Our Water Matters

Waters of Balmorhea

Located in and around the town of Balmorhea, the San Solomon Spring system is an oasis in the middle of an otherwise arid landscape. The system comprises six major springs, including San Solomon, Phantom Lake, Giffin, Saragosa, West Sandia and East Sandia, whose significant flows support the region’s unique wildlife and endangered species. Every year, thousands of visitors swim in these waters with the fish and turtles in the world’s largest spring-fed pool at Balmorhea State Park. 

In a report titled “Hydrologic Conceptualization of San Solomon Springs in the Delaware Basin,” Rebecca Nunu and her colleague, Dr. Ron Green of the Southwest Research Institute, recently released their latest findings on this beloved location. Nunu is a groundwater hydrologist with particular experience and interests in aqueous geochemistry. In explaining her work, she notes that “any spring, river, or groundwater sample has its own ‘geochemical fingerprint.’ This fingerprint can be studied using ions and isotopes, which are natural characteristics of the water. Fingerprints are used to distinguish one water from another with different histories, flow paths, and ages. In my research, I use geochemical fingerprints to determine the sources of water (also known as recharge areas) to springs.” By identifying these sources, it is possible to better protect the flows that supply these springs because the “impact of pumping on spring discharge cannot be determined if source areas to springs are unknown.” According to Nunu, “It is extremely important to constrain recharge areas to springs, especially iconic springs like San Solomon, so that these water resources remain viable for municipal, agricultural, and recreational needs.”

The authors collected water samples from all six springs that contribute to the San Solomon Springs system and subjected them to different forms of analysis. Their findings indicate that there are four flow components that contribute to San Solomon Springs. Nunu explained that these include: “(i) the main component of regional flow through carbonate rocks and upwelling through the Edwards-Trinity Aquifer at the springs; this component originates over 50 miles away in Culberson County and feeds all six springs; (ii) source water that flows through or upwells into the springs which is then added via irrigation return flow to the alluvium; this additional flow component provides recharge to East Sandia and West Sandia Springs; (iii) a separate, local flow component near Saragosa Spring that contributes to its springflow; and (iv) dilute and recent recharge from local precipitation that enters the regional system and discharges at the springs; this component is documented for San Solomon, Giffin, Phantom Lake, and East Sandia, but we are unsure how/if these flow paths feed West Sandia and Saragosa.”

Among the “lessons learned” during this project, the authors note that the “source areas to all six springs are generally west and northwest of the springs” and that “development of water well fields in the source areas located upgradient and west of the springs could be detrimental to the future viability of the springs” with “development of groundwater well fields near the common borders of Culberson, Reeves, and Jeff Davis counties” being of particular concern. Considering that “extraction of groundwater from the source areas that sustain the springs could deplete the springflow if excessive pumping is experienced,” the authors aim to “focus future investigations on areas from which water may be extracted to support growing demands.”

Nunu is hopeful that her research can “play a small role in extending the sustainability and viability of San Solomon Springs. If we know where recharge is coming from, water resource managers can be strategic in protecting these key recharge areas that provide water to the springs. By that same token, pinpointing these areas also provides insight into where development can be least impactful.” According to Nunu, “There is a reason San Solomon Springs is called the ‘Oasis in the Desert.’ This precious gem has bolstered the economy and community for almost a century; the value it has brought to Balmorhea and surrounding areas is immeasurable. My goal is to contribute to our scientific understanding of San Solomon Springs so that the value it brings to Balmorhea continues for generations to come.”

Trey Gerfers is a San Antonio native and serves as general manager of the Presidio County Underground Water Conservation District. He is also chairman of the Presidio County Water Infrastructure Steering Committee and president of the Marfa Parks and Recreation Board. Trey has lived in Marfa since 2013. He can be reached at [email protected]