2021 Honeoye Lake Aeration Engineering Planning Project

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Honeoye Lake is a source of local pride. It is also a source of concern when water quality shows signs of stress in summer months, e.g., reduced clarity, excessive weed growth, low dissolved oxygen, and algae blooms. Honeoye Lake water quality is indeed on the radar of local, state, and federal authorities. In recent years, under statutory requirement of the federal Clean Water Act (Section 303.d), New York State Department of Environmental Conservation (DEC) commissioned a study to model and quantify the role of the lake’s primary pollutant of concern – phosphorus. The result is the Honeoye Lake TMDL (Total Maximum Daily Load) report which sets a numerical target for a maximum phosphorus concentration for Honeoye Lake. In addition, DEC completed the 2018 Harmful Algal Bloom Action Plan which identifies priority actions to combat algal blooms in Honeoye Lake. These two guiding documents have DEC backing and they complement locally-led research and water quality monitoring by HLWTF. It may seem like a lot of studies, but understanding the underlying, complex dynamics causing Honeoye Lake’s “symptoms” is requisite to applying the most promising remedies. See these documents at www.honeoyelakewatershed.org/resources.

The Honeoye Lake HABs Action Plan and TMDL report both estimate that ~93% of the phosphorus fueling summer blue-green algae blooms comes from bottom sediments when the lake is thermally stratified, and the deepest waters become oxygen deprived. Oxygen helps bind phosphorus to sediments; in its absence, weak chemical bonds break, and phosphorus is released. When the lake eventually mixes following a wind event or major storm, the phosphorus-laden deep water becomes available throughout the lake, fueling algae blooms. Based on modeling of this dynamic, DEC recommends evaluating an aeration destratification system to significantly reduce the release of phosphorus from deep lake sediments in the summer in Honeoye Lake. An aeration destratification system works by discouraging thermal stratification in the summer while providing supplementary oxygen through diffusers to deep lake bottom sediments, thereby maintaining adequate oxygen to prevent phosphorus release.

Last year, HLWTF worked with Ontario County Planning Department to submit a successful application for a $30,000 DEC Water Quality Improvement Program grant to evaluate an aeration destratification system for Honeoye Lake. All grant funds will be used to engage a qualified professional engineer/Certified Lake Manager to produce a detailed engineering design for an aeration destratification system. The HLWTF has committed to providing the required 10% ($3,000) local match. A Request for Proposal was released in 2020 and, following a review process by a team of scientists, lake managers and local stakeholders, Ontario County awarded a contract to Princeton Hydro of New Jersey for work to begin in January 2021.

Princeton Hydro will assess the potential for aeration destratification to achieve in-waterbody nutrient inactivation and move Honeoye Lake toward the TMDL target for phosphorus reduction. After engineering planning is complete, the community will work together to determine if aeration is the logical next step to reduce summer spikes of phosphorus in Honeoye Lake.

The consultant’s report will provide equipment specifications, with recommended locations for compressors and diffusers to distribute oxygen in the lake’s deepest waters. Attention will be given to evaluating potential sites for the on-shore compressor(s). The consultant will identify potential impacts that may need mitigation through system design alternatives. Impacts on the lake’s fisheries, benthos, critical environmental areas (e.g., wetlands), recreational uses and access, noise, aesthetics, and others will be considered. These impacts will require review under the State Environmental Quality Review Act if the community pursues an implementation project.

A cost estimate, operating and safety plan, and monitoring plan to measure effectiveness will also be included in the report. Public outreach and comment on the draft report are required and will likely occur through virtual platforms due to ongoing COVID-19 restrictions on public gatherings. HLWTF and the Planning Department look forward to kicking off this important project with Princeton Hydro and partners early in 2021.