Colorado River Storage Project
Fontenelle Working Group
April 19, 2006
The meeting was held at the Seedskadee Refuge. Attendees 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.
Meeting began at 10:00 a.m. Rick Clayton led the meeting. The Fontenelle web page was mentioned by Rick. It can be found linked to Reclamation’s web page at: http://www.usbr.gov/uc/water/crsp/wg/ft/ftcurrnt.html. Meeting notes, data, and meeting presentations can be found there.
Presentation by Rick Clayton: Hydraulic Engineer for Fontenelle and Flaming Gorge for the Bureau of Reclamation.
193,200 acre feet (af) left to fill at Fontenelle Reservoir, 345,000 af is the reservoir’s capacity, there is 29 feet of space left to fill. Presently inflow averages about 200 cubic feet per second (cfs). Releases have been ramped up this week from winter base flows around 875 to 1375 cfs presently. Releases could reach 1750 cfs at the reservoir’s capacity. A graph of Fontenelle’s historical maximum elevations was presented.
Last years forecast predicted higher runoff that what actually happened. The June and July forecasts were raised above previous months, but all the water never materialized. We were unable to fill the reservoir last year because we expected a larger runoff. The reservoir’s water elevation ended up 6 feet below maximum. Ed Clark, of the Weather Service, prepares these forecasts. Forecasts made 3 to 4 months in advance of the runoff are uncertain. Reclamation uses these forecasts as the best available information, but we also try to look at the overall picture to form our own opinion. Reclamation uses data up to and including 2005 data to form averages. This allows us to take into account the recent drought years. Reclamation uses a reservoir routing model to aid in the operation of Fontenelle.
Last years peak flow was above 6000 cfs. This peak was provided to create a flushing flow for the river below the dam. It appeared that sediments were moved during these flows. Fontenelle has more operational flexibility at this time than Flaming Gorge.
Last fall and winter releases were gradually ramped down and the hydrograph was tailed out and then held at just below 1000 cfs. Requested flows were also provided to the Green River Water Park for kayaking recreation.
The power plant can generate power at releases as low as 300 to 400 cfs depending on reservoir water elevation. Maximum power plant generation is 10 megawatts at 1650 cfs or 11 megawatts at 1750 cfs. Cavitation of the penstocks can occur at reservoir water elevation of 6480 feet and lower.
As soon as ice is off the river we try to move toward full release. Brown trout fry are vulnerable to high ramp rates in the spring, so ramp rates need to be as gradual as possible.
Eleven snow tell sites are averaged to obtain a weighted average of conditions. This year conditions were average until January. Since then, above average precipitation has occurred. We have a larger snow pack this year over last year.
River forecast for April 15th is 875 af.
- Minimum probable runoff is 600 af at 90% probability of exceedence.
- Maximum probable runoff is 1200 af at a 10% probability of exceedence.
- Currently we are experiencing a wetter than average water year.
Rick showed the group release patterns that could be made under three different water year predictions. The first week in May, bypass tubes should be opened. Likely release schedules:
- If runoff is on the low side then we may release around 3000 cfs for about ½ week.
- Mid ranged runoff = 4500 cfs for about 4 weeks
- High runoff = 75 cfs for about 3 weeks.
- We would then ramp back down to around 1100 cfs if the reservoir was able to fill.
Water treatment plants need slow ramp rates. Tributary runoff causes turbidity, so these plants need reservoir water to mix with the turbid water.
We like to be releasing 6463 cfs as we start the runoff season. We try to produce as much power as we can without running out of water. Rick tries to keep as much water in the reservoir as he can. He keeps releases below 6500 cfs until July as a rule of thumb. A base flow of 1000 to 1200 cfs would likely benefit fish below the dam, 16,000 cfs is the maximum release from the reservoir.
We are still experiencing storms, and the forecast may be a bit low at this time. Soil moisture conditions may increase runoff. Small upstream reservoirs may be fuller than usual. We need to communicate with these high reservoir operators more often.
Currently, Fontenelle will likely ramp up at 100 cfs/day to a peak of 1725 cfs. Each day releases will be ramped in two stages. Once in the morning at 50 cfs and once in the afternoon at another 50 cfs. The reservoir is usually drawn down no more than one foot each day. It may be drawn down faster under emergency conditions. Flaming Gorge should fill to within 10 feet of full this year. The refuge would like to see as close to a natural hydrograph as possible.
Fontenelle Working Grooup Meeting Minutes:
The next meeting of the Fontenelle Reservoir Working Group is yet to be scheduled and will occur in mid-August of 2006. Contact Rick Clayton for confirmation of the time and location prior to attendance. Rick can be reached at 801-524-3710 or at email@example.com.
|Mike Meyer||Jim bridger PP||307.352.4285|
|W. Russ Findlay||Reclamation||801-379-1084|
|Carol Damberg||Seedskadee Wildlife||307.875.2187|
Email comments/inquires to: ResourceMgr@uc.usbr.gov