REGIONAL GROUNDWATER FLOW SYSTEMS EMERGING FROM THE SACRAMENTO MOUNTAINS IN SOUTH-CENTRAL NEW MEXICO

The Sacramento Mountains are dominated by the Sierra Blanca volcanic field to the north and a 70-mile long north-south trending crest with an average elevation of 9,000 ft to the south. The Sacramento Mountain crest is capped with Permian-age sediments of the San Andres Limestone and Yeso Formation, and these sedimentary rocks slope gradually to the east toward the Pecos River about 80 miles away. Water resources of the Sacramento Mountains have been studied extensively over the past several decades, particularly in the developed areas of Ruidoso, Cloudcroft, and Timberon.

Runoff and recharge from the highlands provide significant contributions to surrounding groundwater basins (Pecos Valley, Tularosa Basin, and Salt Basin). The largest streams originate from the Sierra Blanca volcanic field, infiltrate into the Hondo Basin Permian-age limestone, and become groundwater inflow to the Roswell Artesian Basin and eventually streamflow in the Pecos River. Along the western margin of the Sacramento Mountains groundwater flows to the Tularosa Basin via two flow paths and discharges by evaporation at White Sands. From Cloudcroft to Timberon, a regional perched groundwater system is the primary source for springs and perennial streams in the southern Sacramento Mountains and recharge to the Pecos Slope. Runoff from the southern Sacramento Mountains to the Salt Basin recharges the karst-limestone aquifer and becomes part of a regional groundwater flow system controlled by the structural feature known as the Otero Break.

Understanding the regional groundwater flow systems is important when developing conclusions from site-specific studies in the Sacramento Mountains. Several misconceptions about the regional hydrogeologic system have developed over the years, and have resulted in ill-informed water management decisions.