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Eastern Jf ashington Phase 11 Munieipal Stornm,ater Permit <br />e. Application of fertilizers and pesticides shall be conducted in a manner and at <br />application rates that will not result in loss of chemical to stormwater runoff. <br />Manufacturers' label requirements for application rates and procedures shall be <br />followed. <br />£ BMPs shall be used to prevent or treat contamination of stormwater runoff by pH <br />modifying sources. These sources include, but are not limited to: bulk cement, <br />cement kiln dust, fly ash, new concrete washing and curing waters, waste streams <br />generated from concrete grinding and sawing, exposed aggregate processes, <br />dewatering concrete vaults, concrete pumping and mixer washout waters. The <br />Permittee shall require construction site operators to adjust the pH of stormwater if <br />necessary to prevent violations of water quality standards. <br />g. The Permittee shall require construction site operators obtain written approval from <br />the Department prior to using chemical treatment other than CO2 or dry ice to adjust <br />pH. <br />11. Control De -Watering: <br />a. Foundation, vault, and trench de -watering water, which have similar characteristics to <br />stormwater runoff at the site, shall be discharged into a controlled conveyance system <br />prior to discharge to a sediment trap or sediment pond. <br />b. Clean, non -turbid de -watering water, such as well -point ground water, can be <br />discharged to systems tributary to, or directly into surface waters of the state, as <br />specified above in #8 Stabilize Channels and Outlets, provided the de -watering flow <br />does not cause erosion or flooding of receiving waters. Clean de -watering water <br />should not be routed through stormwater sediment ponds. <br />C. Other de -watering disposal options may include: (i) infiltration; (ii) transport offsite <br />in vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not <br />pollute state waters; (iii) On-site chemical treatment or other suitable treatment <br />technologies approved by the local jurisdiction; (iv) sanitary sewer discharge with <br />local sewer district approval, if there is no other option; or (v) use of a sedimentation <br />bag with outfall to a ditch or swale for small volumes of localized de -watering. <br />d. Highly turbid or contaminated dewatering water shall be handled separately from <br />stormwater. <br />12. Maintain BMPs: <br />a. All temporary and permanent erosion and sediment control BMPs shall be maintained <br />and repaired as needed to assure continued performance of their intended function in <br />accordance with BMP specifications. <br />b. All temporary erosion and sediment control BMPs shall be removed within 30 days <br />after final site stabilization is achieved or after the temporary BMPs are no longer <br />needed. <br />Appendix ]-Minimum Technical Requirements <br />Eastern Washington Phase 11 Municipal Stormwater Permit —August 1, 2014 <br />Page 8 <br />