Water Quality Update

Water Quality - 8/26/2021

Heading into September the lake is starting the transition to fall conditions. The water is cooling from its high of 81 degrees on June 29, to a temperature of 74 degrees as of August 23. With the hours of sunlight decreasing, and nighttime temperatures in the 50’s the lake will continue cooling.

We are treating the lake with alum this week to reduce our cyanobacteria bloom. Our lake has been growing Anabaena for a while now, and most recently some Microcystis colonies have shown up. Treating now will reduce the potential for a late season bloom that could lead to water contact restrictions.


We are still working on our carp removal plan and thank those that have emailed sightings to carp@lakecorp.com. This will give us an idea of where to target our trapping efforts that we will use to estimate population next year.

Our schedule is to use this year to find out which locations have the greatest number of carp so we can plan how to perform a mark-recapture census study. Carp locations sent to us so far are shown on the map below. Thanks to those who have emailed the information, it has been very helpful.

Since the carp are in water of various depth it may require nets unique to the location to efficiently capture them. Capturing and tagging as many as possible will give us the best population estimate. Our consultant is talking to others who have carp removal programs and using their information to tailor a plan for Oswego Lake.

Once the plan is established, we will start setting nets when carp become active in the spring. Results of this initial project will provide us with information for the removal permit and to design a capture and removal plan.

The removal process has to be planned carefully since we may be removing a lot of fish. We will be working in water that is deeper than most other capture projects, so the logistics of transferring fish from the nets to boat, and from boat to truck can be challenging.

Since it will not be possible to remove every carp we will have to repeat the process every few years to keep the population in check. The success of our initial efforts will determine how frequently we need to repeat the project.

Schaefer Island

Schaefer Island has been a neglected feature for many years. We are considering a project to improve it, involving re-grading the shoreline and planting wetland and emergent vegetation on the perimeter. Emergent vegetation provides egg attachment points for frogs and salamanders, while sheltering the tadpoles from predation. There is very little of this habitat on the lake due to the presence of concrete bulkheads instead of natural shorelines.

Plants will consist of native sedges and rushes in the land/water transition and Wapato and lily in deeper water. An example of a small pond with similar vegetation is seen below.

We are working on preliminary designs this year to present to the Board for approval. If we get a green light our goal is construction during the 2023 drawdown. Part of the effort is designing a way to protect the island from wakes, which have eroded the shoreline over time and decreased the size of the island. Once this habitat has matured the roots will help hold the soil and reduce future erosion. Wildlife viewing will be fun during the summer, with the location a common stopover for kayakers and paddleboarders.