Introducing the Massachusetts Statewide Hydraulic Modeling Tool

The U.S. Geological Survey (USGS), in cooperation with the Massachusetts Department of Environmental Protection and the University of Massachusetts at Amherst, have developed a GIS-based hydraulic modeling tool for Massachusetts stream crossing replacement projects. Many thousands of stream crossings in Massachusetts are currently undersized thus acting as barriers to aquatic organism passage and habitat connectivity with limited capacity to withstand floods. The USGS StreamStats web application provides preliminary culvert designs for conveying the 10-, 4-, 2-, and 1-percent annual exceedance probability flood flows, and to meet the Massachusetts Stream Crossing Standards for box, arch, and pipe culvert structures.

The GIS-based hydraulic modeling tool uses automated scripts to create input data files for the U.S. Army Corps of Engineers HEC-RAS hydraulic modeling program. The scripts create a stream profile and then extract required cross-sections upstream and downstream of the existing culvert using elevations derived from lidar data. The stream channel dimensions are estimated using bankfull channel geometry equations, and flood flows are estimated using regional equations.

StreamStats allows the user to generate a stream crossing report with information on location, roadway classification and associated hydraulic design flow, aquatic habitat quality and stream connectivity restoration potential, flood flows, bankfull channel geometry, and preliminary culvert design data. Additionally, the user can download the HEC-RAS input and output files. This web application provides municipalities, engineers, water managers, and others with a stream crossing planning tool that addresses their need to improve flood resiliency and aquatic organism passage with culvert replacement projects.