Item 9: Ordinance Concerning Stormwater Development Standards

Home Browse Search

May 22, 2006 Peggy Keppler, The proposed stormwater ordinance and manual go a long way toward meeting the NPDES permit requirements and implementing the outcomes of the completed basin plans. This step toward increased water quality and flood control is appreciated citywide, yet there are certain places where these proposed actions fall short of the best we can achieve. Part of that is due to the fact that not all basins have completed basin plans to inform the ordinance, and part ofthat is due to omissions or adjustments that could be made to the proposed ordinance. Below I have outlined the concerns of the Santa Clara Community Organization's Land Use Subcommittee on this issue and have recommended changes where they seem feasible. The River Rd/Santa Clara basin comprises approximately one fourth of the total area for all seven basins covered by the proposed ordinance. The quality and quantity of stormwater runofffrom this basin needs to be reflected in the ordinance and manual being proposed for adoption. According to the process outlined by the city for developing integrated strategies from the six basins, identifying, evaluating, and developing proposed capital projects and development standards for each basin precedes the development of an ordinace and BMP manual. (see 13 step process in Volume I of the City's Stormwater Basin Master Plans) The River Road/Santa Clara stormwater basin master plan is unfinished. Given that this basin lacks piped stormwater infrastructure (the primary vehicle for stormwater conveyance and treatment in the rest of the city) and instead relies on natural drainage and open waterways, the challenges of meeting water quality and quantity goals there require different solutions. . PERVIOUS OR IMPERVIOUS? The transition from undeveloped to densely developed correlates to a change from pervious (vegetated land that allow water to infiltrate into the ground) to impervious (roofs, roads, parking lots, driveways) surfaces. Impervious surfaces can not absorb or infiltrate precipitation resulting in greatly increased runoff volumes, higher peak flows, and higher concentrations of pollutants. According to the draft basin plan, our projected percentage of impervious surface at buildout will be 51 %, the highest of all the basins. Given that we have no piped system and thus no possible "mechanical fix" to adequately filter out pollutants, or slow velocity of stormwater, we need to maintain a higher level of impervious area to allow natural filtration and percolation of stormwater into the ground. Preserving and enhancing the existing natural stormwater system is more cost effective, efficient, requires less maintenance, and the system increases in value and efficacy over its lifespan. The goals of the ordinance are best met through development standards, not capital projects in this basin. We need to have language in the ordinance that reflects these priorities for a functioning natural stormwater system. . WATERQUALITY Water quality data for this basin is missing. There has been no macro invertebrate sampling (useful in evaluating water quality issues i.e.: cumulative effects of pollutants