Colorado River Storage Project
Fontenelle Working Group
April 21, 2011
This meeting was held at the Seedskadee National Wildlife Refuge below Fontenelle Dam and attended by sixteen 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.
Hydrology and Operations Presentation - Katrina Grantz
Ed Vidmar welcomed everyone to the meeting. Each person introduced themselves and their interest or involvement with Green River operations.
Katrina Grantz presented the 2011 hydrology of the Green River and what can be expected in terms of Fontenelle reservoir operations this spring and summer.
Fontenelle is currently 41% full which correlates to 31 ft down. The current release is being ramped up to 2,200 cfs with an average daily inflow of 1,700 cfs. The current snow water equivalent in the Upper Green river drainage is 135% of normal. Katrina noted the Drought Monitoring Index has a portion of southwestern Wyoming still listed as drought even though high flows are expected this season. The April 1 forecast for Fontenelle shows an Apr-Jul runoff volume of 980,000 acft as the 50% forecast and 1,250,000 for the 10% exceedence, and 690,000 for the 90% exceedence. The April 15th forecast increased to 1,100,000 ac-ft. The average April-July for Fontenelle is 858,000 acft. Fontenelle reservoir elevation is projected to get to 6505 ft this year.
The plan for releases from Fontenelle are for a current release of 2,200 cfs going to 4,000 sometime around mid May, and then ramping to 5,500 in mid June. The maximum scenario could get to a 7,600 cfs release or even higher, however, this is highly subject to change depending on timing of inflows and how forecasts change.
Forecast Presentation - Ashley Nielson
Ashley Neilson of the Colorado Basin River Forecast Center in Salt Lake City gave an update on the water and weather forecast. The Upper Green river has seen a seasonal precipitation of 129% of average since October 1, 2010.
April has been very wet, with some areas receiving 200% of normal precipitation for first 2 weeks of April. The forecast is for the next 5 days being very wet.
The soil moisture level readings are in the 90% range. This will correlate to a very efficient runoff season.
Ashley then explained how forecasts are made. Temperature, precipitation, radar, satellites, river gages, reservoir release, snow level readings are all taken into account to develop the runoff forecasts. The National Weather Service is currently using two types of forecasting models, a Statistical model and an Ensemble streamflow prediction model.
Ashley presented the Peak flow forecasts pertaining to the Upper Green River. The
Green at Warren Bridge gauge has a most probable forecast peak flow of 3500 cfs and the New Fork at Big Piney has a most probable forecast of 6000 cfs.
30 yr average discussion: The current average is ’71-2000. Beginning in water year 2012, the River Forecast Center will move forward to ’81-2010. The new average is significantly lower than the previous average (857kaf versus 726kaf for the April to July season). Forecasting models are being recalibrated to this new average, which includes a much better snotel station record. The result will likely be forecasts that are slightly lower in terms of volume than what has been seen over the past decade.
CBRFC updates – see NWS Powerpoint
Significant spring flooding expected in Utah and in the Green River Basin, particularly below Flaming Gorge; CBRFC is migrating to new software; working on updating 30 yr avg; evapotranspiration work; analysis of peak flow forecasts; experimental ensemble streamflow prediction forecasts are available (in addition to official ESP forecasts).
Joint Powers Water Board – Bryan Seppie was surprised by releases lower than they expected. Katrina mentioned that to avoid the risk of ice jamming, she waited until the ice was off the river and to accommodate WGFD population study increased releases only moderately. Current release rates will lower the reservoir a slight amount, however, inflows are not high enough yet to allow large releases. Releases will likely be increased around the first week of May. Bryan then asked about July releases. Katrina mentioned that the plan is to move water early (in May and June), to provide flexibility later in the season in case the forecast continues to rise. Bryan was concerned about July thunderstorms; if releases in July are (below 2,500 cfs), there could be issues with high turbidity when thunderstorm runoff enters the river. Currently 3,500 cfs is planned for July, however, this is subject to change. Katrina noted that higher releases in July are beneficial to JPWB.
Discussion of flows for Green River city’s river: The City mentioned that they are hosting a kayak event May 20-21. The City would like 3,500 cfs for event. Katrina mentioned that because it is such a high flow year, it will likely be very difficult to accommodate this request. This year, May is the time when releases need to be high to keep space in the reservoir for flood control purposes. Even though the kayak event is only 2 days, with ramping prior to and after the event, this would be nearly a week of lower flows. Katrina told the city it was likely that this would not be possible, though it will depend on the timing of runoff and what level the releases are around this time.
Discussion of flows through Seedskadee national Wildlife Refuge: The Refuge would like to see flows of 5,000 to 8,000 cfs in order to inundate backwaters for Cottonwood rehabilitation, particularly because it happens to be a wet year. The mentioned that 9,000 would be nice, and ideally would like to see the natural hydrologic cycle. However, they realize that these flows are not ideal for everyone on the river and are willing The Refuge also mentioned that they currently have pumps in the river to move water into the backwaters, so it is very helpful (and important) to have advance notice of when the releases are going to change. Except for extreme situations, Katrina sends out email notification at least 24-hours in advance of any release change.
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:
|Katrina Grantz||Bureau of Reclamation|
|Ashley Nielson||Colorado Basin River Forecast Center|
|Eddy Boe||Wyoming State Engineer's Office|
|John Yarbrough||Wyoming State Engineer's Office|
|Robert Keith||Wyoming Game and Fish Department|
|Anna Senecal||Wyoming Game and Fish Department|
|Erek Roosa||City of Green River Parks and Recreation|
|Allan Wilson||City of Green River Parks and Recreation|
|Katie Duncombe||City of Green River Parks and Recreation|
|Bryan Seppie||Joint Powers Water Board|
|Ben Bracken||Joint Powers Water Board|
|Ed Vidmar||Bureau of Reclamation|
|Kirk Jensen||Bureau of Relcamation|
|Steve Hulet||Bureau of Reclamation|
Email comments/inquires to: ResourceMgr@usbr.gov