LIFETIME PROJECTIONS FOR THE HIGH PLAINS AQUIFER IN EAST-CENTRAL NEW MEXICO

Several thousand water level measurements spanning over 50 years, from over a thousand wells, were used to create aquifer lifetime projections for the High Plains Aquifer in Curry and Roosevelt Counties in east-central New Mexico. Projections are based on past water-level decline rates calculated over ten- and twenty-year intervals, for two scenarios. One scenario is the time until total dewatering of the aquifer, and the other is the time until a 30 foot saturated thickness threshold is reached, an estimate of the minimum necessary to sustain high-capacity irrigation wells. Agriculture has been and continues to be the main water use in the region. Assuming future decline rates match those of the past ten to twenty years, the scenarios may be viewed as the usable aquifer lifetime for domestic and low-intensity municipal and industrial uses, and the usable lifetime for large-scale irrigated agriculture.

Projected lifetimes and progressively enlarging areas of zero saturation are shown on maps. Areas of declining water-levels and decreasing aquifer life are more reliable projections than areas where these quantities have increased. There is high confidence in the results in the region surrounding Clovis and Portales. Discrepancies between lifetime projections derived from the past and current conditions are largely due to differences between actual decline rates and those projected into the future from any given time period in the past.

The results match very well across the state line with lifetime projections for the Texas Panhandle region. The effects of groundwater pumping and water-level declines in east-central New Mexico are similar to those observed in the High Plains aquifer across northwest Texas and western Kansas. Much of the region already has insufficient saturated thickness for large-capacity irrigation wells. Even when considering the lifetime of the entire thickness of the aquifer, projected lifetimes across much of the study area are a few tens of years or less. The results of this study have provided additional impetus for the completion of a regional pipeline system linking Ute Reservoir on the Canadian River to Clovis, Portales, and several smaller towns to supply renewable surface water for municipal, commercial, and industrial use.