Notes:

A Brief History of the NIDThe site we see today was first conceptualized in the 1970s when Congress tasked the U.S. Army Corps of Engineers (USACE) with identifying, inspecting, and inventorying dams in the U.S (National Dam Inspection Act, PL 92-367).Early data gathering for the NID was led by USACE, which published the first inventory in 1975. By 1982, the NID included 68,153 dam records gathered from dam inspections, extensive record searches, and some feature extraction from aerial imagery. These NID databases were available on diskettes and compact discs.In the late 1990s, the NID was transitioned to a web-based platform and viewing the data on a map. Gathering data on dams also transitioned during this time - the most accurate data was now coming from states, territories, and federal agencies. This transition aligned with the establishment of the National Dam Safety Program.Information Available in the NIDSince transitioning to a web-based platform, site visitors have been able to download or export certain data. The NID is currently the only place to find and download national data at such a detailed level.Today, the database contains information for more than 91,000 dams that meet the following criteriaDams where a failure or mis-operation will likely result in loss of human life (high hazard potential).Dams where a failure or mis-operation would likely result in disruption of access to critical facilities, damage to public and private facilities, and require difficult mitigation efforts (significant hazard potential).Dams that meet minimum height and reservoir size requirements, even though they do not pose the same level of life or economic risk as those above – these dams are equal to or exceed 25 feet in height and exceed 15 acre-feet in storage, or equal to or exceeding 50 acre-feet in storage and exceeding 6 feet in height.The NID does not yet contain all dams in the U.S. that meet these criteria. Continued, routine updates to the NID and enhanced data collection efforts, focused on the most reliable data sources (primarily the many federal and state government dam regulatory programs), will help capture these dams and result in a more robust dataset over time.National Inventory of DamsContact NID at NID@usace.army.mil