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AUGUSTIN BERNAL MOUNTAIN BIKE TRAIL PROJECT DRAFT INITIAL STUDY mitigation incorporated and the project would not result in substantial erosion or siltation on or off site. ii) Substantially increase the rate or amount of surface runoff in a manner which would result in flooding on or off site? As discussed above, the project would not create any new impervious surfaces and the project design would ensure that runoff velocities would not increase, thus the project would not result in any on- or off-site flooding. Implementation of the trail project would result in no impact associated with flooding on or off site. iii) Create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff? As discussed above, the project would not create any new impervious surfaces and the project design would ensure that runoff velocities would not increase, thus the project would not result in any increase in stormwater runoff and thus would not result in the capacity of existing or planned stormwater drainage systems being exceeded. As discussed in Section 3.10(a), the City would implement typical BMPs to minimize soil erosion and associated adverse effects to water quality, including measures to stabilize work areas including fiber wattles, silt fencing, concrete washout areas, soil stabilizers, revegetation, or other appropriate measures. Site stabilization measures are noted on Sheets N-1 and N-2 of the trail design plans provided in Appendix A. BMPs implemented during construction would include measures to stabilize work areas includingfiber wattles, silt fencing, concrete washout areas, soil stabilizers, revegetation, or other appropriate measures.As discussed in Section 3.9, Hazards and Hazardous Materials,construction of the project would involve temporary use of common hazardous materials used for construction purposes. However, implementation of MM-GEO-1, as well as appropriate materials handling and spill prevention measures required by MM-HAZ-1, would ensure that water quality would not be degraded by materials used during construction or inadvertent release of those materials. Following construction, the project would not be expected to release pollutants into the storm drain system because trail use would not require the use of any water pollutants. The project would not create or contribute runoff water that would exceed the capacity of existing or planned stormwater drainage systems, and with implementation of the identified mitigation measures, the project would not introduce polluted runoff. Impacts would be less than significant with mitigation incorporated. iv) impede or redirect flood flows? The project site is located in Federal Emergency Management Agency Flood Insurance Rate Maps (Nos. 06001C0318G and 06001C0319G) and is not located within a 100-year or 500-year flood hazard zone(FEMA 2021).The project would have no impact on flood flows. 12956 DUDEK 67 April 2022