SHOKAN, N.Y. — Flooding is the most common natural disaster in New York State. With climate change predicted to increase flooding through more frequent and intense storms, many communities are working to improve their resilience to floods. One common method for reducing flood hazards is to enlarge the culverts and bridges that allow vehicles to safely cross over streams and rivers. Known collectively as road-streams crossings, culverts and bridges are under-appreciated pieces of infrastructure and key components of resilient communities.
Cornell Cooperative Extension of Ulster County offered a week-long training in late May on how to assess and prioritize culverts and bridges for enlargement using a new method piloted in Ulster County. Fourteen participants from three different Soil and Water Conservation Districts, the NYS Department of Environmental Conservation’s Hudson River Estuary Program, and the NYS Department of Transportation spent two days learning and practicing the “MOSCAP” method for assessing culverts and bridges.
The Multi-Objective Stream Crossing Assessment Protocol (MOSCAP) integrates assessment of four elements of road-stream crossings in the field: flood flow capacity, structural condition, geomorphic compatibility, and aquatic organism passage. MOSCAP was developed and piloted by the Ashokan Watershed Stream Management Program (AWSMP) from 2017-2018 and continues to be used by municipalities in the Ashokan Reservoir and Esopus Creek watersheds.
Replacing road-stream crossings is expensive, and with hundreds of them to maintain, transportation agencies often struggle with how to prioritize sites and allocate limited funds. A customizable scoring strategy allows municipalities to rank sites based on their specific priorities. Local municipalities can use the ranking to justify funding for replacement projects.
Trainees learned how to identify signs of geomorphic incompatibility between the stream and the crossing structure. Indicators of geomorphic incompatibility include high levels of stream bank erosion, excessive sediment deposition, and poor alignment of the opening. A geomorphically incompatible structure is at significant risk of catastrophic failure during a flood.
The MOSCAP method is published and available online at the AWSMP website: https://ashokanstreams.org/publications-resources/technical-data/
Development of the MOSCAP, as well as the recent field methods training was made possible with funding from the NYC Department of Environmental Protection. The AWSMP is a collaboration between Cornell Cooperative Extension of Ulster County, the Ulster County Soil and Water Conservation District, and the NYC Department of Environmental Protection.
–Cornell Cooperative Extension Ulster County