David P. Ahlfeld
This document is part of the Connecticut River Watershed Project, a federally authorized collaborative project of the U.S. Army Corps of Engineers (US ACE), the Nature Conservancy (TNC), the University of Massachusetts Amherst (UMass), and the U.S. Geological Survey (USGS). The project began in September 2008 with Congressional funding for this project with TNC and the USACE as equal funding partners.
The Connecticut River Watershed Project will identify management modifications for more than seventy influential dams in the Connecticut River Basin to increase environmental benefits while maintaining beneficial human uses such as water supply, flood control, and hydropower generation. Key project outcomes include a basin-wide simulation model and a basin-wide, multi-objective optimization model. The optimization model will determine possible environmental or hydropower benefits, explore coordinating release decisions, and explore best operating decisions for specific objectives. More information regarding the UMass simulation model can be found in Appendix I.
The models will provide numerous benefits. The models will allow water managers and key stakeholders to evaluate environmental and economic outcomes based on various management scenarios. They will inform flow recommendations that benefit both conservation objectives and humans uses. They will enable the USACE to better manage its dams, providing more natural stream flows while maintaining authorized flood control functionality. These tools will also contribute to decision making for future Federal Energy Regulatory Commission (FERC) licensing of hydropower dams.
The basin-wide optimization model employs a daily time step. The Deerfield watershed, a subset of the Connecticut River Basin, was selected to explore a sub-daily time step. Differences in the output of the sub-daily time step model and the daily time step model provide some insights into the value of increased temporal resolution. While providing beneficial hydropower, Deerfield dams impact the natural hydrology of both the Deerfield River and lower portions of the Connecticut River. Analysis of the sub-daily model examines possible tradeoffs between hydropower operations and meeting environmental targets.