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Feasibility Report Northeast Lino Lakes Drainage Improvement Project WSB Project No. 2029-790 Page 9 Option 2: Outlet to Clearwater Creek This option considers the lands drained by ACD 55 to the east of I-35E and proposes to reroute the drainage to the south to Clearwater Creek via storm pipe (Appendix A, Figure 6). This option benefits 710 acres, of which 495 acres are in Lino Lakes. This option is not recommended due to concerns that the increased discharge could cause bank erosion on Clearwater Creek. Option 3: New Outlet to Peltier Lake and Crossing Under I-35E There is a proposed mixed-use development between 20th Avenue and I-35E. The development would provide surface drainage via a series of connected ponds from I-35E to the 20th Avenue. The objective in recommending an alignment from 20th Avenue to Peltier Lake is to minimize impacts to undeveloped parcels and reduce associated easement acquisitions. Alternative A – Open Channel Conveyance This option includes open-channel flow through a ditch system from 20th Avenue to Peltier Lake along the north property line (Appendix A, Figure 7). While feasible and consistent with the City of Lino Lakes’ I-35 Final Corridor Alternative Urban Areawide Review, it requires double the land acquisitions in a northern alignment resulting in the cost being 20 to 25 percent higher than Alternate B; and thus is not recommended. A southern alignment was considered, but dismissed when RCWD staff noted they would not permit the project with a southern alignment because of potential impacts to wetlands included in the City’s Comprehensive Wetland Protection and Management Plan (CWPMP). Alternative B - Storm Sewer Pipe Outlet This option provides a new outlet to Peltier Lake via a 72-inch storm drain that runs from I-35E to Peltier Lake. This system is capable of capturing the ACD 55 and ACD 72 drainage systems upstream of I-35E, in addition to collecting runoff from the remaining study area (Appendix A, Figure 8). The area above the pipe could be used for public greenspace, as well as storm water ponding as this area develops in the future. In the interim, the landowners could continue to farm on the easement. Because of the size of the proposed pipeline, it would be a permanent feature on the landscape and a potential encumbrance that future developers would need to design around. Option 4 – Peltier Lake Outlet Improvements This option takes advantage of an existing culvert crossing under Peltier Lake Drive and uses an existing drainage way to convey stormwater flows from the study area to Peltier Lake (Appendix A, Figure 9). This option is intended to give affected landowners the most flexibility for future development. The existing drainage way would be permanently restored to a two-stage ditch design, while the eastern portion would be a temporary ditch that could be incorporated as part of future development plans. The intent is that ultimately the alignment would be an aesthetic feature for future developments, with a meandering low flow channel and floodplain bench that can be planted to provide biofiltration and additional water quality benefits for Peltier Lake. Recommended Option Option 4 is recommended as it provides the needed surface water conveyance and stormwater runoff rate and flood control, while also providing an amenity to the community. Because it is