19 - Drainage Presentation - Sandy Creek Upper Tributaries 4 and 6

Home Browse Search

Federal Emergency Management Agency (FEMA) and updated with the survey data. Using the updated survey data, the model produced a large reduction from the existing Special Flood Hazard Area (100 year floodplain) and Floodway. It appears that the City owns drainage easements for the existing drainage channel. Before design and construction of any improvements to Tributaries 4 and 6, boundaries and easements should be resolved to ensure the channels are within the easement. Temporary construction easements will likely be necessary for construction access. A combination of channel improvements and culvert improvements will maximize the decrease in flooding impacts. The channel improvements maintain the top width of the existing channel and create a more uniform grade from Clarksville Street to Lamar Avenue along Tributary 4. Tributary 6 would be deepened similarly from the Tributary 4 confluence upstream to Hubbard Street without widening the channel. It is recommended that the improvements occur in three phases. Phase 1 would consist of channel and culvert improvements from the downstream end of the study up to the confluence of the two tributaries between Simpson Street and Culbertson Street. Phase 2 continues the channel and culvert improvements upstream along Tributary 4 to E. Price Street. Phase 3 replaces the channel and culverts along Tributary 6. The total cost is $10.2m. " Existing Conditions were recorded on both Tributaries as follows: Box culvert at Clark lane with a utility line in the middle of the culvert: Existing Condit:ions Tributary ooith off Clarksville Street is a 15 -foot Mde eoinc etew,fine , veadea� waR channel. Duooat earn of Clarksville Street, time charuoel is earthen aiiiii indemterrotoate .I"he culvert at Clark Lane has a ut'ihtti� line CUt &rectly to to the iniddle of the cLAIvert (ttgeiume .f 1. k'rnua, i— r1 ,,;1p/(frf,%' 1-0'fe f rcnOjg