06-23-25 SWS - Laserfiche WebLink

Home Browse Search

ARDEN HILLS SPECIAL CITY COUNCIL WORK SESSION — JUNE 23, 2025 13 Fisher said they have had some good conversations with the Rice Creek Watershed and the Karth Lake District board regarding the pump system improvements. They can coordinate directly with the DNR regarding available options. There is a three tiered approach of different options for consideration. He said Karth Lake is an isolated lake with no emergency overflow on the lake. If nothing is done it will flood, over time. The City has a permit to pump out the lake. There is a force main that runs down to Cummings Drive and outlets into the storm sewer system. It operates at a two -foot bounce level. When it reaches a certain level, a manual pump is deployed that is connected to the electrical system. They pump it down about two feet and remove the pump. That process needs to be repeated every time the water rises. The Karth Lake Improvement District is requesting a six-inch bounce level vs. two -feet. That would help with erosion around the banks and from a recreation standpoint. The existing system is manually deployed. City Staff has to watch water levels to know when to deploy it and then have to manually remove the pump when the water levels reach the desired depth. They evaluated three options. The first option is to maintain the existing deployable pump but add a water logger device that would be anchored by a buoy which would monitor the lake level. It gives live readings of the lake levels but that can be impacted by wave levels and wind. Public Works Director/City Engineer Swearingen said that is essentially how we act today because the Karth Lake Improvement District is very active. This would just be automated so we get signals when the water rises. Mayor Pro Tem Monson said you still have to manually deploy it. Public Works Director/City Engineer Swearingen confirmed. Mayor Pro Tem Monson remembers Council being interested in it being as automated as possible. Public Works Director/City Engineer Swearingen clarified that they don't deploy it every time. It's on a floating device. We have to manually go down there and turn it on and off. Fisher said the second option is to use the existing pump but add a reinforced concrete structure that would go into the ground and the structure would be connected by a reinforced concrete pipe culvert directly to the lake. They would need to isolate the area for construction. The culvert would be underwater and the structure mimics the level of the lake. That would mitigate wave and wind impact. The pump would be set in there and we would automate that pump. Councilmember Holden asked how old the pump is. Public Works Director/City Engineer Swearingen said this is only a handful of years old and is in pretty good condition. Fisher said the third option is a complete lift station. You would have multiple structures connected. It would be connected to the lake, like in option two, but there would be complete control panel, the pump, the logging device and all of the equipment. This option would likely include replacement of the pumps to fit the project better for the long term. The final piece, if the pumps are upgraded, we would need to explore how that impacts the pump curves associated with the existing the forcemain. The forcemain is in good condition. As long as we can maintain the desired water levels there's no need to replace it. If this option is chosen the 6" forcemain may