Minutes - Public Works Committee - 03/31/2015

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5. COMMITTEE BUSINESS 5.01: Consider Options for Addressing Stormwater Drainage Issues in Low Lying, Land Locked Areas Civil Engineer II Linton reviewed the staff report and identified the 2014 areas of flooding concern. He identified the wetlands within the City, noting that approximately 20 to 25 percent of the City is wetland. He identified areas of flooding concern from previous years beginning in 1985 and moving forward to 2011 for comparison purposes. He explained the staff report focused on three primary areas of concern, and that the staff report lists these in order of priority based on magnitude and severity of property and structure impacts. The Gibbon Street area, rated the highest priority in the staff report, was discussed in detail first. Civil Engineer II Linton reviewed several potential routes of relief for this land-locked wetland, including relative elevation differences and any easements that existed along the routes. He discussed that ditch 66 was cleaned a few years prior and that weirs had been installed. He explained that vegetation management can occur within a wetland but the elevation cannot be changed. He noted that similar plans are available for discussion along the other two areas addressed within the case, but that residents from Gibbon Street are in attendance. Chairperson Riley questioned if there is a good or easy answer. Civil Engineer II Linton stated that while there is no easy answer there are potential solutions. He stated that the potential routes are where solutions could occur. City Engineer Westby stated that there could be a combination of ditches and pipes in the routes. Councilmember Johns stated that it appears the southern route would make the most sense. Chairperson Riley questioned if the route would simply push the problem down the line. Civil Engineer II Linton replied that if the water were to be routed into the ditch he believed that it would continue to flow to Trott Brook. Frank Miske, 17421 Gibbon Street NW, stated that water even reaches high levels at certain times and could also be a concern for overflowing. He stated that the issues on Gibbon Street did not occur until the Iguana Street area was developed. He suggested instead that perhaps the Iguana Street area be routed in the other direction rather than routing their water towards Gibbon Street. Cassandra Miske, 17421 Gibbon Street NW, confirmed that there is a culvert that drains into the ditch in their yard. She stated that it appears that their yard is the end spot for drainage and that is why she believes they have flooding of their yard. She questioned if the capacity of the ponds in the area could be increased. Public Works Committee/March 31, 2015 Page 2 of 8