This is a firm fixed-price purchase order awarded by the U.S. Army Engineer Research and Development Center (ERDC) to Four Peaks Environmental Science & Data Solutions LLC, a small business, to conduct research on the use of the herbicide diquat dibromide for controlling flowering rush in the Columbia River in Washington. The contract has a ceiling value of $168,045.00 and a period of performance through June 30, 2024. The contract was awarded on a sole-source basis due to Four Peaks' specialized expertise in assessing the impacts of this restricted-use herbicide, understanding water exchange characteristics in large hydraulically complex river systems, and evaluating the effects on submersed aquatic plants in the Pacific Northwest region. This effort supports the ERDC's environmental programs and does not have a small business set-aside designation.