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I I I I I I I I I I I I I I I I I I I ri prapped bottom is pl anned for Tucker Gul ch from Hi ghway #58 to downstream of 10th Street. Where the structural walled channel ends, a trickle channel continues to the confluence with Clear Creek. storm sewers and principle outlets for detention facilities. Minimum ve 1 oc it i es of 3 feet per second are requi red to prevent sediment build-up in the pipes and at manholes. Riprap is required at pipe outlets to control scour. Reinforced concrete pipe is planned at the following locations: Structures 1. Bridges - One bridge improvement is planned for the 9th Street bridge over Tucker Gulch. A minimum of 2 feet of freeboard should be provided above the IOO-year design water surface to reduce the potential for debris blockage. The 9th Street bridge replacement is recommended in conjunction with the major channel improvements planned for lower Tucker Gulch. . State Highway #93 crossing of Cressmans Gulch . Welch Ditch Detention Basin outlet . Boys School Road Detention Basin outlet . Interurban RR Detention Basin outlet . Storm sewer improvements along South Golden Road . East Fork storm sewer . Street inlet connections for storm sewers along Jackson and Ford St reets . West Fork storm sewer inlet . 20th Street Tributary storm sewer inlet Various structures are proposed for controlling stormwater for both major and minor runoff events. Where major channel crossings and drop structures are planned, suitable transitions must be provided. In addition, provlslons for maintenance access should be firmly established so that each structure can be properly inspected on a regular basis and repaired as needed to assure structural integrity. The following structures are proposed for use in this master plan: All planned storm sewer improvements utilize RCPs with the exception of one short segment of corrugated metal pi pe (CMP) storm sewer on Kenneys Run downstream of 15th Street. The CMP is used at this location to facilitate connection of two existing CMP storm sewers. 2. Box Cul verts - Reinforced concrete box (RCB) culverts are used at street crossings where design discharges are moderate and where box culverts may provide a less expensive alternative to bridges. Riprap is provided at all culvert outlets to minimize the effects of scour. Minimum velocities are to be limited to 3 feet per second for the 2-year event to minimize sediment deposits. Box culverts are proposed for the 23rd and 24th Street crossings of the West Fork Kenneys Run and for the Johnson Road crossing of the Johnson Road tributary. Allowable headwater elevations were based on confining design flows to the channel area in accordance with UDFCO design criteria for urban streets. 4. Drop Structures - Drop structures are used to lessen the channel slope, thereby reducing channel velocities to acceptable limits. Max i mum drop hei ghts of 2 to 3 feet are des i rab 1 e to most app 1 i ca- t ions. For lower Tucker Gul ch, 4' drops are recommended to obtai n desirable channel slopes. Additional riprap should be used to protect against scour in accordance with the most recent UDFCD cri- teria. Drop structures are proposed at the following locations: 3. Reinforced Concrete Pipe - Reinforced concrete pipe (RCP) culverts are used for street crossings where design flows do not warrant construction of a bridge or box cul vert. RCPs are al so used for . Cressmans Gulch as part of the channelization work being planned by the developer (specific locations are not shown on the master plan drawing) . Tucker Gulch below State Highway #58 VI-2