HomeMy WebLinkAboutE3-Attach3-Maps and NarrativeBurro Creek Hydroelectric Project
Burro Creek Holdings, LLC
Water Rights Application Polarconsult Alaska, Inc.
March 26, 2014 Page 1 of 4
PROJECT DESCRIPTION
Overview
The Burro Creek Hydroelectric Project (project) is a proposed run-of-river hydroelectric project
located on Burro Creek within the limits of USS 1560 near Skagway, Alaska. The project will
divert up to 110 cubic feet per second (cfs) of water from Burro Creek near the westerly
property line of USS 1560 (river mile 0.6, 340-foot elevation). Water will be conveyed to the
powerhouse via an approximately 2,700 foot long 42-inch diameter penstock to a powerhouse
located at 75-foot elevation above a prominent waterfall at mile 0.15 of Burro Creek. Total
head is approximately 265 feet, with net head at full flow of approximately 240 feet. Installed
generating capacity will be approximately 1.6 MW with annual energy generation of
approximately 5,300 MWh. The electricity will be used on site, or sold to the local electric
utility in Skagway or to the Yukon Territory in Canada. Off-site sales would require the
construction of a power line from Burro Creek to the purchasing utility.
Water will be returned to Burro Creek above the waterfall. The project diversion structure will
not impound a significant volume of water, and the flow in Burro Creek downstream of the
project will not be significantly impacted by project operations.
Major project features are described in more detail below.
Diversion and Intake Structure
Burro Creek at the diversion site cascades over cobbles and boulders at gradients of 5 to 10%.
No exposed bedrock is apparent in the creek based on review of aerial imagery and site
reconnaissance. The conceptual diversion and intake structure is a reinforced concrete weir
founded on alluvium and buttressed with local fill. The diversion will incorporate motor
operated gates to pass debris and flood flows, and the intake will be a low-maintenance
inclined plate screen to keep debris out of the penstock.
Penstock
The penstock will be an approximately 2,700 foot long, 42-inch diameter pipeline. The entire
penstock can be constructed of HDPE or PVC pipe. The pipe can be installed above ground or
buried. The installation means will depend on the geotechnical conditions along the penstock /
access route, and the final design and configuration of the penstock bench. A significant
portion of the penstock route crosses exposed bedrock, and it is expected to be more economic
to install the penstock above ground on pipe saddles in such areas.
No major avalanche chutes are apparent along the proposed penstock route.
Powerhouse and Tailrace
The powerhouse will be an approximately 36-foot by 36-foot building housing the turbine(s),
generator(s), switchgear, and controls for the project. Water will exit the power house to a
Burro Creek Hydroelectric Project
Burro Creek Holdings, LLC
Water Rights Application Polarconsult Alaska, Inc.
March 26, 2014 Page 2 of 4
tailrace that returns the water to Burro Creek. The tailrace will be an open ditch armored with
local cobbles and boulders.
Access and Staging
All construction equipment, material, supplies, and personnel would arrive at Burro Creek by
barge. The existing landing area is adequate for landing construction materials and equipment.
Existing cleared areas at Burro Creek are likely adequate for project staging. If not, staging
could also occur in Skagway, or additional staging areas could be cleared to the north of the
existing dock. There is adequate space in this area to maintain a vegetated buffer along the
shore to screen staging activities from view along Lynn Canal.
Existing trails on USS 1560 extend up towards the existing intake at elevation 235 feet. These
trails would be improved and extended to provide for equipment access for construction of this
project. Terrain above the existing intake is favorable for construction of trails up to the
westerly property line of USS 1560.
Construction Schedule
Construction will occur over one or two seasons. The first construction season would focus on
building the access trail up to the new intake site, building the powerhouse and tailrace, and
installing the penstock.
The second construction season, if required, would start with construction of the in-stream
diversion structure before breakup. This would coincide with a period of reliable low flow in
Burro Creek, simplifying the in-stream construction work for the diversion structure.
Burro Creek Hydroelectric Project
Burro Creek Holdings, LLC
Water Rights Application Polarconsult Alaska, Inc.
March 26, 2014 Page 3 of 4
FIGURE 1: PROJECT LOCATION
Burro Creek Hydroelectric Project
Burro Creek Holdings, LLC
Water Rights Application Polarconsult Alaska, Inc.
March 26, 2014 Page 4 of 4
FIGURE 2: PROPOSED PROJECT LAYOUT