OAR 340-051-0060: Guidelines for the Design and Operation of Animal Waste Control Facilities: Collection and Storage Facilities

(1) Liquid Manure Systems: (a) When waste holding lagoons are used to accumulate manure and contaminated drainage waters they should have sufficient usable capacity to contain the maximum accumulated rainfall and manure runoff from the entire collection area for the maximum expected period of accumulation. (As a generalized rule of thumb for design, ponds with capacity equal to 1/2 the average annual rainfall over the entire collection area will usually provide adequate operating and reserve capacity to catch one in ten year peak storm runoff from a feedlot); (b) Waste holding lagoons and collection sumps should be constructed to provide for at least annual removal of accumulated solids to maintain effective storage capacity; (c) Earth dikes should be constructed of good quality soil material, well compacted during construction, with side slopes consistent with accepted earthfill practices for the materials used and stabilized with vegetation recommended by the Agricultural Extension Service, immediately following construction; (d) Waste holding lagoons or collection sumps with earth dikes should be constructed with overflow relief structures to prevent a washout in the event of failure in other parts of the system; (e) Where unusually windy conditions prevail, or surface aeration equipment is used, dikes should be protected to prevent erosion; (f) Reinforced concrete manure holding tanks should be constructed in accordance with, or at least equivalent to, specifications for steel placement and concrete quality contained in a design that has been prepared by or has been reviewed and found acceptable by a qualified structural engineer; (g) Where seasonal groundwater levels rise above the bottom of a below-ground-level tank, drain tile should be laid at the base of the tank before it is backfilled. (2) Solids Handling Systems: (a) Manure solids should be collected, stored, and utilized or disposed of with a minimum of water (or rainfall) addition, in a manner that will prevent water pollution and minimize the production of flies and odors; (b) Where large accumulations of manure are stored during winter months, contaminated drainage collection and holding or disposal facilities should be provided.