North Dakota Administrative Code › Title 89 - Water Commission › Article 89-04 - Water Management Plans for Surface Coal Mining Operations › Chapter 89-04-10 - Dams Constructed of or Impounding Waste Material › Section 89-04-10-02 - Construction of dams

Current through Supplement No. 393, July, 2024
1. Waste shall not
				be used in the construction of dams unless demonstrated through appropriate
				engineering analysis to have no adverse effect on stability.
2. Plans for dams subject to this section
				shall be approved by the state engineer before construction.
3. Construction requirements are as follows:
a. Design shall be based on the flood from
				the probable maximum precipitation event unless the permittee shows that the
				failure of the impounding structure would not cause loss of life or severely
				damage property or the environment, in which case, depending on site
				conditions, a design based on a precipitation event of no less than
				hundred-year frequency may be approved by the state engineer.
b. The design freeboard distance between the
				lowest point on the embankment crest and the maximum water elevation shall be
				at least five feet [1.52 meters] to avoid overtopping by wind and wave action.
c. Dams shall have minimum safety
				factors as follows:
Case ____
Loading Condition ______________
Minimum Safety Factor __________________
I
End of construction
1.3
II
Partial pool with steady seepage saturation
1.5
III
Steady seepage from spillway or decant crest
1.5
IV
Earthquake (cases II and III with seismic loading)
1.0
d.
				The dam, foundation, and abutments shall be stable under all conditions of
				construction and operation of the impoundment. Sufficient foundation
				investigations and laboratory testing shall be performed to determine the
				factors of safety of the dam for all loading conditions in subdivision c and
				for all increments of construction.
e. Seepage through the dam, foundation, and
				abutments shall be controlled to prevent excessive uplift pressures, internal
				erosion, sloughing, removal of material by solution, or erosion of material by
				loss into cracks, joints, and cavities. This may require the use of impervious
				blankets, pervious drainage zones or blankets, toe drains, relief wells, or
				dental concreting of jointed rock surface in contact with embankment materials.
f. Allowances shall be made for
				settlement of the dams and the foundation so that the freeboard will be
				maintained.
g. Impoundments
				created by dams of waste materials shall be subject to a minimum drawdown
				criteria that allows the facility to be evacuated by spillways or decants of
				ninety percent of the volume of water stored during the design precipitation
				event within ten days.
h. During
				construction of dams subject to this section, the structures shall be
				periodically inspected by a registered professional engineer to ensure
				construction according to the approved design. On completion of construction,
				the structure shall be certified by a registered professional engineer
				experienced in the field of dam construction as having been constructed in
				accordance with accepted professional practice and the approved design.
General Authority:
NDCC 28-32-02, 61-02-11,
				  61-03-13
Law Implemented:
NDCC 61-02-14