This Technical Guidance Note was primarily prepared as a contribution to the World Bank economic and sector work—mainstreaming environmental flow requirements into water resources investments and policy reforms jointly supported by the Environment Department and the Energy, Transport and Water Department. The technical note also forms a contribution to the Bank’s hydropower investments. The main objective of the note is to serve as a guidance document as opposed to a technical manual. It has been developed to assist World Bank staff and their clients to identify ways to better incorporate the benefits associated with environmental flow protection into hydropower dam projects.Most of the material in this note will be equally applicable to hydropower dams with either multiple objectives or a single objective, but the integration of environmental flow protection into projects with multiple objectives presents some special challenges. In addition, many issues covered in this note will be applicable to other types of water infrastructure projects.
Hydropower dams play a critical role in the health of river ecosystems throughout the United States, and hundreds of these dams will be relicensed by the Federal Energy Regulatory Commission (FERC) in the coming years. Such licenses lock in the operating and environmental protection requirements of such dams for periods of up to 50 years. Given the complex, dynamic nature of river ecosystems, as well as the impacts of climate change, there is pervasive scientific uncertainty about how to best manage dams for power production while protecting and enhancing environmental values such as water quality and fisheries. Unless dams are managed adaptively, with licenses that provide pathways for gathering and applying new knowledge and responding to changing conditions, we run the risk of locking in mistaken approaches and stymieing environmental improvements on our rivers for the next half century.
Climate and hydrologic fluctuations in the Pacific Northwest lead to large year-to-year variations in the strength of the Columbia River hydropower resource. We describe and present results from a seasonal hydrologic prediction system for the Columbia River basin that gives insight into the seasons-ahead behavior of this resource starting near the beginning of each water year. The forecast system is based on the real-time application of a state-of-the-science, macroscale hydrologic model coupled with ensemble climate forecasts. Estimates of initial land surface conditions, primarily in the form of snow water equivalent, are improved via the assimilation of snowpack observations, and forecast biases are reduced through statistical forecast calibration. The forecast system produces graphical forecast products designed to help water and energy managers understand the current state of the Columbia River basin, the climate outlook for the water year, and the implications of both for future streamflow.
Hydro-Québec is the largest electric power company in Canada with more than 35 000 MW installed for an annual generation of around 189 TWh. Hydro-Québec owns and operates over 57 powerhouses such as Eastmain-1 that was commissioned in 2005. The growing concern regarding the long-term contribution of freshwater reservoirs to atmospheric greenhouse gases (GHG), led Hydro-Québec, to study net GHG emissions from Eastmain-1 reservoir, which are the emissions related to the creation of a reservoir minus those that would have been emitted or absorbed by the natural systems over a 100-year period. This large study is realized in collaboration with Environnement IIlimité Inc., University du Quebec in Montreal and McGill University.Measurement of GHG fluxes were done with the used of a traditional technique, the floating chambers that measures GHG fluxes at the water-air interface and a new approach using automated systems measuring partial pressure of gas in the water column. Follow up of the CO2 and CH4 fluxes at EM-1 reservoir showed a rapid increase in both CO2 and CH4 emissions the first year after flooding and a rapid return to natural aquatic ecosystems values within 2 and 3 year for CH4 and CO2, respectively. Automated system and floating chambers show similar annual GHG mass balance. Overall GHG emissions from Eastmain-1 reservoir are very low in comparison to thermal power plant of the same capacity.