2009-04-28_PWETC_AgendaPacket - Laserfiche WebLink

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210 Action to Date: 211 This subwatershed was added as a problem area in 2006. In an effort to address some of 212 the flooding concerns in this problem area, staff will continue to require redevelopment 213 projects to reduce the volume of water that is sent to this system. A reduction in the peak 214 flow from the commercial properties located in the subwatershed will alleviate the 215 demand on the Gottfried Pit. 216 Recommended 209 action: 217 In an effort to address some of the flooding concerns in this problem area, staff will 218 continue to require redevelopment projects to reduce the volume of water that is sent to 219 this system. 220 H. Area 8: Center Street 22l For years we have been working on finding a resolution for street flooding at the 222 intersection of Center Street and Rice Street. This is the result of the sediment that has 223 accumulated in the ditch located on the east. side of Rice Street in the City of Maplewood. 224 Center Street drains under Rice Street via a culvert, the sediment in the receiving ditch 225 causes Raseville's side of Rice Street to flood. As a result, any solution for this street 226 flooding requires cooperation from Maplewood. Since it is a cross jurisdictional issue 227 that involves the Trout Brook lntercepfor, CRWD needs to be involved. The three 228 jurisdictions have agreed that CRWD will study the problem and recommend a solution. 229 Action to Date: 230 This subwatershed was added as a problem area in 2007. 231 Recommended 2009 action: 232 To date we have not come to an agreement about a solution for this drainage concern. 233 Staff feels that since all the issues surrounding this subwatershed have not been 234 addressed, this subwatershed should be added as a problem area within the CSWMP. 235 I. Area 9: Walsh Lake Subwatersbed 236 On March 24, 2008, the City Council authorized a study of the storm water hydrology of 237 the Walsh Lake subwatershed located in the neighborhood southeast of Midland Hills 238 Golf Course (``Rosewood Neighborhood") due to neighborhood concerns about localized 239 street. flooding and damage to property. This area includes the following streets: Midland 240 Hills Road, Draper Avenue, Rosedale Drive, Westwood Circle, Hythe Street, Skillman 241 Avenue, North Rosewood. Lane, and South Rosewood Lane. 242 An XP-SWMM model was created for this area. The XP-SWMM analysis allows us to 243 evaluate- the performance of the system during intense rain events. The model predicts the 244 elevation of flooding within wetlands, low areas and intersections in this neighborhood. 245 A separate model was executed for the 2, 5, 10 and 100-year storm events. The storm 246 events are 2.8", 3.6", 4.2", and 6" of rain in a 24-hour period, and have annual return 247 probabilities of 50%, 20%, 10%, and 1 %, respectively. 248 The existing storm sewer system in the Rosewood neighborhood consists of a network of 249 pipes that lead to a manhole at Draper Avenue and Midland .Hills Road. From this 250 manhole, the storm water runoff flows through a dual pipe system west to Walsh Lake. 251 Our current design standard for storm sewer is a 10-year event The existing storm sewer 252 system was built in the 1970s. Additional build-out of the neighborhood; which included City of Roseville 2008 Storm Water Anneal Report Page 7 of 14