This Spring VLAWMO is partnering with Ramsey Conservation District to get a better understanding of lakes on the outskirts of the watershed. As part of the 2017-2026 Comprehensive Water Plan, we’re starting the 10-year project cycle with a focus on the far-reaching lakes. As the years go by, our focus will follow the path of the water, leading to the destination, Vadnais Lake. The goal of course, is to improve the whole watershed!
Bathymetry is the process of mapping a lake (or ocean) bottom. These studies occur around the State and country to help understand how the body of water acts. Depth and shape are simple attributes of the lake that make a big difference in the lake’s ecology. For example, a Bathymetry study on Tamarack Lake revealed some surprises that changed the way we look at the lake. Previously assumed to be a bathtub about 6’ deep, we found Tamarack actually has two deep pockets that are 9-10’ deep.
So what does this mean for the lake, and what can we do with this knowledge?
The depth and shape of the lake influence plant growth, how fish behave, and how nutrients cycle in the lake. Deep pockets imply that fish are able to overwinter in these spaces, benefiting from deeper, colder water that can hold more dissolved oxygen. This knowledge also helps us puzzle-piece the role aquatic plants play in the lake. Aquatic plants typically thrive 4-6’ deep. If there’s a deep spot free of aquatic plants, we know that nutrients are being held either in the water column or in the lake bottom. Because aquatic plants also hold nutrients, we can take all these factors and form a picture of what the lake’s ideal would be, striving for realistic goals in water quality improvement.
Once the bathymetry study is complete, watershed management organizations such as VLAWMO use the insight to:
The bathymetry studies are a first step in deepening our knowledge of our local lakes, as each one has unique characteristics. Knowing these details helps us make better management decisions, and prepares us with a baseline to refer to if something unexpected happens in the future. Wilkinson will be the next lake to get a bathymetry study –stay up to date on our website and facebook pages for photos and additional blog entries from this project. In the meantime, find detailed information on each lake in VLAWMO on our waterbodies page.