Siting Manure Storage Structures is part 2 of four articles focused on siting new and expanding animal feeding operations. This article focuses on new structures but could include existing structures and modifications that can be made to minimize environmental impacts around them. The Site Considerations document can be found at http://oema.osu.edu/OEMAPublications.htm by clicking the first link “Site Considerations for Production Facilities.”
It is important to asses the topography of the area being considered for a manure storage structure. Orientation of the structure relative to the physical characteristics of the land, predominate wind direction as well as neighboring structures should be carefully considered.
It is ideal to locate storage ponds and treatment lagoons at least 300 feet away and fabricated structures to be at least 50 feet away from groundwater wells. Drinking water protection areas have been identified as sensitive areas and should be avoided with any type of manure storage structure. If there is a public surface water intake nearby, the recommended set back distance is 1,500 feet between the water intake and the manure storage structure. Another site consideration is streams. These are direct links to larger water resources requiring additional precautions. Therefore, locate manure treatment lagoons and storage structures at least 300 feet away and fabricated structures at least 120 feet away from these surface water resources.
Watersheds level planning is an important component to clean water. If a structure is located within a watershed that supports a cold water habitat be sure to set up additional protocols to protect the area. If the structure has not been built yet, try to locate outside of these sensitive areas.
The aquifer setback is the same as that mentioned in the animal housing article. The ideal location has 15 or more vertical feet of low permeable material between the uppermost aquifer and the bottom of the storage structure. There are additional engineering controls that you can implement to protect these aquifers if there is less than 15 vertical feet to an aquifer. Karst areas (landforms that have developed in or on limestone, dolomite or gypsum and cause sinkholes, underground drainage or caves) are another geographical feature where additional steps need to be implemented to reduce potential impact, especially if actual Karst features are present at the site.
Before siting an earthen manure storage facility, a geological investigation should occur. These types of investigations will assess the surface and subsurface geological characteristics that may impact groundwater. A geological report will outline any applicable site limitations and may include construction recommendations. The vertical distance to bedrock should be investigated as well. Constructing a storage facility with less than 3 feet to bedrock should be avoided. Ohio Department of Natural Resources has developed DRASTIC maps for most of Ohio. DRASTIC maps assess the Depth to water, net Recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone media and hydraulic Conductivity of the aquifer which are key indicators of groundwater vulnerability to contamination and are represented as a DRASTIC Index. An area with a low DRASTIC Index has characteristics which are more protective of groundwater than areas with higher index scores. Locating within areas with low DRASTIC scores are lower risk sites than are those with higher DRASTIC scores.
To reduce the risk of complaints, be sure to locate new structures at least 100 feet away from public roads and property lines. When deciding on a building location, place at least 1,000 feet between a manure treatment lagoon or storage pond and a neighbor’s property or 500 feet between a solid manure structure and a neighbor. For existing sites needing odor control, consider additional manure treatment technologies. Covered storage structures will reduce odors, reduce storage requirements by minimize rainwater and can reduce nutrient loss. Both of these provide a cost savings.
One-hundred year floodplain areas should be avoided. Any area that has a one percent chance of flooding in any given year is a 100-year flood plain. If you are located in an area prone to flooding, you may need to get permits and take additional precautions to minimize the risks of this location. Locating in a floodplain may inundate the storage structure with flood water and compromise the structure and/or displace manure from the facility causing water quality concerns.
Animal operations should strive to have a volume of manure storage sufficient for periods when fields are not available or field conditions are less than ideal for manure nutrient applications. Manure storage will also provide more flexibility to allocate nutrients to fields based on crop need, reducing excess nutrient application.
