Agenda - Council - 07/12/2016 - Laserfiche WebLink

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Staff visited the site again in May of 2015 to drive through the area to get an overview of constraints in the neighborhood. Staff looked at an area on Iguana Street where jacked pipe could be installed. Staff also looked at Gibbon Street and noted that water was flowing from west to east between 17540 and 17511 Gibbon Street through a culvert under the road. This culvert was submerged in 2014 but staff felt a culvert existed based on vegetation patterns, even though it could not be seen. Staff visited the site once again in June of 2015 to meet with the property owners of 17421 Gibbon Street NW and discuss the preliminary findings. At that time, water was flowing through the culvert under Gibbon Street, which was visible, though it appeared to be at slower rate as the eastern pond had filled up since the previous visit. On March 24th, 2015, City staff received surface water surveys from three other property owners residing at 17441, 17511, and 17561 Gibbon Street NW. The surveys stated that each of these three properties also experienced water damage to varying degrees. All elevations used in staff's analysis were obtained from LIDAR sources. LIDAR is relatively accurate; however, heavy vegetative cover can give false results. Water was positively flowing from west to east in 2015 as noted above. This indicates that water likely flows north when the level is high enough. 2.3 Scope City of Ramsey Improvement Project 16-88 proposes storm sewer improvements to provide an outlet for a low-lying land -locked area along Gibbon Street, north of 173rd Avenue. The purpose of the outlet is to provide positive drainage for this low-lying area to maintain lower groundwater elevations, which would provide direct benefit to the adjacent residential properties that previously experienced wet basements. Figure 1 in Appendix A shows the scope of the proposed improvements as depicted by the red line segments. Feasibility Report Gibbon Street and 173rd Avenue Drainage Improvements City of Ramsey Project No. 16-88 Page 4