HomeMy WebLinkAboutTown Creek Hydroelectric Project Field Report and Recommendations for Improvements 2010TOWN CREEK HYDROELECTRIC PROJECT
FIELD REPORT AND RECOMMENDATIONS FOR IMPROVEMENTS
EES CONSULTING, INC.
MCMILLEN, LLC.
March 2010 March 5, 2010
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT I
Contents
Executive Summary .......................................................................................................................1
Introduction ....................................................................................................................................2
Document/Data Review .................................................................................................................3
Background Information ......................................................................................................3
Civil Construction Information ............................................................................................3
Powerhouse Construction Information ................................................................................3
Historical Energy Production Information ...........................................................................4
Streamflow Information .......................................................................................................4
Town Creek Hydroelectric Generation Potential .................................................................5
Interviews........................................................................................................................................7
Site Review ......................................................................................................................................9
Dams and Upper Watershed ................................................................................................9
Powerhouse ........................................................................................................................10
Operational and Maintenance Issues .................................................................................11
Penstock Headlosses.....................................................................................................................12
Recommendations ........................................................................................................................13
Dam Repairs/Modifications ...............................................................................................13
Upper Watershed Access Road ..........................................................................................13
Control System Replacement .............................................................................................14
Turbine Inspection .............................................................................................................14
Maintenance Equipment and Facilities ..............................................................................14
Operations ..........................................................................................................................14
Cost Estimates ..............................................................................................................................16
Dam Repairs/Modifications ...............................................................................................16
Upper Watershed Access Road ..........................................................................................16
Control System Replacement .............................................................................................16
Turbine Inspection .............................................................................................................16
Maintenance Equipment and Facilities ..............................................................................16
Project Schedule ...........................................................................................................................18
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT II
List of Figures
Figure 1—Town Creek Diesel-Hydro Generation .......................................................................... 5
Figure 2 – Town Creek and Loud Creek Hydrology ...................................................................... 6
Figure 3—Town Creek Site Plan .................................................................................................. 20
Figure 4 – Penstock Route and Powerhouse Location .................................................................. 21
Figure 5—Main Impoundment Dam ............................................................................................ 22
Figure 6 – Powerhouse .................................................................................................................. 23
Figure 7 – Main Dam Cross Section ............................................................................................. 24
Photographs
Diversion Dam #1 ......................................................................................................................... 25
Main Impoundment Dam .............................................................................................................. 26
Main Dam Spillway ...................................................................................................................... 27
Main Dam (from downstream) ..................................................................................................... 28
Diversion Dam #2 ......................................................................................................................... 29
Diversion Dam #3 ......................................................................................................................... 30
Powerhouse ................................................................................................................................... 31
Turbine Hydraulics and Load Bank .............................................................................................. 32
Turbine Control Panel ................................................................................................................... 33
Turbine Load Bank Controls ........................................................................................................ 34
Turbine Runner ............................................................................................................................. 35
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 1
Executive Summary
EES Consulting and McMillen LLC staff (Project Team) visited the City of Akutan, Alaska
(City) in October 2009. Based on information reviewed, interviews with O&M staff, and the site
visit; the Project Team was able to offer some observations and recommendations for
improvements for the Town Creek Hydro Project (Project). These observations and
recommendations are listed below:
1. The data suggest that the City has not routinely operated the Project even though the
operation of the Project could offset a significant fraction of the diesel fuel expense for
the City. Total fuel cost in 2008 was nearly $360,000 based on an average price of nearly
$4.00 per gallon. It was estimated that the hydro project could save more than $100,000
annually in fuel cost.
2. Operations and maintenance of the Project could be improved by providing training to
City staff. Training should focus on usual and customary operation procedures and
maintenance of the facilities. Additionally, a plant log book and detailed operating
records need to be maintained (including information on the impoundments and spill).
3. The City should budget for routine and extra-ordinary maintenance. This should include
bringing in a contractor as necessary for annual maintenance activities.
4. To improve operations and maintenance, City staff need safe access to the upper
watershed to allow trash rack cleaning, monitoring/inspection of the dams, and
maintenance of the main dam and diversion dams. Additionally, City staff needs
vehicle(s) and equipment to facilitate maintenance. It is further recommended that a small
storage building be constructed near the main dam for the storage of equipment and
supplies.
