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Honeoye Lake Aeration Engineering Planning Project

Update on the Honeoye Lake Aeration engineering Planning Project and the NYS DEC Honeoye Lake Nutrient Inactivant Pilot Study

By Betsy Landre, Ontario County Planning Department
& Terry Gronwall, HLWTF

Boat on Honeoye Lake for Inactivant Pilot Study

The first phase of the Honeoye Lake Aeration Engineering Project has been completed. A Public Information Webex meeting was held on April 26th, 2022. The final Princeton Hydro Aeration Engineering Planning Report was released in June 2022. The Final Report, Webex presentation, and Webex recording are available at the top of this page.

In September 2022, NYS Department of Environmental Conservation (DEC) announced plans for a Nutrient Inactivant (Alum Treatment) Pilot Study in Honeoye Lake. In recent years, DEC conducted alum treatments on two small lakes in the Lower Hudson Valley to assess impacts of alum treatments on phosphorus levels and lake ecosystems. The Honeoye Lake Alum Treatment was introduced as DEC’s first large lake pilot study. The DEC has been conducting these pilot studies as it evaluates a potential permitting process for the use of Alum Treatments since they are not currently allowed in New York State. The DEC’s Alum Treatment was completed on November 18, 2022. It will be interesting to see how much phosphorus reduction, algae reduction, and water clarity increase occur next summer. DEC’s Alum Treatment Project information is available at: Honeoye Lake Nutrient Inactivant Pilot Study.

The DEC ’s Nutrient Inactivant (Alum Treatment) Study and the Aeration Planning Project engineering design are intended to address the same source of legacy phosphorus in Honeoye Lake. Legacy phosphorus is released from the deep-water lake bottom sediments during periods of lake stratification, when oxygen becomes depleted in the lake’s bottom layer. The DEC intends to monitor the effectiveness of the Alum Treatment over the course of 3-5 years.

The HLWTF will also evaluate the DEC’s Alum Treatment effectiveness and lifespan in conjunction with its annual lake monitoring program. Data collection will help determine if the best long-term strategy for managing legacy phosphorus in Honeoye Lake is 1) a combination of Alum Treatment followed by Aeration or 2) doing additional Alum Treatments in the future provided the DEC establishes a permitting process for such treatments in New York State based on their pilot studies.

While the Alum Treatment is evaluated, the Aeration project committee will review the effectiveness and reliability of existing aeration systems in use in North America. First-hand knowledge from mangers of existing aeration systems can assist the local Honeoye Lake community’s decision-making process. Funding options will also be explored, as well as the best entity to own, manage and maintain an aeration system, if aeration is recommended to be part of the overall Honeoye Lake water quality strategy.

Terry Gronwall (HLWTF and Town of Canadice) and Betsy Landre (Ontario County Planning Dept.) extend thanks to local project committee members who provided data, reviewed draft documents, and raised important questions throughout the Aeration Planning Project:  David Baker, Town of Richmond; Nelson Hairston, Professor Emeritus, Cornell University; Bruce Gilman, Professor Emeritus, Finger Lakes Community College; and Linda Vanderbeck, Honeoye Valley Association

Staff from DEC Region 8 in Avon and Albany are appreciated for their guidance. The aeration design and planning project is funded by a Planning Grant from the NYS DEC Water Quality Improvement Program.

How Does an Aeration System Reduce the Impact of HABs?

By Linda Vanderbeck, Honeoye Valley Association

Green Harmful Algal Bloom on Honeoye Lake

Harmful Algal Blooms (HABs) are obnoxious, unwelcome events that occur every year during the late summer and early fall around the world. HABs are a part of nature’s life-cycle so unfortunately, we will never be fully rid of them. We can however fight back and win battles that limit their frequency, weaken their intensity, and shorten their duration. Fuel for HABs comes from both external sources like stormwater runoff and drainage, and from internal sources like legacy phosphorus found in the lake bottom. Based on New York State Department of Environmental Conservation (NYS DEC) recommendations, the Honeoye Lake Watershed Task Force (HLWTF) together with Ontario County Soil & Water Conservation District (OCSWCD) have implemented a number of projects over the years to curtail storm water runoff into the lake. A few of these projects include: the Honeoye Inlet Restoration Project (pictured above), Debris Guards in Cratsley Gully, Briggs Gully Streambank Erosion Project, and Road Drainage and Stream Crossing Improvement. (For a full project list and details see our Projects Page).

In Honeoye Lake, 93% of HAB fuel - phosphorus - comes from lake bottom sediments (source: NYS DEC Total Maximum Daily Load for Total Phosphorus, page 12 and Harmful Algal Bloom Action Plan Honeoye Lake, page 50) so HLWTF and Ontario County Planning Department (OCPD) are now looking at ways to best curtail these sources. Phosphorus is mostly stored in the “muck” at the bottom of the lake. As long as there is plenty of oxygen in the water, the phosphorus stays in the muck. As summer goes on, the oxygen gets used up and phosphorus leaves the muck but stays in the colder water near the bottom of the lake. Because Honeoye Lake is shallow, strong winds and storms can cause mixing, sometimes called “lake turnover.” When this happens, the phosphorus in the colder deep water at the bottom raises to the surface where blue-green algae live; the sun shines and now there’s a HAB. This HAB-causing process is well understood and accepted throughout the professional and scientific community. Many formal studies have been conducted and peer reviewed that document how phosphorus leaves the muck when oxygen is used up and how this causes HABs. Specifically, research has confirmed that this is the condition that causes Honeoye Lake’s seasonal HABs.

Keeping oxygen in the water and therefore keeping phosphorus in the muck is what aeration systems can do. Two NYS DEC reports, Total Maximum Daily Load for Total Phosphorus and Harmful Algal Bloom Action Plan Honeoye Lake, as well as the HLWTF Honeoye Lake Watershed Management Plan Executive Summary all recommend an aeration system as a way to manage internal phosphorus loading for fighting HABs in Honeoye Lake. Aeration systems add oxygen into the water via a variety of methods and have been successfully deployed for many years in lakes, farm and fish ponds, water supply, fishery reservoirs, and waste water treatment facilities. Lake scientists and engineers have developed mathematical formulas that are applied to quantitative lake data to calculate the amount of oxygen a lake requires to mitigate phosphorus loading. From such analysis, aeration system engineers are able to design aeration systems specific to any given body of water.
No decisions have been made to install an aeration system at Honeoye Lake yet. However, HLWTF and Ontario County Planning Department are currently working with a lake management consultant Princeton Hydro to look at the feasibility of an aeration system. The effort is a planning exercise at this point. There are many additional steps necessary for an aeration system to become a reality including: buy-in from Richmond and Canadice, funding, grant proposals, request for proposals (RFPs), engineering, logistics, training, budgets, and more. Still, an aeration system may never happen. Keep in mind, that not even an aeration system will prevent HABs. Some phosphorus will always find its way into the lake from runoff during heavy rainfalls.
In the coming months more information about the planning effort will become available as well as opportunities for public input. The war on HABs has been waging for many years and we have won a lot of the battles. Now we are strategizing an attack on the mother lode - internal legacy phosphorus.
If we win this battle, it just might be our greatest victory yet!

To understand the strategy for fighting HABs in Honeoye Lake, see:

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