Aquatic Weeds Interfere with Water Flow, But There are Strategies for Eradication


By Kyle Buchoff, California Ag Today Reporter


John Madsen is a Research Biologist with the USDA and is the Site Coordinator for The Aquatic Weed Research Facility at UC Davis. One of the goals of this lab is to identify aquatic weeds that might hinder the flow of irrigation water through canals, ditches or farms.

Madsen, explained, “There are many species of aquatic plants that will infest irrigation ditches and other canals and interfere with the passage of irrigation water. Some of the main species are Hydrilla, a noxious weed in California, and in the Delta, Egeria densa or  Brazilian elodea. California State Parks Division of Boating and Waterways is working on the weeds in the delta.”

Madsen said once the species is identified, the grower must choose the correct herbicide to control the weeds, “Species identification is very important, since different species are susceptible to different herbicides. There are also water restrictions on herbicides. You have make sure you choose the right herbicide for controlling the weed but also make sure it fits the constraints of the habitat. Some herbicides cannot be used too close to irrigation, the water source or drinking water, while others have fewer restrictions.”

Mike Blankinship with Davis, CA-based Blankinship & Associates, a firm that specializes in aquatic weed management, said, “Among the things that we provide are services to various growers and irrigation districts to help them understand their weeds, manage them and ultimately deliver water efficiently. Working with John and others in the irrigation community throughout California, we have come up with a variety of plans and tools that include aquatic herbicides to manage the water supply and deliver it to growers efficiently.”