03-23-09 Drainage and Flooding Committee meeting minutes

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reinforced box (RCB) with headwall and wing walls. The limits of the trunk line replacement are from the outfall to North Sycamore. This configuration has a design capacity of 218 cfs for a 5-year event at the outfall and keeps the HGL below Fleetwood Drive throughout the limits of pipe replacement. This is accomplished by the additional cover over the trunk in the border areas and can easily be accomplished in Alternative 1. The associated construction estimate is approximately $1.23 million including 10% for contingencies. Include 12% for engineering and surveying for $1.37 million. Increases in cost over Alternative 1 are due to replacing the entire storm sewer with new pipe over leaving the pipe in use. 3.3 Alternative 3 Alternative 3 is the addition of a parallel storm sewer trunk line under the northbound travel lane of Fleetwood Drive between Mesquite and North Spruce. This option is similar to Alternative 1 with only about 2,200 LF of pipe placed under northbound Fleetwood Drive. To keep the HGL below the pavement in this alternative, larger pipe sizes have to be used closer to the outfall. This configuration has a design capacity of 218 cfs for a 5-year event at the outfall and keeps the HGL below Fleetwood Drive. The associated construction estimate is approximately $1.00 million including 10% for contingencies. Include 12% for engineering and surveying for $1.12 million. The costs are similar the Alternative 1 because larger size pipe is used downstream for a greater length to increase capacity and keep the HGL below grade. This increases in the larger pipe quantities more than offsets savings in pavement repair. _ 3-2 Klotz Associates Project No. 0127.009.000 Fairmont Park East & Brookglen Drainage Study May 2009 City of La Porte