, 2012.
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Figure 5.4-10. Ice floes stranded on the bank near Slough 11 entrance (RM 135.6) on May 2, 2012.
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Figure 5.4-11. Ice jam forcing water into Slough 9, RM 128, May 2, 2012.
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Figure 5.1-12. Ice jam in Vee Canyon (RM 221.5), April 27, 2012.
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Figure 5.4-13. Ice jam at RM 231, April 27, 2012.
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Figure 5.4-14. Ice jam at RM 207, mouth of Kosina Creek, April 27, 2012.
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Figure 5.4-15. Remnant ice slabs downstream of Vee Canyon at RM 221, May 2, 2012.
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5.4-16. Ice jam remnants stranded on gravel island at RM 196, May 2, 2012.
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Figure 5.4-17. Ice bulldozing head of island at RM 184, May 2, 2012.
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Figure 5.6-1. Frazil ice pans flowing past RM 100, October 16, 2012.
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Figure 5.6-2. Ice bridge in Devils Canyon, RM 151. Flow is from bottom to top. October 22, 2012.
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Figure 5.6-3. Ice bridges at RM 2 in the west channel of the Lower River, October 26, 2012.
Figure 5.6-4. Pressure transducer readings from RM 10, showing a spike in pressure late on October 23 , 2012.
30.5
31
31.5
32
32.5
33
33.5
34
34.5
35
10/14 10/16 10/18 10/20 10/22 10/24 10/26 10/28 10/30Feet above arbitrary datum Water Level at RM 10
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Figure 5.6-5. Upstream end of ice cover, October 29, 2012 at RM 54. The thalweg is on the lower part of the photo --
water is being pushed into side channels in the upper part of the photo as the ice front progresses.
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Figure 5.6-6. Parks Highway bridge at RM 84 on November 1, 2012, prior to ice cover progression.
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Figure 5.6-7. Parks Highway Bridge at RM 84 on November 7, 2012, after ice cover progression. Note flooded gravel
bars on both sides of the river.
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Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Appendix A March 2013
Appendix A. Meteorological and Streamflow Data
Appendix A-1 Talkeetna Weather Station Data Tables
Appendix A-2 Freezing Degree Days Comparison
Appendix A-3 Surface Water Temperature for Susitna Basin Streams
Appendix A-4 Susitna Basin Snow Depth Measurements, 2011–2012
Appendix A-5 Stream Stage and Discharge Data
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Appendix A-1
Talkeetna Weather Station Data Tables
January
2012 Date Temperature
(°F) Wind Speed (mph) Precipitation
Minimum Maximum Mean Maximum Mean (in)
1 -27 -4 -16 5 1 0
2 -20 -2 -11 5 1 0
3 -20 3 -8 6 1 0
4 -24 -4 -14 4 0 0
5 -24 15 -4 12 5 0.06
6 -5 10 2 13 2 0.07
7 0 16 8 8 6 0.01
8 6 12 10 5 0 0.13
9 -11 5 -3 13 1 0
10 6 23 14 18 12 0.29
11 23 28 26 13 7 0.07
12 10 28 19 13 4 0.25
13 -18 10 -3 4 0 0.01
14 -26 -9 -18 5 3 0
15 -22 -6 -14 5 1 0
16 -20 12 -4 6 3 0
17 3 12 8 14 8 0.02
18 -9 19 5 16 6 0
19 -15 16 0 14 3 0
20 15 23 19 26 15 0
21 8 23 16 20 13 0
22 7 17 12 15 7 0
23 1 15 9 9 5 0
24 -16 6 -2 9 3 0
25 -27 -5 -16 4 0 0
26 -11 -2 -6 4 0 0.02
27 -13 -5 -9 0 0 0
28 -27 1 -12 4 1 0
29 -27 0 -14 4 1 0
