On the smallest farms, manure is usually stored as a stacked solid, with a moisture content of less than 80% (20% solids). A manure storage should be large enough to hold all manure and bedding until it can be land-applied. The storage site, or manure storage pad, should be built on a level area that has an impermeable base and should not be located on coarse-grained soils such as sand in order to minimize percolation of nutrients that could leach into groundwater. Under no circumstances should a manure storage pad be located in a low-lying area, floodplain, or other location where surface water can come into contact with the manure storage pad. The manure storage should be covered with a roof so that the manure is kept dry. When rainwater comes into contact with manure, it is considered contaminated and can discharge nutrients. It should be sited and constructed so as to prevent the entry of storm water runoff onto the storage pad.
If covering the manure storage is not possible, then a less preferable method of managing runoff from the storage is to direct runoff from the manure storage to a grass buffer. The grass buffer must maintain a solid stand of a perennial vegetation such as grass, be relatively level (less than 4% grade), and not have any concentrated flow channels such as ditches flowing through it. Also special considerations should be given to keeping solids from collecting on the buffer. This can be done with a concrete wall with weep holes, a wood picket dam, or other device to keep solids from passing to the grass buffer. An improvement to a grass buffer is a vegetative treatment system, which is an engineered system to manage runoff using vegetation.
Storages should be built with appropriate buffers to property lines; residences; and wetlands, water bodies, and potable water sources. Distances and design considerations can be determined by contacting a private engineer, your nearest Natural Resources Conservation Service Center, or your local Cooperative Extension office.
Author: Michael Westendorf, Department of Animal Sciences, Rutgers, State University of New Jersey
Edited by: Chris Henry, Biological System Engineering, University of Nebraska
