Sensitivity of Recreational Access to Reservoir Water Level Variation: An Approach to Identify Future Access Needs in Reservoirs

摘要

Reservoirs support popular sport fisheries and other forms of water recreation. However, access to these systems is often sensitive to variation in water level. Increasing water demands due to population growth and the effects of climate change suggest that maintaining adequate recreational access to reservoirs will become increasingly difficult. Knowledge of the effects of water level variation on boat and shoreline access is required to identify future needs and to aid in prioritizing improvement efforts that promote participation in fishing and aquatic recreation. To address this need, we developed a geographical information systems-based approach to quantify the effects of reservoir water level variation on recreational access and applied the technique to three Colorado River reservoirs in Texas: Lake Buchanan, Lake Travis, and Lyndon B. Johnson Reservoir. The data were used to identify reservoir-specific water levels (m below full pool) at which the availability of access was adversely affected. For the three reservoirs, 33-39% of boat access sites were dewatered with 1-3-m reductions in water level, over 50% of access sites were unusable with an additional 1-2-m loss of water level (i.e., 2-4-m reductions), and over 75% of access sites were lost with 4-8-m reductions in water level. The effect of water level reductions was less for shoreline access than for boat access. Historic water levels in each reservoir were then compared with a regional water availability model to estimate future trends in access for each reservoir. Reservoirs exhibited contrasting trends in future accessibility, ranging from a 92-500% decrease in access for Lake Buchanan to a 5-31% increase for Lake Travis. The techniques developed in this study will assist fisheries managers in working with water authorities and policy makers to minimize, mitigate, or prevent negative effects on recreational access and will aid in identifying and prioritizing reservoirs that require future access improvements.