Colorado River Storage Project
Fontenelle Working Group
August 19, 2008
This meeting was held at the Wyoming Department of Game and Fish in Green River, Wyoming. Ed Vidmar led the meeting. The 13 participants are listed below.
The purpose of operation meetings (held in April, and August) is to inform the public and other interested parties of Reclamation's current and future operational plans and to gather information from the public regarding specific resources associated with Fontenelle Reservoir. In addition, the meetings are used to coordinate activities and exchange information among agencies, water users, and other interested parties concerning the Green River.
Snow accumulation for the water year was at just below average levels. Water inflow to Fontenelle Reservoir was 68% of average this year. Conditions have been dry for several previous years, as well. However, the reservoir did fill this year. The official Apirl 1 st forecast projected the spring runoff water yield would be 705,000 acre feet (af). The actual yield was approximately 582,000 af, which was above the minimum probable forecast. Spring inflows had a double peak. Projections for next year indicate that the reservoir should fill.
It was pointed out that the reservoir’s water elevation must be at a minimum height of 6463 feet above sea level in order to produce power. Therefore, it is not desirable to let the elevation drop below this level. The reservoir is full at 6505 feet.
A prudent base flow for the 2009 water year is a release of 1050 cubic feet per second (cfs) at the dam. This base flow should be set by October 1 st or sooner if possible. Current releases are at 1550 cfs. Reservoir releases are currently being lowered by 100 cfs per day (50 cfs increments twice a day) until 1200 cfs is reached. After that, flows will be lowered by 50 cfs per day until base flows are reached.
Stage changes greater than 100 cfs per day affect the fitness of fish in the river. Changes at release rates below 1200 cfs are particularly hard on these fish if the changes are greater than 50 cfs per day.
Kokanee and Brown Trout spawn in the fall months in the Green River. There are two races of Kokanee; the early runs start entering the river at the end of August and start spawning during the first half of September with the peak of activity typically near the middle of the month. The late run Kokanee start ascending the river in late September and start spawning in early October with activity peaking mid month. Typically some of the late runs are alive well into November. In addition, the Brown Trout population in the Green River below Fontenelle Reservoir is wild (no stocking). The Brown Ttrout spawn October 1-Nov 15 with the peak typically between the 15 and 20 of October. Stabile base flows improve the spawning success of both the Kokanee and Brown Trout.
The kayaking races have been canceled since the structures constructed in the river for this purpose are not functional at the current flow regime.
Last year, base flows were kept at approximately 700 cfs.
Late summer thunderstorms can significantly increase river flows and turbidity. These uncontrolled changes make water treatment difficult for the plant. Changes in the release rate at the dam usually affect the stage of the river at the water treatment plant within 24 hours.
Jim Bridger Powerplant needs to place riprap along the banks in the City of Green River this fall. They need the river to be as low as possible to accomplish this work. They would prefer flows around the 800 cfs level, but this is not likely feasible. Lower flows (1050 cfs) should be seen by next Wednesday (8/27), and the plant could try to finish the riprap work then.
The Seedskadee Wildlife Refuge would prefer that the spring peak occur as close to the natural peak as possible. A peak prior to June is preferable to lessen the chance of washing out breeding bird nests. The refuge would also like flows to remain as high as possible until base flows are set. This would increase food availability for migrating birds.
The USGS gage below the dam is not currently functional, but the USGS plans to send someone to check on it later this week.
The local emergency planning group would like to be notified of planned changes in river flows. Reclamation has an established protocol for public notification of significant flood events. Those parties who would like to know of less significant stage changes can be added to the workgroup’s e-mail list where updates to planned releases are posted. Questions arose this year about whether the boardwalk or other low lying areas in town would be flooded.
Repairs to the dam’s spillway will necessitate the unwatering of the area. A bladder coffer dam will be used to accomplish this. This work is tentatively planned for early next spring.
The workgroup’s next meeting is planned for Tuesday, April 21, 2009 at the Seedskadee Wildlife Refuge.
Fontenelle Working Group Meeting Minutes:
|Robert Keith||Wyoming Game and Fish Departmet|
|Eddy Boe||WY State Engineer's Office|
|John Martin||US Fish and Wildlife Service|
|Walt Bratton||City of Green River, Parks and Recreation|
|Eddie Baker||PacifiCorp Energy|
|Ben Bracken||Joint Powers Water Board|
|Bryan Seppie||Joint Powers Water Board|
Email comments/inquires to: ResourceMgr@uc.usbr.gov