Agenda - Public Works Committee - 03/20/2012

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SUMMARIES AND RECOMMENDATIONS 148 Lane There is an existing low area on the south side of 148 Lane. During the wet spring of 2011, stormwater would pond for extended periods in this low area. A 15" outlet exists approximately 2.5 feet above the bottom of the low area that drains the area to the east. The stormwater below the outlet pipe infiltrates into the soil. A drainage easement exists over this low area. Different sized outlet pipes at different elevations were analyzed. These different sized outlets did not have a significant impact on the high water level in the area. Since the low area is within an existing drainage easement, it is our recommendation that nothing be changed in the area. 149 Lane There is an existing low area on the east side of Lot 3, Block 1 of Ramsey Meadows 4 Addition (5410 149 Lane NW). This low area is connected to the large DNR Wetland to the east with a drain tile. During the wet spring of 2011, stormwater would back up through this drain tile and flooded the low area. It appears that this low area may have been constructed as part of a wetland mitigation plan and may be controlled by Wetland Conservation Act rules. A drainage easement exists over this low area. The outlet from the DNR Wetland, which drains east under Trunk Highway 47 (TH 47), was analyzed. The current outlet has a weir structure that is approximately 0.8 feet above the invert of the 15" pipe that crosses TH 47. Additional culverts under TH 47 were analyzed, but the additional outlets did not have a significant impact on the high water levels in the DNR Wetland. Removing the weir structure was also analyzed. It is our recommendation that the weir structure be removed from the outlet. This will not have a significant impact on the high water level of the wetland; however, the wetland will drain down to an elevation near the elevation of the bottom of the low area at 5 410 149 Lane. The estimated cost to remove the weir structure is $1,265. Rum River Hills Golf Club Rum River Hills Golf Club has been experiencing flooding issues throughout the golf course. The large ponds near the clubhouse drain to the east through an existing outlet structure and 12" pipe. This stormwater then drains over an existing steel weir structure and over a rock dam prior to discharging to the Rum River. Area 1 The ponds near the clubhouse have been flooding and the outlet does not seem to drain the ponds effectively. The existing 12" outlet from the large ponds near the clubhouse has several sags in it and several joints have been compromised. It is our recommendation to replace this pipe and install a new outlet structure with removable planks that will give the golf course more flexibility in controlling the water