In order to implement Section 9.6791 through 9.6797 of this code, the City Manager shall adopt in accordance with EC 2.019, City Manager – Administrative and Rulemaking Authority and Procedures, a Stormwater Management Manual. The Stormwater Management Manual may contain forms, maps and facility agreements and shall include requirements that are consistent with the following goals:
(1) Reduce runoff pollution from development by reducing impervious surfaces and capturing and treating approximately 80% of the average annual rainfall.
(2) Control and minimize flows from development in the Headwater Areas using a variety of techniques to release water to downstream conveyance systems at a slower rate and lower volume, thereby reducing the potential for further aggravation of instream erosion problems.
(3) Emphasize stormwater management facilities that incorporate vegetation as a key element, and include design and construction requirements that ensure landscape plant survival and overall stormwater facility functional success.
(4) Operate and maintain stormwater management facilities in accordance with facility-specific O & M Plans.
(5) Reduce pollutants of concern that are generated by identified site uses and site characteristics that are not addressed solely through the stormwater quality measures by implementing additional specific source control methods including reducing or eliminating pathways that may introduce pollutants into stormwater, capturing acute releases, directing wastewater discharges and areas with the potential for relatively consistent wastewater discharges to the wastewater system, containing spills on site, and avoiding preventable discharges to wastewater facilities, surface waters or ground waters.
(6) Except as otherwise allowed by this land use code, allow disturbances or development within drainage ways only when all of the following conditions exist:
(a) The disturbance or development will not impede or reduce flows within the drainage way;
(b) The disturbance or development will not increase erosion downstream; and
(c) The constructed pipe system is sized to convey all of the runoff from the upstream watershed when the upstream watershed is completely developed.