Dr. Thad Scott and Dr. Steve Patterson have submitted a draft copy of their lake modeling and TMDL report to the PVIA Watershed Committee for review. Dr. Patterson presented results from the report to the full PVIA Board of Trustees at their regular monthly meeting on Tuesday night, September 5, 2017.
This report is a culmination of a long process and a lot of work. The computer modeling project itself began three years ago, and collecting data on which the model was built began seven years ago. The computer model of Wister Lake’s physical and ecological processes was used to simulate reductions in the quantities of phosphorus and sediment entering the lake, and how the lake would respond to those changes.
Model simulations show that the annual load of phosphorus entering the lake needs to be reduced by 78% and the sediment load by 71% in order for the lake to meet Oklahoma Water Quality Standards. These needed reductions are obviously large, and won’t be achieved overnight. Rather, they will be achieved slowly, a few percent a year, over the next several decades. The report establishes the goal we need to work toward.
Fortunately, the model also shows that incremental reductions will benefit the lake–we don’t have to wait for the full reduction in order to see improvements. For example, for every percent reduction in the phosphorus entering the lake, there is a corresponding reduction in the average amount of algae in the lake.
Once the report has been reviewed and approved by both PVIA and the Oklahoma Department of Environmental Quality, it will then be released to the general public. Stay tuned.
PVIA has completed its third application of alum to the waters of Quarry Island Cove at Lake Wister, on July 27 and 28, 2017. Alum (aluminum sulfate) is used every day in the water treatment plant to help remove particles from the water. Its use in lakes is new in Oklahoma–PVIA’s application in August 2014 was the first in the state. Applying alum has both short-term and long-term benefits. In the short term, it clears the water column–similar to its role in the water treatment plant. Applying it in late July or early August means the clearing process helps to reduce the amount of cyanobacteria (aka blue-green algae) in the water, at the time of year it is typically most abundant. Long-term, the alum settles on the bottom of the lake and becomes incorporated into lake sediments. There it forms a chemical barrier that intercepts and immobilizes phosphorus as it is released from lake sediments. By binding this phosphorus, the alum keeps it from being available to fertilize and grow more algae. After each alum application, sediment cores are taken from the lake and analyzed. These tests show that so far over half the phosphorus in the lake sediments in Quarry Island Cove has been permanently immobilized. Based on the results seen in the cove, PVIA hopes that funding may someday be found to apply alum to all of Lake Wister.
Dr. Ken Hammond led the Poteau Valley Improvement Authority as its Chairman for 27 years, until his untimely death in February 2016. He was a member of the PVIA board for 36 years. With his calm, kind demeanor and ready smile, it would be hard to overstate the importance of Ken’s leadership to the success that PVIA had during those years. Ken was a strong advocate for the importance of creating a dependable supply of safe drinking water for the people of LeFlore County and nearby areas. Ken was also a fierce advocate for the protection and restoration of Lake Wister, the source of that drinking water. Under Ken’s leadership, PVIA embarked on a ambitious program to make source water protection an integral part of PVIA’s mission.
To honor Dr. Hammond and his service to PVIA and our community, PVIA commissioned and has installed this plaque in the entryway to the Water Plant. Stop by and see it.