Section 321.38 - Control Facility Design Requirements Applicable to Concentrated Animal Feeding Operations (CAFOs)(a) Purpose. The purpose of this section is to describe the control facility design requirements that apply to concentrated animal feeding operations (CAFOs). Any CAFO operator that does not use a retention control structure (RCS) is not subject to subsections (e), (f), and (g) of this section.(b) Well buffers. Except as provided by subsection (c) of this section, the control facility of an animal feeding operation (AFO) shall be separated from a well by ensuring a minimum buffer zone, as described in this subsection. An AFO shall not locate a new RCS or holding pen within the required well buffer zones: (1) public drinking water supply wells - 500 feet;(2) drinking water wells used for private water supply - 150 feet; or(3) water wells used exclusively for agriculture irrigation - 100 feet.(c) Buffer variance. A CAFO operating under an existing authorization may continue the operation and use of any existing land management units (LMUs), holding pens and RCSs located within the required well buffer zones provided they are in accordance with the recharge feature evaluation and certification required under § 321.34(f)(3) of this title (relating to Permit Applications). For new wells drilled after July 20, 2004, documentation supporting variances of the buffer zones that were previously authorized shall be kept on site and made available to agency personnel upon request.(d) 100-year flood plain. All control facilities, including holding pens and RCSs, shall be located outside of the 100-year flood plain unless the facility is protected from inundation and damage that may occur during the 100-year flood event.(e) RCS design capacity. The following design requirements apply to any CAFO. (1) The design of a control facility shall include measures that will be used to minimize entry of uncontaminated runoff into RCSs.(2) Any CAFO constructing a new or modifying an existing RCS shall ensure that the design specifications and completed construction specifications are certified by a licensed Texas professional engineer. The failure to obtain the certifications or to maintain records verifying the certifications is a violation of this subchapter.(3) Except as provided in this subsection, each RCS, at a minimum, shall be designed and constructed in accordance with the technical standards developed by the Natural Resources Conservation Service (NRCS), American Society of Agricultural and Biological Engineers, American Society of Civil Engineers, American Society of Testing Materials, or other technical standard approved by the executive director that are in effect at the time of construction. Where site-specific variations are warranted, a licensed Texas professional engineer shall document these variations and their appropriateness to the design.(4) Any existing RCS that has been properly maintained without any modifications and has no apparent structural problems or leakage is considered to be properly designed with respect to the RCS sizing, embankment design and construction, and liner requirements of this section, provided that any required documentation was completed in accordance with the requirements at the time of construction. If no documentation exists, the RCS must be certified by a licensed Texas professional engineer as providing protection equivalent to the requirements of this section.(5) Any RCS documented to have been built in accordance with site-specific NRCS plans and specifications is considered to be in compliance with the design and capacity requirements of this subchapter provided that:(A) the site-specific conditions are the same as those used by the NRCS to develop the plan (numbers of animals, runoff area, manure, sludge, and wastewater generated, etc.); and(B) the RCS is operated and maintained in accordance with NRCS requirements.(6) The production area of a new or expanding AFO shall not be constructed in any stream, river, lake, wetland, or playa, except as provided in § 321.41 of this title (relating to Special Requirements for Discharges to a Playa).(7) The design plan must include documentation of the sources of information, assumptions, and calculations used in determining the appropriate volume capacity of the RCSs. Poultry (chickens and turkeys), swine, or veal calf CAFOs subject to the new source performance standards in subparagraph (B) of this paragraph shall be designed in accordance with subparagraphs (B) and (C) of this paragraph or subparagraphs (B) and (D) of this paragraph. For all other CAFOs, the volume must include design rainfall event runoff and normal operating capacity requirements in accordance with subparagraphs (A) and (C) of this paragraph or design rainfall event runoff and evaporation systems in accordance with subparagraphs (A) and (D) of this paragraph. (A) Design rainfall event runoff. All CAFOs, other than poultry (chickens and turkeys), swine, or veal calf CAFOs subject to the new source performance standards in subparagraph (B) of this paragraph, shall have an RCS designed and constructed to meet or exceed the capacity required to contain the runoff and direct precipitation from the 25-year, 24-hour rainfall event, except as required by § 321.42(c) of this title (relating to Requirements Applicable to the Major Sole-Source Impairment Zone) or authorized under § 321.37(d)(3) of this title (relating to Effluent Limitations for Concentrated Animal Feeding Operation (CAFO) Production Areas).(B) New source swine, veal, or poultry (chickens and turkeys) CAFOs. Any swine, veal, or poultry (chickens and turkeys) CAFO subject to the new source performance standards in 40 Code of Federal Regulations (CFR) §412.46 shall have an RCS designed and constructed such that no discharge will occur in accordance with the following: (i) Information used in the design of the RCS shall include, but is not limited to, the following: design rainfall event, additional minimum capacity for chronic rainfalls identified in the evaluation required by clause (ii) of this subparagraph, the requirements of subparagraph (C) or (D) of this paragraph, additional storage capacity for wastewater intended to be transferred to another recipient at a later time, and any other factors that would affect the sizing of the RCS.