Grazing to Protect Surface Water: Considering Critical and Sensitive Areas

By Jason Cavadini and Laura Paine et.al

Many of Wisconsin’s abundant freshwater resources are impaired due to elevated phosphorus (P) and sediment levels (DNR, 2024). In a grazing system, it is important to take into consideration management, weather, and landscape characteristics to minimize impacts to surface water quality (Vadas et al., 2015).

Certain critical and sensitive areas of the farm, such as concentrated surface water flow areas, and certain times of year such as when soils are frozen, can coexist to produce conditions that leave the landscape particularly vulnerable to nutrient and sediment losses. Identifying critical and sensitive areas of your farm and managing them accordingly, especially at sensitive times of year, protects surface water quality while maintaining a productive grazing system.

This article will:

1. Define critical & sensitive areas
2. Help farmers identify where critical and sensitive areas exist on their farms
3. Provide guidance on how to manage them during times of the year when they are most prone to damage, sediment loss, and nutrient transport.

What are critical and sensitive areas on farms?

Unique areas or ecosystems across the landscape that play significant environmental and biological roles are referred to as critical areas. These areas require special protection or management due to the impact damage would have on the broader environment. An example of this would be a perennial stream bottom, where livestock access should be limited to short, infrequent durations through managed grazing to protect the stream banks.

Areas or ecosystems that are more susceptible to damage from agricultural practices are referred to as sensitive areas. These areas may not play as significant roles as critical areas, but they still require special protection or management because of heightened vulnerability. An example of this would be the floodplain adjacent to a stream bottom, which should be grazed only during nonsaturated conditions.