|(a) All livestock trailers shall be washed out on a concrete area which is adequately curbed and sloped to allow for containment of all solids and liquids removed from the trailers. Manure may be separated and allowed to dry in this contained concrete area. Wastewater containing solids shall be conveyed directly from the contained concrete area to the treatment or storage pond(s). The pond(s) may be designed to treat wastewater using evaporation, with or without the recycling of wastewaters, as the sole means of disposal or in conjunction with land application. (b) All pond(s) used for the retention of treated or untreated wastewater shall be adequately lined to control seepage. The following methods of pond lining are acceptable. (1) In-situ clay soils or placed and compacted clay soils meeting the following requirements: (A) more than 30% passing a Number 200 mesh sieve; (B) liquid limit greater than 30%; (C) plasticity index greater than 15; (D) a minimum thickness of two feet; (E) permeability equal to or less than 1 x 10 -7 centimeter per second (the requirements described in this subparagraph apply only to new ponds constructed or modified after the effective date of these regulations); and (F) soil compaction will be 95% standard proctor density at optimum moisture content (the requirements described in this subparagraph apply only to new ponds constructed or modified after the effective date of these regulations). (2) Membrane lining with a minimum thickness of 30 mils, and an underdrain leak detection system. (3) An alternate method of pond lining may be utilized with prior approval from the executive director. (c) The registrant shall furnish certification, signed, sealed, and dated by a Texas licensed professional engineer or licensed professional geoscientist, that the completed pond lining meets the appropriate criteria described in this section prior to using the facilities. The certification must be sent to the agency's Wastewater Permits Section (MC 148) and a copy to the appropriate agency regional office. (d) All wastewater retention ponds shall be operated in such a manner as to maintain a minimum freeboard of two feet and shall be monitored in each pond by use of an in-place gage. Gage measurements of freeboard shall be taken from each pond on each day that trailer cleaning services are provided, and the measurements shall be recorded. These records shall be maintained for a minimum of three years and shall be readily available for inspection by commission staff. (e) All waste containment structures or ponds must be constructed to comply with minimum distance requirements specified in §290.41 of this title (relating to Water Sources) and with the minimum distance requirements specified in 16 TAC §76.1000 (relating to Technical Requirements--Location and Standards of Completion for Wells). (f) All waste containment structures or ponds must be protected from inundation by a ten-year, 24-hour rainfall event.