EFFECTS OF CLIMATE TRENDS AND SEASONAL VARIABILITY ON BRIGHT ANGEL CREEK, A KARST SPRING-FED CREEK WITHIN GRAND CANYON NATIONAL PARK

Bright Angel Creek is a perennial, karst spring-fed, desert stream within Grand Canyon National Park that has become the focus of new water infrastructure. The National Park Service has proposed to divert surface water from Bright Angel Creek before the confluence with the Colorado River to supply potable water to facilities in the inner-canyon and on the South Rim. To inform NPS decision-making related to future water availability and Bright Angel Creek seasonal flow variability, we correlated climate signatures of precipitation and temperature with seasonal flow variables and long-term trends. The deep, limestone karst R-aquifer recharged primarily through precipitation on the North Rim Kaibab Plateau is the source for Bright Angel Creek. The R-aquifer exhibits both paleo and modern karst with numerous springs that display conduit, fracture, and matrix flow regimes. Preliminary results using National Oceanic and Atmospheric Administration climate data from 1925-2021 collected on the North Rim, 1700m above the stream gage, shows warming temperatures and impacts to snowpack and snowmelt signatures. With the National Park Services’ need to forecast water availability and seasonality, these results will help inform water management decisions related to the proposed infrastructure development.