FCRPS Summer Spill 2005
by Federal Action Agencies
Post-operation analysis found that the cost associated with the lost energy production was a little over $63 million.
Approximately $3 million of the cost occurred in the spring and approximately $60 million occurred in the summer.
This report provides a summary of information and research results stemming from 2005 summer spill for fish passage at the Federal Columbia River Power System (FCRPS) dams in accordance with a court order in National Wildlife Federation (NWF) v. National Marine Fisheries Service (NMFS).
2005 Summer Survival Studies' Summary
(Note: The following data is preliminary and the final numbers may change slightly.)
Lower Granite: Tested RSW vs. spillway and route specific survival
Little Goose: Evaluated route specific survival
- Fish Passage Efficiency (FPE, the percent of fish passing via non-turbine routes) was very high under either test condition (RSW 97.5 percent on or without RSW 98 percent) with less spill in the RSW condition (18.5 kcfs versus 30 kcfs).
- Dam survival was higher with the RSW condition 93.9 percent RSW versus 89.5 percent without RSW.
- RSW spill condition had 67.7 percent of fish passing through the RSW with high relative survival (94.5 percent).
- Very few fish were bypassed under spill condition 4 percent with slightly higher numbers bypassed in RSW spill condition 11 percent.
Lower Monumental: Evaluated route specific survival
- Very high overall FPE (97 percent) even with lower spill rates due to adult passage issues.
- Spill effectiveness (percent of fish passing through the spillway divided by the percent of water passing through the spillway) high compared to other projects 1.9:1.
- With lower spill percentage at Lower Granite, the decrease in spill compared favorably to other projects, turbine passage remained low, bypass rates increased offsetting any decrease in FPE.
Ice Harbor: Tested RSW vs. spillway and route specific survival
- FPE very high at 96 percent.
- Lower survival in comparison to other projects, especially the forebay survival (72.2 percent). Important to note these may not be reservoir losses as many of the fish were noted to be holding in the forebay and they represent fish near the end of the migration.
McNary: Evaluated route specific survival
- Spill levels with RSW (23 kcfs) versus non-RSW condition (41 kcfs), FPE reduced slightly (95.2 percent versus 99 percent)
- Dam survival slightly reduced but very high (98 percent RSW versus 99.6 percent non- RSW).
- Survival through the RSW was 99.4 percent.
- Juvenile Bypass System survival high at 98.8 percent which is consistent with previous years information.
FPE lower than Snake River Project (81.2 percent) but still high compared to other Lower Columbia River Projects. Relative dam survival high (96.3 percent). Spillway survival high (100 percent). Bypass and turbine survival similar rates (86 percent). Need to look at bypass survival in relation to tailrace egress conditions
In June 2005, Judge James Redden of the Oregon Federal District Court granted a preliminary injunction to plaintiffs in NWF v. NMFS and directed the U.S. Army Corps of Engineers (Corps) to provide additional summer spill for migrating juvenile salmon and steelhead at Federal Columbia River Power System dams on the Columbia and Snake rivers.
The NMFS 2000 and 2004 Federal Columbia River Power System (FCRPS) biological opinions (BiOps) call for spring and summer spill for fish, but no summer spill at the Lower Granite, Little Goose, Lower Monumental, and McNary dams. Instead, the BiOps call for maximum collection and transport of juvenile fish at those dams in the summer.
The June 20 court order directed the Corps to spill for fish as follows:
A result of the additional spill was relatively more fish left to migrate in-river and less fish transported. The judge encouraged regional parties to discuss issues and reach consensus on how to implement the court-ordered spill operation. The Corps, working with the plaintiffs and others through existing Regional Forum committees, addressed a number of implementation issues, including:
Power Effects and Costs
The National Oceanic and Atmospheric Administration National Marine Fisheries Service's 2004 Biological Opinion for operation of the FCRPS dams for salmon and steelhead addresses needed configuration and operational actions to protect 13 species of listed fish. Snake River fall chinook were the primary Endangered Species Act listed species in the Snake River during the court-ordered spill.
Since the initial listings of the Columbia and Snake river salmon and steelhead, FCRPS biological opinions have called for spill and other operations for fish during spring and summer juvenile migration seasons at various dams. The BiOps have also called for "spreading the risk," or using two migration options including juvenile fish transportation and in-river migration. One key reason to transport fish in the summer is to protect them from the warm-water environment where predators are more active and where the fish may experience more stress than in other seasons.
