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Regional Water Board as shallow water discharges, so that the General Permit is <br /> protective under all circumstances. <br /> c. Dilution Credit. The General Permit assumes minimal dilution is available for <br /> discharges that it authorizes, and therefore no dilution credit is granted in calculating <br /> WQBELs. No dilution credit is granted because almost all discharges of treated <br /> groundwater regulated under this Order are to storm drain systems that discharge to <br /> rivers, creeks, and streams. Many of these creeks and streams are dry during the summer <br /> months. Therefore, for a few months of the year, these discharges may represent all or <br /> nearly all of the flow in some portions of the receiving creeks or streams. These <br /> discharges therefore also have the potential to recharge groundwaterss protected as <br /> drinking waters. <br /> d. Development of WQBELs for Specific Pollutants. To develop WQBELs for pollutants <br /> that demonstrate reasonable potential based on CTR human health criteria(benzene, <br /> bromoform, chlorodibromomethane, 1,2-dichloroethane, and bis(2-ethylhexyl)phthalate) <br /> , the average monthly effluent limitation(AMEL) is established as the most stringent <br /> WQC because the WQC are based on applicable human health criteria. To calculate the <br /> maximum daily effluent limitation(MDEL),the AMEL is multiplied by a MDEL/AMEL <br /> multiplier of 2.01, which assumes a coefficient of variation(CV) of effluent data of 0.60, <br /> because not enough data were available to calculate a CV. <br /> For pollutants with criteria based on Title 22 MCLs (benzene,vinyl chloride), where the <br /> MUN designation is applicable to the receiving water, MDELs are set equal to the MCL, <br /> because the MCLs are levels that shall not be exceeded in the receiving water, and no <br /> credit for dilution is granted. <br /> WQBELs for total residual chlorine are based in Table 4-2 of the Basin Plan. <br /> For the CTR metals and cyanide,WQBELs are not being established at this time. Instead, <br /> trigger values will be set for these inorganic pollutants as a backstop to ensuring that sites <br /> with metals or cyanide contamination are appropriately identified and addressed. <br /> Exceedance of these trigger values in the discharge would trigger actions specified Provision <br /> VI.C.6,which if warranted may also lead to termination of discharge authorization under this <br /> Order. <br /> Table F-6. Summar of WQBELs <br /> No. Compound Discharge to Receiving Waters Discharge to Other Receiving <br /> used as Drinking Water Source��� Waters <br /> AMEL MDEL AMEL NIDEL <br /> �µ�) �µ�L) �µ�) �µ�) <br /> 1 Benzene --- 1 71 142 <br /> 2 Carbon Tetrachloride 0.25 0.5 4.4 8.8 <br /> 3 Chloroform --- --- ___ <br /> 4 1,1-Dichloroethane --- 5 --- --- <br /> Attachment F—Fact Sheet F-23 <br /> For VOC and Fuel General NPDES Permit No.CAG912002 <br />