Aquatic Plants in Clear Lake

Efforts have been ongoing in the past two decades to improve the water quality of Clear Lake. As the waters of the lake have cleared, however, aquatic plants have increased. The increased penetration of sunlight into the water has resulted in the shallow areas becoming excellent habitat for aquatic plants. There are approximately 50 different plants that make Clear Lake home. While aquatic plants provide essential habitat for fish and wildlife in many areas they can be a nuisance to human recreation on the lake.

In 2006 a final Programmatic Environmental Impact Report was certified by the Board of Supervisors to establish the Clear Lake Aquatic Plant Management Program as the means of responsibly managing plant growth in the lake. The Program was codified in 2006 as Ordinance Number 2777.

The primary purpose of the Clear Lake Aquatic Plant Management Program is to develop a clear, locally controlled, regulatory structure for all of Clear Lake within which to abate nuisance aquatic vegetation for the purposes of navigation and recreational use of the lake. This is accomplished by applying for a permit that can be downloaded from the Aquatic Plant Management page. Citizens seeking to abate aquatic weeds can also visit the County Department of Water Resources (DWR), third floor of the courthouse in Lakeport to obtain a permit application. DWR cooperates with the California Department of Fish and Game to determine the start of the season's plant management activity.

The permits are also reviewed by the California Department of Food and Agriculture Hydrilla Eradication Program, who determines potential impact on their efforts, and Lake County Agricultural Commissioner's Office who is involved locally both with Hydrilla eradication and pesticide use regulation. In addition, the State Water Resources Control Board requires any activity involving addition of chemicals to "waters of the United States" comply with the Clean Water Act monitoring and reporting requirements. While the regulatory process, fees, terms and conditions can be perceived as obstacles to abating weeds, the control measures need to be consistent with the current environmental regulations thereby not causing significant adverse impacts to the environment or exposing the county to litigation.

Since Clear Lake is in public trust it is illegal for individual landowners to apply herbicides to "waters of the U.S." Three licensed applicators offer control of aquatic vegetation via herbicide application. One of those companies also offers mechanical removal of nuisance weeds. Mechanical control is limited due to the potential to spread Hydrilla. Mechanical removal can be done by landowners that obtain permit approval for work in non-Hydrilla control areas. DWR is currently the one-stop clearinghouse for all aquatic plant management activities. Contact Angela De Palma-Dow, Invasive Species Program Coordinator, Department of Water Resources by calling 707-263-2341.