Thesis: States that derive their water from the Colorado River Basin must adopt and enforce more water restrictions. Which are topic sentences that support the thesis sentence? Check all that apply. Climate experts predict that droughts in the Colorado River Basin area will become longer, more severe, and more frequent, even more critical to take greater measures to conserve water. When describing the future of water supplies from the Colorado River, engineer Ernest Smerdon said, "That's not a happy pict Rising populations in Nevada, Arizona; Colorado, Utah, and New Mexico have been draining the Colorado River Basin at an un rate. In 1922, the Colorado River region had a period of bountiful precipitation..