Rain gardens are a way for homeowners to reduce polluted run-off by planting a specialized garden. Human development results in an increase in the amount of run-off from precipitation. Roofs and driveways are impermeable and therefore reduce the ability of the land to absorb rainfall. Even closely cropped lawns can increase run-off since they do not hold back rain water as well as native vegetation. In addition to reducing the potential for absorption, human development also increases the amount of harmful chemicals picked up and transported to the lake by rainfall and snowmelt. In most lakes, especially lakes like Loon, phosphates pose the greatest risk. Phosphates are a common chemical, used in many of the products homeowners bring to the lake, most notably in soaps and fertilizers. Since phosphates are often the limiting factor in a lake's fertility, additions of even small amounts can result in large increases in the plant growth in a lake. Unfortunately algae usually makes up the bulk of the new plant growth, turning once clear lakes into green soup.

Rain gardens are the best way to counteract the negative effects of increased run-off. They are an infiltration technique - water is captured in a garden that features native plantings, and the water has a chance to slowly filter into the ground rather than run off into the lake It is a popular way to reduce nonpoint source pollution and has been popular along the East Coast for a number of years. Although not yet mandatory for all development on Wisconsin waterways, they are required on all new development on Loon Lake. The development plan for each lot must include a rain garden engineered specifically to meet the run-off that will be generated by each lot.

To learn more about rain gardens and phosphates, visit these links:

Rain Gardens
Wisconsin DNR - Rain Gardens
Wisconsin DNR - Resources on Rain Gardens

Phosphates in Lakes
Free Essays on Phosphates in Water Pollution
University of Minnesota Extension - Fertilizer - Phosphorus and Water Pollution

Loon Lake
info@loon-lake.org