30 -11 10 0 12 5 0.19
31 6 12 9 4 0 0
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Appendix A-1
Talkeetna Weather Station Data Tables (continued)
February
2012 Date Temperature
(°F) Wind Speed (mph) Precipitation
Minimum Maximum Mean Maximum Mean (in)
1 12 32 22 17 7 0.18
2 21 32 26 10 5 0
3 17 32 24 12 4 0.17
4 -4 14 5 5 1 0
5 6 32 19 13 6 0
6 10 35 24 12 7 0
7 3 34 18 9 2 0
8 1 36 18 13 7 0
9 7 34 20 15 5 0
10 23 35 29 8 2 0.04
11 28 37 32 14 6 0
12 18 33 26 9 2 0.04
13 30 36 33 9 5 0
14 25 32 28 14 8 0.03
15 26 33 30 15 7 0.01
16 23 33 28 12 4 0
17 28 35 32 8 4 0
18 18 32 25 12 6 0
19 18 30 24 12 6 0
20 19 35 27 12 8 0
21 21 28 24 5 0 0.13
22 21 28 24 5 0 0.02
23 8 25 16 7 1 0.06
24 1 19 10 4 0 0
25 1 19 10 8 2 0.13
26 17 28 22 13 7 0.34
27 24 30 28 6 2 0.08
28 -2 25 12 6 2 0
29 -2 24 11 6 1 0
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Appendix A-1
Talkeetna Weather Station Data Tables (continued)
March 2012 Date Temperature
(°F) Wind Speed (mph) Precipitation
Minimum Maximum Mean Maximum Mean (in)
1 -4 23 10 13 6 0
2 12 30 21 6 2 0
3 1 25 16 5 0 0.04
4 -8 17 4 5 0 0
5 -6 15 4 6 2 0.2
6 10 18 14 5 0 0.05
7 10 25 20 8 3 0
8 -8 26 9 8 3 0
9 -5 18 6 6 1 0
10 -11 25 7 15 3 0
11 -2 19 8 8 2 0
12 -9 24 7 7 1 0
13 -6 28 11 10 3 0
14 21 35 28 15 9 0
15 12 41 28 9 5 0
16 1 33 16 6 2 0
17 -2 30 14 7 1 0
18 10 30 20 7 1 0
19 5 34 20 5 1 0
20 -2 34 16 12 2 0
21 0 28 14 8 1 0
22 -6 28 10 6 1 0
23 -6 28 11 8 2 0.04
24 19 35 28 8 6 0.02
25 3 35 19 8 2 0
26 3 36 20 7 3 0
27 21 41 30 12 7 0
28* 33 48 40 9 5 0
29 21 48 34 6 1 0
30 18 45 32 8 2 0
31* 33 43 38 5 2 0.13
*Daily temperature min/max stayed above 32*F
Observation flight
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Appendix A-1
Talkeetna Weather Station Data Tables (continued)
April 2012 Date Temperature
(°F) Wind Speed (mph) Precipitation
Minimum Maximum Mean Maximum Mean (in)
1 28 45 37 8 1 0.02
2 19 43 31 16 3 0
3 16 39 28 6 3 0
4 16 42 28 6 1 0
5* 32 42 36 9 5 0.04
6 30 39 34 6 1 0.27
7 28 37 32 9 2 0.14
8 27 39 34 13 4 0.01
9 19 42 30 6 2 0
10 17 46 32 8 1 0
11 19 51 35 6 1 0
12 19 53 36 6 1 0
13 23 52 38 4 1 0
14 24 55 39 8 1 0
15 30 53 41 9 2 0
16* 34 53 44 6 1 0
17 30 52 41 4 0 0
18* 34 51 42 6 1 0
19 28 55 42 6 1 0
20 27 53 40 8 1 0
21* 34 51 42 10 1 0
22 30 52 41 8 1 0
23 25 51 38 7 2 0
24 24 59 40 10 2 0
25 28 57 42 14 4 0
26* 32 59 44 17 7 0
27 27 55 41 9 2 0
28* 36 51 43 8 3 0.01
29 28 55 42 8 2 0
30 28 55 42 7 2 0
*Daily temperature min/max stayed above 32*F
Observation flight
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Appendix A-1
Talkeetna Weather Station Data Tables (continued)
May 2012 Date Temperature
(°F) Wind Speed (mph) Precipitation
Minimum Maximum Mean Maximum Mean (in)
1 28 46 37 10 2 0
2 21 39 30 8 3 0
3 24 43 34 8 2 0
4 28 48 37 7 1 0
5 27 55 40 9 3 0
6 30 57 44 13 3 0.01
7* 37 54 46 7 2 0
8 28 57 42 16 3 0.01
9* 37 50 44 12 7 0.01
10* 37 51 44 8 2 0
11* 36 48 42 14 3 0.01
12 30 50 38 12 2 0.04
13* 32 51 42 16 4 0.02
14 28 54 41 13 3 0
15* 36 55 46 14 6 0
*Daily temperature min/max stayed above 32*F
Observation flight
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Appendix A-2
Freezing Degree Days
Winter 2011-2012 Cumulative Freezing Degree Days at Talkeetna compared to previous year and
long-term average. Plot created by National Weather Service Alaska River Forecast Center
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Winter 2012-2103 Cumulative Freezing Degree Days at Talkeetna compared to previous year and
long-term average.
