Lake Taneycomo, a 700-ha hydropower impoundment in southwestern Missouri, supports an excellent put-grow-and-take trout fishery with a benefit:cost ratio of 22:1. However, seasonal dissolved oxygen fluctuations resulting from the hypolimnetic discharge from upstream Table Rock Lake have been a concern since 1970. The biological and socioeconomic effects of low levels of dissolved oxygen on the fishery were recently documented. When dissolved oxygen drops below 6 mg/L, fishing success declines. This change in fishing quality affects visitation to the area and the economic benefits generated by the fishery. The net economic benefit of the fishery to the local economy is $9.9 million, and the current estimated loss of benefits is $358,000 per year because of low dissolved oxygen. The U.S. Army Corps of Engineers has proposed a structural modification of Table Rock Dam to solve the problem.