Bypass spill for juvenile anadromous fish out-migration and passage improvements to assist juvenile migrants together cost ratepayers hundreds of millions of dollars annually. The Northwest Power Act requires that the Northwest Power Planning and Conservation Council (the Council) consider the cost-effectiveness of its fish and wildlife program and determine whether its projects employ cost-effective measures to achieve program objectives. Summer bypass spill is regarded by some to be expensive and not cost-effective, while others believe that summer bypass spill is important for the restoration of wild salmon and steelhead populations.
This report presents principles and examples of the application of cost-effectiveness analysis (CEA) to actions intended to improve mainstem passage survival in the Columbia River Basin. CEA principles are reviewed and related analyses and policy issues are discussed. An example of the application of CEA to bypass spill and facility modifications is developed using information from a hydrosystem model (Genesys, operated by the Council), a model of Western power pricing (AURORATM, licensed by the Council from EPIS, Inc.), a model of juvenile salmon and steelhead survival (SIMPAS, Simulated Passage, developed by the National Marine Fisheries Service), and information on costs of facility modifications.
This juvenile passage CEA is preliminary. It is intended more to illustrate the potential for CEA than to determine the cost-effectiveness of particular passage improvements. CEA might increase the rate of implementation of cost-effective passage improvements because it shows that juvenile passage survival can be increased in the long run at a net cost reduction to power consumers. CEA, combined with the ability to borrow against future power revenues, might do even more to speed the implementation of passage improvements, and ultimately, the recovery of listed species.
Simple cost-effectiveness measures may be developed for actions that have measurable survival and cost effects. The measure chosen for this example is the cost of an action divided by the change in the percent of juvenile migrants surviving through the mainstem to below Bonneville Dam. Table ES-1 shows results.
Table ES-1 suggests that extended length screens at Lower Granite and Little Goose, and the Bonneville powerhouse II corner collector, are all highly cost-effective in comparison to August spill at Ice Harbor dam. For example, the extended length screens at Lower Granite dam appear to be approximately 50 times (600/12) more cost-effective for fall Chinook juvenile passage than August spill at Ice Harbor. The cost-effectiveness of the Bonneville corner collector appears to be approximately 6 times (600/95) that of August spill at Ice Harbor.
|Table ES-1. Summary of Juvenile Passage Preliminary Cost-Effectiveness Analysis.|
Cost Per Unit of Juvenile Survival for Selected Passage Actions
Million $ per Year per Percentage Point Increase in Juvenile Survival
Spring/ Summer Chinook
August spill at Ice Harbor
Extended length screens at Lower Granite
Extended length screens at Little Goose
Corner collector at Bonneville
One purpose of our analysis is to show how CEA might be used to identify combinations of actions, or scenarios, that make both ?power consumers? and ?fish? better off. Results of three such scenario analyses are summarized in Table ES-2. For example, the first scenario combines the cessation of August bypass spill at Ice Harbor with extended length screens at Lower Granite and Little Goose dams. Increased power revenues from reduced spill are expected to be greater than the annualized costs of the extended length screens, so net power system revenue (increased power revenues net of passage improvement costs) of $900,000 could be returned to ratepayers annually. At the same time, survival of Snake River juveniles would be expected to increase by 0.31% to 1.11%, depending on the stock, with no effect on Columbia River stocks. In this case, power revenues from reduced spill could fund passage improvements to increase juvenile survival while increasing net power system revenues.
Removable spillway wiers (RSWs) are expected to reduce bypass spill while maintaining or increasing juvenile passage survival. RSWs at Little Goose, Lower Monumental, and Ice Harbor dams are evaluated. It is assumed that bypass spill is reduced by half, but juvenile survival is not affected. The RSW proposed for Ice Harbor appears to be cost-effective: increased power revenues from reduced bypass spill should be more than enough to finance the cost of the RSW. The third example in Table ES-2 shows that net power system revenues from the Ice Harbor RSW are large enough to finance the Bonneville corner collector, which results in a measurable survival benefit, while still leaving $6.26 million annually for ratepayers.
In contrast, a RSW at Little Goose does not appear to be cost effective: increased power revenues are not even enough to pay for the weir. Results for the RSW at Lower Monumental are too close to call. These RSWs might be cost-effective if survival is increased, or if behavioral guidance systems are not required. In addition to illustrating cost-effective alternatives, CEA can help identify potential passage investments that should be put on hold pending an improved showing of cost-effectiveness.
Table ES-2. Summary of Juvenile Passage Preliminary Cost-Effectiveness Analysis.
Results for Cost-Effective Scenarios
Change in Percent Survival of Juveniles to Below Bonneville Dam
Annualized Net Change in Power Revenue plus Facility Costs, Million $ 1.
Snake River Fall Chinook
Snake River Spring/ Summer Chinook
Snake River Steelhead
Columbia River Stocks
Cease August Bypass Spill at Ice Harbor and Construct Extended Length Screens at Lower Granite and Little Goose
Cease August Bypass Spill at Ice Harbor and Build Bonneville Corner Collector
Build Removable Spillway Weir at Ice Harbor and Build Bonneville Corner Collector
1. Net power system revenue. Capital costs of facilities are annualized over 20 years at 4 percent real interest
There are a number of limitations to the preliminary CEA. First, some of the analysis is retrospective in that the extended length screens and Bonneville corner collector are already built. Second, the effects of passage improvements on juvenile survival are uncertain, and some future costs are uncertain. The analysis is based on conservative assumptions regarding biological benefits, and if costs are uncertain, the higher of the range of costs is used. Third, the analysis is based on annual average flow conditions. Results in any given year, or even a short series of years, might be different and affect both cost and effectiveness.
A fourth limitation is that there is currently no direct institutional mechanism whereby power revenues from reduced bypass spill can be used to fund passage improvements. On the other hand, Bonneville Power Administration (Bonneville) has some discretion for funding passage improvements that may be cost-effective. An Implementation Team, made up of representatives from federal and state agencies, the tribes, and utilities, is currently considering possible actions that could offset the juvenile survival effects of reduced summer bypass spill.
One purpose of the analysis is to identify information gaps and uncertainties that limit the identification of more cost-effective ways of increasing juvenile survival. Many information gaps associated with juvenile survival are well known. Delayed mortality, survival through the different passage routes, and spillway survival with RSWs are key uncertainties. On the cost side, the post-installation costs of the RSWs; for research, behavioral guidance systems, and operations should be clarified.