5. Modifications and repairs are needed for the main dam and diversion dams.
Modifications include trash rack that can be hand cleaned, repairs to valves, and clean out
of sediment in each impoundment.
6. It is recommended that an analysis of the impoundment size cannot be made until
operating records are developed over a reasonable period of time to facilitate an analysis.
7. Penstock losses were evaluated. Based on a simple analysis, losses appear to be
consistent with normal practice. Based on a test in 1998, however, losses appear
excessive. Additional information would be needed to further evaluate the penstock,
however, for a 100 kW project capacity the losses are not significantly limiting
generation.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 2
Introduction
Electric Power Systems (EPS) contracted with EES Consulting (EESC) to provide a field review
and recommendations for repairs/upgrades to the Town Creek Hydroelectric Project, which is
owned and operated by the City of Akutan, Alaska. The EESC engineering team includes
McMillen, LLC (MCM) engineers.
On October 24, 2009, Don Jarrett (EESC) and Dan Axness (MCM) joined Robert Kirkman of
the RMA Consulting Group (RMA) in Akutan to perform the field work and develop a
preliminary report with repair/improvement recommendations and cost estimates. This team had
to spend two nights in Unalaska due to weather delay prior to getting a flight to Akutan.
While in Akutan, the team hiked into the Town Creek watershed on October 24, 2009 and saw
the main impoundment dam and diversion dams. The upper part of the watershed had up to 18
inches of snow, so it was not possible to completely assess the condition of all aspects of the
dams. On October 25, 2009, we crossed the bay and hiked up into the Loud Creek watershed.
Again, there was snow cover on the upper part of the watershed, but we were able to see the
locations of previously identified dam sites and the powerhouse location.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 3
Document/Data Review
We reviewed the following information relative to the Town Creek Project.
Grant Application of Akutan Hydroelectric System Repair, City of Akutan, Renewable
Energy Fund Grant Application, AEA-09-004, November 10, 2008
Egor Eispov, LCMF Inc., Alaska Energy Authority, Akutan Rural Power System Upgrade,
2007
Electric Power Systems, City of Akutan Hydro Inspection Report & Upgrade Cost Estimates,
May 2003
Alaska Power Systems, ASTF Grant Agreement 92-4-277, Unitized Village Scale Hydro-
diesel Generation System, April 1994
Akutan Hydropower Feasibility Study, HDR/Ott Water Engineers and Dryen & LaRue, 1989
Akutan Hydropower, Preliminary Design Report, Ott Water Engineers, 1980
Background Information
The City of Akutan entered into an agreement with a developer for the construction and
operation of the Town Creek Project. The developer, Alaska Power Systems (APS), packaged
the powerhouse equipment and performed construction of the Project at Akutan in 1990. Three
small diversion dams were constructed to divert water to a main impoundment dam in the
watershed above Akutan. The small diversion dams used 6 inch polyethylene (PE) pipe to run
water from the small drainages to the main dam. From the main dam at elevation 800 feet above
MSL, a 10 inch PE pipe (penstock) was installed to bring water to the powerhouse. The
powerhouse, located at 26 feet above MSL, had a unique hydro turbine-generator with a drive
train that would allow a small diesel to connect to the turbine-generator through a clutch.
Civil Construction Information
There is very limited documentation of the construction of the main dam, diversion dams, and
penstock in the above documents. The ASTF Grant Agreement has good information on the
powerhouse equipment (which does not reflect the current equipment arrangement). This
documentation includes dam design information performed by Shannon & Wilson, but is more
schematic in nature with respect to the dams and does not show the locations of the intake
screens, penstock and valves, etc.
Powerhouse Construction Information
There is good information on the powerhouse and generating equipment, which was installed by
APS. Information from the EPS report indicates that significant issues have existed with the
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 4
diesel-hydro system control. The hydro turbine generator has a rating of 160 kW; however, it is
connected to a load bank that may consume 50 kW or more for the purpose of providing
frequency regulation. The original connected diesel had a rating of 150 kW.
