1986-24 (2) - Laserfiche WebLink

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(c) The site is not located on the primary sand ridge or designated aquifer recharge area as delineated by the County's Environmental Planner; (d) Side slopes are 4' horizontal to 1' vertical and properly vegetated to 2' below the control elevation. (5) Discharges from the development project shall be handled to a point of legal positive outfall. Tailwater stages of the receiving waters, as reported in the Master Plan or as generated from data in the Master Plan, must be taken into account in design. Enlargement of existing downstream facilities may be required. (6) The bottom of dry retention areas shall be sloped at a minimum .2% to a permeable drain. A detention area shall have an outlet device, and shall not be lower than the elevation of the off-site receiving channel or water body. (7) Where permitted, open drainage -ways shall retain natural design characteristics and be so designed and protected that they do not present a hazard to life or property. The design shall include measures to protect against scour and erosion and provide for stable side slopes. Whenever possible, such waterways shall provide for adequate flushing action by prevailing winds and currents to assure the prevention of stagnant water and debris accumu- lation. (8) Disposition of Stormwater Runoff - The stormwater management system for development located predominantly on excessively drained soils should maximize stormwater infil- tration. This shall be accomplished through the use of bottomless inlets, perforated pipe, grading to retard runoff, natural or artificial retention or detention basins, or other methods, depending on the characteristics of the land area. Specific guidelines are as follows: (a) Areas and lots shall be developed to maximize the amount of natural rainfall which is percolated into the soil and to minimize direct overland runoff into adjoining streets and water courses. Stormwater runoff from roofs and other impervious surfaces should be diverted into swales, or terraces on the lot. (b) Street drainage shall be by grassed swales or curb and gutter in accordance with County specifications, provided all curb and gutter systems shall discharge or direct water into or across�a grassed swale area or other filtering medium. Whenever practical, as indicated by soil characteristics, water table elevation, and topography, the overflow from any swale used shall be diverted to percola- tion areas, ponding areas or natural or artificial seepage basins of sufficient capacity to retain and provide for the