Making Cedarville Bay a Boater Destination Again
To the Editor:
Two articles dealing with ecological issues of Cedarville Bay have appeared in this paper during the past month. Reporter Jonathan Eppley has effectively highlighted a number of points on those issues. Still, people have asked even more questions. This note is to hopefully clarify some of the critical Cedarville Bay issues and to identify the position of the Les Cheneaux Waterways Restoration Group.
Cedarville Bay is presently the equivalent of an unbalanced aquarium. A well cared for aquarium can be maintained for years without a major effort. That ecological balance is what we are striving for in Cedarville Bay.
Between 1994 and 2008, more than three tons of phosphorus have been discharged in the Clark Township Wastewater Treatment Plant polished lagoon water. Discharge volumes range from 25 to 35 million gallons per campaign and there are two discharge campaigns each year. The volume of each discharge is equivalent to one third to one half the volume of Cedarville Bay. With minimal water movement out of Cedarville Bay, the plume of nutrient-rich lagoon water fertilizes aquatic plants in the bay for at least three weeks before slowly dissipating.
The Waterways Restoration Group has three objectives: (1) Control the intense weed growth in Cedarville Bay with special effort on the invasive aquatic weed, Eurasian watermilfoil (EWM); (2) To limit the nutrient source for aquatic weeds; (3) To remove residual nutrients found in the bottom sediment. These objectives all support a common goal to make Cedarville Bay a boater destination again.
The major aquatic plant nutrient of concern is phosphorus. In our region, phosphorus levels in the water are a primary determinant of the ability of aquatic plants to grow. One of the selling points to develop the present treatment plant was to reduce nutrient levels in Cedarville Bay. The fact is that there is no substantial difference in the concentration of phosphorus in the water of Cedarville Bay in 2008 than was recorded 1994, as reported by AquaTerra Labs.
To address our first objective, at great expense and effort on the part of the Watershed Council and Flotation Docking Systems, nuisance weed growth was well controlled in 2008. Aquatic weevils planted by the Watershed Council in 2007 have contributed to control of watermilfoil along the margins of Cedarville Bay. The Watershed Council also contracted with Flotation Docking Systems to manage weed growth using a mechanical weed harvester around the launch ramp, township dock, and navigation areas to the federal channels last summer. Boaters appeared pleased with the ability to traverse Cedarville Bay during 2008, compared to the previous several years.
To address our second objective, the Watershed Council conducted an experiment to identify levels of iron chloride to be mixed with the lagoon water. Iron chloride binds with phosphorus and the resulting complex settles to the bottom. Last spring, a discharge volume of about 25 million gallons contained only four pounds of phosphorus. This is contrasted with 500 pounds of phosphorus in each discharge experienced during early years of the present system. This is an improvement of 125 fold. If this level is reduced another fourfold, and can be consistently achieved, then the adverse impact of lagoon discharge nutrients on Cedarville Bay will be considered negligible from an excess nutrient standpoint. Other readily available, relatively cheap, and simple existing technologies can be used to lower the annual phosphorus to a desirable level.
Objective three is to remove a large portion of the nutrient-rich sediment from Cedarville Bay by dredging. How much volume should be removed without creating yet another ecological insult has yet to be determined.
As these three objectives are being addressed, a number of additional issues need to be clarified with the DEQ. First, is to identify which phosphorus removal technologies are acceptable to the DEQ. As the existing treatment plant went online in 1993 an engineering firm, Capital Consultants (presently known as C2AE) made several recommendations on handling of polished lagoon water. The DEQ position on these recommendations needs to be confirmed before updating a course of action can be discussed with C2AE. An updated recommendation from an engineering firm is required before action can be taken, but at a cost to the township of around $25,000. It is prudent to have a preview from the DEQ on what approaches are, or are not, acceptable for Clark Township before committing to an expensive engineering review.
A second point is the quality of water being discharged. Among the 10 Les Cheneaux study sites, only Cedarville Bay has a phosphorus level higher than that of northern Lake Huron. This discharge act is in violation of Rule 98 of the 1986 Water Quality Standards and goes against recommendations of the Michigan Phosphorus Policy Advisory Committee (2007).
Third, once an effective system is designed for ecologically acceptable phosphorus levels, then that system needs to be sized to accommodate projected demand on the treatment plant at least 20 years from the time it goes online.
Fourth, the Waterways Restoration Group will work with the DEQ to identify state and federal grants to fund upgrades to the treatment plant.
Dredging of the federal navigation channels is a separate project being coordinated with the Army Corps of Engineers.
My graduate degree is a master's in microbiology from Central Michigan University, not a PhD. "Lakeside" Bob Smith Cedarville