Historical Energy Production Information
Filings and other data for the Alaska Energy Authority Power Cost Equalization (PCE) Program
were obtained from 1999 to 2009. Earlier studies for the City of Akutan include energy
production in the late 1980’s. Power plant log sheets were also reviewed. This review indicates
that there has been very limited hydro operation in the last 10 years. Figure 1 presents monthly
generation for both diesel and hydro. As can be seen from the figure, annual energy production
has been increasing over the last 10 years. Average annual production over the 10-year period
was 538,000 kWh. Production in FY2009 was 566,000 kWh. In 1989, the City’s energy
production was 305,000 kWh, so energy consumption has nearly doubled in the last 20 years.
As can be seen from the historical production, hydroelectric production never amounted to any
significant portion of the City’s needs.
Streamflow Information
While APS apparently did streamflow measurements in the tributaries that come out of the
watershed, there is little documentation of the studies. According to APS, the hydro project
would be able to generate 2,000,000 kWh annually. Based on studies done on North Creek and
Loud Creek, hydroelectric production from a watershed of this size would be expected to be less.
For example, Loud Creek has a drainage area estimated at 1.1 square miles with 10.8 cfs average
discharge and Ott Engineers estimated 1,820,000 kWh annually. The Town Creek drainage
intercepted by the dams was estimated by APS at 0.63 square miles, correcting for head
production might be expected to be on the order of 1,700,000 kWh. Unfortunately, no further
hydrology studies have been performed to correlate the small amount of streamflows to a longer
record to obtain a better estimate of average annual production. Given the variability of monthly
average flows, energy production from Town Creek will unlikely be able to supply all needs of
the City.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 5
Figure 1—Town Creek Diesel-Hydro Generation
Town Creek Hydroelectric Generation Potential
We were unable to find any hydrologic information for Town Creek from the APS
documentation. A review was made of the available hydrologic information for adjacent
watersheds. Based on information from the HDR/OTT Report on Loud Creek and North Creek, a
simple analysis of generation was performed. The average monthly flows for Loud Creek were
factored for Town Creek and used to calculate generation based on the installed capacity at the
Town Creek Hydro Project. Figure 2 presents the average monthly discharges for both creeks.
Generation analysis based on average monthly data typically overstates the amount of generation
potential. Furthermore, the Loud Creek data was only measured at the mouth and was corrected
to the diversion location based on a drainage area correction. Additionally, the average monthly
flows that were reported for Loud Creek were based on very limited gage information. Finally,
during the winter months, it is likely that more of the discharge is from lower elevation runoff.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 6
Figure 2 – Town Creek and Loud Creek Hydrology
Using the average monthly flow data and installed capacity to calculate monthly energy
production and additionally taking 50% of the calculated value (to reflect the issues discussed
above), it is estimated that monthly energy production could be as high as 54,000 kWh for an
annual total of 648,000 kWh annually. Annual energy consumption varies in the City, but in the
most recent full fiscal year use was 538,000 kWh. It is doubtful that hydroelectric generation can
fully replace diesel. It is likely that some diesel generation will be required for acceptable
frequency regulation. For all of these reasons, it is estimated that hydroelectric generation will
displace about 75% of the typical energy generation.
Based on the above analysis and assumptions, hydroelectric generation is estimated to be
approximately 404,000 kWh. This hydroelectric generation will displace the use of diesel
generation. Based on the assumption that diesel generation efficiency is approximately 13
kWh/gallon, hydroelectric generation would displace 31,080 gallons of diesel annually. In 2008,
diesel fuel cost was reported as $3.96 per gallon. Thus, the hydroelectric generation would offset
$123,000 of fuel cost annually.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 7
Interviews
We met with Mayor Joe Bereskin and Demetri Tcheripanoff to better understand some of the
Project history and problems. As we had read, the original Town Creek Project was conceived by
Alaska Power Systems (APS). Apparently APS went bankrupt and the City was not able to
obtain any Project documentation aside from that contained in the final report for the ASTF grant
and some O&M manuals, which were provided by APS. According to the Mayor, APS gear was
“homemade” and not very reliable.
We asked about issues associated with the main impoundment dam and the diversion dams. The
City has experienced problems with the intakes in the diversion dams (which feed water to the
main dam). These small diversion dams have become clogged with sediment and there is not any
way to easily clean them out. There are screens of some type that become clogged with organic
debris. According to City staff, the main dam has similar problems.
