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:085 Consideration will be given to installing and replacing surface level structures such as street lights, traffic signals and utility poles, with structures that have extensive subsurface footings that reach stable material. Rationale Modern soils and structural engineering practices are able to identify the probability and expected extent of changes in ground conditions, such as subsidence, due to seismic events. A soils study of the Santiago Creek streambed, surrounding the bridge supports area, will enable soils and structural engineers to determine whether the existing bridge structure was designed adequately to withstand the most probable seismic event and to recommend further structural enhancements as may be needed, which could be installed jointly during the bridge widening phase of the proposed project. A soils study will also be performed for the rest of the affected segment of Bristol Street. This study will also provide sufficient data with which to determine the most appropriate structural characteristics of the various new and replaced ground-level street improvements and traffic control facilities. The costs vs. benefits of any extraordinary structural measures that may be identified can also be determined so that funds are not allocated to unusual structural supports for such non-critical facilities (compared to earthquake- protection for a hospital or school classroom). Erosion and Water Quality Significant Effects Construction of the proposed street improvements will temporarily expose the ground surface to the forces of wind and possibly water movement, if conducted during a rainstorm. Also, construction of the widened Santiago Creek Bridge during the rainy season could generate debris piles that would add to the sediment run-off that would result from stormwater flows along the creek. Uncontrolled sedimentation, whether from street cnnstrnction run-off or within the stormwater flows along Santiago Creek, contribute to the pollution of downstream waters, which receive this mn-off. Finding The following measures have been incorporated into the project which, if properly implemented, would avoid or substantially lessen the possible erosion effects to a level of insignificance. Straw or other suitable materials will be placed over uncovered soils, as needed, during street construction activities. This would reduce the amount of erosion.