-500
0
500
1000
1500
2000
2500
3000
1-Oct7-Oct13-Oct19-Oct25-Oct31-Oct6-Nov12-Nov18-Nov24-Nov30-Nov6-Dec12-Dec18-Dec24-Dec30-Dec5-Jan11-Jan17-Jan23-Jan29-Jan4-Feb10-Feb16-Feb22-Feb28-Feb5-Mar11-Mar17-Mar23-Mar29-Mar4-Apr10-AprFreezing Degree Days Date
Long Term Freezing Degree Day Comparison
Long Term Average FDD 2011/2012 FDD 2012/2013 FDD
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Winter 2012-2013 Cumulative Freezing Degree Days at Talkeetna and forecast through 3/01/2013
compared to long-term average. Plot created by National Weather Service Alaska River Forecast
Center.
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Appendix A-3
Surface Water Temperature (⁰F) for Susitna Basin Streams
Collected by the National Weather Service Alaska River Forecast Center
Date Montana Creek
(near Montana)
Susitna River
(near Sunshine)
Talkeetna River
(above RR bridge)
Willow Creek
(near Canyon)
26 Mar 2012 31.6 31.5 32.2 32.5
27 Mar 2012 31.6 31.5 32.2 32.5
28 Mar 2012 31.6 31.5 32.2 32.5
29 Mar 2012 31.6 31.5 32.2 32.5
30 Mar 2012 31.6 31.5 32.2 32.5
31 Mar 2012 31.6 31.5 32.2 32.5
01 Apr 2012 31.6 31.5 32.2 32.5
02 Apr 2012 31.6 31.5 32.2 32.5
03 Apr 2012 31.6 31.6 32.2 32.6
04 Apr 2012 31.6 31.6 32.2 32.7
05 Apr 2012 31.6 31.5 32.2 32.8
06 Apr 2012 31.6 31.5 32.2 33.1
07 Apr 2012 31.6 31.5 32.2 33.4
08 Apr 2012 31.6 31.5 32.2 33.4
09 Apr 2012 31.6 31.5 32.2 33.3
10 Apr 2012 31.6 31.5 32.2 33.3
11 Apr 2012 31.6 31.5 32.2 33.4
12 Apr 2012 31.6 31.5 32.2 33.3
13 Apr 2012 31.6 31.5 32.2 33.4
14 Apr 2012 31.6 31.5 32.2 33.3
15 Apr 2012 31.6 31.5 32.2 33.2
16 Apr 2012 31.6 31.5 32.2 33.3
17 Apr 2012 32.2 31.5 32.2 33.1
18 Apr 2012 32.4 31.5 32.2 33.1
19 Apr 2012 32.4 31.5 32.2 33.1
20 Apr 2012 32.4 31.5 32.2 33.1
21 Apr 2012 32.4 31.5 32.6 33.2
22 Apr 2012 32.4 31.5 32.8 33.5
23 Apr 2012 33.1 31.6 34.5 34.3
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FERC Project No. 14241 Appendix A – Page 10 March 2013
Date Montana Creek
(near Montana)
Susitna River
(near Sunshine)
Talkeetna River
(above RR bridge)
Willow Creek
(near Canyon)
24 Apr 2012 33.5 31.6 34.8 34.3
25 Apr 2012 33.8 31.6 35.1 34.5
26 Apr 2012 33.8 31.4 35.1 34.5
27 Apr 2012 33.5 31.5 35.1 34.8
28 Apr 2012 33.2 31.6 35.1 35.1
29 Apr 2012 32.9 31.6 35.1 35.2
30 Apr 2012 32.7 31.8 35.1 35.2
01 May 2012 34.3 33.1 37.6 36.1
02 May 2012 34.3 33.1 37.6 36.1
03 May 2012 34.9 34.4 37.9 36.8
04 May 2012 35.2 33.8 38.3 37.4
05 May 2012 35.7 35.8 38.9 38.2
06 May 2012 36.1 36.7 39.6 38.9
07 May 2012 36.5 37.9 40.3 39.6
08 May 2012 36.8 38.4 40.3 39.6
09 May 2012 37.1 38.9 40.5 39.9
10 May 2012 36.7 39.1 39.9 39.6
11 May 2012 36.9 39.6 40.1 39.8
12 May 2012 37.5 40.2 40.3 39.7
13 May 2012 38.2 41.1 40.7 40.1
14 May 2012 39.1 41.6 40.9 40.2
15 May 2012 39.8 41.9 41.2 40.6
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Appendix A-4
