The degree of protection of surface waters is sufficient if waste control facilities are designed and operated in accordance with the following subsections.     
       (1) Wastewater holding facilities. If a meat processing operation utilizes holding facilities, any holding facility shall be designed and operated to retain all wastewater produced by the meat processing operation for a 30-day period, plus all rainwater which would enter the holding facilities as a result of a 25-year, 24-hour rainfall as defined by Hershfield, Rainfall Frequency Atlas of the United States, U.S. Weather Bureau, Technical Paper No. 40, 1961, or the latest revision thereof. Wastewater holding facilities shall be dewatered within 14 days after any one of the following events occur:                (A) collection of a quantity of rainwater in excess of 20% of the quantity of rainfall which would enter the holding facility as a result of the 25-year, 24-hour rainfall, as defined in thissection.                    (B) collection of more than 50% of the volume of wastewater which the pond was designed to retain, such that sufficient capacity is no longer available to retain an addition of all rainwater that would enter the holding facilities as a result of a 25-year, 24-hour rainfall, plus all wastewater produced by the meat processing operation for a 15-day period.           
             (2) Evaporation facility. If a meat processing operation utilizes an evaporation facility, it shall be designed to retain wastewater with no overflow during a 10-year period of above-normal rainfall. Local weather bureau rainfall data may be used in designing these facilities.             
               (3) Irrigation facility. If a meat processing operation utilizes an irrigation facility, it shall be of adequate capacity to dewater all wastewater holding facilities within a 14-day period. If farmland or pastureland is irrigated with wastewater from the meat processing operation or its wastecontrol facilities, the annual application rate (including rainfall) shall not exceed 200% of the expected consumptive use for the particular crop as defined by McDaniels, Consumptive Use of Water by Major Crops in Texas, Texas Board of Water Engineers,  Bulletin No. 6010, 1960.               
                 (4) Isolation of wastewater. Wastewater must be isolated from outside surface drainage by ditches, diking, or other suitable structures where necessary to provide adequate environmental protection. Such diversion structures shall be designed to be effective during peak flows expected at times when a 25-year, 24-hour rainfall, as described in this section may occur.                
     Source Note:        The provisions of this §321.54 adopted to be effective July 3, 1986, 11 TexReg 2894.