The applicator plans to use glyphosate and an approved aquatic surfactant, which is systemic herbicide that is effective on Water Lily.
The applicator may also use penoxsulam for control of the submerged Curly Leaf Pondweed. The brand of the penoxsulam product, Galleon SC, is classified as an EPA Reduced-Risk Aquatic Herbicide.
Both are fully approved for these uses by the US Environmental Protection Agency and Washington State Department of Ecology. Washington State Department of Ecology has issued an Environmental Impact Statement on the use of these products for aquatic weed control, which is available here: https://apps.ecology.wa.gov/publications/SummaryPages/0010043.html, and a Supplemental Environmental Impact Statement, which is available here: https://apps.ecology.wa.gov/publications/SummaryPages/1710020.html.