A geothermal resource data base: New Mexico

Mesilla/Conejos-Médanos Basin: U.S.-Mexico Transboundary Water Resources

“…[m 2 , square meters; m/day, meters per day; m/m, meters per meter; m 3 /day, cubic meters per day; hm 3 Geothermal waters that are associated with the region's known geothermal systems upwell from depths of greater than 1 km to recharge shallower groundwater supplies. The brackish (1800 to more than 4800 milligrams per liter (mg/L) DS concentrations) waters are evidence of deep groundwater circulation and ascend in the northernmost portion of the Basin at Radium Springs, in the west near the East Potrillo Mountains, and along the East Bench along the eastern border zone of the Mesilla Valley [83,84]. Discharge estimates for the East Bench range from 0.01 to 19 hm 3 /year and between 0.5 and 1.6 hm 3 /year for the East Potrillo Mountains [83][84][85].…”

“…The brackish (1800 to more than 4800 milligrams per liter (mg/L) DS concentrations) waters are evidence of deep groundwater circulation and ascend in the northernmost portion of the Basin at Radium Springs, in the west near the East Potrillo Mountains, and along the East Bench along the eastern border zone of the Mesilla Valley [83,84]. Discharge estimates for the East Bench range from 0.01 to 19 hm 3 /year and between 0.5 and 1.6 hm 3 /year for the East Potrillo Mountains [83][84][85]. No estimates are available for the Radium Springs system [83].…”

“…This condition is evident in several nested wells in the Mesilla Valley and in two paired deep wells on the West Mesa (Figure 2). Locations where upward vertical gradients are persistent and throughout the water column [5,17] are near the U.S./Mexico border, where groundwater gradients (Figure 5) indicate a confluence of horizontal flow directions where several faults occur (Figure 2) [60,84]. The location of the upward gradients may also result from the thinning aquifer (Figure 3), in contrast to farther south, where vertical gradients are neutral and the aquifer thickness remains relatively uniform (Figure 3) [17,72].…”

“…Groundwater temperatures generally increase with depth at a rate of about 35 • C per km in the Basin but can be affected by groundwater advection in places [98]. For example, temperature gradients are much higher within known geothermal areas, where waters ascend from depths of over 1 km (e.g., East Bench, East Potrillo Mountains, and Radium Springs) (Figure 1) [83,84]. Localized groundwater upflow zones within these geothermal areas can have temperatures exceeding 55 • C, and geothermal waters at Radium Springs are close to 100 • C [83,99].…”

Salinity Contributions from Geothermal Waters to the Rio Grande and Shallow Aquifer System in the Transboundary Mesilla (United States)/Conejos-Médanos (Mexico) Basin

“…Salinity contributions from geothermal waters, meaning salinity from waters of naturally elevated temperature, have not been studied as extensively in this region as some of the other salinity mechanisms and are the focus of this research. Three prominent geothermal systems have been identified in the study area, where previous research has largely focused on geothermal energy production and development rather than salinity contributions [12][13][14][15][16]. Upwelling waters associated with these geothermal systems have naturally elevated salinities ranging from about 1800 to 4800 mg/L and therefore have the potential to degrade surrounding freshwater supplies [15][16][17].…”