20A - AA FIRST ST BRIDGE REPLACEMENT PROJECT

Home Browse Search

LSA ASSOCIATES, INC. INITIAL STUDY/MITIGATED NEGATIVE DECLARATION JULY 2010 FIRST STREET BRIDGE REPLACEMENT PROJECT CITY OF SANTA ANA The proposed project would increase the impervious surface area by approximately 0.30 ac compared to the existing roadway facility. Any increase in volume and velocity of runoff would not be substantial and would be conveyed to the existing downstream conveyance channels which are engineered, hardened, and regularly maintained. Project runoff would not be directed to unpaved areas prone to erosion. Therefore, the proposed project would result in less than significant impacts related to soil erosion and the loss of topsoil and no mitigation is required. C. Would the project result in the loss of a unique geologic feature? No impact. The proposed project is located in a built-out area, where no unique geologic features are present. The proposed project would not impact any unique geologic features on the site and no mitigation is required. D. Is the project located on strata or soil that is unstable or that would become unstable as a result of the project and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction, or collapse? No impact. The site is already built-out and the vicinity of the site is relatively flat and developed with urban uses. Therefore, the proposed project will not result in on-or off-site landslides, lateral spreading, subsidence, liquefaction, or collapse. No impact is expected and no mitigation is required. E. Where sewers are not available for the disposal of wastewater, is the soil capable of supporting the use of septic tanks or alternative wastewater disposal systems? No impact. The proposed project does not include the use of septic tanks or alternative methods for disposal of wastewater. The proposed project is a bridge replacement and street widening project; no sewage disposal systems are planned. There would be no project impact related to the disposal of wastewater and no mitigation is required. VII. Hazards and Hazardous Materials Would the project: A. Create a significant hazard to the public or the environment through the routine transport, use or disposal of hazardous materials? Less than significant impact with mitigation. According to the Initial Site Assessment (LSA, July, 2010) no hazardous materials are associated with the operation of the bridge or roadway. However, lead-containing materials and asbestos-containing materials (AGMs) and polychlorinated biphenyls (PCBs) may be present in the existing bridge structure and on the First Street. In general, ACMs and lead-containing materials have been documented in the rail shim sheet packing, bearing pads, support piers, and expansion joint material of bridges as well as asphalt and concrete. Short-term impacts related to construction activities consist mostly of fugitive dust emissions and equipment exhaust. 07/25/10 «P:\DMJ0701\MND\4.0 Environmental Analysis.doc» 4-17 20A-68