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. Review stability of embankment for pile driving equipment loading • Hydraulic Analyses which include the effects of the gravity storm system discharging into the Canal with the Canal subjected to tidal action due to the removal of the tide gates based on the following scenarios: Geometry (a) existing condition, before the upgrade of 5th Avenue Pump Station (b) existing condition, after the upgrade of 5th Avenue Pump Station (c) add sheet-pile walls to (b) (d) add flap gates to (c) Existing conditions are defined as the topographical survey developed by Winz/er and Kelly, 2003. Rain and Tide (1) 25-yr rain, 2-yr tide — with geometries (b) and (d) (2) 25-yr rain, 25-yr tide — with all four geometries Items 1 and 2 above subject to change upon analysis. A tota/ of no more than six (6) scenarios will be studied. Modeling Extents The downstream end of the HEC-RAS model will be a section downstream of the existing tide gates for Bayfront Canal. The upper limits will include the end of the Canal segment near the cul-de-sac at Douglas Court and the upstream end of the Atherton Channel segment where it becomes a culvert under Marsh Road. Hydraflow models will only be developed for gravity drain systems that discharge to the Canal or Channel within the modeled segment of channel. The limits of the gravity system are bounded by the Bayfront Canal, Douglas Court, Bayshore Road and Marsh Road. Steadystate modeling • HEC-RAS will be used to develop models of the Canal and Channel. • Hydraflow Storm Sewers or SWMM will be used to develop models of the gravity culvert systems within the limits defined previously. Results • Map of approximate flooding extents for each scenario. • Recommendation of total storage volumes required to mitigate for flooding in the various areas (above or below ground). • Recommendation of locations requiring flap gates. • Decrease in pump rates for each scenario. Assumptions • Sea level rise will not be considered in our analysis per the direction of the City. ATTY/AGR/2011.107MREC0 i t 701011