Global changes facing the U.S. Army Corps of Engineers (USACE) can result in increased water demand and higher potential for drought, including areas of the country formerly thought to have ample supplies of water.
The droughts of the 1970's led UASCE to establish policy and guidance for the preparation of Drought Contingency Plans in the context of water management. ER 1110-2-1941, Drought Contingency Plans (pdf, 169 KB), was published by USACE in 1981 to guide the development of drought contingency plans (DCPs) that respond to public needs with respect to drought, including:
- identification of potential modifications to project regulation to increase capability to respond to a drought (given existing authorities and other constraints);
- planning on a regional, basin-wide and project basis;
- coordination with appropriate stakeholders during droughts; and,
- identification of long-term opportunities to modify project storage allocations.
These DCPs were directed to be prepared for each Corps project or system of projects that have controlled reservoir storage.
Updating Drought Contingency Plans to Account for Climate Change
Climate change has and is anticipated to continue to affect the frequency, duration, and spatial extent of drought in the United States. USACE recognizes the necessity of using the best available and actionable science on climate change impacts to water resources in updating DCPs to account for changing climate conditions, changing demographics and water demand, and improvements in technology and drought monitoring over the last decade to support sustainable water management.
An interdisciplinary and interagency Project Development Team (PDT) was established to compile drought contingency plan information and compare and contrast contents and methods previously used for forecasting drought frequency and intensity in order to evaluate gaps and robustness, develop analytical tools, and set the stage for future updates to plans and their guidance, if necessary.
Significant progress has been made to compile information related to existing drought contingency plans. This progress has been documented in a 2015 progress report. Also in 2015, the web portal was augmented to centrally store water control manuals, deviation policies, and current and historic deviations. In 2016, we continue to add information to the portal, and also to evaluate projected climate hydrology for utility in updating drought contingency plans.
For more information, see Drought Contingency Plans Fact Sheet (pdf, 186 KB).
2015 Progress Report
USACE has released USACE Drought Contingency Planning in the Context of Climate Change (pdf, 2.42 MB). The report reviews the status of the project delivery team and contains an overview of climate, climate change, and drought in the United States to aid in planning for current and future droughts at USACE projects. This report also summarizes the findings of 142 drought contingency plans covering 301 projects with respect to drought determination, drought actions, water law, potential surplus water availability, and drought history. Most of the plans reviewed were completed prior to 2000, before information on climate change was widely available. An internal USACE secure web portal was developed to capture the results of the project delivery team, including drought contingency plans, deviations, pilot information, and other drought-related information.
U.S. Army Corps of Engineers Western Drought Contingency Actions: Report to Congress
USACE has released a report to Congress on U.S. Army Corps of Engineers Western Drought Contingency Actions. In passing the Energy and Water Appropriations Act of 2016 (H.R. 2029, P.L. 114-113), Congress requested that USACE provide to the Committees on Appropriations of both Houses of Congress a report addressing Western drought contingency planning for any Western state subject to a gubernatorial drought declaration during water year 2015. The report presents the requested information in the context of USACE water management and drought contingency planning. It characterizes the water year 2015 drought, including the locations affected by gubernatorial drought declarations; discusses USACE water management policies addressing water control manuals, drought contingency plans, and deviations; and presents the requested information. Climate change impacts on the frequency and magnitude of drought are presented to provide background for USACE actions to improve preparedness and resilience to Western drought.
USACE Reservoir Sedimentation in the Context of Climate Change
USACE has released a new progress report, USACE Reservoir Sedimentation in the Context of Climate Change (pdf, 5.55 MB). USACE is the largest operator of dams in the United States. Each USACE dam was planned, designed and built to provide specific benefits to the American public, including navigation, flood risk reduction, hydropower generation, recreation, and water supply. Most of the USACE dams have operated for more than 50 years, with some approaching 100 years of operation. Sedimentation impacts all of these dams to varying degrees by reducing reservoir volumes over time. Even though sedimentation was taken into account in design, there may be gradual loss of functionality with respect to a dam's authorized purpose(s) over time due to sedimentation.
Changing hydrologic conditions can affect the amount of sediment input to reservoirs and also where sediment deposits within a reservoir. Knowledge of current reservoir storage capacity and how changes in sedimentation and reservoir storage volume are critical to updated DCPs. Understanding reservoir storage baseline is necessary to determine which reservoirs are vulnerable today from sedimentation and to project how current and future sedimentation will affect storage and operations during drought periods. USACE is currently conducting that baseline study. As part of the reservoir sediment baseline, six USACE districts were selected for detailed analysis as a representative sample of reservoirs in a variety of environmental settings. Information obtained from the pilot districts was used to develop a web portal to collect and house reservoir sediment information from across the Nation, including analytical data supporting efficient and sustainable reservoir sediment management.
USACE released a report in 2016 that summarizes the findings of the six pilot districts and the additional information housed in the new web portal. It provides recommendations on how to best achieve planned reductions in existing data gaps and how to identify the minimum survey frequency required to accurately project sedimentation impacts to reservoir project benefits. Only by understanding the rate at which sedimentation is encroaching on the authorized reservoir purposes can USACE develop plans to sustainably manage its reservoirs and maximize reservoir service life. This information also supports the development of updated DCPs.
For more information, see USACE Reservoir Sedimentation in the Context of Climate Change (pdf, 5.55 MB).