Section 329IAC10-20-12. Erosion and sedimentation control measures; general requirements

   (a) Erosion and sedimentation control measures must be instituted to minimize the off-site migration of any sediment. All run-off from disturbed acreage must pass through a sedimentation basin or an approved alternative sediment control practice. The commissioner may require additional erosion and sediment control measures based on site-specific conditions.

  (b) A storm water or sedimentation basin or series of basins permitted and constructed under this article must be constructed in accordance with the following:

(1) Be designed to handle, simultaneously, the run-off resulting from the ten (10) year, twenty-four (24) hour precipitation event and the sediment storage volume required by subdivision (3).

(2) An appropriate combination of principal and emergency spillways shall be provided to discharge safely the run-off from a twenty-five (25) year, twenty-four (24) hour precipitation event with a minimum of two (2) feet of freeboard.

(3) Provide a minimum of three (3) years of sediment storage volume. The following requirements apply:

(A) Sediment must be removed from sedimentation basins when the volume of sediment accumulates to fifty percent (50%) or more of the designed sediment storage volume.

(B) A sediment storage volume of less than three (3) years may be approved by the commissioner if an annual approved maintenance program will be performed.

(4) Provide a detention time of at least twenty-four (24) hours for the ten (10) year, twenty-four (24) hour precipitation event. A detention time of less than twenty-four (24) hours may be approved by the commissioner if the following is demonstrated by the owner, operator, or permittee:

(A) The discharge will not result in the release of a significant quantity of sediment from the MSWLF.

(B) Will not violate any local, state, or federal laws pertaining to discharges.

(5) The principal spillway must be located at a height above the maximum elevation of the designed sediment storage volume required by subdivision (3).

(6) Discharge in compliance with all applicable state and federal laws.

(7) The length-to-width ratio of the flow path shall be 2:1 or greater from the inflow to the outflow. Baffles may be used within the basin to achieve this ratio.

  (c) If deemed necessary by the commissioner, additional erosion and sediment control practices may be required in the drainage areas of permanent basins for the purposes of increasing the life of the basin and increasing the overall efficiency of removing sediment from run-off.

  (d) Alternatives to the requirements in subsections (b) through (c) may be approved by the commissioner. Factors that will be considered include the following:

(1) The amount of water collected from disturbed areas and undisturbed areas.

(2) Use of erosion control measures on disturbed areas.

(3) Sedimentation control measures utilized in the drainageways.

  (e) The commissioner may require the submittal of the following information for any storm water/sedimentation pond or basin to verify it is designed and constructed properly:

(1) Basin plan view.

(2) Typical cross section.

(3) All the inlet and outlet elevations.

(4) Assumptions used to size the basin.

(5) Calculations used.

(6) Justifications.

  (f) A storm water pollution prevention plan must be prepared in accordance with 329 IAC 10-15-12. The plan must be updated whenever there is a change at the MSWLF that would significantly affect the storm water discharges authorized under the MSWLF's permit. The plan must be kept on site and must be available to the commissioner at the time of an on-site inspection.

  (g) A written nonstorm water assessment including the following shall be kept in the facility record:

(1) A certification statement that storm water discharges entering waters of the state have been evaluated for presence of contaminants and nonstorm water contributions. The certification shall include a description of the method used, the date of any testing, and the on-site drainage points that were directly observed during the test.

(2) A statement that the facility does not allow detergent or solvent-based washing of equipment or vehicles that would allow washwater additives to enter any storm drainage system or receiving water.

(3) A statement that all interior maintenance areas floor drains that have the potential for maintenance fluids or other materials to enter storm sewers are connected to a sanitary sewer or other appropriate collection system, and that all maintenance fluids or other materials are properly disposed in accordance with all applicable local, state, and federal laws.

(Solid Waste Management Division; 329 IAC 10-20-12; filed Mar 14, 1996, 5:00 p.m.: 19 IR 1848; filed Mar 19, 1998, 11:07 a.m.: 21 IR 2786; filed Aug 2, 1999, 11:50 a.m.: 22 IR 3827; readopted filed Jan 10, 2001, 3:25 p.m.: 24 IR 1535; filed Feb 9, 2004, 4:51 p.m.: 27 IR 1823, eff Apr 1, 2004)