Susitna Basin Snow Depth Measurements, 2011-2012
Su-Valley High SNOTEL Site Daily Measurements of Snow Depth and Snow Water Equivalent,
2011-2012. Compiled by the NRCS
Bentalit Lodge SNOTEL Site Daily Measurements of Snow Depth and Snow Water Equivalent,
2011-2012. Compiled by the NRCS
0.0
10.0
20.0
30.0
40.0
50.0
60.0
Depth (in)
Su Valley SWE and Snow Depth
SWE (in)
Snow Depth (in)
0
10
20
30
40
50
60
Depth (in)
Bentalit Lodge SWE and Snow Depth
SWE (in)
Snow
Depth
(in)
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Appendix A-4
Susitna Basin Snow Depth Measurements, 2011-2012 (continued)
Tokositna Valley SNOTEL Site Daily Measurements of Snow Depth and Snow Water Equivalent,
2011-2012. Compiled by the NRCS
Pt. McKenzie SNOTEL Site Daily Measurements of Snow Depth and Snow Water Equivalent, 2011-
2012. Compiled by the NRCS
0
10
20
30
40
50
60
70
80
Depth (in)
Tokositna Valley SWE and Snow Depth
SWE (in)
Snow
Depth
(in)
0
5
10
15
20
25
30
35
40
Depth (in)
Pt McKenzie SWE and Snow Depth
SWE (in)
Snow
Depth
(in)
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Appendix A-4
Susitna Basin Snow Depth Measurements, 2011-2012 (continued)
Snow Course Data for the Susitna Basin, 2011-2012
Compiled by the NRCS
Snow Course Elevation
(ft)
Date
Reported
Snow
Depth (in)
Water
Content
(%)
Depth
Last
Year
(2011)
Depth
Average
(1971-2000)
Alexander Lake 160 --- --- --- --- ---
30 Jan 2012 41 10.9 8.3 8.6
29 Feb 2012 62 14.3 11.3 10.7
28 Mar 2012 51 15.2 12.0 12.0
--- --- --- --- 9.8
Archangel Road 2200 --- --- --- --- ---
--- --- --- 5.8 12.1
01 Mar 2012 60 17.6 7.6 13.5
02 Apr 2012 57 18.4E 9.5 16.3
01 May 2012 39 15.6 10.7 14.9
Bentalit Lodge 150 01 Jan 2012 --- 5.2 5.2 ---
01 Feb 2012 --- 6.4 6 ---
01 Mar 2012 --- 8.3 7.8 ---
01 Apr 2012 44 12.1 7.8 ---
01 May 2012 5 1.9 4.2 ---
Blueberry Hill 1200 --- --- --- --- ---
01 Feb 2012 50 13.4 12.6 11.5
29 Feb 2012 58 15.8 13.5 13.8
29 Mar 2012 52 16.4 13.6 16.0
01 May 2012 34 13.2 14.9 17.4
Chelatna Lake 1450 --- --- --- --- ---
--- --- --- 5.8 8.3
28 Feb 2012 59 13.8 --- 10
29 Mar 2012 50 14 9.1 11.6
02 May 2012 35 13 8.1 10.9
Curtis Lake 2850 --- --- --- --- ---
--- --- --- 3.2 3.2
29 Feb 2012 30 5.5 3.5 3.9
02 Apr 2012 29 5.8 4.2 4.3
--- --- --- --- ---
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Snow Course Elevation
(ft)
Date
Reported
Snow
Depth (in)
Water
Content
(%)
Depth
Last
Year
(2011)
Depth
Average
(1971-2000)
Denali View 700 --- --- --- --- ---
01 Feb 2012 47 11.5 9.9 9.6
29 Feb 2012 54 13.4 11.7 11.4
29 Mar 2012 46 14 11.4 13.4
01 May 2012 22 8.7 11.1 12.3
Dunkle Hills 2700 --- --- --- --- ---
--- --- --- --- ---
28 Feb 2012 33 7.6 --- ---
29 Mar 2012 32 8.8 8.5 ---
--- --- --- 8.5 ---
Dutch Hills 3100 --- --- --- --- ---
--- --- --- --- 19.6
28 Feb 2012 90 27.9E --- 23
29 Mar 2012 69 25 13.5 27.5
02 May 2012 69 27 17.5 28.7
