Update: Long Lake Drawdown

From Samantha Berger of the City of Apple Valley.

Good Morning Long Lake Residents,

I wanted to provide you with a brief update on happenings at Long Lake.

Pipe Work - Some of you may have noticed some pipes present along the lake bed. Inspections during the drawdown revealed a separated stormwater pipe on the northwest side of the lake. We have a contractor coming next week to complete the work. They will access the site through the park and along the exposed the shoreline. Work will include replacing the pipe and removing the accumulated sediment in the lake. Engineering staff will be communicating with residents in the area. This is pretty standard replacement work, it’s expected for them to be completed by next week. Once the pipe work is complete, we will close the drawdown valve.

Aquatic Plant Management – With the mild winter we had, typically this leads to a big year of curly-leaf pondweed (CLP). Ideally, the drawdown will help with the CLP population, but time will tell. We have Blue Water Science who will complete the typical pre-treatment survey, and have a contractor prepared to complete the treatment as well. Stay tuned for more.

Fish Exclusion Fence – With water levels down, the City will be installing a temporary fish exclusion fence. It will look similar to the attached image. The purpose of the “experiment” is to determine the extent that fish have on the aquatic vegetation and to determine whether an “alternative stable state” is possible in the lake. In presentations I have seen, the fenced in area has shown better plant growth, leading to the conclusion that the fish are affecting the plant and lake health. We will need to wait for mid-summer to evaluate, since the water level will take time to refill.

Fisheries Assessment As part of the evaluating the drawdown effectiveness, we will be conducting an additional electrofishing survey on the lake. We have not lined up a contractor yet, but will keep people posted on when that will plan to occur.

Shoreline Seeding - The City did complete some native wet meadow seeding along the park shoreline.

Drone Photos- The City did recently fly over Long Lake to check out the drawdown. See attached photos, kind of cool! You can see the circle of rocks along the drawdown pipe location.

Good Housekeeping - if you haven’t used this time to clean up your shoreline, now is a good time. Consider participating in the Landscaping for Clean Water Workshop or adding your own native plants to your shoreline. Grants are available at the City, County, and State level!

Jessica “retired” – In case you didn’t hear, Jessica Schaum, our Natural Resources Coordinator has “retired” from public service to focus on her new floristry adventure! She is, and will be missed, but we are very happy for her and her new adventure!

I know it’s been a strange weather year, so we will be at the mercy of the rain to get the lake refilled. Pray for rain after the pipe gets fixed! While it may not be normal, the drawdown does provide an opportunity for sediments to consolidate, for new vegetation to take root, and for the eco-system to reset. Hopefully we will see results in the fish and plant community in response to the drawdown. As always, we look at adaptive management on the lake so we will pivot if the science tells us to do so.

Wishing everyone a joyful spring! Take care and let me know with any questions.

Thanks,

Sam

Samantha Berger

City of Apple Valley | Water Resource Specialist

952.953.2462 | samantha.berger@applevalleymn.gov