§ 30.53.140. Grading Practices/Drainage and Erosion Control.

In order to minimize and control runoff and the associated erosion and sedimentation of downstream wetland areas, all development activities on project sites within the Lagoon Overlay Zone shall comply with each the following grading methodology and erosion control practices:

A.

Projects shall be conditioned to ensure that runoff from impervious surfaces shall either be directed towards existing publicly owned discharge and drainage systems or retained on-site in settling ponds or other drainage/erosion control measures. Where, due to factors of topography, neither direction of runoff into storm drain systems nor retention on site is possible, runoff shall be appropriately discharged at non-erosive flows and velocities through the use of energy dissipation devices.

B.

Temporary erosion control measures shall include the use of berms, interceptor ditches, sandbagging, hay bales, filtered inlets, debris basins, silt traps, or other similar means of equal or greater effectiveness. All such erosion control measures shall be installed prior to the commencement of grading in the areas for which the erosion control measures are intended and shall be removed within 30 days of project completion.

C.

For projects involving a total of more than 25 cubic yards of cut and/or fill grading, no grading shall occur during the rainy season, identified for purposes of this Chapter as the period from November 15th to March 31st. This Section shall not apply to approved wetland restoration projects.

D.

In addition to other erosion control measures required pursuant to this Chapter, all graded slopes shall be stabilized prior to the November 15th onset of the rainy season through the provision of vegetative erosion control. Vegetative erosion control may be achieved through measures such as: landscape planting, seeding, mulching, fertilization, and irrigation. The installation of vegetative erosion control shall occur with sufficient time to achieve landscape coverage prior to the November 15th start of the rainy season.

E.

All graded areas disturbed but not completed prior to November 15th, including graded pads and stockpiles, shall be suitably prepared to prevent excessive soil loss during the November 15th to March 31st rainy season.

F.

All permits shall be subject to the submittal of a polluted runoff control plan. The required plan shall incorporate the use of structural and non-structural Best Management Practices (BMPs), to the extent necessary, to minimize the discharge of pollutants carried by runoff from urban development into surface water drainage, and to maintain post-development peak runoff rate and average volume at levels similar to pre-development levels. The plan shall include, but not be limited to the following Best Management Practices (BMPs), as applicable: silt traps, catch basins, oil/grit separators, street sweeping and cleaning program, low-maintenance landscape and pesticide management plan, solid waste management public education program. Post-construction structural BMPs (or suites of BMPs) should be designed to treat, infiltrate or filter storm water runoff from each storm, up to and including the 85 ^th percentile, 24-hour storm event for volume-based BMPs, and/or the 85 ^th percentile, one-hour storm event, with an appropriate safety factor, for flow-based BMPs. The plan shall include a monitoring component to ensure long-term maintenance of BMPs as relevant, and to allow for continued evaluation of the effectiveness of the polluted runoff control plan in meeting the goals of the LUP regarding the protection and enhancement of sensitive resources.

(Ord. No. 733)