Changes to Whitewater Recreation in California's Sierra Nevada from Regional Climate Warming

Download or read book Changes to Whitewater Recreation in California's Sierra Nevada from Regional Climate Warming written by Scott Thomas Ligare and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Whitewater recreation is an aesthetic ecosystem service potentially affected by climate warming alterations to runoff. In California's Sierra Nevada, climate change is likely to reduce water availability with warmer air temperatures and potentially decreasing precipitation. The corresponding changes in the timing and magnitude of streamflow will affect whitewater boating opportunities. In this study 128 whitewater runs were identified on the west-slope of the Sierra Nevada within a 13 basin study area that ranged from serene float trips to remote, difficult, kayak expeditions. A spatially explicit one-dimensional rainfall-runoff model was used to estimate the unregulated hydrology at specific locations within flow thresholds amenable to whitewater recreation. Climate warming scenarios were simulated by increasing air temperature by 2°, 4°, and 6° C and assuming no change in other climate variables such as precipitation. Mild warming increases the average number of boatable weeks per year, but more extreme warming decreases the average boatable weeks per year across the Sierra Nevada. Runs in low elevation drainages, such as the Cosumnes and the Tule River Basins, are most vulnerable to changes in boatable weeks. Yet high elevation watersheds, such as the Kern River, also have a large reduction in boatable weeks. Watersheds in the central Sierra Nevada show an increase in boatable weeks due to its many gorge type runs at middle elevations. Overall, elevation, run type, and volume of snowmelt was the best predictor of resiliency for Sierra Nevada whitewater runs. Recreation is important for river management, yet it is difficult to quantify and to plan for. This research provides a sensitivity analysis of climate warming for the Sierra Nevada and presents a method that can be applied to other regions and whitewater rivers. Climate warming is forcing managers to make decisions with uncertainty in water availability, making allocation decisions difficult among often conflicting uses (e.g., ecology, hydropower generation and recreation). Reduction in whitewater recreation opportunities in unregulated rivers due to climate warming and continued increases in population will likely increase the importance of whitewater boating on regulated rivers, and thus the reliance on reservoir operations for meeting multiple demands.