VARIABLE RECHARGE AND ITS IMPORTANCE ON ANNUAL WATER AVAILABILITY AND PREDICTING GROUNDWATER LEVELS IN THE HONDO BASIN, SOUTH CENTRAL NEW MEXICO

Recharge in the Hondo Basin occurs as areal recharge through volcanic and other rock outcrops, as infiltration through drainages, and as streamflow losses from various creeks and the Rio Bonito and Rio Hondo. Significant recharge events occur after above average winter precipitation, monsoonal precipitation, or tropical storms. These recharge events can result in groundwater levels rising tens to hundreds of feet in a given year, particularly after extended periods of drought.

During drought periods, surface water supplies are diminished, and many water users are compelled to rely more heavily on groundwater supply wells. Locally, large fluctuations in water levels can adversely affect well yields during periods of prolonged drought, especially for wells that are completed at relatively shallow depths.

Predicting water availability and pumping and non-pumping water levels in the basin is complicated by the dynamic nature of the recharge events. Large recharge events can replenish groundwater storage more rapidly than it can be removed. Groundwater flow models that do not account for dynamic recharge are prone to over predicting long-term drawdowns in the aquifer.