Laserfiche WebLink
<br />. <br /> <br />3. Minimize impervious surface coverage to the maximum extent practicable. <br /> <br />4. In designated shoreland areas the development shall meet the impervious surface <br />requirements of the Shoreland Ordinance regardless of conveyance systems. <br /> <br />5. Have a proposed design, suggested location and phased implementation of effective, <br />practicable storm water management measures for plans designed, engineered and <br />implemented to achieve the following results: <br /> <br />a. Volume control <br />Designer shall be required to provide soil boring analysis to determine the <br />inf1ltration rate prior to approval of plans. <br /> <br />b. Phosphorus control <br />Storm water shall be treated to remove sixty (60) percent of the post- <br />development phosphorus load on an annual basis before discharge to natural <br />water bodies. Where water quality ponding is exclusively used to meet the <br />phosphorus removal requirement, the ponds must be sized to store the site <br />runoff from a two and one-half (2.5) inch rainfall below the normal outlet <br />elevation. <br /> <br />c. Total Suspended Solids <br />Treatment also must achieve a sixty (60) percent removal of suspended solids. <br /> <br />. <br /> <br />d. Oil and grease control <br />For all storm water plans for commercial or industrial developments and all <br />other uses where the potential for pollution by oil or grease, or both, exists, the <br />ftrst one-half (0.5) inch of runoff will be treated using the best oil and grease <br />removal technology available. This requirement may be waived by the city when <br />the applicant can demonstrate that installation of such practices is not necessary. <br /> <br />e. Runoff rate control <br />Refer to city's design standards. <br /> <br />(b) All storm water facilities shall be designed, installed and maintained to effectively <br />accomplish the following: <br /> <br />1. Minimize predevelopment peak runoff rates for the two (2) year, twenty-four <br />(24) hour storm event. <br /> <br />2. Minimize predevelopment peak runoff rates for the ten (10) year, twenty-four <br />(24) hour storm event. At a minimum, the storm sewer system shall be <br />designed for this storm event. Low areas must have an acceptable overland <br />drainage route with the proper transfer capacity when the event is exceeded. <br /> <br />. <br /> <br />3. Minimize predevelopment peak runoff rates for the one hundred (100) year, <br />twenty-four (24) hour storm event. <br /> <br />12 <br />