03-23-09 Drainage and Flooding Committee meeting minutes

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(NAVD 88, 2001 Adj.) and outfall flow line of 9.69 (NAVD 88, 2001 Adj.) with an outfall of 116 cfs which is inadequate. Exhibits 3, 4 and 5 is a ponding analysis based on the inability of storm runoff to be able to get into the storm sewer system. This can be due to an inadequate number of inlets or inlet capacity or due to an inadequately sized storm sewer system. The increases in ponding elevation are in 6-inch increments. When the ponding depth approaches 18- inches over the top of the curb or inlet, areas that become inundated are consistent with repetitive loss data and elevations of ponding very based on runoff rather than tail water impacts on the storm sewer system. 2.5 Alternatives Evaluation The alternatives evaluated include adding a storm sewer trunk line in addition to the exiting storm sewer trunk to double capacity, replacing the existing trunk line with pipe for more capacity and replacing or adding partial storm sewer improvements. In addition to storm sewer improvements, roadway profile modifications were investigated either in combination with storm sewer improvements or completely independent. Improvements evaluated include: 1. Add Storm Trunk Parallel to Existing Trunk with Pavement Repair - Add an additional storm sewer trunk line with additional inlets along the northbound side of Fleetwood Drive and parallel to the existing trunk line from South Sycamore to the outfall. Replace pavement on the northbound side of Fleetwood Drive without lowing the roadway. 2. Storm Sewer Replacement with Minimum Pavement Repair - Replace existing storm sewer trunk line along Fleetwood Drive with larger pipe or box for more capacity and minimize street repair. 1-6 Klotz Associates Project No. 0127.009.000 Fairmont Park East & Brookglen Drainage Study May 2009 City of La Porte