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Small Farms

Runoff needs to be either controlled or managed, depending upon risk, even for small farms. If manure runoff reaches a ditch or stream, it pollutes the environment. There are three options to managing or controlling open lot or barnyard runoff, by using a grass buffer (or filter), a vegetative treatment system, or a containment. Which you choose, should depend upon the risk of the facility to surface water:

Grass Buffers

The traditional definition of a grass buffer is a narrow strip of perennial vegetation (usually 30-60 feet wide) between cropland and a stream or other surface water. Runoff passes through buffers some “filtering” of pollutants mostly by gravity settling in the buffer area. No attempt to control solids or flow is done in a buffer. Buffers are the least effective at managing runoff, and should be used only in low risk cases. For example, an open lot that is very far away from surface water resource, or has a low risk to surface water, because of distance and topographic conditions, or is a very small lot or barnyard that cannot be controlled with a VTS or a containment, would be a candidate for a buffer. A buffer is considered a minimum, if nothing else, every open lot or barnyard should have a buffer.

Vegetative Treatment System

A Vegetative Treatment System (VTS) refers to a combination of treatment steps for managing runoff. The VTS first separates the solids from the liquids in runoff. A settling basin (or other structure) collects open lot or barnyard runoff for a short period of time (15-96 hours). A slow, controlled, and evenly distributed release to a Vegetative Treatment Area, then follows, where the soil further treats the runoff and prevents it from leaving the property. Once the runoff is in the soil, natural processes allow the plants to consume the nutrients and transpire the liquid. In this system the soil is storing the runoff.

A rule of thumb is that a VTA needs to be at least as large as the open lot or barnyard area. More information on VTS can be found on the eXtension website at What is a Vegetative Treatment System?. VTS are still considered to be a relatively new approach to runoff control and management, not all states allow their use, check with your state regulatory authority before installing a VTS. Not all VTS systems can prevent discharges from occurring, so they are far superior to a buffer, but not as proven and accepted as a containment.

Containment

A containment is commonly referred to as a runoff retention structure, holding pond, or catch basin. They are designed to full contain annual runoff from an open lot or barnyard and have been the primary method for managing runoff for three decades, and since they fully contain the runoff, they have the least risk of a discharge, when sized and managed appropriately. Containments usually also utilize sediment basins, to remove solids, and require an irrigation or dewatering system to land apply the nutrients to cropland. In most states a liner is required either earthen or synthetic, check with your state regulatory authority before installing a containment.

Page developed and maintained by Chris Henry, University of Nebraska Extension