Item A-MWMC Facilities Plan - Laserfiche WebLink

Home Browse Search

9. ENVIRONMENTAL REPORT period could improve water quality in effluent discharge, thus reducing the potential for adverse affects to wildlife, fish, and habitat in the river. Construction Period Construction impacts would be temporary and would be primarily related to the installation of a third (bank) outfall on the Willamette River. Excavation and construction activities at the outfall site could increase the potential for erosion and the dischar.~ge of sediment into the river. Accidental spills of petrolettm product and hazardous material and releases of debris and other materials used for site construction activities could also occur during the construction period but sound practices would reduce/eliminate river impacts. Operational Period Compared to System Alternative 1, implementation of System Alternative 5 would likely result in a net beneficial impact to water quality in the Willamette River. The quality of effluent discharged to the Willamette River, and thus water quality in the Willamette River, would be higher under System Alternative 5 than under System Alternative 1. Implementation of System Alternative 5 would reduce the potential for untreated sewage discharges to the river during peak flow periods. Additionally, under System Alternative 5, water discharged from the WPCF would meet NPDES requirements for TSS and CBODs. Table 9.4.2-1 compares NPDES permit limits for TSS and CBOD5 with predicted discharges in treated effluent under System Alternative 5. TABLE 9.4.2-1. Comparison of WPCF NPDES Permit Conditions with Predicted Conditions Under System Alternative 5 {Parallel Primary/Secondary Treatment) MWMC Facilities Plan, Eugene-Springfield Permit Limit/Removal Predicted Discharge/Removal Parameter Requirements Efficiency Maximum Week TSS 28,000 lb/day 20,550 lb/day Maximum Week C BOD5 24,000 lb/day 14,160 lb/day Maximum Month TSS Removal 85 percent 87.6 percent Maximum Month CBODs 85 percent 86.5 percent Removal Mitigation Construction best management practices (BMPs), including spill prevention, control, and countermeasures (SPCC) planning and sediment and erosion control practices, will be implemented to minimize and avoid erosion and the discharge of sediment, petroleum products, hazardous materials, and construction debris from the project site. 9.4.3 Biological Resources Wetland and riparian areas are the primary habitat types of concern in the vicinity of the WPCF. Compared to System Alternative 1, System Alternative 5 could result in temporary, MWMC_9.0._REV14.DOC 9-11