ARCHIVED REPORTS_DRAFT ENVIRONMENTAL IMPACT REPORT

Home Browse Search

seasonally-based,moderate increase in ammonia levels will attenuate through natural processes downstream in the receiving water as ammonia is utilized by phytoplankton and other primary producers,thus reducing the pollutant's downstream impact from that projected in the near-field. More importantly,projected median ammonia concentrations in the San Joaquin River are projected to remain below the more stringent chronic EPA ammonia objective calculated for the river on a year round basis. With the exceptions of aluminum and temperature,none of the water quality parameters evaluated in this report are anticipated to exceed relevant water quality objectives,and on average are estimated to be present at concentrations well below objectives. Any near-field thermal impacts resulting from the WQCF's expanded discharge capacity will be mitigated as necessary(e.g.,implementation of a cooling tower to lower effluent temperature prior to its discharge into the receiving water)to ensure no adverse thermal effects on fisheries and aquatic resources in the San Joaquin River. The proposed project is not expected to result in far-field exceedances of applicable water quality objectives or standards in the Delta. Additionally,the proposed project will be operated to ensure compliance with the NPDES regulatory program(i.e.,future effluent limitations)which will make sure that water quality objectives in the receiving water are met. Furthermore,the reduction in water quality that would result from the proposed project will not unreasonably affect actual or potential beneficial uses. Project Identified as Providing Maximum Benefit to the State Considering the 17.13 MGD(ADWF)increase in discharge capacity that is sought relative to the range of year-round flows observed in the San Joaquin River,the difference in downstream pollutant concentrations produced by effluent undergoing tertiary filtration compared to effluent This Page Intentionally Left Blank undergoing additional MF/RO treatment is essentially de minimis for most constituents once WQCF effluent and receiving water are well-mixed. With regard to the effluent-to-land disposal control measure,the difference in projected downstream receiving water quality when the WQCF is discharging at the currently permitted 9.87 MGD(ADWF)capacity compared to the proposed 27 MGD(ADWF)build-out capacity is generally slight,relative to water quality objectives,for most constituents once WQCF effluent and receiving water are well-mixed. Therefore,the critical comparison to be made between alternatives is a balancing of the generally very minor degradation in downstream receiving water quality for a small number of parameters attributable to the discharge of 17.13 MGD(ADWF)tertiary treated effluent against the environmental impacts of effluent-to-land disposal and MF/RO treatment,and the significant socio-economic impacts of these two alternative control measures as estimated by the IMPLAN® model. Based on the balancing of environmental and socio-economic impacts associated with the four scenarios described above,the City has identified the proposed project as the project providing best practicable treatment or control consistent with maximum benefit to the people of the State. City of Manteca Antidegradation Analysis 119 June 2007 City of Manteca Antidegradation Analysis 120 June 2007