E. Fork Chulitna 1800 --- --- --- --- ---
01 Feb 2012 48 12.2 8.9 10.5
29 Feb 2012 53 14 10.8 12.7
29 Mar 2012 51 15.4 10.7 14
01 May 2012 35 13.3 12.3 15.7
Fishhook Basin 3300 --- --- --- --- ---
01 Feb 2012 77 20.8 10.2 15.4
01 Mar 2012 75 23.2 10.9 17.7
02 Apr 2012 70 24.2 12.1 20.5
01 May 2012 58 23.6 15.6 22.1
Fog Lakes 2120 --- --- --- --- ---
30 Jan 2012 27 5 4.2 4.4
29 Feb 2012 31 5.1 4.6 5.3
02 Apr 2012 30 5.8 5 6.2
01 May 2012 --- 5.8 4.5 5.3
Halfway Slough 3500 --- --- --- --- ---
01 Feb 2012 36 7.9 6.4 ---
29 Feb 2012 42 9.2 6.4 ---
29 Mar 2012 34 9.3 6.2 ---
01 May 2012 0 0 --- ---
Independence Mine 3550 --- --- --- 9 13.9
01 Feb 2012 81 21.2 10.6 18.1
01 Mar 2012 85 27.1 12.5 21.2
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Snow Course Elevation
(ft)
Date
Reported
Snow
Depth (in)
Water
Content
(%)
Depth
Last
Year
(2011)
Depth
Average
(1971-2000)
02 Apr 2012 77 28.2 13.1 24.2
01 May 2012 69 28.9 18.5 27.1
Independence Mine 3550 01 Jan 2012 53 14.2 --- 11.1
01 Feb 2012 68 14.8 --- 14.1
01 Mar 2012 70 17.8 9.9 16.5
01 Apr 2012 67 19 10.5 18.9
--- --- --- 15.2 21.1
Lake Louise 2400 --- --- --- --- 2.8
30 Jan 2012 23 4.2 2.4 3.3
27 Feb 2012 26 5.2 4.1 4
30 Mar 2012 30 6.6 4.2 4.6
02 May 2012 13 4.5 3.9 2.9
Little Susitna 1700 --- --- --- --- ---
01 Feb 2012 54 13 5.2 9.6
01 Mar 2012 54 14.5 6.3 11.6
02 Apr 2012 50 15.1 --- 13.3
01 May 2012 24 9.4 6.4 9.2
Moose Creek 4500 --- --- --- --- ---
30 Jan 2012 22 5.1 1.9 ---
27 Feb 2012 30 7.1 2 ---
30 Mar 2012 28 7.7 1.2 ---
02 May 2012 0 0 0 ---
Nugget Bench 2010 --- --- --- --- ---
--- --- --- --- 10.9
28 Feb 2012 58 14.8 --- 12.9
29 Mar 2012 45 14.5 9 15.5
02 May 2012 31 12 10.5 15.3
Ramsdyke Creek 2220 --- --- --- --- ---
--- --- --- --- 16.3
28 Feb 2012 81 23.5 --- 18.9
29 Mar 2012 68 22.5 13 22
02 May 2012 45 18.8 15 21.9
Sheep Mountain 2900 --- --- --- --- ---
30 Jan 2012 31 7.2 4.3 4.5
27 Feb 2012 38 9.4 4.7 5.4
30 Mar 2012 37 10.3 4.8 6
02 May 2012 16 6.6 0 3.9
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Snow Course Elevation
(ft)
Date
Reported
Snow
Depth (in)
Water
Content
(%)
Depth
Last
Year
(2011)
Depth
Average
(1971-2000)
Skwentna 160 --- --- --- --- ---
30 Jan 2012 41 10.8 8.3 8.5
29 Feb 2012 59 14.2 12 10.5
28 Mar 2012 48 14.5 11.8 11.6
--- --- --- --- ---
Square Lake 2950 --- --- --- --- ---
30 Jan 2012 19 3.5 3.5 3.2
29 Feb 2012 32 5.2 --- 3.8
02 Apr 2012 29 5.8 3.2 4.2
--- --- --- --- ---
Susitna Valley High 380 01 Jan 2012 30 7.4 4.4 5.7
01 Feb 2012 41 9 5.5 7.5
01 Mar 2012 48 10.9 6.2 9.4
01 Apr 2012 38 11.2 6.2 10.2
01 May 2012 13 4.5 3.2 5.6
Talkeetna 350 --- --- --- --- ---
01 Feb 2012 36 7.5 6.3 6.2
29 Feb 2012 42 9.2 6.5 7.6
29 Mar 2012 34 9.6 6.3 8.7
01 May 2012 8 3.1 4.1 5.4
Tokositna Valley 850 --- --- --- --- ---
--- --- --- --- 13.6
28 Feb 2012 67 15.6 --- 15.7
29 Mar 2012 57 16.4 12.9 18.7
