S.D. Admin. R. 74:29:11:23

Current through Register Vol. 51, page 67, December 16, 2024

Section 74:29:11:23 - Pond and surface impoundment design and construction requirements

The following design and construction requirements apply to ponds and surface impoundments:

(1) General design and construction requirements include:

(a) A geotechnical and stability analysis shall be performed to determine the suitability of the site and materials for construction;

(b) A minimum of three feet of freeboard;

(c) Maximum side slopes of 3 horizontal to 1 vertical;

(d) A minimum bottom slope of 2 percent;

(e) Provisions for migratory bird and wildlife protection; and

(f) A minimum capacity of normal operating levels plus storage for a 100-year, 24-hour storm event;

(2) If ponds or surface impoundments are to contain fluids that have the potential to pollute surface or ground water, double liner systems must be incorporated into their design. The liners shall be separated by a leak detection, collection, and recovery system. The bottom liner shall be a composite liner, either consisting of an upper geomembrane liner and a lower compacted soil liner, or of a geosynthetic clay liner. Liner systems must be constructed of materials that have the strength, thickness, and chemical properties needed to prevent failure due to pressure gradients, physical contact with the waste or fluids to which the liners are exposed, climatic conditions, stress of installation, and stress of daily operation;

(3) Geomembrane and soil layer composite secondary liner design and construction requirements include, at a minimum:

(a) The soil liner shall have a compacted maximum coefficient of permeability of 1 x 10^-7 centimeters per second. The department may require a test pad to document field permeability. The applicant shall use field testing methods approved by the department and shall take an undisturbed sample for laboratory comparison of field values;

(b) The soil liner shall have a one-foot compacted thickness placed in six-inch scarified and compacted lifts with no materials greater than three inches in diameter;

(c) The soil liner shall meet compaction specifications equivalent to 95 percent standard proctor density with a moisture content of 0 to 6 percent of optimum moisture; and

(d) The geomembrane and soil liner shall be in direct contact, with minimal void spaces, to minimize lateral flow of liquids at the geomembrane/soil liner interface;

(4) Geosynthetic clay composite secondary liner design and construction requirements include, at a minimum:

(a) For bentonite clay encapsulated by geotextile layers, the geosynthetic clay liner shall be overlain by a geosynthetic liner. The geosynthetic liner shall have a minimum 60 mil thickness;

(b) For bentonite clay bonded to a geomembrane liner, the geomembrane liner shall have a minimum 60 mil thickness. During installation, the geomembrane will be the upper layer of the composite liner; and

(c) Installation of geosynthetic clay liners must be consistent with the manufacturer's specifications and recommendations;

(5) Geomembrane liner design and construction requirements include, at a minimum:

(a) The primary or uppermost liner shall have an 80 mil thickness, and the secondary or bottom geomembrane shall have a 60 mil thickness;

(b) Geomembrane liners shall be compatible with the fluids to be contained;

(c) Geomembranes shall have a life expectancy longer than the life of the facility; and

(d) Installation of geomembrane liners must be consistent with the manufacturer's specifications and recommendations;

(6) Leak detection, collection, and recovery system design and construction requirements include, at a minimum:

(a) The system shall be designed to collect and rapidly remove fluids to minimize hydraulic head on the secondary liner;

(b) The system shall consist of a drain layer of clean sand or gravel, or a geonet drainage product. The system shall be constructed of materials chemically resistant to the fluids contained in the pond or impoundment;

(c) The system shall have a minimum hydraulic conductivity of 0.01 centimeters per second;

(d) The drain layer shall cover the entire pond or impoundment if possible, but at a minimum must cover the pond or impoundment to the high water mark;

(e) The system shall be capable of draining fluids to a collection gallery for recovery. If the collection gallery is not free draining, it will need to be continuously pumped to minimize hydraulic head on the secondary liner; and

(f) The permit application must include a leakage response plan detailing actions that will be taken in response to the detection of liner system leakage including notification, reporting, monitoring, and repair.

Alternative impoundment lining systems may be approved if they provide an equivalent degree of protection to surface and ground water.

S.D. Admin. R. 74:29:11:23

33 SDR 160, effective 4/17/2007.

General Authority: SDCL 45-6B-81.

Law Implemented: SDCL 45-6B-41.