Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0011 - Water Quality
Chapter 20 - PERMITTING, DESIGN AND OPERATION STANDARDS CONFINED SWINE FEEDING OPERATIONS
Part D - ANIMAL WASTE MANAGEMENT
Section 20-37 - Liquid Animal Wastes

(i) Liquid animal waste may be applied by center pivot sprinkler on slopes with a grades of up to ten (10) percent. Overland flow irrigation systems shall not be developed to spread liquid animal wastes on sites having greater than one (1) percent slope or less than 0.4 percent slope.

(ii) The minimum depth of unsaturated soil strata on which a land application system may be developed is four (4) feet.

(iii) All land application sites shall be protected from up slope runoff by diversion ditches capable of intercepting the overland flow from a 25-year 24-hour storm event. Diversion ditches are not required if it can be shown that a storm of this size will not have an impact on the site.

(i) Spray irrigation application shall not leave the property used as the land application site.

(ii) Surface runoff containing animal wastes shall not leave the application site.

(iii) Liquid animal wastes shall be only applied to lands with a low potential for public access.

(iv) Public access to all application sites shall be restricted by signing at points of potential public access. The access restriction shall apply one (1) year after the application of liquid animal wastes.

(v) Crops shall not be harvested during the seven (7) days after the application of liquid animal wastes.

(vi) Direct human consumption crops, which are consumed fresh, shall not be harvested during the ninety (90) days after the application of liquid animal wastes.

(vii) Turf grass or sod grown on land where liquid animal wastes are applied shall not be harvested for one (1) year after application of liquid animal wastes.

(i) A buffer zone of one-fourth (1/4) mile is required between a land application site and any building with human occupancy or area of public use, not including public roadways.

(ii) Liquid animal waste shall not leave the property where it is applied.

(iii) Liquid animal waste shall not be land applied within 200 feet of a perennial, intermittent, or ephemeral water body or water well permitted for current domestic purposes.

(i) Liquid animal waste shall be evenly distributed over application sites at a rate that shall not exceed the agronomic rate and at a rate that shall not result in any surface runoff from the site.

(ii) Land application of liquid animal waste shall not be undertaken when soil is saturated, frozen, or covered with ice or snow or immediately before or during a storm event.

(iii) Surface application by means other than center pivot irrigation may be used when the land slope is no more than five (5) percent or when the yearly average soil loss is less than five (5) tons per acre as determined by the Universal Soil Loss Equation. Injection or surface application with immediate incorporation shall be used when the land slope exceeds five (5) percent and the yearly soil loss is greater than five (5) tons per acre as determined by the Universal Soil Loss Equation.

(iv) Sprinkler type land application systems shall be equipped with a backflow prevention device to protect any water source or well connected to the system. The required level of protection is a reduced-pressure principal backflow prevention device or air gap. All devices must be approved by the Foundation for Cross-Connection Control, University of Southern California.