Under the Road or Over It? Choosing a Crossing for Kettle Marsh

Rainy Nights on Marsh Road

1Kettle Marsh Wildlife Refuge protects a large freshwater marsh and the hardwood forest beside it. Marsh Road, a two-lane county road, runs for 2 km between the two. Every spring, refuge biologist Dr. Henrietta Mwangi leads student volunteers from Linwood Middle School on animal surveys. The students work from the road shoulder in bright vests, always with refuge staff, and only in the early morning when traffic is light.

2Spotted salamanders and wood frogs spend most of the year in the forest. On the first warm, rainy nights of spring, many of them cross Marsh Road to lay their eggs in shallow pools at the edge of the marsh. Painted turtles cross the other way in early summer to dig nests in sandy ground. Frogs and salamanders eat large numbers of insects, and herons, raccoons and snakes eat them in turn. Each spring the volunteers count the wood frog egg masses in the marsh pools and the animals found dead on the road.

3The marsh also does work for the town of Linwood. During heavy rain it soaks up water and lets it drain slowly into Willow Creek, which lowers flooding downstream. Two small pipes under Marsh Road are the only way water can flow from one side of the marsh to the other, so the road acts like a low dam. About 800 amphibians and turtles are killed on the whole 2 km of road each spring.

4In 2025 the refuge tested an idea on one 400 m stretch of road: a low fence that animals cannot climb, which guides them to a tunnel under the road. A camera in the tunnel recorded 520 animal crossings that spring. A second 400 m stretch was left unchanged so the two could be compared.

5The refuge now has to pick a plan for the whole road. It has $400,000 to spend, and the road must stay open to fire trucks and ambulances at all hours. Its goals are to save as many animals as possible, keep the marsh's water flowing and keep drivers safe.