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USACE Releases 2016-RES-01 – Status and Challenges for USACE Reservoirs: A Product of the National Portfolio Assessment for Water Supply Reallocations

Published May 11, 2016
2016-RES-01 – Status and Challenges for USACE Reservoirs: A Product of the National Portfolio Assessment for Water Supply Reallocations

2016-RES-01 – Status and Challenges for USACE Reservoirs: A Product of the National Portfolio Assessment for Water Supply Reallocations

ALEXANDRIA, VIRGINA.   U.S. Army Corps of Engineers (Corps) multi-purpose reservoir projects manage the risks of flooding, ensure reliable supplies of water for public health and economic production, generate clean and affordable electricity, provide safe and enriching opportunities for water-based recreation to the public, and maintain adequate levels of streamflow to support navigation and commerce on the inland waterways, aquatic and wildlife habitat, and water quality.  Many of the Corps dam and reservoir projects have passed the end of their original 50-year planning lives and are entering a life-cycle phase of long-term maintenance and modification.  In 2008, the Corps began the National Portfolio program with a survey and assessment of the reservoir project portfolio in support of its overall strategic goal of managing the life-cycle of water resources infrastructure systems in order to consistently deliver sustainable services.  This report presents major findings of the survey, discusses considerations and case studies related to project modifications, as well as ongoing work and next steps to better understand the status and challenges in continuing to operate and maintain these complex and dynamic projects to best serve the evolving needs of today and future generations. 

The survey collected information on water management, water supply and reservoir sedimentation at 465 reservoir projects across the United States that together impound about half of all constructed reservoir storage space in the country.  The water management portion of the survey developed over 37 million daily measurements of inflows, storage and releases; the equivalent of an average forty year period of record for the surveyed projects.  The survey effort was leveraged to add water supply data to the Corps operations management database, enabling tracking and reporting for the hundreds of water supply storage agreements that the Corps maintains with state and local interests across the country.  The survey of reservoir sedimentation assisted with cooperative development of the national Reservoir Sedimentation (RESSED) database.

In subsequent years, assessments and products were developed focusing on these areas, as well as considerations related to environmental concerns and future uncertainty.  A 2010 assessment of water supply needs led to a priority list for water supply storage reallocation studies at 52 projects across the country.  Through the normal budget and appropriations process, the Corps has since been able to fund study work at 26 of the 52 priority projects, as well as 10 other projects that were identified as needs evolved.  The Corps Committee on Water Quality assessed ongoing efforts to improve water quality and ecological functions through relatively simple structural and operational modifications, as well as evolving water quality and ecological concerns that may challenge the Corps in meeting the authorized purposes of dam and reservoir projects.  Since 2010, cooperative work with the Nature Conservancy’s Sustainable Rivers Program has been funded through the National Portfolio program.  A 2013 pilot study assessed the use of down-scaled global climate model data in forecasting conditions related to future streamflow and reservoir operations.

Next steps for the National Portfolio program are recommended to continue in these areas of concern, and include developing methods, tools and training to better inform the complex tradeoff considerations that are involved in assessing modifications to multi-purpose reservoir projects; continuing to periodically collect and assess water management data; developing policy and technical guidance related to project modifications to enhance water quality and ecosystems; and collaborating with ongoing efforts to better understand risks and obstacles related to sedimentation and sediment management and the potential impacts of climate change at dam and reservoir projects.

Download 2016-RES-01