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Fontenelle DamFontenelle Reservoir


Colorado River Storage Project

Fontenelle Working Group
Meeting Minutes
April 21, 2009

Participation

This meeting was held at Seedskadee National Wildlife Refuge on the Green River below Fontenelle Dam. Russ Findlay led the meeting. Meeting participants are listed below.

Purpose of Meeting

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.

Hydrology Presentation - Katrina Grantz

The hydrology presentation began with reservoir and basin current conditions. Fontenelle Reservoir is 34% full (119,000 acre-ft). The reservoir elevation is 6470 feet above sea level or 36 feet from top of pool. Inflow has been increasing and the five-day average is 1870 cfs. 950 cfs is the current release. Basin snow water equivalent (SWE) conditions are currently 96%, slightly above the conditions this time last year. The temperature and precipitation outlook for the next thirty days is slightly above average temperature and slightly below average precipitation.

The April most probable water supply forecast for the April to July spring runoff season is 715,000 acre-feet. The minimum probable (90% exceedence) is 485,000 acre-feet and the maximum probable (10% exceedence) is 990,000 acre-feet. The most probably forecast was updated mid-April to 750,000 acre-feet, or 87 percent of average. The historical average for the 1971-2000 period is 858,000 acre-feet and for the 1976-2005 period is 759,000 acre-feet. Given this forecast, Fontenelle is expected to receive more inflow this year than in the past three years.

The reservoir is expected to fill by August this year. June and July is expected to be the peak inflow period. Last year the peak release was 4,200 cfs for three days. The peak release this year is currently projected to be 3,900 cfs for 2 weeks with additional ramp up and down, making for a month of releases above powerplant capacity. This peak release flow, however, is highly provisional and subject to change based on changing basin and reservoir conditions. The maximum probable peak release (10% exceedence) is 6,000 cfs for a month and the minimum probable (90% exceedence) peak release is 1,200 cfs for a month.

Questions and general discussion followed the hydrology presentation.

General Discussion

Chuck Green of Reclamation at Fontenelle Dam described work that will begin next week on the stilling basin at the dam and requested that releases be held constant at 950 cfs until the work is completed. Dewatering, cleaning, and inspection of the stilling basin is scheduled to begin April 28th and to last two weeks. They plan to slowly dewater the stilling basin (no more than three feet a day) to avoid destabilizing the rip rap and banks of the stilling basin. A reusable rubber bladder coffer dam will be used for this work. This is the first time the dam will be used and though it is expected that releases of 1,200 cfs may not affect the coffer dam, it seems prudent to keep releases steady. Chuck noted that there is a very small possibility that the unit could trip offline. Chuck described the emergency action plan for such a event during the work. Because the power plant is the primary outlet of the dam, if the unit is not operating water is not being released downstream of the dam. Chuck figures that they have about 1 hour from water in the river and stored in the banks to either get the unit back online or if it seems like that can't be done in time, to deflate one portion of the coffer dam and release water through the bypass tubes (and stilling basin) to keep water flowing in the river. Chuck is working with Robb Keith of the Fish and Wildlife service to rescue any stranded fish in the stilling during this work.

Robb Keith of the Fish and Wildlife service indicated that they would like to see a flushing flow this year, especially after the recent years of drought on the Upper Green. He reasoned that if we delayed ramping up releases, it might be possible to get a higher peak later this summer. Robb said he would like to target a release as high as safety and reservoir operations will allow. Robb mentioned that 6,000cfs or higher (even up to 10,000cfs) would be great. Chuck Green noted that the max release through the powerplant is 1,725 cfs and releases above that go through the bypass tubes. Based on last years' peak release, Robb figures that a peak of about three days can do a lot to mobilize the sediment on the streambed. In low flows the sediment fills the pools; high flows scour out the pools and redeposit the sediment on point bars. For the river and the fish the quicker the ramp-up and the slower the ramp down, the better.

It was noted by Ben Bracken and Bryan Seppie of the Joint Powers Water Board that the water treatment plant does better with a slower ramp up. However, with advance notice certain ramp rates could be accommodated. It was also noted that, given the flexibility, it is preferable if the ramp up does not occur over the weekend. The preferred ramp rate was reviewed to be up 100 cfs per day (in two 50cfs increments) when flows are lower (e.g., below 1,000 cfs). When flows are higher, (e.g., closer to 2,000 cfs) it is preferred to ramp up 200 cfs per day (broken into two increases of 100 cfs), and at flows above 2,000 cfs, it is preferred to ramp up 500 cfs per day, in two increments of 250 cfs. They noted that it takes about one to two days for flows to get from Fontenelle Dam to the City of Green River, depending on the flow rate.

It was noted that the Safe Channel Capacity for the City of Green River is 11,500cfs. Katrina discussed that Reclamation does not send out press releases if reservoir releases are within the range of normal operations, even if the flows are higher than has seen in the previous year(s). Bypasses are considered normal operations for Fontenelle Dam. Katrina noted that in a prior conversation with Judy Valentine, the Emergency Management Coordinator, it was established that the normal email distribution from Katrina to the working group and public would suffice as primary notification about normal changes to operations. If the Emergency management office deems public notification is warranted, Reclamation is happy to do a joint press release with the City of Green River. However, if downstream flooding is expected, Fontenelle Dam has a protocol for public notification via press releases that includes the National Weather Service and Reclamation.

