Statistical Relationships Between Groundwater, Climatic, and Economic Factors in Southeastern Arizona

Abstract

Hydrologic, climatic, and economic factors interact in complex ways to influence groundwater conditions. These relationships can be difficult to measure and simulate but are important to understand for long-term water resource planning purposes. Knowledge of factors linked with groundwater levels in a basin can help water managers develop targeted and effective strategies to incentivize desired water use outcomes. Existing studies focus on areas of large-scale irrigated agriculture or highly urbanized areas, and utilize data on groundwater use. In much of rural Arizona, and much of the world, groundwater use data is not available and difficult to collect. The goal of this study is to instead explore responsiveness of groundwater level data to economic signals in rural areas. We focus on two rural areas in southeastern Arizona, along the upper portion of the Santa Cruz and San Pedro watersheds. Using an econometric approach, we employ a fixed effects regression model with a groundwater level metric as the dependent variable, and climatic and economic factors as explanatory variables. We find well counts, housing units, per capita income, and planted acreage have statistically significant relationships to groundwater levels in these rural areas at the annual scale. We also highlight some of the challenges of data availability when performing econometric studies related to groundwater in rural areas. Despite these challenges, this unique approach could be helpful to understanding influences on groundwater conditions in areas of the world where water use data is unavailable.