Assessing Stream Crossings for Wildlife Safety

Matt Morris, an SVT AmeriCorps Member, assessed a culvert in Harvard.

Wildlife in the region around Harvard, Littleton, and Boxborough may soon benefit from the efforts of SVT and other conservation groups who have assessed local culverts and stream crossings.

We have evaluated 46 crossings and culverts in the region to determine whether any could be upgraded or renovated to create safe wildlife corridors.

“Whether they swim, hop, crawl or slither, the stream flowing through the underground culvert is the critical path for many species to survive,” said Don MacIver, President of the Littleton Conservation Trust. “It may be the route for a slow-moving snapping turtle trying to find a sandy area to lay its eggs or the long distance migrant American eel returning from the Sargasso Sea winding its way through many barriers reaching far inland to a home stream bed.”

Culverts make it possible for cars, bicycles, and pedestrians to cross over a stream, but they can create blockages in the stream itself and prevent fish and other wildlife from safely navigating the waterway.

For example, culverts that sit below water level on one side of a road but above water level on the other side prevent fish from swimming upstream. Culverts that encompass only the width of a stream and not any of the adjacent land offer no help to small animals that travel along stream banks in search of food and nesting habitat. If forced to cross over the road, these animals risk being hit by cars.

“Upon climbing down an embankment there almost always is a surprise as to what the culvert and stream are like – possibly massive granite stonework, abandoned piping, or a poured concrete sluiceway,” said MacIver.

Marc Sevigny, Clerk of the Harvard Conservation Trust, explained that “Simple design changes when replacing a culvert can mean the difference between safe passage of fish and wildlife under roadways, or a barrier to their free movement.”

The assessments were completed by SVT and our partners in the  High Ridge Initiative (HRI), which aims to protect more than 1,900 acres of forest and farmland in the region. We used assessment protocols developed by North Atlantic Aquatic Connectivity Collaborative. In Fall 2019, SVT sponsored training sessions in the protocols for the HRI partners.

The assessment team is now reviewing their data to identify which culverts are good candidates for improvements. To help pay for the upgrades, the three communities may be eligible for state funding through the Massachusetts Municipal Vulnerability Preparedness (MVP) program

The MVP program encourages Massachusetts towns and cities to improve their resiliency to the effects of climate change, and it provides funds to help communities perform vulnerability assessments and implement specific projects.

Culvert upgrades are listed as a “nature-based solution” for mitigating the effects of climate change. The upgrades enhance flood resiliency, improve river and stream ecosystems, and allow for aquatic and terrestrial wildlife passage, making the people and wildlife of a community more able to withstand climate change.