Simulated and observed 2010 flood-water elevations in selected river reaches in the Moshassuck and Woonasquatucket River Basins, Rhode Island

Scientific Investigations Report 2013-5191
Prepared in cooperation with the U.S. Department of Homeland Security-Federal Emergency Management Agency
By: , and 

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Abstract

Heavy persistent rains from late February through March 2010 caused severe flooding and set, or nearly set, peaks of record for streamflows and water levels at many long-term U.S. Geological Survey streamgages in Rhode Island. In response to this flood, hydraulic models were updated for selected reaches covering about 33 river miles in Moshassuck and Woonasquatucket River Basins from the most recent approved Federal Emergency Management Agency flood insurance study (FIS) to simulate water-surface elevations (WSEs) from specified flows and boundary conditions. Reaches modeled include the main stem of the Moshassuck River and its main tributary, the West River, and three tributaries to the West River—Upper Canada Brook, Lincoln Downs Brook, and East Branch West River; and the main stem of the Woonasquatucket River. All the hydraulic models were updated to Hydrologic Engineering Center-River Analysis System (HEC-RAS) version 4.1.0 and incorporate new field-survey data at structures, high-resolution land-surface elevation data, and flood flows from a related study.


The models were used to simulate steady-state WSEs at the 1- and 2-percent annual exceedance probability (AEP) flows, which is the estimated AEP of the 2010 flood in the Moshassuck River Basin and the Woonasquatucket River, respectively. The simulated WSEs were compared to the high-water mark (HWM) elevation data obtained in these basins in a related study following the March–April 2010 flood, which included 18 HWMs along the Moshassuck River and 45 HWMs along the Woonasquatucket River. Differences between the 2010 HWMs and the simulated 2- and 1-percent AEP WSEs from the FISs and the updated models developed in this study varied along the reach. Most differences could be attributed to the magnitude of the 2- and 1-percent AEP flows used in the FIS and updated model flows. Overall, the updated model and the FIS WSEs were not appreciably different when compared to the observed 2010 HWMs along the Woonasquatucket and Moshassuck Rivers.

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Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Simulated and observed 2010 flood-water elevations in selected river reaches in the Moshassuck and Woonasquatucket River Basins, Rhode Island
Series title Scientific Investigations Report
Series number 2013-5191
DOI 10.3133/sir20135191
Year Published 2014
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New England Water Science Center
Description Report: v, 35 p.; Tables 3 and 4; Appendix 1
Country United States
State Rhode Island
Other Geospatial East Branch West River;Lincoln Downs Brook;Moshassuck River Basin;Upper Canada Brook;West River;Woonasquatucket River Basin
Datum North American Datum of 1983
Projection Polyconic projection
Online Only (Y/N) Y
Additional Online Files (Y/N) Y