Phosphorus

Many fertilizers contain phosphorus as one of their components. In fact, the 3 numbers listed on the fertilizer container represent the percentage, by weight of the contents, of the 3 major nutrients required for healthy plant growth: nitrogen-phosphorus-potassium. It is commonly believed that fertilizing with phosphorus will help to “green up” lawns. However, it is the nitrogen that is responsible for making grass greener. Furthermore, most soils in the Midwest already have adequate amounts of phosphorus to grow healthy lawns.

Stormwater Runoff
It is estimated that 90% of properly applied fertilizers will be absorbed into the ground and 10% will leave the site of application through stormwater runoff. This stormwater runoff finds its way to lakes, streams, wetlands, ponds, retention areas, and detention/retention areas. It is in these areas that the excess phosphorus may have detrimental effects. Approximately 1/3 of the land area in the Village drains directly to Bangs Lake, either through direct piping or surface runoff. The remaining 2/3 drain to other areas, including the 40 or so detention basins/ponds located within the Village. On a larger scale, the Village of Wauconda lies in the Fox River Watershed. Much of the stormwater runoff in the Village eventually makes its way to the Fox River, unless it is absorbed into the ground, evaporates, or is otherwise contained in a basin or pond.

Phosphorus Levels
The Lake County Health Department Lakes Management Unit collects regular water samples from Bangs Lake and tests the levels of many water quality parameters. One of these parameters is phosphorus. In 2008, the level of phosphorus was 0.020 milligrams per liter which was about a 1/3 of the county median (0.065 milligrams per liter). Looking at data from 2000 to 2008, Bangs Lake has the 8th lowest phosphorus level among the 163 lakes in Lake County. Detrimental effects are likely to be seen at a phosphorus concentration of 0.030 milligrams per liter. Even though the level of phosphorus in Bangs Lake is low, Lake County recommends that all municipalities adopt an ordinance banning the use of fertilizers that contain phosphorus.

Fertilizer Education
The Village has decided to hold off on an ordinance and instead, continue to educate residents about phosphorus. The Village encourages all residents to look at the label and consider using fertilizers that do not contain any phosphorus. Although Bangs Lake has low levels of phosphorus, it is wise to keep as much phosphorus out of the area streams, wetlands, and stormwater detention/retention areas as possible. View a list of retailers that sell phosphorus-free fertilizers (PDF).