Flood-inundation mapping tools for two rivers in and Connecticut

The lower in Westerly, Rhode Island and Stonington and North Stonington Connecticut, and the mainstem Pawtuxet River in Cranston, Warwick, and West Warwick, Rhode Island incurred historic flooding during late March and early April 2010. In cooperation with Rhode Island Emergency Management Agency and the U.S. Army Corps of Engineers, flood-inundation maps depicting the areal extent and approximate depth of flooding, were developed for 1-ft increments of stage, for flood flows at the USGS Pawcatuck River at Westerly (01118500) and the Pawtuxet River at Cranston (01116500) streamgages, respectively.

For the lower Pawcatuck River, flood-inundation maps were developed for river stages from 6.0 to 16.0 ft, and for the mainstem Pawtuxet River for stages from 8.0 to 22.0 ft. Both maximum stages exceed the period-of-record peak stage at these streamgages, which occurred during the late March and early April 2010 floods. Flood- inundation maps referenced to current and forecasted water levels at streamgages can provide emergency management personnel Flood-inundation map for a reach of the lower Pawcatuck and residents with critical information for flood River, Rhode Island and Connecticut, corresponding to a response activities such as evacuations and stage of 15.0 feet, gage datum. The map approximately road closures, and post-flood recovery efforts. depicts the March 30, 2010, peak flood stage of 15.38 feet The flood-inundation maps are nonregulatory, at the USGS Pawcatuck River at Westerly, RI streamgage but provide Federal, State, and local agencies 01118500. and the public with estimates of potential flooding extent during flood events.

Study areas for the Pawcatuck and Pawtuxet River flood-inundation mapping studies, Rhode Island and Connecticut (red boxes).

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Flood-inundation map for a reach of the Pawtuxet River in Warwick, Rhode Island, near Interstates I-295, I-95, the West Warwick Wastewater Treatment Facility, and the Warwick Mall, corresponding to a stage of 21.0 feet above gage datum. This approximates the March 31, 2010, peak flood stage of 20.79 feet at USGS Pawtuxet River at Cranston, RI streamgage 01116500.

Reports documenting the two flood-inundation mapping studies are available for the lower Pawcatuck River at https://pubs.er.usgs.gov/publication/sir20185112 and the mainstem Pawtuxet River at https://pubs.er.usgs.gov/publication/sir20185043. Contacts: Gardner Bent, [email protected]; Greg Stewart, [email protected].