City staff reported that the hydro turbine runs well but is not presently being used because of the
failure of the main impoundment dam level sensor. The Mayor noted that the control system
seems overly complex and is difficult for them to troubleshoot problems. The recent
improvements by EPS were helpful as new components are off-the-shelf as opposed to the
custom-built equipment originally supplied by APS. The Mayor noted the difficulty for the City
to properly operate a hydro project with local residents.
We asked about the construction of the main dam and diversion dams. The City staff was not
very knowledgeable about the construction. They did not know that the contractor had brought in
a dozer and backhoe for construction and had been able to get the equipment up to the upper
watershed. City staff noted that the intake screen on the dams clog with weeds and it is difficult
to clean them as they are underwater.
We asked about the City water supply system. The City water supply system diverts water into a
separate system and runs directly to the City water treatment plant. There is no interconnection
between the Town Creek Hydro Project and the City water supply system.
We asked about the status of the Town Creek Hydro Project and the Alaska Department of Dam
Safety. The Mayor noted that a dam safety person had been to the site and concluded that the
main dam is subject to regulation due to its height.
We asked about construction of an access road to facilitate operation and maintenance of the
dams. The Mayor noted that the soils are very erodible and the residents would not want to see
an ugly road from below.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 8
We asked about the second diesel generator power plant, which the City maintains as a backup to
the diesel-hydro system. The Mayor stated that there is no reason to install any monitoring of this
facility or interconnect it in any way to the diesel-hydro plant.
The regular hydro operator was out of town, so we were not able to interview that person. We
asked for his contact information.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 9
Site Review
Figures and photographs of the watershed, dams, and powerhouse are included in Appendix A.
Figure 3 illustrates the Town Creek site showing the main impoundment dam and diversion dams
located in the upper watershed. Figure 4 shows the penstock route and powerhouse location.
Figure 5 illustrates the main impoundment dam design. Figure 6 illustrates the powerhouse as
originally supplied by APS. Figure 7 shows a cross-sectional view of the main dam.
Dams and Upper Watershed
The team hiked into the upper watershed along the penstock route and visited the main
impoundment dam and the three diversion dams (see photographs in Appendix A). The upper
watershed had up to 18 inches of snow so inspection was difficult. Due to snow and ice on the
ponds, we were not able to see much more than the dams and the spillways.
Even without snow, access to the upper watershed where the dams are located would have been
difficult. There is no road and hiking directly up the side of the mountain is strenuous as the
grade is more than 30% in one location.
It was noted that the spillways are pipes on the crest of the dam and there is concern about the
potential for overtopping if the pipes become frozen due to snow and ice. Should there be a rain-
on-snow event while these pipes are obstructed, the dams would be overtopped and likely fail.
At the main dam, we were unable to operate the penstock shutoff valve or the sluice valve; they
are apparently jammed. We could not see the screen on the penstock intake. The screen may be
damaged or have large openings as evidenced by the amount of debris found in the needle
(spear) valves.
The diversion dams all appear to be silted in. Diversion dam #3 is damaged and sheet piling has
been washed out or frost jacked. In addition, the wooden cap protecting the upper end of the
vinyl sheet piling has deteriorated.
It is difficult to determine if the main dam was properly sized for the watershed flows. During
our visit, there was very little inflow into the main dam or the other diversion dams as we saw
very little spill at any of the dams even though the hydro project was not operating. While studies
have suggested that the upper basin will provide adequate water for operation in the winter, there
is no documentation of the basin hydrology. From our observations while on site, we noted that
above elevation 400 there was snow accumulation beginning and above 800 foot there was
substantial accumulation of snow. It would be possible to increase the active storage in the main
dam to allow additional operation by cycling (operating the hydro project for short periods of
time and then shutting it down to allow the reservoir to refill). It should be noted, however, that
operation will be limited by the winter inflows. Furthermore, the cost to increase the volume
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 10
significantly (say to double its storage) could be expensive as it would involve the design and
construction of a new dam if the reservoir water surface elevation were increased. We believe
that more operating data is needed to assess whether there would be any benefit to increasing the
active storage.
