FLOOD03503 - Laserfiche WebLink

Home Browse Search

COMMENTARY - SHEET 6 OF 12 Floodplain regulation is the recommended plan for this reach as it pertains to the major drainage system or lOO-year design frequency. The overall plan for the Kenneys Run dra i nageways i ncl udes the construct i on of three stormwater detention basins which are designed to fully control peak flow rates for more frequent runoff events (i.e., 2-, 5-, and lO-year storms) and to reduce, to a minor degree, peak flows from the lOO-year event. As indicated on the plan drawing, the resulting 100-year water surface for the improved condition is only 1.0-foot less than the 100-year water surface for the unimproved condi- tion. This minor reduction in the 100-year flood elevation has a minor impact on the floodplain boundary as shown on Sheet 6 and as presented in the FHAD Report, however, significant benefits are obtained by the control of more frequent events. COST ESTIMATE - SHEET 6 OF 12 ITEM Channel Improvements Street Crossings Utility Relocation Storm Sewer Improvements Subtota 1 Contingencies (15%) Engineering, Legal & Administrative (15%) Structural improvements recommended for this reach are designed to increase the hydraulic capacity of the existing minor drainage system. For the reach downstream of the East Fork/West Fork confluence, typical Type R inlet loca- tions are shown to improve normal street drainage. A contiguous storm sewer system is recommended to improve hydraulic performance by adding a short storm sewer segment downstream of 15th Street where an open channel currently exists. At 20th Street, major inlet improvements to the existing system are planned for the West Fork, East Fork and the 20th Street tributary. The improved junction will el iminate current inlet restrictions and allow the existing 96" CMP to operate at full capacity. TOTAL CONSTRUCTION COST Right-of-Way Acquisition TOTAL CAPITOL COST OF IMPROVEMENTS TOTALS IN EACH JURISDICTION The plan for the East Fork storm sewer is discussed in the commentary for Sheet 11. City of Golden Jefferson County The system improvements shown on Sheet 6 are not designed to eliminate problems associated with major flooding, but will reduce the frequency of flooding along Jackson and Ford Streets and improve the handling of nuisance stormwater runoff occurring on a regular basis. The purchase of flood insurance by private property owners should be encouraged and the City should continue its strict enforcement of floodplain regulations and maintain its participation status in the National Flood Insurance Program. Individual floodproofing by means of structural changes, grading or locating valuable contents to higher levels should also be encouraged. Annual Operation and Maintenance Costs COST $ 1,000 -0- 21,000 254,000 276,000 41,400 41,400 358,800 29,000 387,800 I I I I I I I I I I I I I I I I I I I 387,800 -0- (2,400)