SECTION 785:25-3-7. Minimum outlet conduit capacities

(a)   Requirements for outlet conduit capacity shall be as follows:

(1)   All dams subject to the Board's jurisdiction shall have at least one outlet conduit of sufficient capacity to prevent interference with natural streamflow and injury of downstream appropriators and domestic users. Absent evidence to the contrary, the minimum size of the outlet conduits shall be as set forth in subsection (d) of this section.

(2)   The height of the outlet conduit shall be no more than five feet (5') above the natural stream channel unless otherwise ordered by the Board. The capacity of the reservoir below the outlet conduit shall be designated as the inactive pool.

(b)   Conduit operation. All conduits shall be gate- or valve-operated on the upstream side and shall be maintained in an operable condition at all times.

(c)   Conduit design life. The design life expectancy of the conduit shall be equal to or greater than the design life of the dam.

(d)   Minimum size outlet conduit requirements. The outlet conduit must be of sufficient size to draw down the entire reservoir to the inactive pool within twenty (20) days, provided that minimum size outlet requirements are as follows:

(1)   For less than 100 acre-feet normal pool capacity (at principal spillway), the minimum size of conduit is 6-inch pipe.

(2)   For 101 to 150 acre-feet normal pool capacity (at principal spillway), the minimum size of outlet conduit is 8-inch pipe.

(3)   For 151 to 200 acre-feet normal pool capacity (at principal spillway), the minimum size of outlet conduit is 10-inch pipe.

(4)   For 201-250 acre-feet normal pool capacity (at principal spillway), the minimum size of outlet conduit is 12-inch pipe.

(5)   For 251-300 acre-feet normal pool capacity (at principal spillway), the minimum size of outlet conduit is 14-inch pipe.

(6)   For 301-350 acre-feet normal pool capacity (at principal spillway), the minimum size of outlet conduit is 15-inch pipe.

(7)   For 351-500 acre-feet normal pool capacity (at principal spillway), the minimum size of outlet conduit is 16-inch pipe.

(8)   For more than 500 acre-feet normal pool capacity (at principal spillway), the minimum size of outlet conduit is 24-inch pipe.

(e)   Amendments of minimum requirements for good cause. Minimum size requirements may be amended by the Board for good cause. However, conduit must be of sufficient size to draw down the entire reservoir to the inactive pool within a period of not more than twenty (20) days.

[Source: Added at 21 Ok Reg 2625, eff 7-1-04]