Many of the approximately 25,000 roadway crossing structures over rivers and streams in Massachusetts are undersized (Massachusetts Culverts and Small Bridges Working Group, 2020). Poorly-designed or undersized culverts and bridges can limit fish and wildlife movement, divide habitat continuity, and negatively affect aquatic organism passage, survival and population growth. (Massachusetts Department of Fish and Game, Division of Ecological Restoration, 2012). Additionally, undersized culverts can lack the resiliency needed to withstand large floods. Potential increases in flood magnitude and frequency from climate change may exacerbate these challenges over time. Improved designs for stream-crossing projects would provide better aquatic organism passage, stream continuity, and resiliency to future floods while minimizing adverse impacts such as upstream flooding, road flooding, road washouts, erosion, and degradation of rare species habitat.
To address these issues, MassDEP, in cooperation with the USGS and UMass Amherst, began a series of studies to develop a GIS-based hydraulic modeling tool to create preliminary culvert designs for stream-crossing replacement projects in Massachusetts. This tool will help municipalities evaluate potential culvert designs and facilitate the permitting of stream-crossing projects to meet the Massachusetts Wetlands Protection Act Regulations. Furthermore, a preliminary evaluation of the hydrology, hydraulics and ecological conditions of the project sites will be provided.
Photographs showing Bronson Brook at Dingle Road in Worthington, Massachusetts, before (top) and after (bottom) a stream crossing replacement. The 2008 replacement culvert project was designed to meet the Massachusetts Stream Crossing Standards. Click on images to enlarge. Photographs (top) by the Massachusetts Department of Fish and Game, Division of Ecological Restoration, and (bottom) by Paul Nguyen. Photographs used with permission.
Phase I
Phase II
Phase IIA
- Survey 30 stream crossings across Massachusetts
- Use the GIS-based hydraulic modeling tool to develop preliminary culvert designs for box, arch, and pipe culverts to convey the 10-, 4-, 2-, and 1-percent AEP flood flows and to meet the Massachusetts Stream Crossing Standards at 30 stream crossings across Massachusetts
- Integrate the preliminary culvert designs into the USGS StreamStats web application
- Compare the GIS- and field-based hydraulic models at the 30 stream crossings across Massachusetts
- Assess the accuracy of the hydraulic modeling tool and to improve it based on these comparisons
- Hydrolink newsletter - Summer 2025
Phase III
- Use the GIS-based hydraulic modeling tool to develop preliminary culvert designs for box, arch, and pipe culverts to convey the 10-, 4-, 2-, and 1-percent AEP flood flows and to meet the Massachusetts Stream Crossing Standards at stream crossings in the Deerfield, Hudson-Hoosic, and lower Housatonic watersheds, western Massachusetts
- Integrate the preliminary culvert designs into the USGS StreamStats web application
Phase IIIA
- Use the GIS-based hydraulic modeling tool to develop preliminary culvert designs for box, arch, and pipe culverts to convey the 10-, 4-, 2-, and 1-percent AEP flood flows and to meet the Massachusetts Stream Crossing Standards at stream crossings in the Westfield and upper Housatonic watersheds, western Massachusetts
- Integrate the preliminary culvert designs into the USGS StreamStats web application
Phase IIIB
- Survey cross-section data in about 20 coastal river reaches in Massachusetts
- Develop regression equations to estimate hydraulic geometry (width, mean depth, and cross-sectional area) for coastal rivers in Massachusetts
- Incorporate the coastal hydraulic geometry equations into USGS StreamStats
Phase IV
- Develop updated regional regression equations to estimate peakflows in urban areas of Massachusetts
- Incorporated the urban peakflow equations into USGS StreamStats
- Use the GIS-based hydraulic modeling tool to develop preliminary culvert designs for box, arch, and pipe culverts culverts to convey the 10-, 4-, 2-, and 1-percent AEP flood flows and to meet the Massachusetts Stream Crossing Standards at about 6,000 stream crossing in selected watershed across Massachusetts
- Integrate the preliminary culvert designs into the USGS StreamStats web application
Unnamed tributary to Trapfall Brook at Harris Road in Ashby, Massachusetts, on October 1, 2021. The shallowness of water in the culvert could impede aquatic organism passage.
Pearl Hill Brook at Mill Creek Drive in Ashby, Massachusetts on October 1, 2021. The drop at the outflow of the culvert would impede aquatic organism passage.
