Sewers and Phosphorous Levels in Cazenovia Lake
Recently there was a letter to the editor which voiced disappointment that sewers were not specifically discussed at the Lake Summit. The CLA is not opposed to sewers and is investigating the actual benefit they would bring to the lake. In a perfect world we would have sewers around the lake and we would be supportive of that. However, our mission is to research, determine the facts and communicate what we learn. There were some mis-leading statements in the letter which we would like to clarify.
It is true that sewers would unquestionably lead to reduced phosphorus levels. However, it is not true that if we had sewers around the lake that this would solve the Milfoil and Harmful Algal Bloom (HAB) problems. It is all about the relative amounts of Phosphorus relative to other sources. This is backed up by experiences at other lakes in NYS which have sewers and no septic systems.
The first example, Honeoye Lake near Rochester, installed sewer systems in 1978 around the lake hoping to reduce or eliminate weed growth. Studies conducted in 2005 have shown mixed results at best with phosphorus levels remaining high and weed growth prospering. They have 2 invasive weeds, Milfoil and Curly Leaf Pondweed. They also experience HABs and have had beach closures due to HABs every year between 2012 - 2021. In fact, Honeoye had the sixth highest frequency of algal blooms of 184 lakes across the state in the year 2020.
Additionally, Conesus Lake has 100% sewer coverage around the lake however, they currently have the invasive weed Starry Stonewart. Similar to Honeoye, they experience HABs yearly.
Cazenovia Lake has installed sewers from the village on the East side of the lake to just North of Seven Pines. Part of the research SUNY-ESF is conducting in collaboration with the CLA is to look at phosphorous levels at the shoreline around the lake. The initial finding is that the levels of organic matter and markers for septic system inputs in the section on the east side which has sewers is not significantly different than the west side which do not have sewers. This shows the complication of identifying sources of phosphorous as there are many factors, not just sewers.
Students from Cazenovia college have found high phosphorus concentrations’ in several of the creeks that feed Cazenovia Lake. An Oneonta study has found that nearly 45% of the phosphorus in Cazenovia Lake is contained in the lake sediment. Sediments within the lake can provide phosphorus to the water just like sediments entering the lake from its creeks. Understanding the relative importance of these different sources, Lake sediments, creek and septic systems is critical to both protecting and restoring our lake.
Sewers around Cazenovia Lake will continue to be studied and data is being collected that will guide us in our recommendation. As with all public service infrastructure, sewers remain the responsibility of the Town however, in order to undertake a project like this there would need to be strong public support.
(Photo attribution: Washington State Department of Transportation)