Owing to the remoteness and vastness of the Grand Canyon area and the complexity of the subsurface system there, several basic aspects of the groundwater hydrologic system remain unknown or uncertain including locations of recharge, direction and timing of flow paths, and locations of discharge. An improved understanding of the groundwater-flow regime is necessary to predict timing and location of potential subsurface transport from source areas (natural or mined ore bodies) to discharge areas (springs, Colorado River and tributaries). Conceptual models of groundwater flow synthesize what is known and hypothesized about the groundwater-flow regime into a framework that contextualizes past and present observations of the hydrologic system. Conceptual models also identify the unknown properties or conditions that contribute to the greatest uncertainties in understanding regional groundwater flow. In this way, conceptual models are used to guide the collection of additional critical data that would be required to develop a numerical groundwater-flow model capable of simulating potential effects of mining within a reasonable limit of uncertainty.
Questions this study could help answer
Findings
Conceptual models of groundwater flow in the Grand Canyon region were developed. Highlights from this work include:1
Gravity surveys for estimating possible width of enhanced porosity zones across structures on the Coconino Plateau were completed. Highlights from this work include:3,4
Ongoing
Task 10: Update regional groundwater model
1
Knight, J.E., and Huntoon, P.W., 2022, Conceptual models of groundwater flow in the Grand Canyon region, Arizona: U.S. Geological Survey Scientific Investigation Report 2022–5037, 51 p., https://doi.org/10.3133/sir20225037.
2 Knight, J.E., and Jones, C.J., 2022, Soil-Water-Balance (SWB) model archive used to simulate potential mean annual recharge in the Grand Canyon region, Arizona: U.S. Geological Survey data release, https://doi.org/10.5066/P9FQ7BSY.
3 Wildermuth, L.M., 2022, Gravity surveys for estimating possible width of enhanced porosity zones across structures on the Coconino Plateau, Coconino County, north-central Arizona: U.S. Geological Survey Scientific Investigations Report 2022–5031, https://doi.org/10.3133/sir20225031
4 Wildermuth, L.M., 2021, Data from “Gravity surveys for estimating possible width of enhanced porosity zones across structures on the Coconino Plateau, Coconino County, north-central Arizonaâ€: U.S. Geological Survey data release, https://doi.org/10.5066/P9ZYHEBB
Jacob Knight
Hydrologist
Arizona Water Science Center
520.670.3336
jknight@usgs.gov
Fred Tillman
Hydrologist
Arizona Water Science Center
520.670.3312
ftillman@usgs.gov
Libby Wildermuth
Hydrologist
U.S. Geological Survey, Arizona Water Science Center
520.670.3335
lwildermuth@usgs.gov