While in the upper watershed, the Project Team noted that one tributary of Town Creek was not
diverted to the main dam. This tributary, located on the western side of the basin, is the City’s
water supply. Based on our observations, the City was not making full use of this water resource.
Consideration could be given to diverting this water to the main dam and then supplying the
City’s water needs from the penstock. There does not appear to be any documentation of this
tributary’s flows. However, we noted a significant amount of flow.
Powerhouse
The hydro-diesel powerhouse was visually inspected (see photographs in Appendix A). The
original powerhouse configuration had a diesel engine directly connected to the hydro turbine
through a clutch arrangement. It is not known when this arrangement was changed; however, the
arrangement now has a separate diesel gen-set.
The hydro turbine is a two-jet impulse machine manufactured by Canyon Hydro in Deming,
Washington. This is a compact horizontal unit that is rated for 150 kW with a net head of 685
feet and 3.5 cfs discharge. The deflectors are hydraulically operated with a counter weight for
emergency operation. The needles are also hydraulically operated and have limit switches for
open/closed position indication. A visual inspection was made of the turbine runner and the
runner appears to be in excellent condition. The general condition of the turbine appears good.
The turbine shutoff valve (8 inch 300# gate valve) is outside of the powerhouse and is hand
operated. The condition of this valve is not known. For typical hydro projects, this shutoff valve
would be located indoors and be protected from the elements.
The hydro turbine is connected through a flexible coupling to an 1800 RPM synchronous
generator rated at 140 kW, 0.8 power factor, which produces power at 480 V.
The hydro turbine-generator uses a Thomson & Howe control system. This system utilizes a load
bank for regulation of frequency, allowing rapid response to changes in system load. Impulse
turbines do not regulate frequency well (due to slow needle closure timing), so generally either
deflector control or a variable load bank must be used. Thomson & Howe also supplied small
hydraulic power units for the needles and deflectors.
While we were there, the Mayor attempted to put the hydro unit on-line. The unit began to spin,
came up to synchronous speed, closed in and loaded up to 10 kW. Shortly thereafter, the unit
tripped off. According to the Human-Machine Interface (HMI), there was no alarm that indicated
why the unit tripped off-line. It was not clear what the issue was with putting the hydro unit
online. The HMI indicated a penstock pressure of 331 psi when the unit was off-line. As noted
previously, the main dam level sensor is not functioning so there is no way to monitor the
amount of water in the main dam.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 11
The HMI system for control and monitoring of the diesel-hydro powerhouse was inspected. The
Mayor demonstrated the HMI system, which uses a desktop PC in the City Hall. This is the new
HMI system, which was developed and installed by EPS. The diesel gen-set was producing 80
kW at 490 V on October 26, 2009 at 17:00.
The diesel in the powerhouse is a relatively new John Deere with a generator rating of 150 kW.
The controls for the diesel are using the Thomson & Howe original equipment, which has been
modified by EPS. While there, we observed that the diesel was operating satisfactorily and
system frequency looked stable.
Operational and Maintenance Issues
The plant operating log sheets were reviewed. It was noted that there is not much detail with
respect to the operation or maintenance of the hydro turbine. Typically a power plant will have a
log book which allows an operator to document on a daily basis maintenance and operating
information. Information documented in the plant log book could include:
• Weather conditions and temperature
• Needle position
• Temperature of bearings, etc
• Maintenance performed
• Any unusual noises
• Outages and their causes
• Penstock pressure
• Main impoundment water level and any spill
• Diversion dams water level and any spill
Information of this type documented over a long period of time will facilitate analysis of the
Project and allow better recommendations for improvement. Because of the difficulty in
accessing the upper watershed, it appears that City staff rarely visit, inspect or maintain the
diversion dams and main dam. With reasonable access, vehicles and equipment City staff would
be able to perform these necessary visits and inspect and maintain the dams.
Based on the site visit and interviews with the City staff, we have the following
recommendations with respect to operations and maintenance:
• Maintain a plant log book as described above.
• Build a road to the upper watershed.
• Construct a small building for storage and maintenance activities.
• Provide City staff vehicles and equipment for maintenance of the dams.