(ii) An evaluation of the adequacy of the designed RCS using the most recent version of the Soil Plant Air Water (SPAW) Hydrology Tool, or other tool approved by the executive director. The evaluation must include all inputs to SPAW including, but not limited to, daily precipitation, temperature, and evaporation data for the previous 100 years, user-specified soil profiles representative of the LMUs, planned crop rotations consistent with the nutrient management plan, and the final modeled result of no discharges from the designed RCS. For those CAFOs where 100 years of local weather data is not available, a simulation with a confidence interval analysis conducted over a period of 100 years may be used.(C) Design capacity requirements for systems using irrigation.(i) The RCS shall be designed for the authorized number of animals to include any storage volume required by a hydrologic needs analysis (water balance) that documents that the typical irrigation demands of the adopted crop and irrigated land area will not be exceeded.(ii) Precipitation inputs to the water balance shall be the average monthly precipitation reported in a National Weather Service current publication.(iii) The consumptive use requirements of the cropping system shall be developed on a monthly basis, and shall be calculated as a part of the water balance.(iv) The maximum required storage value calculated by the water balance shall not encroach on the storage volume required for the design rainfall event.(v) Wastewater application rates used in the water balance shall not induce uncontrolled runoff or create tailwater that causes a discharge.(vi) All process-generated wastewater produced during a 21-day or greater period.(vii) Any other relevant volume needed in the water balance, including any required under the air standard permit in § 321.43 of this title (relating to Air Standard Permit for Animal Feeding Operations (AFOs)).(D) Design requirements for evaporation systems. Evaporation systems shall be designed: (i) to withstand a ten-year (consecutive) period of maximum recorded monthly rainfall (other than catastrophic). In any month in which a catastrophic rainfall event occurs, the water balance shall replace such an event with not less than the long-term average rainfall for that month as determined by a water balance; and(ii) to maintain sufficient volume to contain rainfall and rainfall runoff from the design rainfall event without overflow. The depth for this volume must be at least one vertical foot allocated within the RCS above the volume required in clause (i) of this subparagraph.(f) Dewatering system. An irrigation system or other liquid removal system used by an AFO must be designed to ensure that the system is capable of dewatering the RCSs on a regular schedule. RCSs shall be equipped with irrigation or wastewater removal systems capable of dewatering the RCSs whenever needed to restore the operating capacity. Dewatering equipment shall be maintained in proper working order.(g) RCS embankment and liner design.(1) For RCSs where the depth of water impounded against the embankment at the spillway elevation is three feet or more, the RCS is considered to be designed with an embankment. The pollution prevention plan shall include a description of the design specifications for the RCS embankments. The following design specifications are required for all new construction or the modified portions of existing RCSs.(A) Soils used in the embankment shall be free of foreign material such as rocks larger than four inches, trash, brush, and fallen trees.(B) The embankment shall be constructed in lifts or layers no more than eight inches compacted to six inches thick at a minimum compaction effort of 95% Standard Proctor Density (ASTM D698) at -1% to +3% optimum moisture content.(C) All embankment walls shall be stabilized to prevent erosion or deterioration.(D) Embankment construction must be accompanied by certified compaction tests including in-place density and moisture in accordance with ASTM D1556, D2167, or D2937 for density and D2216, D4634, D4944, or D4959 for moisture, and D2922-91 or D6938-07 for moisture and density, or equivalent testing standards.(E) Additional protection for new or modified portions of existing RCSs that are constructed with embankments designed to contain runoff from a drainage area shall be constructed with a spillway or other outflow device properly sized according to NRCS design and specifications to protect the integrity of the embankment.(F) For all new construction or the modified portions of existing RCSs, each RCS must have a minimum of two vertical feet of freeboard constructed with materials equivalent to those used at the time of design and construction between the top of the embankment and the structure's spillway. RCSs without spillways must have a minimum of two vertical feet of freeboard between the top of the embankment and the required storage capacity.(2) For all new construction and for all structural modifications of existing RCSs, each RCS must meet the requirements for lack of hydrologic connection or have a liner consistent with subparagraph (B), (C), or (D) of this paragraph. (A) This subparagraph applies to lack of hydrologic connection requirements. Documentation must show that there will be no significant leakage from the RCS; or that any leakage from the RCS will not migrate to water in the state. A permit or authorization will require documentation of the lack of hydrologic connection certified by a licensed Texas professional engineer or licensed Texas professional geoscientist and must include information on the hydraulic conductivity and thickness of the natural materials underlying and forming the walls of the containment structure up to the wetted perimeter. If it is claimed that no significant leakage would result from the use of in-situ materials, documentation must be provided that leakage will not migrate to waters in the state. The operator must at a minimum include maps showing groundwater flow paths, or that the leakage enters a confined environment. A permit or authorization will require a written determination by an NRCS engineer, a licensed Texas professional engineer or a licensed Texas professional geoscientist that a liner is not needed to prevent a significant hydrologic connection between the contained wastewater and waters in the state.