CELINA — A U.S. Environmental Protection Agency report indicates the 2012 alum treatment reduced the internal phosphorus load in Grand Lake St. Marys by 55 percent.
“To no one’s surprise, the report revealed that a significant amount of phosphorus was inactivated as a result of the alum treatment, and we are satisfied with the results, but this was always one part of a multi-faceted, multi-year plan for the lake and for the watershed,” Ohio EPA Director Scott Nally said.
The state will not apply a third alum treatment to Grand Lake St. Marys in 2013.
Since 2011, the state has worked with the Grand Lake St. Marys Restoration Commission and the Lake Improvement Association to implement several new practices as part of a comprehensive, long-term plan to reduce the bioavailability of phosphorus in addition to the alum treatments.
The practices included dredging, rough fish removal, the installation of a phosphorus treatment train in a Grand Lake St. Marys tributary, lake leveling, aerators and the installation of littoral wetlands. The state also took steps to declare the Grand Lake Watershed a “watershed in distress,” completed a state nutrient management plan and implemented land management practices.