Flood and Storm Tracker (FaST) Maps

These maps were created to help assess impacts on nonindigenous aquatic species distributions due to flooding associated with storms. Storm surge and flood events can assist expansion and distribution of nonindigenous aquatic species through connection of adjacent watersheds, backflow of water upstream of impoundments, increased downstream flow, and/or creation of freshwater bridges along coastal regions. These maps will help natural resource managers determine potential new locations for individual species, or to develop a watchlist of potential new species within a watershed.

PDF One Pager NAS FaST

Initial FaST Maps are generated within days of a storm. How we do this.

Revised FaST Maps are generated once actual flooding data becomes available. See how.

Disclaimer: This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.



Midwest Spring Flood - Initial map

Upper Mississippi River Basin
March 18, 2019
Central US Flooding


Hurricane Lane - Revised map

Hawaiian Islands
August 17, 2018 - August 27, 2018
Hurricane Lane

Hurricane Florence - Initial map

The Carolinas
September 14, 2018
Hurricane Florence

Hurricane Michael - Initial map

Florida Panhandle
October 10, 2018
Hurricane Michael


Hurricane Harvey - Final map

Gulf coast of east Texas and western Louisiana
August 25, 2017 - September 3, 2017
Hurricane Harvey

Hurricane Irma - Final map

Peninsular Florida and Atlantic coast of Georgia and South Carolina
August 30, 2017 - September 16, 2017
Hurricane Irma

Hurricane Maria - Final map

Island of Puerto Rico
September 16, 2017 - October 3, 2017
Hurricane Maria

Hurricane Nate - Final map

Eastern Gulf Coast states
October 4, 2017 - October 11, 2017
Hurricane Nate

Hurricane images courtesy of NASA and NOAA

The initial USGS NAS FaST maps are created within 2-3 days of an event to quickly identify flooded 8-digit hydrologic units (HUC-8s) based on USGS Water Science Centers stream gages or storm tide sensors with water heights at or above flood stage. This map integrates flooded hydrologic units with known locations of established, or possibly established, introduced aquatic species. All hydrologic units surrounding known locations of introduced species are included as possible areas of infestation, until actual hydrologic connections have been determined (step 2, revised maps). The NAS FaST map identifies both the established species within a hydrologic unit and the potential species for new introductions (defined as established species in adjacent watersheds) due to flooding impacts.

The refined NAS FaST map enhancement provides information only on the locations with flooding conditions that could breach drainage divides. We utilize information on the relative flood height using the best available data from the USGS Water Science Centers including stream gages, storm surge gages, inundation maps (when available), and identified high water marks along with National Oceanic and Atmospheric Administration modeled storm surge. This information is combined with information on the elevation of the hydrologic units at the 8-digit level (HUC-8s) boundaries (drainage divides) identified from digital elevation models. The flood elevation data was mapped with the hydrologic units' drainage divide elevations to determine if the flooding conditions were of sufficient height to breach the boundary. These "connection points" are identified along the hydrologic units' boundaries.

Hydrologic units identified as being flooded and potentially connected as part of the refined NAS FaST map are established based on the best available data. This map may not include all flooded areas. The refined NAS FaST map focuses on the potential spread of nonindigenous aquatic species between hydrologic units and is not a map of flood inundation.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2019]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [8/18/2019].

Contact us if you are using data from this site for a publication to make sure the data are being used appropriately and for potential co-authorship if warranted. For queries involving fish, please contact Matthew Neilson. For queries involving invertebrates, contact Amy Benson.