Code of Maryland Regulations › Title 26 - DEPARTMENT OF ENVIRONMENT › Part 4 - SUBTITLES 19-30 › Subtitle 20 - SURFACE COAL MINING AND RECLAMATION UNDER FEDERALLY APPROVED PROGRAM › Chapter 26.20.21 - Ponds and Sediment Control Measures › Section 26.20.21.08 - Impoundments

Current through Register Vol. 51, No. 14, July 12, 2024
A. General
				  Requirements. The requirements of this section apply to both temporary and
				  permanent impoundments. Impoundments shall be designed and constructed to
				  ensure:
(1) Compliance with USDA, Natural
				  Resources Conservation Service, Maryland Conservation Practice, Standard Pond
				  Code 378 (January 2000), as incorporated by reference in COMAR
				  26.17.02.01 a -1B(2);
(2) Compliance with requirements of COMAR
				  26.17.04.05 a if the embankment is
				  more than 15 feet in height as measured from the upstream toe of the embankment
				  to the crest of the emergency spillway;
(3) Impoundments meeting the Class (b) or (c)
				  criteria for dams in "Earth Dams and Reservoirs", TR-60 shall comply with
				  "Minimum Emergency Spillway Hydrologic Criteria" table in TR-60 and the
				  requirements of this regulation;
(4) The minimum elevation at the top of the
				  settled embankment shall be 1 foot above the water surface in the pond with the
				  emergency spillway flowing at design depth;
(5) The height of the embankment is a minimum
				  of 5 percent over the design height to allow for settlement, unless it has been
				  demonstrated to the Bureau that the material used and the design will ensure
				  against all settlement;
(6) The top
				  width of the embankment is not less than the quotient of (H+35)/5, when H is
				  the height, in feet, of the embankment, as measured from the upstream toe of
				  the embankment;
(7) Perimeter
				  slopes are stable, are not steeper than 2:1, and are protected against erosion
				  where water enters the impoundment;
(8) The combined upstream and downstream side
				  slopes of the settled embankment are not less than 5:1 with neither slope
				  steeper than 2:1;
(9) The crest of
				  the emergency spillway is a minimum of 1 foot above the crest of the principal
				  spillway;
(10) A cut-off trench is
				  installed before initiating the placement of fill material for the embankment
				  with side slopes not steeper than 1:1;
(11) The embankment foundation area is
				  cleared of all organic material and the entire area scarified;
(12) The embankment begins by placing and
				  spreading fill material at the lowest point of the foundation, is brought up in
				  horizontal layers not to exceed 8 inches as required to facilitate compaction,
				  and is compacted as specified in the design approved by the Bureau;
(13) Fill material used in the construction
				  of the embankment is free of sod, large roots and other vegetative matter,
				  frozen soil, and coal processing waste;
(14) The embankment slope is protected
				  against surface erosion and against damage caused by sudden drawdown;
(15) The embankment faces and surrounding
				  areas are vegetated, except that the faces where water is impounded may be
				  riprapped or otherwise stabilized in accordance with accepted design practices;
				  and
(16) Newly constructed areas
				  and those areas disturbed by the construction are vegetated immediately upon
				  completion of the construction.