Storm Water Pollution Prevention Plan (SWPPP) - the City of Lompoc!

OrderUse of an ATS can effectively reduce a site's risk of impactingreceiving waters.51. Dischargers located in a watershed area where a Total Maximum DailyLoad (TMDL) has been adopted or approved by the Regional WaterBoard or U.S. EPA may be required by a separate Regional WaterBoard action to implement additional BMPs, conduct additionalmonitoring activities, and/or comply with an applicable waste loadallocation and implementation schedule. Such dischargers may alsobe required to obtain an individual Regional Water Board permitspecific to the area.H. Effluent Standards52. The State Water Board convened a blue ribbon panel of storm waterexperts that submitted a report entitled, “The Feasibility of NumericEffluent Limits Applicable to Discharges of Storm Water Associatedwith Municipal, Industrial and Construction Activities,” datedJune 19, 2006. The panel concluded that numeric limits or actionlevels are technically feasible to control construction storm waterdischarges, provided that certain conditions are considered. The panelalso concluded that numeric effluent limitations (NELs) are feasible fordischarges from construction sites that utilize an ATS. The StateWater Board has incorporated the expert panel’s suggestions into thisGeneral Permit, which includes both numeric action levels (NALs) andNELs for pH and turbidity, and special numeric limits for ATSdischarges.Numeric Effluent Limitations53. Discharges of storm water from construction activities may becomecontaminated from alkaline construction materials resulting in high pH(greater than pH 7). Alkaline construction materials include, but arenot limited to, hydrated lime, concrete, mortar, cement kiln dust (CKD),Portland cement treated base (CTB), fly ash, recycled concrete, andmasonry work. This General Permit includes an NEL for pH (6.0-9.0)that applies only at sites that exhibit a "high risk of high pH discharge."A "high risk of high pH discharge" can occur during the completeutilities phase, the complete vertical build phase, and any portion ofany phase where significant amounts of materials are placed directlyon the land at the site in a manner that could result in significantalterations to the background pH of any discharges.54. For Risk Level 3 discharges, this General Permit establishestechnology-based, numeric effluent limitations (NELs) for turbidity of500 NTU. Exceedances of the turbidity NEL constitutes a violation ofthis General Permit.2009-0009-DWQ 9 September 02, 2009