TMT Worries Not Enough Water for Flow Augmentationby Mike O'Bryant
Columbia Basin Bulletin - January 12, 2001
The third worst water year of the past 11 years has Technical Management Team members worried there won't be enough water available to augment flows for endangered salmon this coming summer, let alone enough to keep all chum salmon redds watered below Bonneville Dam or to keep the power system from falling into another power emergency.
Already the water year is stacking up to be one of the worst in a decade, with snowpack in many places at 60 percent of normal and rainfall at 65 percent of normal. The conditions place the water supply forecast as measured at The Dalles Dam at 80.4 million acre feet of water, or 76 percent of normal for January through July. That puts the region in a similar situation to the one it found itself in during the low water years 1992-94, according to Rudd Turner, U.S. Army Corps of Engineers.
In this type of year it is unlikely all the competing needs for Columbia River Basin water will get what they want. There is the need to save more water for the spring and summer flow augmentation that will help juvenile salmon navigate their trip to the ocean. Absent a significant change in weather through winter and spring, the only action that can be taken now to ensure augmentation flows later is to drop flows in the lower Columbia River lower to allow more water to be stored in the large upstream reservoirs, such as Lake Roosevelt that backs up behind Grand Coulee Dam.
There is the need to maintain flows below Bonneville Dam to ensure chum salmon redds remain watered. The lower Columbia River chum that spawn every fall downstream from the dam are listed as threatened under the federal Endangered Species Act. Salmon managers at TMT think flow through Bonneville Dam should be set at a daily average 140,000 cubic feet per second, or at the least to set the tailwater elevation out of the dam at a minimum of 12 feet so that the redds near Ives and Pierce Islands remain covered with water.
And, finally, there is another need to keep flows at Bonneville Dam at about 130 kcfs to ensure a certain level of power production that will maintain the balance between power production and the demand for electricity. Below that level, the region could experience another power emergency like the one of Dec. 8 through 12, 2000, according to Pat McGrane of the Bureau of Reclamation.
"Even the most optimistic view isn't good," McGrane said. "Right now, we're trying to achieve a balance between flows for chum and the need for power."
Salmon managers have been asking for flows at Bonneville to be set at 140 kcfs to protect chum redds since November, but that level has not been achieved for several weeks. More recently the weekly average has been 132 kcfs. Yet, to maintain flow at that level requires the BOR to continue to draft Grand Coulee Dam, which will make it difficult to refill the reservoir this year. That's water that will be needed for flow augmentation later on.
"We understand that we can't do it all every year," said Cindy Henriksen of the Corps. "We're showing you this information so that you know what's ahead. We want to do the best for the chum, but we're also concerned for spring and summer flow augmentation. All of us can look at this information and then look at the choices we make and how those choices affect the future."
According to information provided by Turner, the appropriate lake level at the end of April (flood control elevation for that time of year) at Grand Coulee Dam for an 80.4 MAF year is 1,283.3 feet. However, to meet that flood control elevation, flows at Bonneville Dam should be closer to 100 kcfs in January, not its current 130 kcfs.
In fact, if flows at Bonneville Dam continue at the 130 kcfs rate, the April elevation at Grand Coulee will be 1,261 feet, over 22 feet lower than needed. However, Lake Roosevelt elevation will increase to 1,285 feet by May and to 1,289 feet by June. Those predictions are based on normal weather from now through winter and spring.
Information from BOR, which McGrane said is more optimistic than the Corps', but appears to be more pessimistic in the short run, shows that if flows at Bonneville Dam continue at 130 kcfs, Grand Coulee elevation will drop to 1,236 feet by the end of January and to 1,217 feet by the end of February. At flows of 120 kcfs, that changes to 1,241 feet in January and 1,234 feet in February. At flows of 110 kcfs, the change is to 1,246 feet in January and 1,249 feet in February.
Will weather turn, giving the Northwest the much needed rain and snowpack? Tom Farrell of the Northwest River Forecast Center said that snowpack as of Jan. 1 was below or well-below normal, as is precipitation across the region. The only weather indicator close to normal is temperature. The west side temperatures have been very close to normal, while temperatures east of the Cascades this winter are 1 to 2 F lower than normal. Farrell predicts average precipitation from April through July.
On the other hand, Kyle Martin, Columbia River InterTribal Fish Commission, said that other than a short blast of rain late this week, the rest of the month looks dry and it looks like January will end up below average in precipitation and snowfall. The long-term outlook doesn't look much better, according to Martin, who, like the River Forecast Center, uses weather to help forecast flows. He predicts precipitation this spring will be 70 percent to 90 percent of normal.
"It looks like we probably won't meet NMFS' target flows this summer, but we still could meet those flows this spring," Martin said. "But that will require a maximum flow at Bonneville of 125 kcfs. Flows on the Snake River look fairly ugly this year."
Martin predicted a fairly warm spring, similar to last year when the region experienced an early spring freshet and runoff. He also had noticed a warming in the southern ocean that could mean an El Nino event in 2002. "Perhaps that drying cycle has already begun," he said.
Martin recommended lowering Columbia River flows now to start saving that water for spring flow augmentation.
However, that recommendation was not what was in salmon managers' minds. Chum salmon are still showing up near Ives Island below Bonneville Dam, according to Christine Mallet, Oregon Department of Fish and Wildlife. She said biologists saw three new chum downstream from Hamilton Creek and two established redds close to the edge of the river that were close to being dewatered. Both Mallett and Jim Nielsen, Washington Department of Fish and Wildlife, said Washington is not prepared to sacrifice any redds now and wants TMT to order 140 kcfs of flow and a tailwater elevation of 12 feet to protect the fish and their redds.
Dave Wills, a new TMT member from the U.S. Fish and Wildlife Service, said his agency isn't prepared to sacrifice any redds and asked that the tailwater elevation be raised to 12.5 feet.
However, NMFS' Chris Ross recommended lowering the tailwater elevation from the current 12 feet to 11.7 feet, an action he believes will allow the region to store additional water "while still protecting most of the chum." Scott Bettin, Bonneville Power Administration, said his agency would like the tailwater target to be set at 11.5 feet.
Turner asked to drop the daily average flow to 130 kcfs and McGrane concurred, saying that at the rate water is being let out of Grand Coulee Dam, the lake elevation is likely to reach 1,240 by the end of January.
"When Coulee hits about 1,240 feet, all other storage projects will be down about 50 feet," McGrane said. "Reclamation is getting less inclined for Grand Coulee to be the only reservoir impacted. The days of drafting only Coulee are numbered. Reclamation has other obligations for the water."
He added that if the Bonneville Dam daily flow average remains as is, the region will be in trouble. 132 kcfs is still too high, he said.
TMT river operating agencies agreed to drop the tailwater elevation to 11.7 feet and to manage flow to maintain that elevation. McGrane believes that will result in a drop in daily average flows.
NRCS snowpack summary: www.wcc.nrcs.usda.gov/water/snow/colu_snowsum.pl
NRCS snowpack updates: www.wcc.nrcs.usda.gov/water/w_data.html
Northwest River Forecast Center: www.nwrfc.noaa.gov
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