CHALLENGES OF CONDUCTING HYDROGEOLOGICAL FIELD WORK IN GRAND CANYON NATIONAL PARK

Graduate students and research technicians at NAU have been installing and maintaining stream gages at numerous karst springs, collecting samples for cation/anion and stable isotope analyses, and measuring water quality parameters for nearly 20 years at Grand Canyon National Park. As the park upgrades its water supply and delivery infrastructure, it is imperative to characterize and forecast the quantity, quality, and vulnerability of water resources. Through a cooperative agreement with the National Park Service, scientists at Northern Arizona University (NAU) have been conducting hydrologic research within the park and adjoining Kaibab National Forest to characterize and better understand the regional aquifers. However, Grand Canyon terrain and climate present unique challenges for data collection, gage designs, and logistics. While many sites are along maintained trails, several instrumented cave springs are far from any roads or trails and make access uniquely difficult. Flash floods, wildfires, bison, deer, beavers, park visitors, and rare climate events all provide opportunities to learn what can go wrong with instrumentation and how to improve designs. Despite these challenges, many sites are approaching a 10-year data record, and many projects addressing aquifer characterization have been successful. Results from dye tracer tests, precipitation and snowmelt analyses, and temperature correlations have shown fast travel times ranging from 2-6 days through over 5000ft of sedimentary stratigraphy. These projects have also highlighted the complexity of flow paths through the region’s multi-layered karst and fault driven groundwater flow system.