A method for measuring accumulations of manure, litter, and process wastewater is required. For underfloor pits, tanks, and similar storage devices or structures with limited access, the applicant may propose a method of measuring manure, litter, or process wastewater accumulations, subject to the Department approval. A permanent depth marker is required for all other storage or treatment structures, including runoff holding ponds, liquid manure storage pits, and treatment lagoons. The marker shall be made of a durable material, permanently fixed, referenced to a permanently fixed bench mark or fixed elevation reference point adjacent to and outside of the waste containment area, located where the depth marks can be easily and safely viewed for facility management and inspections, clearly marked in at least one-foot increments, with a reference number or numbers, and with the following clearly marked:
008.01 The freeboard level;008.02 The level indicating the volume needed to contain all runoff and direct precipitation, or the runoff and direct precipitation of the 25-year, 24-hour rainfall event, as appropriate. Pumping shall begin as soon as possible anytime this storage level is exceeded. This can be identified as the "must pump level";008.03 The level indicating the volume needed for the minimum design storage capacity. The capacity required for the storage period volume shall be available prior to the start of the storage period. In no case shall the minimum storage period be less than needed to provide adequate storage through the winter months. This can be identified as the "winter pumpdown level"; and008.04 For lagoons, the level needed for the minimum treatment volume, marked on the depth marker or clearly posted on a sign adjacent to the lagoon. The minimum treatment volume is the amount of liquid needed to maintain proper lagoon function to be considered a lagoon for land application purposes and this volume shall be maintained above any sludge accumulations.130 Neb. Admin. Code, ch. 8, § 008