Primary roads shall meet the requirements of §12.569 of this title (relating to Roads: General) and the additional requirements of this section.
  (1) Certification. The construction or reconstruction of primary roads shall be certified in a report to the Commission by a qualified professional engineer with experience in the design and construction of roads. The report shall indicate that the primary road has been constructed or reconstructed as designed and in accordance with the approved plan.
  (2) Safety Factor. Each primary road embankment shall have a minimum static factor of 1.3.
  (3) Location.
    (A) To minimize erosion, a primary road shall be located, insofar as is practicable, on the most stable available surface.
    (B) Fords of perennial or intermittent streams by primary roads are prohibited unless they are specifically approved by the Commission as temporary routes during periods of road construction.
  (4) Drainage control. In accordance with the approved plan:
    (A) each primary road shall be constructed or reconstructed, and maintained to have adequate drainage control, using structures such as, but not limited to bridges, ditches, cross drains, and ditch relief drains. The drainage control system shall be designed to safely pass the peak runoff from a 10-year, 6-hour precipitation event, or greater event as specified by the Commission;
    (B) drainage pipes and culverts shall be installed as designed, and maintained in a free and operating condition and to prevent or control erosion at inlets and outlets;
    (C) drainage ditches shall be constructed and maintained to prevent uncontrolled drainage over the road surface and embankment;
    (D) culverts shall be installed and maintained to sustain the vertical soil pressure, the passive resistance of the foundation, and the weight of vehicles using the road;
    (E) natural stream channels shall not be altered or relocated without the prior approval of the Commission in accordance with applicable §§12.509-12.511 and §§12.513-12.524 of this title (relating to Hydrologic Balance: General Requirements, to Hydrologic Balance: Water-Quality Standards and Effluent Limitations, to Hydrologic Balance: Diversions, to Hydrologic Balance: Sediment Control Measures, to Hydrologic Balance: Siltation Structures, to Hydrologic Balance: Discharge Structures, to Hydrologic Balance: Acid-Forming and Toxic-Forming Materials, to Hydrologic Balance: Permanent and Temporary Impoundments, to Hydrologic Balance: Underground Mine Entry and Access Discharges, to Hydrologic Balance: Surface- and Ground-Water Monitoring, to Hydrologic Balance: Transfer of Wells, to Hydrologic Balance: Water Rights and Replacement, to Hydrologic Balance: Discharge of Water Into an Underground Mine, to Hydrologic Balance: Postmining Rehabilitation of Sedimentation Ponds, Diversions, Impoundments, and Treatment Facilities, and to Hydrologic Balance: Stream Buffer Zones); and
    (F) except as provided in paragraph (3)(B) of this section, structures for perennial or intermittent stream channel crossings shall be made using bridges, culverts, low-water crossings, or other structures designed, constructed, and maintained using current, prudent engineering practices. The Commission shall ensure that low-water crossings are designed, constructed, and maintained to prevent erosion of the structure or stream bed and additional contributions of suspended solids to streamflow.
  (5) Surfacing. Primary roads shall be surfaced with material approved by the Commission as being sufficiently durable for the anticipated volume of traffic and the weight and speed of vehicles using the road.

Source Note: The provisions of this §12.570 adopted to be effective April 7, 1997, 22 TexReg 3093; amended to be effective November 4, 1997, 22 TexReg 10640; amended to be effective December 28, 2020, 45 TexReg 9503