What is the grassy stuff in our screens?

It is pond weed! Commonly, Sago Pondweed which is an aquatic invasive weed that is widely found in the United States, South America, Europe, Africa and Japan. Like many of the other Districts the 17 western states, HID uses Copper Sulfate products and mechanical methods to treat and remove pond weed.

Sago pond weed thrives and grows quickly (4” – 6” per day) on hot sunny days. Its reproduction cycle is most active June – August. HID screens the head of every piped lateral, treats with herbicides weekly and removes the pond weed with machines. Our field crew is doing all they can to keep up with this nuisance. They work daily to treat canals, clean screens, repair & maintain infrastructure, and maintain a safe level of water in our canals.

There is a restricted-use product available called Acrolien, brand name Magnicide H, that can be used to treat pond weed and algae but is costs about three times as much as copper sulfate products and it is toxic to humans, fish, animals and wildlife. Due to the high toxicity levels of Acrolien, HID opts to use more eco-friendly products.

For more information you can access this report on Aquatic Invasive Species prepared by Portland State University.
https://agsci.oregonstate.edu/sites/agscid7/files/ag-ed-sci/sytsma_aquatic_invasive_weeds.pdf