The Strawberry hydroelectric project in Wyoming, US, has become the ninth project to be certified as low impact by the Low Impact Hydropower Institute (LIHI).
The project – the first facility to earn LIHI certification in Wyoming – is located on Strawberry Creek on 10ha of the Bridger-Teton National Forest in Lincoln County. The 1500kW run-of-river facility is owned and operated by Lower Valley Energy, and licensed by the Federal Energy Regulatory Commission (FERC). It is the first hydro power facility to earn LIHI certification in Wyoming.
The LIHI certification program is relatively new, having certified its first plant in March 2001. The Institute’s voluntary certification program is designed to help consumers identify environmentally sound, low impact hydro power facilities for emerging ‘green’ energy markets. While some hydro plants will not qualify, the certified total is expected to grow significantly.
‘We are pleased to be able to certify the Strawberry project as low impact,’ said Richard Roos-Collins, chair of LIHI’s Governing Board. ‘I am impressed with the way Lower Valley Energy’s management team approached the certification effort.’
Asked if he saw an upswing in the interest in the Institute’s Low Impact certificationprogram, Fred Ayer, LIHI’s Executive Director, responded: ‘Yes, and here’s why. We issued our first Low Impact certification in 2001. As of 1 May 2003 we had certified four projects, but since then we have added five projects, have one pending, and two more scheduled to be filed on 15 March. I’m expecting 2004 to be a banner year.’
The Strawberry Project consists of a reinforced concrete gravity dam 6.7m high and 33.5m long with a 12.2m long overflow spillway at an elevation of approximately 2113.6m, an intake sluice, a reservoir with a surface area of 0.8ha, a penstock, a power house with three turbine-generator units, a substation with associated transmission lines, and an operator’s dwelling.
The 37km long penstock results in a bypassed reach approximately 3.2km long. A 3m wide road provides access along the penstock and to the dam and impoundment. The applicant diverts all flow up to 1.3m3/sec from Strawberry Creek for power generation; there are no required minimum flows for the bypass reach. Facility operations dewater the bypass reach between late October and mid April. Below the facility boundary Strawberry Creek is dewatered by irrigation diversions (between June and September) and by natural subsurface flows. The applicant operates the project manually in a run-of-river mode.
The project is located on Strawberry Creek within National Forest land managed by the US Forest Service (USFS), approximately 4km upstream of the National Forest border at the mouth of the canyon containing the stream, and 12km upstream of Strawberry Creek’s confluence with the Salt river.
I am impressed with the way Lower Valley Energy’s management team approached the certification effort
A natural barrier at Shoshone Falls on the Snake river, to which the Salt river flows, prevents migration of any anadromous fish to the drainage. Irrigation diversions immediately outside the National Forest border dewater the stream in the growing season and block passage for native cutthroat trout.
Other factors limiting fish habitat downstream of the facility include high channel gradient and water velocities in certain reaches. According to the Wyoming Game and Fish Department (WGFD), the karst limestone geology of the area causes the stream in some locations to flow underground to subsurface streams, sink holes, and caves, with waters reemerging lower in the watershed. This natural phenomenon contributes to dewatering of Strawberry Creek downstream from the facility, and is the direct cause of dewatering in several reaches above the project site. Where Strawberry Creek does have surface flows upstream of the facility, extremely cold water temperatures makes for marginal fish habitat. Land and snow slides in the upper reaches of the watershed further disrupt flows and fish passage and degrade water quality and aquatic habitat. A decrease in grade at the dam site results in warmer surface flows, while the impoundment creates habitat that supports a recreational fishery of stocked Snake River cutthroat trout.
The Strawberry project meets LIHI’s eight environmentally rigorous Low Impact criteria addressing river flows, water quality, fish passage and protection, watershed health, endangered species protection, cultural resources, recreation use and access, and whether or not the dam itself has been recommended for removal.
Strawberry successfully completed LIHI’s application process, which includes a public comment period, review by an independent technical consultant, consultations with state and federal natural resource agencies, and evaluation by the LIHI Governing Board, including leaders in the river conservation and renewable energy fields.
The Board’s vote to certify the Strawberry project was unanimous and as part of that certification, the Board requires that the Lower Valley Energy, working with state and federal agencies, file a FERC required trout habitat improvement plan with FERC by the end of 2004 and receive their approval for the plan by March 31, 2005.
For further information about the Strawberry Project, or any of the other projects certified as Low Impact, please contact Fred Ayer, LIHI Executive Director at +1 207 773 8190, or visit the LIHI website at www.lowimpacthydro.org.
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