Objective 9.4.1. - Level of Service Standards.

Maintain the following minimum stormwater management Level of Service Standards for planning capital improvements and reviewing development applications to ensure that development does not negatively impact drainage basins.

Policy 9.4.1.1. Require the rate of stormwater discharge from new development to be equal to, or less than the rate of discharge that existed prior to development, based on a 25-year frequency—24-hour duration storm event. The post development point(s) of discharge shall be the same as the pre-development point(s) of discharge for a project site. The discharge is to include any discharge to an existing or proposed watercourse, swale, ditch, or storm sewer system that connects to a receiving watercourse in the WO district. All stormwater discharge shall be consistent with the requirements of Chs. 62-3, 62-4, and 62-25, F.A.C., for water quality. These requirements may be increased in areas of known flooding.

Policy 9.4.1.2. Design trunk storm sewers and major drainage channels to accommodate the stormwater runoff resulting from a design storm of 25-year frequency—24-hour duration, consistent with Chs. 62-3, 62-5, and 62-25, F.A.C.

Policy 9.4.1.3. Design internal, or on-site drainage facilities on any project to accommodate the stormwater runoff resulting from a design storm of ten-year frequency—critical duration based on the project site's time of concentration, and consistent with the intent of Chs. 63-3, 62-4, and 62-25, F.A.C., and the Land Development Code.

Policy 9.4.1.4. Require that all projects discharging into the WO District on the Future Land Use Map meet or exceed the design standards of Chs. 62-3, 62-4, and 62-25, F.A.C., and local design standards for discharge into Outstanding Florida Waters. The Board of County Commissioners may waive this policy if the proposed stormwater management system provides equivalent levels of stormwater treatment, ensuring that groundwater hydrology characteristics are not altered, impacted, or changed from the existing pre-development condition.

Implementation Mechanism:

(a)

Equivalent stormwater treatment methods which ensure that construction, alteration, or operation of stormwater systems do not discharge, emit, or cause violation of applicable Outstanding Florida Water quality standards shall be included in the Land Development Code.

Policy 9.4.1.5. All projects not within the WO District shall be designed and constructed to detain, and permit the filtration of stormwater runoff consistent with Chs. 62-3, 62-4, and 62-25, F.A.C., and adopted land development regulations.

Policy 9.4.1.6. Require that all detention or retention basins be designed utilizing side slopes not greater than 4:1 (e.g., 5:1). Side slopes may be as steep as 2:1 for that area of the drainage basin which will have a normal water level depth greater than six (6) feet or where safety fencing is provided.

(Ord. No. 18-04 , § 12(Exh. J), 8-23-18)