Appendix A Water Quality Memo - Laserfiche WebLink

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2 An existing 12-inch water line and a bank of 12 phone conduits cross the Santa Ana River, suspended under the deck of the existing bridge. These utilities would be temporarily relocated during construction and then permanently relocated to the new bridge. Water quality best management practices (BMPs) would be included to treat stormwater runoff such as a vegetated swale adjacent to Fairview Street in the Fairview Triangle rest area. Fairview Street would remain open during the construction period with two southbound lanes and one northbound lane, with lanes shifted to one side of the bridge while the other side is replaced. Therefore, no detours would be required for vehicles traveling along Fairview Street. Access to properties would be maintained. During construction, pedestrians and bicyclists would be detoured away from the Fairview Street bridge to the 17th Street bridge to cross the Santa Ana River by way of the SART between the hours of 9:00 a.m. and 7:00 p.m., when the gates to the SART are open and unlocked. After hours, pedestrians and bicyclists wishing to cross the Santa Ana River would be detoured to adjacent City streets such as King Street. Construction of the proposed Project would require temporary closures of a portion of the SART for the demolition and placement of the bridge superstructure. The SART includes a Class I bike path on the eastern side and a regional riding and hiking trail on the western side. The portion of SART affected by Project construction would need to be temporarily closed four times for approximately 8 hours each time during two summer periods for the placement of precast concrete girders. During these periods, SART users would be detoured and signage would be provided to display the dates of the closures and to identify the detour routes. Work on the north and south sides of the bridge would be completed during separate periods so that SART users can be detoured to the trail on the opposite side of the Santa Ana River at 5th Street (refer to Figures 3A and 3B for the detour plans). There are gates and ramps located on both sides of the SART at 5th Street that provide access to bicyclists and pedestrians for these detours. Details regarding the detour are being coordinated with Orange County (OC) Parks. Other short-term closures of up to 15 minutes would be allowed with flagmen. A temporary detour within the river bed may be required as a contingency. This would involve construction of dirt and gravel ramps with asphalt topping to and from the SART and the river bed as shown on Figure 2. Construction vehicles would access the Santa Ana River from the gate and ramp at the County of Orange access road at the northwest corner of the bridge, and would use the existing concrete access ramp into the river approximately 250 ft west of the Project area (Figure 2). All access roads to the SART that are utilized by construction vehicles or for detour routes would be reconstructed and restored to pre- construction conditions or better prior to Project completion. 2.0 REGULATORY SETTING 2.1 Federal Law and Requirements Clean Water Act In 1972, Congress amended the Federal Water Pollution Control Act, making the addition of pollutants to the waters of the United States (U.S.) from any point source unlawful unless the discharge is in compliance with a National Pollutant Discharge Elimination System (NPDES) permit. Known today as the