In recent years the attention given recreation in multiple purpose water resource development has increased dramatically. However, because of their very nature, the benefits and losses accruing to such projects from recreation, or the lack of it, have been extremely difficult to quantify. One of the factors that affects recreation benefits is the fluctuation in the water level of the impoundment. This research was undertaken with the goal of making available to the water resources planner an improved tool for including a realistic recreation benefit-loss function in the development of a model to determine optimum reservoir operation policy. Primary attention was given to reservoirs whose water levels changed appreciably during the recreation season, but data from reservoirs that were not drawn down were also collected in order to maintain a control, so that relevant conclusions could be drawn. Background information including the normal level of recreation activity, accessibility of the area to centers of population, weather patterns, topographic features, and other data pertinent to specific cases were also gathered. A computerized analysis was developed in order to quantify the results and to draw conclusions on the basis of statistical inferences developed from the data. For the reservoirs which showed widely fluctuating water levels, no statistically significant relationship was shown to exist between water level and recreation attendance for the month of July for the nine year period, 1958-66. (Author)