Projects

Twin Lakes Phosphorus Reduction Project

(D. Jayne, November 11, 2025)

Background:

TLIA has been working to improve water quality by reducing phosphorus loading to Twin Lakes. TLIA’s Water Quality Advisory Committee presented a project to the board to harvest phosphorus-bearing aquatic vegetation at the west end of Upper Twin Lake and remove it from the lake. Each pound of phosphorus removed from the lake avoids the growth of approximately 500 pounds of algae. The Board voted to present information on the proposal at the July Annual Meeting. The membership voted at the meeting to move forward with the project.

Next Steps:

Baseline data gathering is first needed to predict how much phosphorus will be removed by mechanical harvesting. Baseline information will be gathered by sampling the vegetation on a grid-based survey of the areas considered for harvesting and analyzing the plant tissue for phosphorus content. This summer the baseline data will be gathered and analyzed. Sampling must be done during peak plant growth, which is approximately July 15 to August 7th. Results will probably be known around mid-August. Results will be shared with TLIA members. The base line data can be used for multiple seasons of harvesting.

Harvesting of the vegetation would occur the following summer, assuming we received encouraging results from base line sampling. Harvesting would occur during mid-July to early August so that the maximum amount of phosphorus can be removed. Project permitting and deciding whether to purchase our own harvester can also proceed once base line work is done.

Fund Raising:

Fund raising towards our goal of $150,000 will allow multiple seasons of harvesting whether we purchase a harvester or choose to use a contractor. For further information contact: Doug Jayne (509) 710-7188, or Mike Knowles at (509) 863-4359.