Notice of Intent:Hydrologic Assessment of Grand Canyon NPâ¿¿s source Water and associated groundwater monitoring and modeling

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As Grand Canyon National Park begins the process of upgrading the parks water supply and delivery infrastructure, it is critical that we develop a better understanding of the quantity, quality, and vulnerability of water resources. Currently, our understanding of the overall source water area for the park water supply (Roaring Springs) is poorly defined and needs to be evaluated. This study should help us improve our understanding of the surface area on the Kaibab Plateau that drains through springs associated with Bright Angel Creek. With this information, we will be better able to assess the available water supply, especially in light of climate change, and how vulnerable the water supply is to contamination. The intent of the proposed project is to delineate the source water area for Bright Angel Creek using dye tracing and spring monitoring techniques (for dye trace methods Jones et al. in review. For spring monitoring protocols see springstewardshipinstitute.org and Graham Schindelâ¿¿s 2015 NAU masterâ¿¿s thesis). Current monitoring efforts of springs in Grand Canyon provide some insight into the behavior of aquifers showing that water during spring snow melt typically takes less than 2 weeks to reach the Roaring Springs system. This type of information allows us to understand the relationship between precipitation, aquifer storage, and spring flow. However, our data are limited and without a solid understanding of the surface area directly related to all springs feeding Bright Angel Creek, we cannot estimate the future water yield from these aquifer systems with any certainty. Additionally, these springs are the outlet of karst aquifers. Karst aquifers are defined by caves, sinkholes, and bedrock that easily dissolve by slightly acidic waters. Due to the nature of these systems, water can move rapidly through these systems, often as fast as a surface stream making them vulnerable to contamination from surface activities that feeds into the aquifer. Without delineating the surface area associated with the springs, it is impossible to accurately determine potential sources of contamination that could impact these spring and stream ecosystems and the parkâ¿¿s water supply.

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