2012-10-10 Handouts @ Worksession

Home Browse Search

CITY OF CENTERVILLE - 2013 STREET AND UTILITY IMPROVEMENT PROJECT Storm Sewer Improvements The existing storm sewer system has been reviewed by City and Stantec staff. Please refer to Figures X and X for a graphic depiction of the layout of the existing system and the proposed improvements. PROPOSED PIPE INSTALLATIONS There are a number of places where it has been determined that additional pipe and storm sewer structures are needed. These improvements will help surface drainage which will in -turn add to the durability of the street surface. Subsurface drainage improvements are also proposed with the use of draintile either in front of the curb, if it is being salvaged, or behind the curb in areas of full street reconstruction. STORM SEWER CROSSING ISSUES The City of Centerville has been experiencing some serious problems due to heaving of fat clays and other moisture laden subgrade soils around existing storm sewer crossings. This annual heaving and settling from freeze -thaw cycles produces uneven roadways and often leads to deteriorated pavements. It is recommended that all storm sewer crossings be excavated and restored with suitable material in order to reduce movement of the future roadway. Figure X illustrates the cross section of these proposed improvements. PROPOSED STORM WATER MANAGEMENT The proposed project area lies within the Rice Creek Watershed District (RCWD). Therefore, the District will have permit authority over the project and the storm water management within the project. In order to meet the infiltration requirements of the District, it will be necessary to install infiltration basins (rain gardens), swales, or other Best Management Practices (BMPs) throughout Area A. In the attached Appendix A, potential BMP sites are identified (Figures X). It is important to note that these locations were chosen based on existing topography. Locations will need to be adjusted as more information is collected. Once engineered locations are proposed, Stantec and City Staff will conduct one -on -one meetings with any affected residents. Theses meetings will supplement the design process by allowing residents to provide feedback as to their level of interest in the program and in eventual maintenance of the BMP. An exact location and design of the BMP can be concluded based on this feedback. While some BMPs will be able to be constructed within the existing right -of -way and adjacent easements, others will require additional easements. A cross section of proposed infiltration basins is shown in Figure X. City of Centerville Project No: 193 80 8 Stantec 2013 Street and Utility Improvement Project �%+ Page 8