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Watershed Management See What You Can Do

Aquatic Plant Control

Phosphorus is the nutrient that most often stimulates excessive growth of aquatic plants, leading to a variety of problems known collectively as eutrophication. Elevated phosphorus levels are causing premature aging of many Michigan lakes. Once in a lake, a single pound of phosphorus can generate hundreds of pounds of aquatic vegetation.

The primary sources of phosphorus input to Houghton Lake were studied in 1972 (Pecor et al. 1973). The study estimated relative phosphorus contributions to be: Major tributaries, including the Cut River, Spring Brook, Denton Creek, and Knappen Creek (41.4%); precipitation on the lake surface (41.3%); forest and marsh drainage, including three minor tributaries (10.7%); residential drainage, including two minor tributaries (4.4%); shallow groundwater, including septic system drainage (1.9%); and deep groundwater (0.3%).

Since the 1972 study, phosphorus from septic systems was controlled with the installation of sanitary sewers around the lake. Although precipitation is one of the largest sources of phosphorus to Houghton Lake, there is little that individual communities can do to control the phosphorus in precipitation. However, much of the phosphorus in residential runoff is lawn fertilizers. Often, on established lawns, there is sufficient phosphorus available in the soils to support healthy lawn cover. In these situations, excess phosphorus in fertilizers can be washed into area lakes and streams. To help address this problem, the four townships bordering Houghton Lake (Markey, Lake, Roscommon, and Denton) as well as Roscommon County all adopted an ordinance that limits phosphorus fertilizer use.

10 Ways To Protect The Lake

1. Don't use lawn fertilizer that contains phosphorus.
2. Use the minimum amount of fertilizer recommended on the label—more is not necessarily better!
3. Water the lawn sparingly to avoid washing nutrients and sediments into the lake.
4. Don't feed ducks and geese near the lake. Waterfowl droppings are high in nutrients and may cause swimmer's itch.
5. Don't burn leaves and grass clippings near the shoreline. Nutrients concentrate in the ash and can easily wash into the lake.
6. Don't mow to the water's edge. Instead, allow a strip of natural vegetation (i.e., a greenbelt) to become established along your waterfront. A greenbelt will trap pollutants, and discourage nuisance geese from frequenting your property.
7. Infiltrate drainage from your downspouts rather than letting it flow overland to the lake.
8. Don't dump anything in area wetlands. Wetlands are natural purifiers.
9. If you trailer your boat from lake to lake, wash your boat and trailer before launching back into Houghton Lake.
10. Don't be complacent—our collective actions can make or break the lake!