Sediment and Small Habitats - Exel: Drexel University's Research Magazine
 
 

_FEATURE A WATERSHED MOMENT

_Sediment and Small Habitats

Sediment by erosion or runoff from farm fields can cause a “domino effect” on the ecosystem, according to David Keller, project coordinator within the Fisheries Department at the Academy.

_David Keller

Keller is the project coordinator for fisheries at the Academy of Natural Sciences of Drexel University.

The biggest threat to water quality isn’t what’s inside the stream, it’s what’s next to it. Sediment created by erosion or runoff from farm fields can cause a horrible “domino effect” on the ecosystem, according to David Keller, project coordinator within the Fisheries Department at the Academy.

Not only does the sediment affect the light penetration and water quality, but it can also change the substrate composition already in the river. Runoff sediment can fill in pore spaces, or spaces in between the substrate, which can transform the stream bottom from something more coarse to something more fine.
“Some animals use that substrate and pore space for habitat. So when you introduce sediment into a stream, it fills in the pore space and alters the habitat for the animals that live in the stream, like fish, salamanders and macroinvertebrates,” says Keller.

Though sediment runoff is a common problem throughout the area, special circumstances have caused Keller and other Academy scientists to focus on a very specific part of land along Barrett’s Run, in the Cohansey River watershed in New Jersey. There, the American Littorial Society, an environmental nonprofit, is currently restoring a seven-acre tract of farmland to a grassy meadow in hopes that their efforts will reduce sediment and improve water quality.

Currently, Academy scientists are assessing the impact of the new meadow by installing traps up and down the slope of the field that will measure the amount of fine sediment running off during storms. If successful, the meadow vegetation will hold onto the soil, slowing water flow and increasing infiltration into the ground.

Grounded

Academy scientists are looking for reductions in sediment runoff in a seven-acre tract of farmland that is being restored to a meadow of grasses.