📌 Important Upcoming Town Committee Meetings

Update on Uncle Harvey's Pond

Tuesday, February 6th at 7 pm Orleans Town Hall, Nauset Room

The Marine and Fresh Water Quality Advisory Committee, after considering a wide range of alternatives, recently voted to recommend the use of alum in Uncle Harvey’s Pond to control the phosphorous that contribute to the blooms of dangerous cyanobacteria in the water. The study of Uncle Harvey’s Pond found that 67% of the phosphorus load is generated by existing sediment in the pond. Alum treatment is often the “go to” strategy for moderate to severely impaired lakes and ponds caught in the grip of toxic algae growth. Alum works by binding phosphorus in the water column and converting it into an aluminum phosphate compound that cannot be used by algae or weeds as food. As the alum settles to the bottom of the pond, it forms a “cap” that can absorb additional phosphorus as it is released from the sediments below. This remediation strategy is not reversible.

Alum treatments are considered safe when properly applied in low pH environments like Cape ponds, and many Cape ponds and lakes have been treated with alum over the years without any apparent toxicity.

It is important to understand that any pond remediation technique has limited effectiveness, especially when watershed sources of pollution such as septic systems are unchecked. Every strategy has different costs and degrees of public acceptance. The trick is to balance the three factors of effectiveness, cost and community consent. You may have heard or read about differing opinions and concerns in the community about the safety and potential long-term effects of alum.

If you have questions about alum, we urge you to attend this meeting with the Marine and Fresh Water Quality Advisory Committee and learn more.