Lake Leelanau Watershed 201

Last year we started an initiative to educate our community on matters of importance to watershed protection. We are back again this year with more water content, building off what you learned last year to build a community of water protectors. We invite you to read this month’s blog post to build on your knowledge of watersheds and help put the Watershed in Watershed Wednesdays!

Just tuning in? Click here to read our first article about watersheds and other past blog posts.

To begin, let’s review the concept of a watershed. A watershed, also known as a drainage basin or catchment area, is an area of land that drains rainwater or snowmelt into a specific lake, river, or ocean. Watersheds are divided by high elevation points in the landscape's topography, called watershed divides or ridgelines. In the case of Lake Leelanau, its watershed encompasses an area of approximately 140 square miles, just under 90,000 acres. This vast expanse of land serves as a critical link between the surrounding ecosystem and the 8,607-acre lake itself, influencing the quality and quantity of water that reaches Lake Leelanau.

Lake Leelanau Watershed base map courtesy of the Leelanau Conservancy.
Lake Leelanau Watershed base map courtesy of the Leelanau Conservancy.

Main water sources of Lake Leelanau

Lake Leelanau is divided into North Lake Leelanau and South Lake Leelanau, and while the two lakes are connected and considered to be one lake, historically they were different lakes, and therefore their inputs differ. Based on a study done in the late 1990s, South Lake Leelanau (SLL) receives 46.8% of its water supply from subsurface groundwater discharge, another 39.5% from surface flow (i.e., streams or runoff), and the remaining 13.7% from atmospheric deposition (i.e., precipitation). North Lake Leelanau receives 2.1% of its water supply from subsurface groundwater discharge, another 90.8% from surface flow (predominantly from SLL), and the remaining 7.1% from atmospheric deposition. 

Rivers and Streams in the Lake Leelanau Watershed 

The main river systems that flow into SLL are Victoria Creek (also known as the Cedar River) and Cedar Run Creek, both flowing in from the southwest corner of SLL, as seen in the map above. But there are many other smaller creeks and streams that flow into both lakes, such as: 

  • Beaudwin Creek
  • Belnap Creek
  • Cedar Creek
  • Clearbrook Creek
  • Houdek Creek
  • Mebert Creek
  • Rice Creek
  • Solon or Cedar Run Creek
  • Weisler Creek
  • Several small unnamed creeks

All of these streams and rivers are important for various aquatic and fish species. However, the water quality of the streams is threatened by poor land use and development adjacent to them, which can lead to excessive accumulation of sediment in the channel. This can bury large woody debris and other in-stream habitat, which essentially turns the system into an aquatic desert. 

Wetlands in the Lake Leelanau Watershed

As defined by the EPA, wetlands are areas where water covers the soil or is present either at or near the surface of the soil all year or for varying periods during the year, including during the growing season. Wetlands play an indispensable role in maintaining the overall health of the lake. Wetlands act as a natural water filtration system, removing pollutants and excess nutrients before they enter the lake.

On their way to Lake Leelanau, the main tributaries, the Cedar River and Cedar Run Creek, pass through Solon Swamp, a 548-acre currently undisturbed wetland complex. This acts as a significant filter that extracts nutrients in the water before they enter the lake. The diversity of ecosystems and micro-habitats in the Swamp also provide a haven for wildlife like sandhill cranes and rare wetland plants. A recent Floristic Quality Index ranked this wetland area as 91.1, which is considered extremely rare. Protection of this area is of utmost importance to the health of Lake Leelanau.

Lake Leelanau Watershed wetland map courtesy of the Leelanau Conservancy.
Lake Leelanau Watershed wetland map courtesy of the Leelanau Conservancy.

How YOU Can Protect the Lake Leelanau Watershed

In general, the soil in our watershed is quite permeable, so land use practices have a greater potential to impact water quality than is the case in many other watersheds in the state with less permeable soils.

To help you reduce your impact on our watershed, whether you live on or away from the lake, here are a few tips and tools recommended by the EPA:

  • Conserve water every day. Take shorter showers, fix leaks, and turn off the water when not in use.
  • Take care of your septic system by following septic best management practices and getting your septic system inspected regularly.
  • Stand up against development that threatens critical areas in our watershed.
  • Follow Shoreline Best Management Practices if you live on the lake.
  • Protect the lake from pollutants. Don’t pour toxic household chemicals down the drain; take them to a hazardous waste center and never pour used oil or antifreeze into the storm drain or the street.
  • Use hardy plants that require little or no watering, fertilizers, or pesticides in your yard.
  • Do not over-apply fertilizers. Consider using organic or slow-release fertilizers instead.
  • Recycle yard waste in a compost pile and use a mulching mower.
  • Help manage stormwater and use surfaces like wood, brick, or gravel for decks and walkways, which allows rain to soak in and not run off.
  • Pick up after your dog, and dispose of the waste in the toilet or the trash.
  • Drive less—walk or bike; many pollutants in our waters come from car exhaust and car leaks.

We urge you to use these maps and this information to gauge your impact on Lake Leelanau and its surrounding watershed. Even if you do not live on the lake, your activities still affect the lake!

Main photo by Jim Kobberstad

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