River-Ditch Hydrologic Connections in a Traditionally Irrigated Agricultural Valley in New Mexico

Abstract

Traditional irrigation systems of northern New Mexico are limited by river flow, and thus water scarcity due to drought and population growth menaces their permanence. This study was conducted to examine the relationship between river flow and ditch flow in an agricultural valley of this region to better manage these ancient systems. Daily flow records for the March–November 21–215 periods were analyzed. Positive moderate-to-strong associations were identified with Pearson correlation coefficients. Statistical evidence at a 5% significance level was found in the overall relationships using a model-based approach accounting for serial autocorrelation and heteroscedasticity. The overall change in flow from the main ditches to every unit increase in river flow ranged from .561 to .1397. Covariance analysis indicates that ditch flow at a given point in time is best understood as a function of current river flow and recent-past river-ditch flow. Observations indicated dynamic irrigation management in this valley subject to water availability. The findings can be used to develop water management strategies to best use the limited water resources feeding these systems.