02 May 2012 39 14.2 14.1 17
Tokositna Valley 850 01 Jan 2012 59 10.3 9.3 9.6
01 Feb 2012 54 12.5 10.7 13.6
01 Mar 2012 67 15.7 12.4 16.2
01 Apr 2012 59 16.4 12 18.7
01 May 2012 39 14.3 14.1 17
Upper Oshetna River 3150 --- --- --- --- ---
30 Jan 2012 24 4.3 3.7 3.4
29 Feb 2012 36 6.5 4.1 3.9
02 Apr 2012 30 7.5 4.1 4.9
--- --- --- --- ---
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FERC Project No. 14241 Appendix A – Page 17 March 2013
Snow Course Elevation
(ft)
Date
Reported
Snow
Depth (in)
Water
Content
(%)
Depth
Last
Year
(2011)
Depth
Average
(1971-2000)
Upper Sanona Creek 3100 --- --- --- --- ---
30 Jan 2012 31 5.9 4.2 4
29 Feb 2012 39 7.4 4.3 4.4
02 Apr 2012 37 9 5.5 5.2
--- --- --- --- ---
Willow Airstrip 200 --- --- --- --- ---
01 Feb 2012 38 9.1 5.1 5.7
29 Feb 2012 53 11.3 6 6.9
29 Mar 2012 42 11.6 --- 8.1
01 May 2012 19 6.5 4.6 4.1
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Appendix A-5
Preliminary Recorded Stream Stage, Stage Equivalent Discharge and Measured Discharge Data
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
9.00
9.50
10.00
10.50
11.00
11.50
12.00
Flow (kcfs) Stage (ft) Susitna River at the Denali Hwy
Daily
Mean
Stage
(ft)
Daily
Mean
Flow
(kcfs)
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0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
Flow (kcfs) Stage (ft) Susitna River at Gold Creek
Daily
Mean
Stage
(ft)
Daily
Mean
Flow
(kcfs)
Actual
Flow
Measur
ement
(USGS)
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Appendix A-5
Preliminary Recorded Stream Stage, Stage Equivalent Discharge and Measured Discharge Data
(continued)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
0.00
1.00
2.00
3.00
4.00
5.00
6.00
Flow (kcfs) Stage (ft) Talkeetna River at Railroad Bridge
Daily
Mean
Stage
(ft)
Daily
Mean
Flow
(kcfs)
0
50
100
150
200
250
0
10
20
30
40
50
60
Flow (kcfs) Stage (ft) Susitna River at Park's Highway Bridge
Daily
Mean
Stage
(ft)
Daily
Mean
Flow
(kcfs)
Actual
Flow
Measu
remen
t
(USGS)
ICE PROCESSES STUDY
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Appendix A – Page 21 March 2013
Susitna River at Sunshine discharge during freeze-up, 2012. Gage stopped reporting on
10/13.
Susitna River at Gold Creek discharge during freeze-up, 2012. Gage stopped reporting on
10/20.
0
20000
40000
60000
80000
100000
120000
Discharge (CFS) USGS Gage 15292780 Susitna River at Sunshine
Sunshine 2012 (Provisional)
Sunshine Long-Term Average
Sunshine Maximum
0
5000
10000
15000
20000
25000
30000
35000
40000
10/1/201210/2/201210/3/201210/4/201210/5/201210/6/201210/7/201210/8/201210/9/201210/10/201210/11/201210/12/201210/13/201210/14/201210/15/201210/16/201210/17/201210/18/201210/19/201210/20/2012Discharge (cfs) USGS Gage 1529000 Susitna River at Gold Creek
Gold Creek 2012 (Provisional)
Gold Creek Long-Term Average
Gold Creek Maximum