This year the Corps funded biological research under its Anadromous Fish Evaluation Program and gathered information during the court-ordered summer spill operation to inform the region on the biological results of the operation on a dam-by-dam basis. Prior to the court order, several studies were planned including an evaluation of transport versus in-river survival, project survival studies at McNary Dam, and an evaluation of Removable Spillway Weir (RSW) effectiveness at Ice Harbor and Lower Granite dams. Following the court's spill order, regional agencies and tribes agreed to conduct project survival studies at Little Goose and Lower Monumental dams.
The project studies conducted this year are important in developing dam operations for in-river fall chinook in relation to the planned comprehensive fall chinook study. In September, the Fish Passage Center reported on a preliminary analysis of juvenile survival rates through the reach of river from Lower Granite Dam to McNary Dam based on PIT-tag data. Bonneville Power Administration (BPA) collected data on the cost of the additional court-ordered spill in terms of lost power generation revenues and other costs. Following is a summary of those studies and analyses.
While the 2005 research and analysis provides important information on juvenile survival, these studies do not provide immediate data on whether the summer spill operation will increase adult returns. A comprehensive research program to adequately answer this question of adult returns would require data from multiple out migrations and would likely take several years or more.
The Corps contracted with U.S. Geological Survey (USGS) and NOAA- Northwest Fisheries Science Center to perform radio telemetry research of juvenile fish survival through the dam passage routes and for a short distance through the downstream reservoir during the 2005 summer spill period. Research was conducted at each of the five dams (Lower Granite, Little Goose, Lower Monumental and Ice Harbor on the Snake River and McNary Dam on the Columbia River). At Lower Granite and Ice Harbor dams, data were also collected to evaluate fish passage over both conventional spillway operations and RSW operations.
Specific highlights of each of the project survival studies are provided in the PowerPoint slide presentation "2005 Preliminary Summer Spill Data," at www.salmonrecovery.gov. A synopsis of the information by project can be found at the end of this document.
PIT-tag Reach Survival Data and Estimates
The NOAA Northwest Fisheries Science Center annually estimates reach survivals of Snake River fall chinook through the Snake and into the lower Columbia rivers. That survival estimate will not be available until the spring of 2006, when researchers can obtain a better estimate of how many of the 2005 juveniles "hold over" in reservoirs this winter and migrate to the ocean as yearlings next spring. The holdover group of Snake River fall chinook is important because, while it comprises only a small percentage of the total out migration, in recent years it has accounted for greater than 50 percent of the subsequent adult returns to the Snake River.
Analyses of 2005 in-river survival could be interpreted as evidence that 2005 overall/system survival improved compared to previous years. However, a direct comparison to previous years cannot be made because fish transportation was maximized in previous years leaving very few fish to migrate in-river. A better comparison would be to use overall system survival, which includes both the survivals of those fish migrating in-river and those transported (including delayed mortality effects, or D-value).
Using both the NOAA Northwest Fisheries Science Center's and Fish Passage Center's empirical in-river survival estimates for the Lower Granite to McNary reach of 2004 and 2005, respectively, the estimated relative difference in overall system survival of juvenile Snake River fall chinook between the 2005 summer spill operation compared to a no spill (i.e., maximum transport, 2004 BiOp) 2004 operation could range from an adverse effect of about -6 percent (assuming a D-value of 0.41) up to a beneficial effect of nearly +7 percent (assuming a D-value of 0.18). (In absolute terms, the estimated system survival differences range from -1 percent to +1 percent.) These estimates assume the range of D-values identified in the 2004 BiOp for transportation and an equal in-river survival level in the McNary to Bonneville reach. It should be noted that little or no empirical in-river survival information for Snake River fall chinook is available in the lower Columbia River reach from McNary Dam to Bonneville Dam.
These results highlight the uncertainty in the data and the need to conduct a comprehensive evaluation of the relative survival to adulthood of juveniles transported versus those that migrate in-river.
Migration and Spill Timing
There are two main sources of information on the timing of the fall chinook migration this year. One source is fish passage or smolt indices. These passage indices provide a general indication of the shape and timing of the migration but are general to fall chinook and not specific to wild fish. Another source of information is PIT tag data from the U.S. Fish and Wildlife Service (USFWS)/NOAA study of wild, surrogate , and hatchery fall chinook (Connor et al, preliminary information).
