Bugs Pay for Days of Steady Reservoir Releases to Reduce Costs to Hydropower Customers and Sustain Funds to Maintain Infrastructure

Abstract

Steady low reservoir releases allow downstream aquatic invertebrates (bugs) to lay and hatch eggs and increase production. These releases also reduce revenue from hydropeaking operations, increase costs to hydropower customers, reduce funds to maintain project infrastructure, repay project loans, and exacerbate hydropower production-ecosystem conflicts. This paper has the purpose to (1) quantify tradeoffs between the number of days of bug flows and hydropower revenue, (2) identify ways to reduce costs to hydropower customers, and (3) inform the design of a financial instrument to increase bug production, compensate hydropower customers for costs, and reduce conflict. A linear program identified tradeoffs between hydropower revenue and number of days of steady low releases per month for different contract and market energy prices and monthly release volumes across March to October months when bugs are most productive. We found that bug flows on 8 weekend days per summer month in 2018 from Glen Canyon Dam, Arizona reduced hydropower revenue by $300,000 (June) to $600,000 (August). Shifting bug flow days to Spring/Fall months reduced costs. To reduce conflict, we suggest creating a new financial instrument funded by the Federal Treasury for ~$300,000 to $600,000 per month. The instrument can give ecosystem managers more flexibility to choose days for steady low releases that advantage bugs and pay hydropower producers for costs. Next steps are to engage Federal agencies on the benefits and limitations of the proposed instrument and expand to steady high releases that mobilize sediment, build sandbars, and disadvantage non-native, invasive fish populations.