City says lake treatments have reduced harmful algae; more work planned at Willow and Goldwater

City of Prescott water managers told the Council Subcommittee on Water Issues on July 1 that recent treatments have reduced harmful algae and improved conditions at city lakes, but they said additional work is planned at Willow and the Goldwater lakes to address low oxygen, high pH and sediment inflows.

The update focused on results from a June 1 phosphorus‑binding treatment at Watson Lake, ongoing muck treatments at Upper Goldwater Lake and an emerging Willow Lake management plan. Jeremy Cordova, Environmental Project Manager for City of Prescott Public Works, summarized early monitoring, said the city removed more than 220 pounds of phosphorus from Watson Lake and reported a 45% phosphorus reduction and 25% clarity improvement at Upper Goldwater after a month of treatments.

The work matters, Cordova told the subcommittee, because the lakes are popular recreation and recharge features and because low dissolved oxygen and high pH can create conditions that trigger public‑health actions and reduce fish habitat. "We get a large bit of aquatic weed and harmful algae blooms," Cordova said, adding…