11102 EVERGREEN WAY 2018-01-01 MF Import

If the wetpond is designed per std. �420A, then a 72 inch diameter catch basin with a 48 inch deep sump or a forebay with a 15 minute residence time in a two year storm (equivalent to volume of 0.25 inches of precipitation over the contributing impervious surfaae) must be provided for grit removal prior to the pond. The catch basin or forebay must be accessible for sediment removal. At a minimum a 15 foot wide gravel access road with a minimum compacted thickness of 6 inches must be provided to the catch basin or to the perimeter of the forebay. If the wetpond is designed per std. �420B, access must be provided to the first cell of the pond to facilitate future sediment removal. A fifteen foot wide qravel access road to the bottom of the pond, with a minimwa conpacted thickness of six inches and a maximum slope of 6:1, is called for fn the standards. The cell volume would need to be increased to compensate for the volume displaced by the road. Rip-rap 12" deep and 2' wide should be placed from the end of tha swale to the bottom of the pond. The access road to the wetpond, and therefore the width of the area dedicated to the City, must be a minimum of 15 feet wfde. Pipes in wetpond areas must have sufficient cover to allow for future sediment removal without damage to the pipe. A minimum of 2 feet of cover, both horizontally and vertically, is required. The inlet and outlet structures to the wetpond must be designed so that all stormflow is forced to travel the full length of the wetpond. All ponds with a maximum depth qreater than three feet are required to be fenced with a six foot high perimeter fence unless one of the following conditions is met: 1) a 10 foot wide safety bench for every three feet of design water depth and the side slopes of the pond are no greate. than 3:1 (H:V) ; or 2) the maximum water depth of the facility does not exceed three feet during a two year storm, nor exceed three feet for more than four hours for a 25 year storm; the side slopes are a maximum of 3: 1 (H:V) ; and the facility is a dual use facility; or i 3) specific City Council approval is granted for an exemption per the criteria in the City's Design and Construction Standards and Specifications.