07-08-25 Agenda Packet - Laserfiche WebLink

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Page 3 of 3 • As such, pumping is an essential component of the City’s surface water management responsibilities within the entire watershed. It is not merely a means to protect the lowest-lying properties or to enhance the aesthetics of lakeshore properties. • The DNR Pumping Strategy can be improved upon. KLIDB recommends an alternative pumping strategy (Proposed Strategy) of starting to pump sooner, at 935.5, and only removing half a foot at a time by turning the pump off at 935.0. This strategy is superior to the DNR Pumping Strategy on nearly all metrics (reduced bounce, higher average levels). The Proposed Strategy would require pumping in 81% of all years versus 75% for the DNR Pumping Strategy but pump for 2.5% fewer days, thereby extending the expected life of pumping equipment. Recommendation for Implementation: The City’s lake level management process should be modernized to reduce the current labor-intensive pumping and monitoring process. Digital monitoring and remote pump activation would allow better control of lake level fluctuations.4 The upcoming City’s 2026 PMP Street and Utility Improvements project (2026 PMP) provides an opportunity to include funding for a new fixed pump and automated controls housed in a vandal resistant pump house. A cinder block pump house could also serve as the retaining wall replacement item planned within the 2026 PMP and may cost less than a landscape block type of retaining wall. Climate change and any future development that expands impervious surfaces within the watershed increase the likelihood of flooding should a back-up pump be unavailable. The existing floating pump could be a back-up should a new primary pump need repairs. Since the pumping of Karth lake is an essential component of surface water management and flood control for the entire watershed, the cost of improvements to the pumping infrastructure is more appropriately borne by owners of all properties within the watershed, not merely owners of lakeshore property. The Karth Lake Improvement District Board supports the feasibility and design objectives initiated by the City and described in the Bolten & Menk, Inc. 2026 PMP study regarding storm sewer pumping improvements and retaining wall replacement design.5 KLIDB also urges a solution that is consistent with a long term vision for the health and functionality of the Karth Lake watershed. 4 Methods for automated lake level measurement are relatively inexpensive. The DNR has extensive experience with this and is ready to be a resource for the City’s planners. Further, equipment to remotely monitor and control the existing and potential new pump is available. 5 Pp. 11-12 of Exhibit A to 2026 PMP Street and Utility Improvements, City of Arden Hills.