• Develop an operations budget, which includes funding for assistance to the City for
technical support, spare parts, operator training and major maintenance.
• Provide training for City operations staff in hydro project operation, maintenance, and
documentation activities.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 12
Penstock Headlosses
The frictional losses in the penstock have been estimated based on the following:
Main impoundment dam water surface elevation 800 ft above MSL
Turbine runner elevation 26 ft above MSL
Penstock length 3000 ft
Penstock diameter 10 in
Penstock material Polyethylene (PE) pipe
Turbine maximum discharge 3.5 cfs
There is no documentation about the penstock that we were able to obtain; other than statements
in the data reviewed that 10 inch PE pipe was used. We were able to confirm the 10-inch-
diameter PE pipe at the powerhouse just upstream of the outdoor 8 inch isolation valve. Standard
IPS PE pipe comes in different pressure ratings. The gross static head is 776 feet, which is 335
psi. A PE pipe with a diameter to wall thickness ratio of 7.3 has a pressure rating of 320 psi, so
this is likely what was used. They may have used a combination of lighter wall thickness pipe
further up the penstock. Nonetheless, based on the assumptions above, the estimated headloss
due to friction at full load is 64 feet. Thus, the net head at the turbine would be 710 feet of head.
This is consistent with information obtained from Canyon Hydro (the turbine manufacturer) that
the turbine was designed for 685 feet net head and 3.5 cfs.
A test of the penstock was performed by Precision Power Company in 1998. Pressures in the
penstock were measured at the powerhouse and at two points along the penstock. In this test
report it was noted that at very high outputs (150 kW) there was excessive pressure drop. The
report stated that the pressure at the powerhouse was 340 psi with no flow, 330 psi at 50 kW and
300 psi at 100 kW. According to the report, output from the plant is limited to around 110 kW.
Based on the information available, it appears that the penstock is limiting the output of the
project and may have been undersized for the rated discharge of the turbine. Additional operating
information and investigation of the actual sizes and wall thickness of the penstock would need
to be made before an evaluation could be made. Given that the City’s demand does not exceed
100 kW at this time, this evaluation could be made at a later date.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 13
Recommendations
Dam Repairs/Modifications
Modifications and repairs to the dams in the upper watershed are needed for maximizing the
capture of water in the watershed.
The modifications recommended for the main impoundment dam include:
1. Replace all three valves. (2) 10" valves at the dam and (1) 8" valve at the powerhouse
near the harbor.
2. Provide insulated valve vaults for all three valves (6' dia. Cmp).
3. Move the air vent downstream to fit the valve vault around the upper valve.
4. Install an 8-ft wide by 20-ft tall trash rack that consists of a vertical 8' dia. CMP with the
face cutoff at an angle.
5. Extend the 3- 12" overflow pipes 80 ft into the pool to provide overflow protection when
the pool is frozen.
6. Provide air vents for the three overflow pipes to prevent siphoning.
7. Re-locate level sensor into trash rack in a stilling well.
Modifications recommended for the smaller impoundments include:
1. Excavate small ponds (~ 50 cy each).
2. Provide small trash racks for the three small ponds (8-ft x 3-ft horizontal trash racks).
3. Install sediment sluice pipes through the vinyl sheet piling on the three small dams.
Backfill and replace slope protection.
Following the implementation of the above dam modifications, we recommend that the operation
closely monitor the spills from the impoundments. By documenting the operation of the project
and the spill from the impoundments, a better determination as to the sizing of the main dam can
be made. As noted in the recommendations below, a plant log book and detailed records of
operations needs to be made to allow an analysis to be performed.
Upper Watershed Access Road
1. To properly operate the dams in the upper watershed, reasonable access must be provided
so the staff can safely travel to these locations and inspect and maintain the dams. An
access road with reasonable grades would allow ATV access in the summer and
snowmobile access in the winter.
2. Provide an access trail for 4-wheeler/gator/snowmobile
a. Use some gravel from the harbor.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 14
b. Use cellular confinement material (grid) or geotextile to form a base and sides
where the trail cuts through ridges.
c. Re-establish vegetation to maintain low visibility of trail.
Control System Replacement
Given the difficulty of City operations staff to get unit to properly parallel with the diesel, it is
recommended that the control system be replaced. EPS will address this recommendation and the
associated estimated cost in their report.
