Stable Riverbanks Help Farmers Make Hay
Today we are hearing from Melanie Carter, a Partners for Fish and Wildlife Program Civil Engineer with the Virginia Field Office, stationed in Southwestern Virginia. I specialize in aquatic habitat restoration in the Upper Tennessee River Basin.
We hear complaints from farmers when riverbanks erode into their hay fields. As the bank retreats, trees fall into the river and valuable productive land is lost. Animals like muskrats start burrowing into the vertical bare soil, creating holes in the field. Rainwater enters the holes, perpetuating bank instability. Land along the river becomes dangerous for farming equipment access. The worst part about bank erosion is that the river is now overwidened and can’t access its floodplain during high flows. Nourishing nutrients and fine sediments are no longer deposited in the field to replenish the soil and productivity declines.
The Partners for Fish and Wildlife Program collaborates with farmers in the Upper Tennessee River Basin to restore riverbanks using bioengineering techniques. In this watershed, there are over 30 fish and mussel species listed as endangered or threatened under the federal Endangered Species Act, making stable riverbanks essential to protect these species.
Our restoration projects begin with stabilizing the toe of the riverbank at is original location. We use a mix of materials such as boulders, coir logs, or large woody debris, in order to provide habitat along the river’s edge for fish and macroinvertebrates. Next, soil is added in lifts behind the toe protection to reduce sediment entering the river during construction. Riverbanks are returned to a more gentle angle to allow vegetation to establish. And riverbank height is adjusted to ensure a connection between the river and its floodplain.
Native woody vegetation, such as willows and elderberry, are most effective at keeping banks in place, preventing erosion as well as providing habitat for birds and pollinating insects. We also encourage the farmer to create a riparian buffer along the river. You don’t need large hardwood trees to hold things together! Small shrubs and trees work just fine, reducing the shading effects on the field. Many of these species bear fruit and nuts that the farmer can harvest or enjoy the wildlife they attract.