§ 6.06.00. Stormwater management.

1.

Purpose: This chapter shall govern the design and construction or alteration of all stormwater management and drainage systems, natural or man-made, within the unincorporated portions of Okaloosa County in order to protect, maintain, and enhance both the immediate and long term health, safety, and welfare of the citizens of the county, while permitting landowners reasonable use of their property.

2.

Definitions: As used in this ordinance, the following terms shall have the stated meaning.

a.

Open basin: The term open basin refers to a watershed with a positive outlet.

b.

Closed basin: The term closed basin refers to a watershed that contributes to a depressed area, lake or sink that does not have a positive outlet.

c.

Positive outlet: The term positive outlet refers a point of stormwater discharge into surface waters which under normal conditions would drain by gravity or other means to the Blackwater River, Yellow River, Shoal River, Choctawhatchee Bay, Santa Rosa Sound, East Bay or Gulf of Mexico.

d.

Critical storm: The term critical storm refers to the specific storm event that produces the highest rate of net storm water runoff, defined as the post-development rate of discharge less the pre-development rate of discharge. To determine the critical storm, the post-development and pre-development rates of discharge must be compared for a range of frequencies up through the 25-year frequency (i.e. two, five, ten, and 25-year) and a range of durations through the 24-hour duration (i.e. one, two, four, eight and 24-hour).

e.

Legal positive outfall: The term legal positive outfall refers to a positive outlet into which the applicant has a legal right to discharge stormwater. A legal right to discharge can be established by existing conditions or easement.

f.

Retention basin: A stormwater collection location in which the collected volume is primarily recovered via percolation through the basin floor. Recovery of available pond volume via evaporation and transpiration is negligible in comparison to the soil percolation rate.

g.

Detention basin: A stormwater collection location in which the collected volume is discharged at a controlled rate via weir or orifice. Detention basins can be dry during non-rainy periods (dry detention or detention with filtration systems) or be ponds with a constant water surface (wet detention pond with treatment volume, permanent pool volume, littoral zone and control elevation). Detention basins include all basins that have surface outlets, such as those with underdrain and side drain systems.

(Ord. No. 11-01, § 2, 1-18-11)