City of Kenmore Integrated Aquatic Vegetation Management Plan

Herrera prepared the 2017 Integrated Aquatic Vegetation Management Plan (IAVMP) for the lower Sammamish River and north Lake Washington for the City of Kenmore, Washington with funding by a Washington Department of Ecology grant. Herrera mapped the distribution and density of all aquatic plants within the 220-acre study area in two days using sonar equipment and BioBase software, measured species composition using grab sampling and underwater video, and documented historical plant management actions.

Herrera developed plant management scenarios at various levels of intensity and cost, and conducted meetings with the steering committee and general public to present the scenarios and select a preferred scenario addressing different needs for public, residential, and commercial properties within the City limits. The IAVMP identified cost-effective methods for controlling a variety of noxious weeds to meet a wide range of management objectives and budget constraints.

Herrera was then hired to prepare the 2020 IAVMP update that included evaluating effectiveness of recent herbicide treatments, re-assessing stakeholder needs, and developing additional plant management alternatives using a recently approved herbicide and additional manual and biological control methods. Specific management strategies were developed for multiple City projects that focused on diver dredging rather than herbicide application as directed by the City Council. Herrera performed a second detailed aquatic plant survey of the entire study area in 2021 that recommended which City project areas needed plant management to address recreational impacts.