Aquatic Barrier Inventory & Prioritization Tool

Aquatic Barrier Tool

Frequently asked questions

Photo: Kazuend

What is the purpose of this Inventory and Prioritization Tool?

The objective of this inventory and tool is to build a community of practice among resource managers and enable them to identify high priority aquatic connectivity restoration projects. Regularly updating barriers in this inventory allows it to better reflect the degree of aquatic habitat fragmentation from aquatic barriers across political boundaries at a national scale. We provide a collaborative atmosphere where all resource managers can contribute to the collective effort of restoring rivers and streams through aquatic barrier removal.

You can help improve the inventory by sharing data, assisting with field reconnaissance to evaluate the impact of aquatic barriers, joining a 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.

What can the Inventory and Prioritization Tool do?

The prioritization tool allows users to summarize and download barrier inventory information at different scales. It also allows users to prioritize barriers at different scales using different filtering approaches and different prioritization scenarios.

In planned future enhancements, it will be possible to summarize accomplishments over multiple years, such as miles restored through barrier removal by year.

What kind of barriers does the Inventory track?

We track dams (including diversions, weirs, low head dams), assessed road stream crossings, and waterfalls. We do not track beaver dams or other non-structural barriers at this time, though it is possible that we may track other types of barriers in the future.

What data sources are included in the Inventory?

This inventory is compiled from multiple sources at multiple scales. To best leverage data sources that are regularly updated by their data providers within existing efforts, we update with the best available data from data providers approximately four times a year.

For a list of datasets included in the inventory, please see this link. If you know of a data source we have not included, please fill out this form and we will contact you to ensure that it is included.

How is the Inventory maintained and updated?

The objective of this inventory is to highlight the efforts of states and local partners by compiling information and readily updating it from living sources of truth on a regular basis. For efforts consistently maintained by partners, we have set up automatic scripts to extract data approximately four times a year and check for updates to incorporate into the National Inventory and Tool. For static efforts, data is incorporated into the inventory when identified. We readily work with our partners and technicians to edit data and identify new structures using aerial maps, as well as attribute social feasibility.

If you are interested in helping to maintain our database and incorporate local relevance into its attributes using ArcGIS online, please contact us.

How can I report a missing barrier?

Our inventory is the most comprehensive aquatic barrier inventory within the United States, but it is not perfect and is still lacking barriers, particularly low head dams and diversion structures. If you are exploring the tool and notice a missing barrier, please contact with the coordinates, or when prioritizing within the tool, scroll to the bottom of the sidebar for the barrier in question and click Report a problem with this barrier.

The master inventory will likely be updated fairly quickly, but it may take several months for the public facing tool to reflect the new barrier. If you would like to know the priority of the new barrier, we can provide you with offline results via email.

How are barriers prioritized within the Tool?

Within the tool, a user can prioritize dams, assessed road stream crossings, or both barrier types together. Waterfalls are included within network analysis as well, but are not prioritized. A priority barrier to remove would be one that reconnects high quality habitat. For this reason, we calculate and use four metrics for each barrier:

  • Miles restored by the potential removal of the structure
  • Percent natural land cover within the floodplain of the structure's upstream network
  • The percent of the upstream network that is altered by canals and ditching
  • The complexity of the upstream network (number of stream size classes)

These four metrics can be combined into three scenarios:

  • network length
  • watershed condition
  • combined network lenght and watershed condition

Within the prioritization tool, users can identify a targeted set of filters to prioritize based on a wide range of available filters. These filters include the number of threatened and endangered species in a HUC12, landowner type, environmental justice, number of barriers downstream to the ocean, and more. Once an output is generated, users can toggle between priorities for the area of interest and also explore results for perennial reaches only or all (perennial vs ephemeral/intermittent) reaches.

Planned future enhancements include the ability to prioritize barriers for larger species vs smaller ones.

More information about how barriers are prioritized can be found here.

How does the Prioritization Tool deal with "beneficial barriers"?

To incorporate local relevance into the inventory such as the presence of beneficial barriers which prevent the migration of invasive species, SARP works to code barriers within a Social Feasibility field. Barriers that may be invasive barriers are marked as such, and therefore not available for prioritization in the tool. However, this data is lacking, and unless this information is available within an existing inventory, we rely on our partners to tell us where these invasive barriers are located.

To report an invasive species barrier miscoded within the inventory, as with missing barriers, please contact with the coordinates, or when prioritizing within the tool, scroll to the bottom of the sidebar for the barrier in question and click Report a problem with this barrier..