Oklahoma Administrative Code › Title 252 - Department of Environmental Quality › Chapter 656 - Water Pollution Control Facility Construction Standards › Subchapter 11 - Lagoon Standards › Section 252:656-11-3 - Lagoon construction details

Current through Vol. 41, No. 20, July 1, 2024
(a)
Soil borings.
Provide soil boring data conducted by an independent
				soil-testing laboratory. Borings shall extend at least 5 feet below the
				proposed lagoon bottom and at least one boring shall be at least 25 feet deep
				or into bedrock. Borings shall be conducted during the time of highest
				groundwater level. Provide enough borings to accurately represent the soil
				characteristics of the entire lagoon site. If bedrock is encountered, describe
				its general characteristics and identification, and the corresponding
				geological formation(s). Include a map showing the location of each boring, a
				log of soil types encountered at each boring, the elevation of the water table
				where encountered and the permeability of soil samples taken from the same
				elevation as the proposed lagoon bottom. Fill and seal all borings after
				testing.
(b)
Dikes.
(1)
Material.
Construct dikes of
				relatively impervious material and compact them to at least 90% Standard
				Proctor Density to form a stable structure. Remove vegetation and other
				unsuitable materials before construction.
(2)
Top width.
The top of the
				dike shall be at least 8 feet wide for maintenance vehicles.
(3)
Slope.
Inner and outer dike
				slopes shall not be steeper than 1 vertical to 3 horizontal (1:3). Steeper
				slopes will only be considered where surface construction is of soil cement or
				other material that will prohibit vegetation growth. Inner dikes shall not be
				flatter than 1 vertical to 4 horizontal (1:4).
(4)
Freeboard.
Design the lagoon
				to maintain at least 3 feet of freeboard above the design maximum water depth
				at all times.
(5)
Lagoon
				shape.
Round, square or rectangular lagoons with rounded corners, with a
				length not more than three times the width constructed without islands,
				peninsulas or coves.
(6)
Erosion control.
Protect inner dikes from wave action and outer
				dikes from runoff and floodwaters.
(A)
Seeding.
Where riprap is not used, apply at least 4 inches of
				fertile top soil to dikes to establish an adequate vegetative cover. Before
				prefilling, establish vegetation on dikes from the outside toe to 2 feet above
				the lagoon bottom on the interior as measured on the slope. Specify perennial,
				low-growing grasses that spread rapidly. Do not use alfalfa or other
				long-rooted vegetation for seeding since the roots of this type are apt to
				impair the water holding efficiency of the dikes.
(B)
Additional protection.
Provide extra protection where inner dikes may be subjected to severe wind
				action, such as lagoons larger than 5 acres and where the lagoon surface will
				often be exposed to strong winds. Also, protect areas of turbulence in aerated
				cells and all pipe penetrations. Install riprap, soil cement or other
				recognized material. Protect the inner dikes from 1 foot vertically above the
				high water elevation to 2 feet vertically below the minimum operating
				elevation. Place riprap on a filter bed at least 6 inches thick, and use
				material that will stay in place and resist erosion.