Pioneer Farm bank erosion study

Science Center Objects

Riparian grazing allows cattle free access to streams, but may accelerate erosion by the removal or trampling of vegetation. This study measured stream bank erosion, channel morphology, and stream substrate through seven experimental intensive-rotational pastures. It also evaluated the use of photo-electronic erosion pins (PEEPs) for measuring bank erosion in this type of geomorphic setting.

Photograph of a cow using a streambank for scratching

Cattle cross the stream and cause bank erosion by trodding. In addition, the cattle often use the raw banks for scratching which causes more loss of vegetation.

Problem

The research component of Pioneer Farm (University of Wisconsin-Platteville) is part of the Wisconsin Agricultural Stewardship Initiative (WASI). WASI is a collaborative, research-oriented effort among farmers, university researchers, agricultural and environmental organizations and governmental agencies.

Their mission is the infusing of production agriculture with environmentally compatible and economically sustainable management practices. Pioneer Farm helps address these challenges through on-farm systems research that measures environmental impacts, documents research results and provides science-based information, training, and education related to agriculture and the environment.

The Galena River runs through seven intensive rotational grazing pastures that are part of Pioneer Farm. Traditional styles of riparian grazing that allow cattle free access to streams may accelerate natural processes of erosion in a meandering stream by removal or trampling of vegetation. Fencing off buffer strips along streams has been shown to reduce local bank erosion but has a high cost to farmers because alternative pastures, water sources, and additional fencing are needed. Some studies have shown that bank vegetation can be improved and bank erosion reduced by riparian intensive rotational grazing, although results vary from study to study.

 

Objectives

The goals of this study were to: (1) establish a long-term monitoring program to measure bank erosion, channel morphology and position, and stream substrate along the Galena River through the seven pastures, and (2) determine if there are changes in the amount of bank erosion over time. An additional goal was to evaluate the usefulness of photo-electronic erosion pins (PEEPs) for measuring bank erosion in this type of geomorphic setting. Changes in bank conditions will be put in context with historical and current hydrologic conditions and cattle grazing schedules.

 

Approach

Approximately 30 cross sections were surveyed with a total station and approximately 150 erosion pins were placed in the eroding banks in different geomorphic settings. Three photo-electronic erosion pins (PEEPs) were installed in banks near the two existing gaging stations. Approximately 60 photo points were established. One time-lapse digital camera will be installed to overlook the stream and the pastures, set to take a photograph every day. The area of exposed, non-vegetated, banks along the reach were measured. Substrate was characterized by use of Wolman pebble counts near a subset of cross sections. The cross sections were resurveyed after major floods.