Authorizations to discharge from quarries located between 200 feet and 1,500 feet of a water body within a water quality protection area in the John Graves Scenic Riverway require the permittee to satisfy the following performance criteria. An evaluation of these performance criteria must be incorporated into the Technical Demonstration, as required in §311.77 of this title (relating to Technical Demonstration). (1) The down-gradient perimeter of the quarry must include a final control structure to manage the discharge of wastewater and/or storm water. The final control structure must be designed and constructed as follows. (A) Certification of the final control structure design and construction must be provided by a licensed Texas professional engineer. Design and construction plans and specifications must be maintained on site and made available at the request of the executive director. (B) The final control structure side slopes must not exceed a gradient of 1:3 (33%). (C) The final control structure must be designed to impound, at minimum, the volume of water resulting from a 25-year, 24-hour rainfall event for the final control structure drainage area. (D) The final control structures must be properly stabilized (via use of vegetation, riprap, and/or other acceptable technique) to prevent the final control structure from being a source of pollution and/or to prevent structural failure. (E) The final control structure must be inspected once every 14 calendar days and within 24 hours of any rainfall event totaling 0.5 inches or greater. Where an inspection identifies failure and/or problems with the final control structure, corrections must be made within seven calendar days of the inspection. Records of these inspections and any site stabilizations must be maintained on site for a period of three years and made available to the executive director, upon request. (F) A minimum 200-foot vegetative buffer must be maintained between the final control structure and any water body. (2) All treatment, detention, and water storage tanks and ponds must be operated to maintain a minimum freeboard of two feet. (3) A permanent depth marker shall be installed and maintained on all treatment, detention, and water storage tanks and ponds. The depth marker shall identify the volume required for the design rainfall event, as specified in paragraph (1)(C) of this section, and freeboard. (4) The quarry operation must demonstrate compliance with all the requirements of 36 Code of Federal Regulations Part 800 (Protection of Historic Properties) and 9 Texas Natural Resources Code, Chapter 191 (Antiquities Code). (5) The quarry operation must not have a detrimental effect on any federal endangered/threatened, aquatic/aquatic-dependent species/proposed species; or their critical habitat. (6) Waste management units must be located a minimum horizontal distance from water wells, in accordance with 16 TAC Chapter 76 (relating to Water Well Drillers and Water Well Pump Installers), or where those regulations do not apply, the minimum distance to a water well must be 500 feet. (7) Secondary containment of chemical and fuel storage is required. Where quarry operations overlay aquifer and/or aquifer recharge areas and sufficient confining layers do not exist to preclude contamination of groundwater, tertiary containment is required for all chemical and fuel storage. (8) Quarry operations must not be located on natural hazard land, areas subject to frequent flooding, or in areas of unstable geology. |
