Aquatic Barrier Inventory & Prioritization Tool

Aquatic Barrier Tool

National Aquatic Barrier Inventory & Prioritization Tool

Improve aquatic connectivity by prioritizing aquatic barriers for removal using the best available data.

Aquatic connectivity is essential

Fish and other aquatic organisms depend on high quality, connected river networks. A legacy of human use of river networks have left them fragmented by barriers such as dams and culverts. Fragmentation prevents species from dispersing and accessing habitats required for their persistence through changing conditions.

Recently improved inventories, brought to you by the Southeast Aquatic Resources Partnership (SARP) and partners, enable us to describe, understand, and prioritize aquatic barriers for removal, restoration, and mitigation. Through this tool and others, we empower you with information on documented barriers and standardized methods to prioritize barriers of interest for restoration efforts.

This tool and inventory were made possible by funding from the U.S. Fish and Wildlife Service, American Rivers, the National Fish and Wildlife Foundation, U.S. Forest Service, and state wildlife grant funding from Florida and Texas. This effort would not be possible without the collaboration of our partners from numerous state, federal, and non profit organizations as well as the National Fish Habitat Partnership.

In addition to state and local datasets, national barrier datasets used in this inventory include the National Inventory of Dams, USGS Waterfalls of the Conterminous U.S., and USGS Database of Stream Crossings in the U.S. Barriers are snapped to aquatic networks derived from the USGS High Resolution National Hydrography Dataset supplemented with additional information from the National Wetlands Inventory. Along with national data sources, several other regional and state efforts to collect barrier data were included in this inventory and are regularly updated within. To see a list of data sources as well as a link to submit a missing data source, click here.

This inventory and prioritization tool are planned for a full national expansion by the end of 2025. Barriers for Alaska, Nevada, California, the Great Lakes Region, and the Northeast Region are currently incomplete.

This inventory and prioritization tool is designed to guide users in identifying high priority barrier removal projects. To access information about to funding sources for barrier removal, please visit the Fish Passage Portal. The portal is a "one-stop shop" for anyone who needs information, funding, or resources to improve fish passage and aquatic connectivity projects. It provides landowners and public lands managers the tools to find funding across the federal government, as well as access to data, planning, and geospatial information.

Enhancing aquatic connectivity by empowering people with actionable data:


The aquatic barrier inventory is the foundation for identifying and prioritizing aquatic connectivity projects with partners. It provides essential information about the location, status, and characteristics of potential aquatic barriers.

Scroll down for more information.


In order to maximize partner effort and return on investment, aquatic barriers are prioritized based on their contribution to the aquatic network if removed. Quantitative metrics provide actionable information to assist barrier removal projects.



Aquatic connectivity teams make barrier removal projects a reality. By combining effort across organizations and jurisdictions, partners work together to identify, prioritize, and implement barrier removal projects.

Learn more about Aquatic Connectivity Teams by choosing a region from Explore regions at the top.

The Aquatic Barrier Inventory:

This inventory is a growing and living database of dams, culverts, and other road crossings compiled by SARP with the generous support from many partners and funders. Originally developed within the Southeast as part of SARP's Aquatic Connectivity Program, this inventory and tool have been expanded to a broader geographic area to empower state-level Aquatic Connectivity Teams and other collaborators with the best available information on aquatic barriers. The inventory directly supports prioritization of barriers by including metrics that describe network connectivity, landscape condition, and presence of threatened and endangered aquatic organisms.

This inventory consists of datasets from local, state, and federal partners. It is supplemented with input from partners with on the ground knowledge of specific structures. See an example of how the inventory can assist local partners to identify and prioritize barriers for removal.

If you have recently completed a dam removal, fish passage, or barrier remediation project, please use the following links to report these projects so they may be included in the inventory:

At a Glance

  • 49 states, Washington DC, Puerto Rico, and U.S. Virgin Islands
  • 540,642 inventoried dams(2,815 removed for conservation)
  • 288,490 road-related barriers assessed for impact to aquatic organisms(6,573 removed for conservation)

Data version: 3.10.0 (7/8/2024)

Note: the information on barriers is not yet complete or comprehensive. It depends on the availability and completeness of existing data and level of partner feedback. Some states are more complete than others but none should be considered 100% complete.

Map services

If you would like to access map services of a recent version of the aquatic barriers and connectivity results (may not match the exact version here), you can import one of the following connectivity analysis map services into your GIS tool of choice:

Get started using this tool:

Summarize the inventory

Explore summaries of the inventory by state, county, or different levels of watersheds.

These summaries are a good way to become familiar with the level of aquatic fragmentation for many states across the U.S. Find out how many aquatic barriers have already been inventoried in your area! Just remember, the inventory is a living database, and is not yet comprehensive across these states.

Prioritize aquatic barriers for removal

Identify barriers for further investigation based on the criteria that matter to you.

You can select specific geographic areas for prioritization, including counties, states, and watersheds. You can filter the available barriers based on criteria such as likely feasibility for removal, height, and more. Once you have prioritized aquatic barriers, you can download a CSV file for further analysis.

Explore the inventory by region:


Southeast region map

Great Plains & Intermountain West

Great Plains & Intermountain West region map


Southwest region map

Pacific Northwest

Pacific Northwest region map

Great Lakes

Great Lakes region map

Pacific Southwest

Pacific Southwest region map


(in development)
Alaska region map


Northeast region map

Get involved!

You can help improve the inventory by sharing data, assisting with field reconnaissance to evaluate the impact of aquatic barriers, joining an Aquatic Connectivity Team, or even by reporting issues with the inventory data in this tool.

Contact us to learn more about how you can help improve this barrier inventory and tool.

Roaring River Dam Removal, Tennessee, 2017. Mark Thurman, Tennessee Wildlife Resources Agency.
Roaring River Dam Removal, Tennessee, 2017. Mark Thurman, Tennessee Wildlife Resources Agency.

Need Help?

If you are not able to get what you need from this tool or if you need to report an issue, please let us know!