Item 9: Ordinance Concerning Stormwater Development Standards

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Comments on Stormwater Development Ordinance and Stormwate t'age J OI 0 * The Stormwater Management Manual says: "The purpose of this manual is to provide stormwater management principles and techniques that help preserve or mimic the natural hydrologic cycle and achieve water quality goals." However, the entire focus of the Manual is on "mimic" and not "preserve". The ordinance and Manual need sections that recognize and prioritize the preservation of soils, trees, vegetation and existing drainage ways as ways to reduce pollution and polluted runoff. There should be pollution reduction credits and requirements not only for tree preservation, but for soil preservation, and post-construction soil quality. Too often, developers compact soils, dramatically reducing their ability to filter stormwater. Flow Control Standards * The flow control provisions applied in the Headwaters (higher elevation) area require developers to keep the peak rate of flow of stormwater runoff to pre-development levels. However, there does not seem to be a requirement that addresses the total volume or duration of runoff. Other stormwater publications we have consulted indicate that these are important parameters to be considered, too. We would appreciate an explanation of why this ordinance is not requiring developers to control total volume or duration of runoff, as well as peak flow rates. * One stated purpose of the Flow Control standards in the Manual is to recharge groundwater. The River Road-Santa Clara area relies on groundwater and recharge, and also needs these protections. The Manual and ordinance should require that "on-site filtration methods are preferred and required to the maximum extent practicable" in the River Road-Santa Clara Basin, in addition to this requirement in the Headwaters area. Disturbances or Development within Drainage ways There is a section in the Stormwater Management Manual (section 1.7.2) that describes the conditions under which disturbance or development within drainage ways is to be allowed (e.g., if it does not impede stormwater flow, cause erosion downstream, etc). Two concerns: * This provision is found in the Manual, but not the ordinance. Is this because the ordinance is intended to put conditions only on new development or redevelopment, and this provision is intended to apply more broadly (e.g., to dumping, etc.)? Or is this an oversight? Shouldn't the provision be in the ordinance as well as the Manual? * I am assuming there must be legal reasons why the City cannot outright prohibit disturbance or development of a drainage way, but instead merely restricts it, and provides this listing of conditions to clarify its stormwater-related purposes in doing so? Can the City supplement this somewhat weak provision with an outright prohibition on fill in another more general part of the City code--similar to the previous Open Waterways ordinance? Or, can a parallel provision be put in City code to restrict fill of a drainage way under the same conditions as listed in the Manual (but regardless of whether the fill is done as part of a development application?). Here is a recent photo depicting a fence and retaining wall built by a property owner in the middle of Flat Creek (one of the major drainage ways in River Road). The culvert in the foreground runs under Elkay Drive. This type of activity seems important to prevent in the future (and undo in this case)--yet it appears to be currently outside the reach of any "regulations, including this proposed new stormwater development ordinance. I hope the City and County can work together to find a way to prohibit this kind of activity, which surely has an adverse effect on stormwater drainage in the area, yet seems objectionable on other grounds as well. The property in question is within County, not City jurisdiction, but City development codes would apply. 5/23/2006