The USDA ARS and California State Parks, Division of Boating and Waterways have initiated a study to address concerns that dissolved oxygen may be depleted by plant decomposition under herbicide-treated beds of water hyacinth. Using state-of-the-art miniaturized dissolved oxygen / temperature recording datasondes, the oxygen concentration will be measured before and after treatment of waterhyacinth in channel-side and back-bay areas of the California Sacramento / San Joaquin River Delta, as well as under untreated water hyacinth and in open water areas. Herbicide treatments that will be evaluated include 2,4-D, glyphosate, and imazamox.

The study will be six weeks in duration, and encompass six sites using 25 datasondes. We anticipate that the study will accurately depict the true dissolved oxygen dynamics associated with mats of water hyacinth and their treatment.

This study is conducted in cooperation with DRAAWP, the Delta Region Areawide Aquatic Weed Project.