Turbine Inspection
It is recommended that a service technician from Canyon Hydro be brought to the site to perform
a full inspection of the unit. While the unit has not had a lot of hours of operation, it is nearly 20
years old and inspection and servicing are recommended by a factory technician.
Maintenance Equipment and Facilities
It is recommended that equipment be purchased to allow proper maintenance of the project. It is
not cost effective to have contractors perform maintenance of the main dam and diversion dams
at such a remote location. In order to get the City operators to routinely inspect and maintain the
dams and road, they will obviously need this equipment and a vehicle for transport. These dams
need to be cleaned out and maintained on a regular basis. Additionally, if a road is built to allow
year-round access to the dams, equipment will be needed for accessing and performing the
maintenance. Finally, a storage building will be needed to store the equipment and allow
equipment maintenance to be performed.
Equipment purchased should include:
• Small trackhoe/excavator – A small tracked excavator would allow maintenance and
repair of the four dams as well as maintenance on the access road.
• Generator set – Generator set would provide portable power for maintenance on the dams
and could also provide temporary power for the storage building.
• Solar panel – A solar panel would be used to keep equipment battery charged.
• Trash pump – A diesel powered trash pump is needed to allow maintenance of the dams.
• Gator – A Gator (rubber tired all terrain vehicle) would allow access to the upper
watershed for operations and maintenance personnel.
A small building (20 ft by 24 ft) will allow the equipment (track hoe, etc) to be stored indoors.
The building would also provide a place where supplies can be stored and equipment
maintenance can be performed.
Operations
The City staff should document all operation and maintenance of the plant in a log book and
maintain operating records to allow evaluation of the project operation and maintenance. A plant
log book should document daily activities (including any maintenance activities) and weather
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 15
information for the project. Daily data forms should document project operating information,
such as power, reactive power, volts, amps, Bearing temperatures, spill at the diversion dams and
main dam, icing, etc. Outage reports should be maintained and an annual outage report be
produced along with annual generation statistics.
Operators should receive regular training in hydroelectric project operations. Operators should
receive routine safety training.
An independent review of the project operation and maintenance should be performed annually
to determine areas where operations can be improved.
Typically hydroelectric projects should achieve an availability of 95%. Thus, any time there is
water available, the project should be generating power for use by the City.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 16
Cost Estimates
Dam Repairs/Modifications
The three small impoundments will be excavated to remove sediment, have fill compacted
around the scoured areas at the dam crest, be fitted with 3-ft by 8-ft trash racks, and have the
pressure-treated wood sheet pile protection replaced.
The main impoundment dam will have the overflow pipes extended into the reservoir to provide
ice-free overflow protection. In addition, the main penstock will have the outlet valve, the sluice
valve, and the powerhouse valve replaced. All of these valves will be protected in 5 to 6-ft
diameter corrugated metal pipe valve vaults. The cost for these repairs is estimated at
approximately $297,000, which includes surveying, design, permitting, construction
management, materials, and labor.
Upper Watershed Access Road
The access to the impoundments will be improved with a new ATV road. The low-visibility
road will use a geotextile base in places to stabilize the surface and reduce erosion. Finally,
vegetation will be established along the road and construction areas. Estimated cost for the road
construction is approximately $266,000, which includes surveying, design, permitting,
construction management, materials, and labor.
Control System Replacement
To be estimated by EPS.
Turbine Inspection
Cost for a Canyon Hydro factory technician to travel to Akutan and inspect the turbine is
estimated at $11,000. An allowance for repairs (bearings and packing, etc.) of $5,000 is
recommended. With a contingency, the total recommended budget would be $26,000.