(B) This subparagraph applies to RCS liners using in-situ material. In-situ material is undisturbed, in-place, native soil material. In-situ materials must at least meet the minimum criteria for hydraulic conductivity, thickness, and calculated specific discharge, as described in subparagraph (C) of this paragraph. Samples shall be collected and analyzed in accordance with subparagraph (E) of this paragraph. This documentation must be certified by a licensed Texas professional engineer or licensed Texas professional geoscientist.(C) This subparagraph applies to constructed or installed earthen liners. Constructed or installed liners must be designed by a licensed Texas professional engineer. The liner must be constructed in accordance with the design and certified as such by a licensed Texas professional engineer. Compaction tests and post construction sampling and analyses will provide support for the liner certification. Liners shall be designed and constructed to have hydraulic conductivities no greater than 1 x 10-7 centimeters per second (cm/sec), with a thickness of 1.5 feet or greater or its equivalency in other materials, and not to exceed a specific discharge through the liner of 1.1 x 10-6 cm/sec calculated using Darcy's Law with the water level at the spillway depth. Constructed or installed liners must be designed and constructed to meet the soil requirements, lift requirements, and compaction testing requirements identified in the permit or authorization. The operator shall maintain the liner to minimize the percolation of wastewater through the liner.(D) This subparagraph applies to geosynthetic liners. Geosynthetic liners that meet the specific discharge requirements in subparagraph (C) of this paragraph are acceptable if certified by a licensed Texas professional engineer. Documentation must be presented to the executive director for review and approval before putting into service. Installation of the liner shall be certified by a licensed professional engineer that the liner and subgrade were completed according to the manufacturer's recommendations and current standards. Seams shall be completed in accordance with the manufacturer's requirement. When wedge weld seams are used, non-destructive seam testing shall be conducted on the complete length of the wedge weld by standard air pressure testing. The certification must document compliance with all of the following standards: ASTM D5888 Storage and Handling of Geosynthetic Clay Liners, ASTM D5889 Quality Control of Geosynthetic Clay Liners, and ASTM D6102 Guide for Installation of Geosynthetic Clay Liners.(E) This subparagraph applies to liner sampling and analyses of in-situ material and earthen liners. (i) The licensed Texas professional engineer or licensed Texas professional geoscientist shall use best professional practices to ensure that corings or other liner samples will be appropriately plugged with material that also meets liner requirements of this subsection.(ii) Samples shall be collected in accordance with ASTM D1587 or other method approved by the executive director. For each RCS, a minimum of two core samples collected from the bottom of the RCS and a minimum of at least one core sample from each sidewall. Additional samples may be necessary based on the best professional judgment of the licensed professional engineer. Distribution of the samples shall be representative of liner characteristics, and proportional to the surface area of the sidewalls and floor. Documentation shall be provided identifying the sample locations with respect to the RCS liner.(iii) For earthen liners, undisturbed samples shall be analyzed for hydraulic conductivity in accordance with ASTM D5084, whole pond seepage analysis as described in ASABE Paper Number 034130, Double Ring Infiltrometer (stand pipe), or other method approved by the executive director.(F) A permit or authorization shall include provisions whereby the executive director may, upon written notice, require the operator to install a leak detection system or monitoring well(s), based upon a determination that significant potential exists for the contamination of water in the state or drinking water.(G) Documentation of lack of hydrologic connection, liner, and capacity certifications by a licensed Texas professional engineer or licensed Texas professional geoscientist must be completed for each RCS and kept on site.(h) Manure storage. The AFO operator shall provide manure storage capacity based upon manure and waste production, land availability, and the NRCS Field Office Technical Guide or equivalent standards. When manure is stockpiled, it shall be stored in a well-drained area with no ponding of water, and the top and sides of stockpiles shall be adequately sloped to ensure proper drainage. Runoff from manure storage piles must be retained on site. If the manure areas are not roofed or covered with impermeable material, protected from external rainfall, or bermed to protect from runoff in the case of the design rainfall event, the manure areas must be located within the drainage area of the RCS and accounted for in the design calculations of the RCS.30 Tex. Admin. Code § 321.38
The provisions of this §321.38 adopted to be effective April 1, 1987, 12 TexReg 904; amended to be effective September 18, 1998, 23 TexReg 9354; amended to be effective July 15, 2004, 29 TexReg 6652; amended to be effective July 31, 2014, 39 TexReg 5786