The Fish Passage Center released an analysis of Passive Integrated Transponder (PIT)-tag data in September 2005, drawing the following conclusions:
The point estimate for subyearling chinook survival was the highest recorded in recent years (2001-2005) in the reach from Lower Granite Dam to McNary Dam during the period when spill was occurring in the Snake River.
And, unlike other recent years where survival either remained low throughout the summer period as in 2001 and 2002 or declined as in 2003 and 2004, the 2005 survival increased significantly later in the season.
There are several considerations or concerns to note about these conclusions:
BPA analyzed the financial impacts of the additional summer spill during 2005 in terms of lost energy generation, flexibility impacts, market price effects and transmission effects. To do the analysis, BPA created a theoretical operation of the Lower Snake projects and McNary based on how those projects would have been operated if not for the court order. This theoretical operation was patterned after actual historic operations over the past several years. The theoretical operation was compared to the actual 2005 summer spill operation. The spill operation affected system reserves and reduced system flexibility to respond to power needs. The risk that BPA would not be able to respond to major Northwest or West Coast wide power system incidents was increased.
While in-river and per dam survival estimates appeared to be relatively high, the survival to adult return is more pertinent and will be required for the full understanding of the issue of whether transportation or in-river migration is better for juvenile Snake River fall chinook migrants. This is a key question that has not yet been answered by current data. As adults return from this year's juvenile migration, the region will have better information, but even then there likely will not be conclusive results. The Agencies are planning to design and conduct comprehensive studies to address the transport versus in-river migration issue for listed Snake River fall chinook.
The Agencies continue to believe that, based on knowledge gained from scientific studies, transport during low-water years likely poses less risk to the population than leaving the fish in the river to migrate. The Agencies will continue to work with the region to try to gain more certainty about the best operations for salmon and steelhead, especially those out migrating during the summer.
Most salmon and steelhead in the Columbia River Basin encounter one or more hydroelectric dams as they migrate to and from the ocean. Fish passage systems provide various routes to help salmon and steelhead get past the dams.
Adult fish swim up fish ladders that are built into the dams. These systems have been demonstrated to work well, and overall adult survival through the system of dams is high.
Juvenile fish migrate past the dams by several routes: through the turbines, through juvenile bypass systems, through spillways, or by collection and transported in barges or trucks.
Turbine passage is often considered to be the least desirable juvenile bypass route, with a survival rate of 85 to 95 percent. Bypass systems and spill are meant to divert fish away from the turbines.
Juvenile fish bypass systems at the dams guide fish away from turbines by means of submerged screens installed in front of the turbine intakes. As fish follow currents down toward the turbines, the screens guide the fish back up to bypass channels in the dam. The fish are then either bypassed back out to the river below the dam, or they may be loaded into barges or trucks for transport. Survival rate through bypass systems is typically 98 percent or higher.
The Corps has operated a juvenile fish transportation program since the 1970s. Juvenile salmon and steelhead collected in the bypass systems at four lower Snake and Columbia river dams (Lower Granite, Little Goose, Lower Monumental and McNary) can be collected and placed in specially designed barges and trucks for transport past the remaining dams to a release point below Bonneville Dam. The survival rate for transported fish is about 98 percent to point of release, although research continues to better determine any delayed effects once the fish are released back into the river and if these effects can be minimized.
Spill passage is widely recognized as one of the safest means of juvenile fish passage. Water is routed through spillway openings rather than going through turbines to generate power or being used for other purposes. Water and fish rush through the spillway and into the river below the dam, with spill survival ranging from 93 percent to 100 percent. The biological opinion calls for spring and summer spill for juvenile salmon and steelhead passage at the lower Columbia and Snake river dams.
Other operations also aid in fish survival. When providing spill for fish passage, spilled water plunges to the river below the dam with enough force to supersaturate atmospheric gases in the water. These gases can build up to levels that are dangerous to salmon and other aquatic life. To avoid this, the Agencies actively monitor levels of total dissolved gas in the river and adjust patterns and quantities of spill to stay within allowable levels. Also, the Agencies monitor summer water temperatures in the lower Snake River and to help cool Snake River temperatures, cold water is released from Dworshak Dam on the North Fork of the Clearwater River during the summer months.
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