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EXHIBIT A <br />SCOPE OF SERVICES <br />The is a supplement agreement to the previous contract with Philip Williams and Associate, <br />LTD. This work involves additional review services required for the completion of the project. <br />At this time, PWA has completed the scope of services as included in the original contract. Completed <br />tasks include: <br />• Task 1. Project Initiation/Data Collection. PWA visited the site several times to conduct <br />field reconnaissance of both on-site and off-site conditions. Site visits were required to determine <br />existing site conditions and to visually confirm the existence of, and state of, relevant <br />infrastructure (such as inlets/outlets to storm drains). Data collection included the compilation of <br />local and regional hydraulic and hydrologic studies of the area, maps of site topography and <br />storm drain design plans. <br />• Task 2. Assessment of Proposed Drainage Plan. FWA reviewed the proposed site drainage <br />plan, and the existing hydraulic analysis of the proposed development. PWA also met with the <br />County to verify the appropriate design criteria. Our results indicated that the proposed site <br />drainage plan did not comply with the appropriate county criteria, and that there were also <br />potential unaddressed CEQA impacts from the project. The inability to comply with County <br />standards results from existing conditions (combination of high tides and existing stormwater <br />flow). As such, we recommended that the development include comparable storage to existing <br />conditions to prevent any future flood impacts. <br />To address the potential project impacts, PWA conducted two assessments: 1. Calculation of the <br />loss of usable, on-site flood storage; and 2. Change to rainfall-runoff conditions expected as a <br />result of the site development. To address item 2, PWA created a hydrologic rainfall/runoff <br />model of the site (using the ACOE code HEC-HMS with ACFCD methodology to the extent <br />possible) to evaluate the impact of development and decreasing surface permeability on <br />subsurface storage volumes. Increasing impervious surface area reduces the amount of rainfall <br />infiltrating into the soil during a storm event. These findings were summarized in PWA, April <br />17, 2003 memo. <br />Additionally, storage is lost as a result of fill placed on the site to raise the new buildings above <br />the design flood. PWA calculated estimates of onsite detention lost with water inundation to <br />elevation 6.9 feet. These findings are summarized in PWA, Apri17, 2003 memo. <br />• Task 3. Snmmary of Findings/Recommendations. As described above, PWA has detailed <br />our key findings and calculations in 2 memos. During meetings with the City, Gounty and the <br />Developer's staff we have suggested several potential measures to mitigate the potential project <br />impacts resulting from decreased flood storage and increases in onsite runoff. <br />The next steps in this process are for the developer team to propose an appropriate mitigation plan to <br />compensate for the impacts described above (with input from PWA as requested), PWA to review the <br />proposed plan, and provide guidance to the City regarding the adequacy of the revised plan. <br />The additional scope of services is outlined below: <br />Contractual Services Agreement-supplement Tract 7382 Hydraulic Analysis Consultant <br />Page 3 of 3 <br />Revised 5-02 <br />