LOW-HEAD DAM BASICS

The Low-Head Dam Inventory is a national dataset that captures low-head dams in the U.S. Dams included must meet the following definition:

• A river-wide artificial barrier that generally spans a stream channel, blocking the waterway and creating a backup of water behind the barrier, with a drop off over the wall of not less than six inches and no more than 25 feet.

The U.S. Army Corps of Engineers enters and updates information about low-head dams. Are you responsible for a low-head dam? Is there a low-head dam near you that is not yet included in the dataset? Please contact us – the helpdesk will review the information provided and verify it prior to loading it into the dataset.

Site visitors can find information about low-head dams by using the “Explore Map” button on the homepage. From there, you can type in a location or click on an existing dam identified on the map. Visitors can also use the search functions and filters to select a particular geographic location, such as county, state. The results will be shown as a list of low-head dams that can be individually selected. A user guide will be available in 2026.

The initial data is based on information collected since 2021. About 13,000 structures were initially identified. The U.S. Army Corps of Engineers is completing an initial review of this data to confirm structure locations and inclusion in the dataset. Site visitors will see continued changes to available data.

The U.S. Army Corps of Engineers will continue to work with others to refine and improve available data to help improve public safety. Additional and improved data will be added as it is received. If you have information about a dam already in the dataset, or know of a dam to add, please contact our helpdesk. Email the helpdesk at NID@usace.army.mil.

If you are responsible for a low-head dam in the inventory or have information to add, please contact the helpdesk. Email the helpdesk at NID@usace.army.mil.

Dams across the country are operated and maintained by many different entities. You can view the responsible entity for each dam within the Description page if the information is available.

If known, the Low-Head Dam Inventory will list a responsible entity for each structure within the Description page. However, this information is not yet available for most dams in the inventory. If you are responsible for a low-head dam in the inventory, please contact the helpdesk. Email the helpdesk at NID@usace.army.mil.