QUANTIFYING THE BASE FLOW CONTRIBUTION OF SOUTHERN UTAH AND NORTHERN ARIZONA TO THE COLORADO RIVER: DEVELOPING A BASIN-WIDE WATER BUDGET ANALYSIS

The flow of the Colorado River is over-allocated, yet while managers vigilantly account for surface water discharge, they pay little attention to groundwater, a major contributing source of water to the river. Past studies conducted on the base flow of the Colorado River have contrasting findings; some rule out the significance of groundwater contribution, while others show groundwater contributing the majority flow to the Colorado River. Part of the challenge in quantifying the base flow component of the river is the remoteness and lack of groundwater data for many sub-basins of the Colorado Plateau. Thus, this study sets out to reveal the importance of base flow and its contribution to surface flow, to better inform future water resource management. To expand the knowledge of Colorado River base flow quantities, new groundwater discharge data were collected and extant data were further analyzed. This study focuses on the understudied sub basins of Southern Utah and Northern Arizona, specifically, the Dirty Devil River, Escalante River, Paria River, Kanab Creek, and Little Colorado River by monitoring springs on plateau escarpments and the base flow of each tributary. Base flow is a significant component of the low flow of the Colorado River. Management is complicated by a patchwork of state and local laws governing the Colorado’s water as well as a lack of extant data within the drainage basin. New studies are recommended to better understand base flow as a majority source of Colorado River water.