In 1985, White Lake was designated one of 43 Great Lakes Areas of Concern, due to problems, termed “Beneficial Use Impairments,” identified in and around the lake. Since 1992, the White Lake Public Advisory Council has been working with state and federal environmental agencies to address these impairments. One of the eight Beneficial Use Impairments identified for White Lake is “Eutrophication and Undesirable Algae.”

What is eutrophication?

Eutrophication occurs when nutrients, such as phosphorus and nitrogen, enter a lake and cause excessive growth of aquatic plants and algae. Scientists classify lakes according to their level of productivity, or their “trophic” status. Chlorophyll levels are measured to estimate how much algae is present, which indirectly indicates the amount of nutrients in the lake. There are four trophic states: oligotrophic, mesotrophic, eutrophic and hypereutrophic. Oligotrophic lakes have had little nutrient inputs and are usually clear. Mesotrophic lakes have moderate plant growth. Eutrophic lakes tend to be cloudier and have lots of plants. Hypereutrophic lakes are very high in nutrients and are the most biologically productive, with large amounts of plants, fish and other animals. The different trophic states occur naturally, but can be affected by wastewater disposal, sedimentation, and runoff from lawns, roads, farms, and development.

What are the effects of eutrophication?

Eutrophication can increase turbidity (stirred up particles in the water) and decrease oxygen levels which can eliminate certain fish species in a lake. Large mats of plants can also affect navigation and make swimming less appealing. Not all aquatic plants are undesirable. Weed beds provide important shelter for fish to spawn and live, one reason wetland areas are so important. Algae are important food for fish and small aquatic animals, including zooplankton. Too much algae, however, can make lakes murky and affect fishing and swimming.

What has caused eutrophication in White Lake?

Logging of the White River watershed beginning in the 1830s is likely one of the largest causes of eutrophication in White Lake. Tree removal caused erosion and sedimentation, sending nutrients down the river and into the lake. Creating straight channels in the wetlands north of the lake to help move logs made the problem worse because there were fewer wetlands to filter nutrients. Eutrophication accelerated in the 1950s through the 1970s, from discharges by municipal sewage treatment facilities and the tannery, causing high nitrogen and phosphorus levels.

What’s the current status?

Transferring discharges from White Lake to the Whitehall wastewater system in 1973 helped to reduce nutrient inputs, lessening the problem. Unfortunately, invasive nuisance aquatic plants, such as Eurasian milfoil with its thick plant beds, established in the lake during the 1970s. In 1996, the GVSU Annis Water Resources Institute (AWRI), supported in part with funding through the Muskegon Conservation District, conducted an initial survey of aquatic growth in White Lake. Since then, the AWRI has completed several studies of the White Lake system with funding from the Michigan Department of Environmental Quality (MDEQ) and the White Lake Association. One conclusion from these studies was that increased weed growth in White Lake became worse between 1997 and 2007, possibly due to lower lake levels, and increased ability of sunlight to penetrate the water column from the filtering out of algae by zebra mussels. The studies also showed the primary source of nutrients was from the White River and water seeping up through the lake bottom sediments from shoreline runoff was also a significant source of nutrients.

Between 2006 and 2010, the White Lake Public Advisory Council and the state developed restoration goals for each impairment to measure progress and assess when they could be considered restored. The Eutrophication and Undesirable Algae impairment will be removed when the following conditions have been met for five years:

• White Lake is not on the state’s list of impaired waters, updated every two years, as required by the federal Clean Water Act, due to nutrients or excess algal growth.

• Phosphorus and chlorophyll are at levels considered to keep the lake at the lower end of the eutrophic state (no more than 30 ug/l for phosphorus and 10 ug/l for chlorophyll) to limit the production of nuisance algal blooms.

• Secchi disk samplings are clear to two meters. Secchi disks measure the transparency of water in a lake.

• White Lake’s trophic status index is within 50 to 55. The index is a tool that summarizes water quality measurements into a value to be compared to other lakes. The lower the value, the lower the productivity of the lake. Maintaining an index of 50 to 55 will keep White Lake at the lower end of a eutrophic state.

Data collected in 2004, 2005 and 2006 by AWRI researchers show these targets are being met. If a final sampling this summer confirms this positive trend, the MDEQ will assemble a technical committee to decide whether to recommend removal of this impairment.

What’s next?

While the days of algal blooms and excessive weeds from industrial and municipal discharges are over, White Lake will remain a eutrophic lake when the Eutrophication and Undesirable Algae impairment is removed. A remaining concern of the White Lake Public Advisory Council, along with other groups and area citizens, is nutrients on the lake bottom that can be stirred up, fertilizer runoff, and improperly maintained residential septic systems around the lake. Reducing nutrient inputs from shoreline lawns will help limit excess weed growth, according to Tom Thompson, secretary/treasurer of the White Lake Association and a member of the White Lake Public Advisory Council. “There’s been increased awareness by area residents about the importance of using phosphorus free fertilizer,” he says, “and that will be good for keeping weed growth in balance. Leaving buffer strips instead of mowing all the way to the lake’s edge is a good idea also.” The White Lake Public Advisory Council will continue its work on aquatic weed growth with groups such as the White River Watershed Partnership, through implementation of a watershed management plan for the White River watershed.