Hal Zehr of the City of Green River noted that work will be done on the Kayak Park this summer, but that they should be able to work around the proposed release schedule.

Carl Millegan of Seedskadee Wildlife Refuge mentioned that a cottonwood restoration program is being started by the Refuge (up to $500,000). May 2nd is the pilot plant project date. They expect to plant 300 trees. Carl would like to delay the peak to be as late and as high as possible. He would like a peak of 6,000 cfs to 10,000 cfs, but realizes that 6,000 may be more reasonable given the forecast. Carl noted that the Refuge plans to pump water to the planted cottonwood trees on the point bars. He says that flushing flows are needed once in every five to ten years and would like the cottonwoods to establish naturally (rather than by pumping). Carl noted that he would like to relate release rates (in terms of cfs) to river stage in the refuge. Katrina mentioned there is a USGS stream gage below the dam that reports both flow and river stage on the USGS web site. It was also suggested that the Refuge could measure stream stage at various flow rates with a stream gage. It was pointed out that the measurements should be at the most critical locations and that side channels may be a good place to monitor. An alternative "low tech" option was proposed: putting a stick in the ground and noting when the water reaches that stick and how high it gets on the stick and relate that to the known releases at Fontenelle Dam.

Carl also asked about current Fontenelle Reservoir operations and why Reclamation no longer operates by "filling and spilling". Katrina and Chuck explained that Reclamation doesn't like to use the spillway because it is an uncontrolled release. Five feet above the spillway equates to roughly 20,000 cfs of water and that can be a very destructive flow. Katrina also noted that a large portion of the headwaters (at high elevations) is ungaged by snotel stations and this can equate to a large inflow that may or may not arrive, typically just when the reservoir is near its peak. It was further noted that the dam can release 14,900 cfs from its controlled outlet works (power plant and bypass tubes) and that this should be enough of a peak for most flushing needs. It was noted that there are multiple needs on the Green below Fontenelle Dam including fish, river, habitat, water treatment plant, power generation, safety and though these demands can sometimes conflict, we do plan to try to balance the requests as best possible. Priorities, according to the FWS, were laid out to be: safe operation of the dam and channel capacity, filling the reservoir (to reserve water for the baseflow season), flushing flow as often as possible. Oxygen levels were also noted as important: at 700-900 cfs and temperatures around 80°F, the oxygen levels drop and the fish have trouble.

Given the discussion, Katrina outlined a proposed release pattern for the upcoming spring. Keep releases at 950 cfs until the work in the stilling basin is complete. Ramp up to powerplant capacity (approximately 1700 cfs) after that. Over 4-5 days, ramp up to 4,000 or maybe even 6,000 cfs, depending on how the summer shapes up. The ramp up rates is subject to the prior discussion. The preferred ramp down rate was reviewed with Robb to be: from 6,000 to 3,000 cfs ramp down 500 cfs per day (in two increments of 250 cfs), and then 250 cfs per day, and then below 2,000 cfs down to 200 cfs per day and then 100 cfs per day.Robb indicated that it is preferable to make two steps per day.

The final discussion was related to concern about Aaron Million's proposed pipeline out of the Green River below Fontenelle Dam. Robb Keith questioned whether operations of Fontenelle Dam could be affected by the pipeline and whether the Green River could support such a project. Ben Bracken and Mike Besson noted there is almost no likelihood that this project will go through for several reasons. It was also noted that any water right issued for the project will be a new water right and by Wyoming state law cannot supersede senior rights in the basin. In addition, even if everything were to pass, any change to operations of Fontenelle Dam for the project would be subject to a separate NEPA process.

Next Meeting

The workgroup’s next meeting was planned for Tuesday, August 18, 2009 at the Wyoming Department of Fish and Game in Green River, Wyoming. After the meeting, Walt Bratton of the City of Green River offered to host the next meeting at Green River City Hall and this is where the meeting is now scheduled to be held. UPDATE: The August workgroup meeting has been rescheduled for August 25, 2009.

Attendees

Name

Organization

Katrina Grantz Bureau of Reclamation
Eugene Smith Seedskadee Nat'l Wildlife Refuge
Hal Zehr City of Green River
Mike Meyer Jim Bridger Power Plant
Kate Kirk Seedskadee/ Cokeville Meadows
Steve Burt contract guide
Robert Keith Wyoming Game and Fish Department
Carl Millegan US Fish and Wildlife (Seedskadee)
Mark Neeley Bureau of Reclamation
Steve Hulet Bureau of Reclamation
Chuck Green Bureau of Reclamation
Ed Boe WY State Engineer's Office
John Beyer US Fish and Wildlife
Ben Bracken Joint Powers Water Board
Bryan Seppie Joint Powers Water Board
Mike Besson Wyoming Water Development Commission
Russ Findlay Bureau of Reclamation

Email comments/inquires to: ResourceMgr@usbr.gov