Optima Lake is a reservoir in Texas County, Oklahoma. The lake is located near the towns of Hardesty and Guymon in the Oklahoma Panhandle. The lake has never reached more than 5 percent of its design capacity[1], and now is effectively empty. Rapid declines in streamflow (related to large-scale pumping from the High Plains Aquifer) coincided with the completion of dam construction[1] to make this lake a dramatic example of unanticipated environmental impacts.