2007-01-23_PWETC_AgendaPacket - Laserfiche WebLink

Home

hired URS to create an XP-SWMM model for this area. This analysis will allow us to evaluate the performance of the system during intense storm water events and evaluate the impact of developing additional lots within the study area on the elevation of flooding within rear yards, low areas and intersections in this neighborhood. The findings of this report will be brought forward in 2007. . Area 2- St. Rose of Lima Area The intersection of Dellwood and Skillman Avenue, located near St. Rose of Lima Church, experiences street flooding during periods of intense precipitation. Runoff from approximately 14.5 acres of residential land use is tributary to this intersection either directly or via the storm sewer along Dellwood and Skillman Avenues. In addition runoff from a portion of the St. Rose of Lima property is tributary via the Dellwood Avenue storm sewer, adding about 5.7 acres of mostly impervious surface. An analysis of the existing trunk system indicated it can handle a 2 year rain event. As a result, during intense rainfall events, the trunk system experiences surcharge, thereby causing the intersection to flood to a 1.9 foot depth. Recommendation: The CSWMP recommended a two tier solution for this street flooding problem. Option 1: Construct a pond in the storm water retention on the St. Rose of Lima site. The site is approximately 28% of the total tributary area, and contributes 39% of the total runoff volume. Just implementing this option reduces the intersection flooding to 1.6 feet. Estimated cost: $148,159. Option 2: Expand the pond in Mayflower Park and construct a parallel storm sewer to direct runoff from the intersection to the expanded pond. This would effectively turn this neighborhood park into a storm sewer retention pond. Just implementing this option reduces the intersection flooding to 1.0 foot. Estimated cost: $549,678. Options 1 & 2: implementing both options would eliminate the intersection flooding. Estimated cost: $697,837. Action to date: We have not done any additional work in this problem area. Stafffeels that due to impacts to the neighborhood park, any proposed solution would involve extensive public participation. . Area 3: South Owasso Blvd (Ladyslipper Park) As a part of the 2006 S. Owasso Blvd Reconstruction project, the City completed the improvements to the storm water runoff being discharged into Ladyslipper Park. Between Rice Street and Western Avenue, approximately 160 acres of single family residential property drain into Lake Owasso through a drainage ditch that cuts through City of Roseville 2006 Storm Water Aunual Report Page 3 of 11