15 - Laserfiche WebLink

Design Requirements 123. NPDES Permit design requirements include, but are not limited to, the following: a. Source control, site design, implementation, and maintenance standards when a regulated project (such as a commercial, industrial, residential subdivision, mixed use, or public project) creates and/or replaces 10,000 square feet or more of impervious surface (5,000 square feet for auto service facilities, retail gasoline outlets, restaurants, and uncovered parking lots), including roof area, street, and sidewalk. b. Hydromodification standards when a regulated project creates and/or replaces a total impervious area of one acre or more. c. Compliance with a Diazinon pollutant reduction plan (Pesticide Plan) to reduce or substitute pesticide use with less toxic alternatives. d. Compliance with a Copper Pollutant Reduction Plan and a Mercury Pollutant Reduction Plan. 124. The following requirements shall be incorporated into the project: a. The project developer shall submit a final grading and drainage plan prepared by a licensed civil engineer depicting all final grades and onsite drainage control measures including bio-retention swales. Irrigated bio-retention swales shall be designed to maximize stormwater entry at their most upstream point. The grading and drainage plans shall be subject to the review and approval of the City Engineer prior to the issuance of a grading or building permit, whichever is sooner. b. In addition to natural controls, the project developer may be required to install a structural control(s), such as an oil/water separator(s), sand filter(s), or approved equal(s) in the parking lot and/or on the site to intercept and pre- treat stormwater prior to reaching the storm drain. The design, location(s), and a schedule for maintaining the separator shall be submitted to the City Engineer/Chief Building Official for review and approval prior to the issuance of a grading or building permit, whichever is sooner. The structural control shall be cleaned at least twice a year(once immediately prior to October 15 and once in January). c. The project developer shall submit to the City Engineer the sizing design criteria and calculations for a hydromodification facility, if required, and for the treatment of stormwater runoff. The design criteria and calculations shall be subject to the review and approval of the City Engineer and shall be submitted prior to the issuance of a grading or building permit, whichever is sooner. 22 of 28