Preliminary Evaluation of Professor C. E. Jacob’s Contributions in the Field of Water Resources of New Mexico

From 1965 till his death on January 30, 1970, Professor C. E. Jacob was chairman of Ground Water Hydrology at New Mexico Institute of Mining and Technology. During the last three decades ground water studies have advanced considerably due to his efforts, original achievements, and philosophies. He is therefore considered by many as one of the founders of modern groundwater hydrology. In this study, taken from unpublished reports and notes, Jacob projects the decline of the water table in the Ogallala aquifer of the Southern High Plains of New Mexico and Texas. After developing approximate analytical solutions for steady and unsteady flow as a function of flow depth, slope, water table configuration, and recharge, numerical results are obtained by digital computation. Representative values of porosity and hydraulic conductivity, required for this purpose, were obtained from an analysis of well data. The author concludes that the hypothetical time required for draining the aquifer, without pumping and without recharge, is from 5,000 to 8,000 years. At pumping rates prevailing during the decade 1951-1960, with natural recharge and discharge operating, the aquifer will be depleted in less than 100 years. Starting with complete exhaustion, the aquifer would recover to within 2 percent of its initial (1938) storage in 5,600 to 5,700 years. If pumpage had ceased at the end of 1958, recovery to within 2 percent of initial storage would probably not exceed 1,500 years. These estimates assume that no local or temporary climatic fluctuations of the water table take place during the time spans considered.

Project No. 3109-133