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• • Draft Supplemental Environmental Impact Report Page IV.G-6 • Forward Inc. Landfill 2018 Expansion Project Flood Hazards • The proposed expansion areas, including the South Branch of South Littlejohns Creek • realignment at Forward Landfill are located within FEMA Flood Insurance Rate Map (FIRM) • panels 0636F (October 16, 2009). The south expansion area is within flood zone designations B (between 100 and 500-year flooding) and C (minimal flooding). • • Some portions of the site along the former course of the North Branch of South Littlejohns Creek • are mapped as within Zones AE and AO, with 100-year flood depths of 1 to 3 feet. However, since preparation of the FEMA map,the North Branch has been realigned to the north and west • of the landfill fill area, and is now designed to carry the 100-year flood flows. The North and • South Branches of South Littlejohns Creek on the site are subject to regular maintenance for • flood control. This maintenance consists of clearing trees and shrubs from the banks and dense vegetation from the channel. • • A Central Valley Flood Protection Board encroachment permit with endorsement by the San • Joaquin County Flood Control and Water Conservation District is required for any work within the channels or within 25 feet of the top of bank of the creeks, and the realignment of the South • Branch must be approved by the Board. Questa Engineering Corp (Questa)has developed plans • for the realigned South Branch channel.The new channel is designed to carry the 100-year flood • flows within its banks. Erosion protection would be provided in areas with high velocities or sharp bends. • Surface Water Oualitk The RWQCB Order R5-2003-0049 requires quarterly surface water quality monitoring at four • points on the landfill site, when surface water is evident. Two of the sampling locations,FSW-1 and ASW1, are located upstream of the landfill and represents background conditions. The • other sampling points, FSW-2 and ASW-2, are located immediately downstream of the landfill, • and are designed to evaluate surface water quality impacts from the landfill. The designated sampling points are within the affected area of the proposed expansion. • • Beneficial uses of Littlejohns Creek, as specified in the San Joaquin River Basin Plan, are • agricultural supply, industrial service and process water, contact and non-contact water, recreation, wane fresh water habitat, preservation of rare, threatened, and endangered species, • and groundwater recharge. Surface water samples are collected quarterly for field parameters (temperature, specific conductance,pH, and turbidity), and, chloride, sulfate, nitrate as nitrogen, total dissolved solids • (TDS), carbon bicarbonate, total organic carbon, chemical oxygen demand, dissolved metals • (calcium,magnesium, sodium, potassium),volatile organic compounds, and total petroleum • hydrocarbons (oil and grease). Surface water sampling and analysis are not always performed • at the Austin Road and Forward Units because, at times,there is no water to sample at those points. • • • • • •