Modeled subaerially exposed river sand available for aeolian transport along the Colorado River in Grand Canyon in support of resource impact analysis for Post-2026 reservoir operational alternatives

These data were compiled in support of the Post-2026 Operational Guidelines and Strategies for Lake Powell and Lake Mead (Post 2026) Environmental Impact Statement (EIS). These data were used to illustrate how six operational strategies (one baseline and 5 alternatives) for Glen Canyon Dam could affect sand exposure for aeolian landscape and cultural site resources within Grand Canyon National Park along the Colorado River between Glen Canyon Dam and Lake Mead. The objective of this study was to quantify potential responses of the exposed sand area metric to those alternatives. Specifically, we predict subaerially exposed sand area (i.e., above water) from 2027 to 2060 under each alternative representing different Colorado River water management scenarios. The scenarios were implemented under 1200 possible hydrological futures per alternative. Model output data provide an estimate of the exposed sand area for the Colorado River reach between Glen Canyon Dam and Bright Angel Creek in Grand Canyon National Park, based on single-day maximum river discharge and multiple-day river discharge patterns. These data can be used for relative comparisons across alternatives in terms of more or less exposed sand area.