Maintenance Equipment and Facilities
The following figures show an estimate of equipment prices that will aid in operation and
maintenance of the system. Freight from Tacoma is included in the previous costs as it is
assumed all would be barged together with construction equipment. Also included below is a
cost estimate for a building, which would be used to store equipment in the area near the main
impoundment dam.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 17
Description
Purchase
New
Purchase
Used (2006) Source
TB125 Excavator (6500lbs),
heated cab $ 31,770.00 $ 22,500.00
Star Rentals, Tacoma, Mike Evert
206-805-2119
70KVA Generator $ 35,751.00 $ 16,900.00
Star Rentals, Tacoma, Mike Evert
206-805-2119
6" trash pump diesel
powered/trailer mounted,
hoses included $ 15,900.00
Star Rentals, Tacoma, Mike Evert
206-805-2119
60W solar panel with 7amp
charge controller $ 499.99 Northern Tool, 1-800-221-0516
Gator XUV, heated cab 4x4 $ 19,000.00
Craig Taylor Equipment, 907-376-
3838
Pre-manufactured Metal
building $ 12,000.00 R&M Steel Co., Tom, 208-454-1800
door: 8x10w
10' tall ceiling
4" insulation
120lb snow load
Package weight <3000 lbs
FOB Tacoma
Site Prep work / concrete
pad for building $ 12,000.00
Procurement assistance and bidding is estimated at $15,000.
Contingency @ 30% is $42,600
Total estimated cost is $184,500.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 18
Project Schedule
A preliminary Project implementation schedule is as follows:
2009-2010 Preliminary engineering and permitting.
2010 Surveys, final design and permitting approvals. Final design report completed.
Development of procurement specifications (for equipment) and bidding.
Development of construction specifications/contracts and bidding. Bid evaluation
and recommendation. Award of contracts.
2011 Construction and delivery of all equipment. Construction monitoring and Project
startup and testing.
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 19
APPENDIX A
FIGURES AND PHOTOGRAPHS
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 20 Figure 3—Town Creek Site Plan Main Impoundment DamDiversion Dam 1 Diversion Dam 2 Diversion Dam 3
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 21 Figure 4 – Penstock Route and Powerhouse Location Penstock Powerhouse
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 22 Figure 5—Main Impoundment Dam • ...... ,-.......... . ... ...... ::::::----> .. " End .. _u __ .... , "_01_, --o.:>TE5: II_poIOO_ .... ~ ..... _ -----C<OH 50<> .... ('1<0""", ..,... " ___ I . SpoIwoy--.-...,.,' •
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 23 Figure 6 – Powerhouse r"-'-o
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 24 Figure 7 – Main Dam Cross Section AIR VENT VALVE BOX WOODEN SHEETPILE COVER EXISTING COMPACTED FILL ROCK RIPRAP FLUSH WITH TOP OF FILL PENSTOCK INTAKE SCREEN VERFLOW PIPES (EXISTING GROUND SURFACE VALVE BOX BEDROCK FOUNDATION NEW TRASH RACK SIZED FOR 2OCFS@ O.25fPS APPROACH VELOCITY AREA '" 60SF ViNYl SHEET PILING NOPERABLE BUTTERFLY VALVES EXISTING CONDITION CATWALK FOR TRASHRACK AND SCREEN ACCESS AIR VENT TO PREVENT SIPHONING NEW CMP VALVE VAULT; MOVE AIR VENT AS NECESSARY EXTEND OVERFLOW PIPE BELOW WINTER ICE LAYER INSTALL NEW RESILlEN"F WEDGE VALVE PROPOSED 'itrPOWERHOuSE------"",,--SLUICE PIPE NEW eMP VALVE VAULT TO POWERHOUSE------""---~SLUICE PIPE AKUTAN HYDROPOWER TOWN CREEK MAIN INTAKE SITE I ·1 I , ·1 McMILLEN,LLC j! _0_ __ .. r==~9::::--=-,--,------m, I ~ __ ~ __ ~ ____ ~ _________ ~ ____ _L ____ ~ ____ L_ __ ~~ __ ~ _____ ~ ____ ~ ____ ~ ___ ~ __ ~ ____ ~
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 25
Photographs
Diversion Dam #1
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 26
Main Impoundment Dam
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 27
Main Dam Spillway
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 28
Main Dam (from downstream)
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 29
Diversion Dam #2
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 30
Diversion Dam #3
,
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TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 31
Powerhouse
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 32
Turbine Hydraulics and Load Bank
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 33
Turbine Control Panel
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 34
Turbine Load Bank Controls
TOWN CREEK HYDROELECTRIC PROJECT—FIELD TRIP REPORT 35
Turbine Runner