Colorado River Storage Project
Fontenelle Working Group
April 26, 2012
This meeting was held at the Seedskadee National Wildlife Refuge below Fontenelle Dam and attended by seventeen participants. See below for a list of participants.
The purpose of working group 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.
Ed Vidmar opened the meeting and welcomed everyone. Each paticipant introduced themselves and their interest or involvement with Green River and Fontenelle Reservoir operations. Ashley Nielson of the River Forecast Center provided an overview of water year 2012 hydrology and seasonal water supply forecasts. She also informed the group on the National Weather Service’s updates to the 30-year average. Katrina Grantz of Reclamation reviewed fall and winter 2011-2012 Fontenelle Reservoir operations and provided projections for upcoming spring and summer 2012 reservoir operations. Mark Neeley of Reclamation reported on the inspection of the stilling basin at Fontenelle Reservoir and discussed plans for upcoming work on the stilling basin. Meeting participants joined in general discussion to ask questions and voice concerns, interests, and ideas.
Ashley Nielson of the Colorado Basin River Forecast Center and forecaster for the Upper Green River Basin presented the 2012 hydrology and the upcoming seasonal water supply forecast. This winter started out with above average precipitation for October followed by a dry December. January precipitation in the Upper Green was average. The seasonal temperatures have been above average for the basin with March and April setting several record warm temperatures. The long range forecast indicates warmer and dryer than normal conditions. All this amounts to below average water supply forecasts for the Upper Green Basin the April 1st forecast for the April to July runoff season was 665,000 acre-feet (92% of average). On April 15th the forecast decreased to 645,000 acre-feet (89% of average). Ashley indicated that given the persistent warem and dry conditions, the May 1st forecast would likely be lower than the April 15th.
Ashley spoke on the National Weather Service's move to a new 30-year average. Beginning this water year, the new averages are for the 1981 to 2010 period (old averages were for the 1970-2000 period). The forecast models have been recalibrated and all reporting is based on the new period. Because the new 30 year period includes the recent drought, the new averages are significantly lower in the Upper Green Basin, when compared with the old averages. The new average for Fontenelle reservoir is 726,000 acre-feet of April thru July inflow volume, which is a 16% reduction when compared with the old averages. Flaming Gorge shows an 18% reduction when compared to the old averages.
Katrina Grantz of Reclamation's Upper Colorado Region and reservoir operations coordinator for Fontenelle Reservoir, presented current basin and reservoir conditions as well as observed and projected reservoir operations. She indicated that Fontenelle reservoir is currently 30 feet from full, or 42% of full reservoir capacity, which is typical for this time of year. Reservoir daily average inflows are approximately 1,200 cfs and releases are approximately 1,000 cfs. The April 25th SWE for Fontenelle was 42% of normal. Snowpack peaked three weeks earlier than average this year at 84% of average and significant melt has already occurred.
In terms of observed and projected reservoir operations, Katrina noted that last spring (2011) saw inflows significantly above average (168% of average) and releases peaked at 8,800cfs. This year is significantly drier and based on the April 15th forecast for April-July inflows to Fontenelle Reservoir, releases will be significantly lower. Given the most probable inflow forecast, the reservoir is projected to fill late this summer and the largest release from Fontenelle is expected to be about 2,600 cfs for several weeks in June, however this is subject to change with revised forecasts and observed inflow conditions. Given the reasonable minimum inflow forecast (90% exceedence), the reservoir would barely reach 6,500 feet in elevation (or six feet below the spillway crest), which is considered full, however releases would likely not exceed 1,100 cfs. Given the reasonable maximum inflow forecast (10% exceedence), the reservoir would fill and the maximum release would be approximately 6,200cfs for several weeks in June. Note that these projected operations are highly provisional and subject to change as basin conditions change, forecasts are updated and actual inflows are observed.
Katrina noted that concrete repair work on the spillway is scheduled for August and September. To accommodate this work, she has received a request to keep the reservoir elevation approximately 3 feet below the spillway crest (6,503 or below). This will limit water splashing over the spillway lip onto the workers when the wind blows.
Mark Neeley of Reclamation's Colorado River Storage Project Power Office gave a presentation on the inspection and planned repairs of the Fontenelle River Outlet Works (ROW) stilling basin. The unwatering and repair time to accomplish the necessary work should take about six weeks. The timing for the unwatering/construction will need to be related the hydrology of the basin and the planned spring releases. If the stilling basin is unwatered and there is an immediate need for ROW releases, the basin will be cleared out and releases will begin. There was discussion on the capability and planning of the use of the West Canal outlet works. The canal would only be used if the power plant was shut down, and then only for a short period of time (i.e 10 to 12 hours). The use of the West Canal has its own issues and capabilities. Most Work Group members agree that the July thru October timeframe would be the best time to perform the needed work in the ROW stilling basin. Any reduction in flows will need to consider river water temperatures below the dam. Increased water temperatures are detrimental to the fishery.
Ben Bracken (Joint Powers Water Board) indicated that the river is subject to turbidity events in the summer due to thunderstorms. These events can produce turbidities in excess of 800 NTUs which negatively impact the water treatment plant's operations. A steady flow release regime from Fontenelle in the summer months (July and August ) in the range of 1500 - 1700 cfs greatly enhances their ability to address these events.
Robert Keith (Wyoming Game and Fish Department) would like to see the reservoir maintain enough water in storage to keep flows high enough (i.e., 800cfs or above, if possible) throughout the fall and winter months. He said that 400-600 cfs in the winter in the river is not good for the fish. He would rather see something on the order of 1,300 cfs for the summer and then 800 cfs for the winter.
The next Fontenelle Working Group meeting is scheduled for August 18, 2011 at 10:00 am at the Joint Powers Water Board water treament plant boardroom in Green River, Wyoming.
Fontenelle Working Group Meeting Minutes:
|Ed Vidmar||Bureau of Reclamation, Provo|
|Katrina Grantz||Bureau of Reclamation, Salt Lake City|
|Ashley Nielson||Colorado Basin River Forecast Center|
|Mark Neeley||Bureau of Reclamation, Salt Lake City|
|Mike Meyer||Pacificorp, Jim Bridger Power Plant|
|Mike Besson||Wyoming Water Development Office|
|Jade Henderson||Wyoming State Engineer's Office|
|Robert Keith||Wyoming Game and Fish Department|
|Carl Milligan||US Fish and Wildlife Service, Seedskadee NWR|
|Gene Smith||US Fish and Wildlife Service, Seedskadee NWR|
|Erek Roosa||City of Green River Parks and Recreation|
|Allan Wilson||City of Green River Parks and Recreation|
|Bryan Seppie||Joint Powers Water Board|
|Ben Bracken||Joint Powers Water Board|
|Russ Findlay||Bureau of Reclamation, Provo|
|Kirk Jensen||Bureau of Relcamation, Fontenelle|
|Steve Hulet||Bureau of Reclamation, Flaming Gorge|
Email comments/inquires to: ResourceMgr@usbr.gov