The NRCS Model to Estimate Monetary Benefits of Watershed Dams from a Specific Storm or Series of Storms

Since 1948, the National Resource Conservation Service (NRCS) has assisted local communities to build nearly 12,000 dams in 47 states. NRCS planned, designed, and constructed the watershed dams through USDA Watershed programs. The projects provide flood control, erosion control, water supply, and/or recreation. This paper describes the basis of the NRCS watershed benefits model that estimates the monetary benefits provided by each watershed project in the nation each day based on the rainfall that occurred in the drainage area of each dam. The model summarizes the benefits data by various geographical units such as watershed project, county, congressional district, state, and nation. It accumulates the benefits for various time intervals (daily to year-to-date) as well annual benefits and any user-defined period back to 2005. The model archives the rainfall amounts and monetary benefits computed for each geographical area for future use. The model uses the National Weather Service (NWS) daily rainfall data, NWS precipitation depth-duration-frequency data, and the NRCS National Inventory of Dams (NID) data. The monetary benefits data comes from the NRCS watershed database that includes the results of the economic analyses completed during the original project planning. NRCS updates the monetary benefits annually to current dollars. The total average annual monetary benefits for all watershed projects with dams is over $1.4 billion. The monetary benefits consider flood damage reduction to crops, pastures, fences, farm buildings, equipment, livestock loss, residential and commercial properties, utilities, roads, railroads, and bridges, as well as non-flood benefits such as water management (irrigation), livestock water, municipal water supply, recreation, and improved fish and wildlife habitat. The information from the model is helpful for educating residents and decision makers about the value of these projects, the benefits they provide to their community, and the need to maintain this important public infrastructure so it can continue to serve generations to come. The model reports the benefits immediately after a storm occurs so that news stories can report on the damage that did not occur due to the watershed projects, during the news cycle while the rest of the media is focusing on the devastation caused by the storm. The benefits model has been incorporated into the NRCS DamWatch application so that it is readily available to all DamWatch users.