Earthen ponds are the main form of water storage for ranching operations in the central plains of the U.S. During drought, these ponds can dry up and the ranchers must haul water to the cattle or move the animals to another location. Implementing either of these strategies reduces profit. A better understanding of the water balance of stock ponds is needed to improve pond design and management. Also, a good model of pond hydrology could be used in conjunction with historical weather records to predict the probability of the pond dewatering in any given season. A stock watering pond in the Flint Hills of Kansas was instrumented to measure all water inputs, outputs, and the changes in water storage. This paper will discuss the installation of the instruments and their performance during the summer of 2005.