7.2 Challenges

Challenges to future development and sustainable use of this aquifer include the following (Sharp et al., 2019a).

• Increased demand for water: The area overlying the aquifer from San Antonio to Austin to Waco is one of the fastest-growing metropolitan areas in the USA (Mace, 2019). The population of this area is predicted to nearly double by 2050 (Potter and Hoque, 2014).
• Effects of urbanization on groundwater systems (Sharp, 2019; Beal et al., 2020): Most of the growth is expected to be urban and suburban, expanding over the recharge and contributing zones. This creates the potential for contamination and changing rates and locations of recharge.Effects of projected climate change (Loáiciga and Schofield, 2019): Projections are for higher temperatures and greater variations in precipitation and, therefore, variation of recharge. Groundwater extraction will have to be adapted to these fluctuations and trends.
• New, emerging types of contaminants (Mahler and Musgrove, 2019): Numerous chemicals are used in our urban society and the Edwards Aquifer, like most karst aquifers, is highly vulnerable to contamination. This raises questions about its use both as a water resource and for the well-being of aquifer/spring-dependent species.
• Accommodating surface-water/groundwater interactions and conduit/matrix flow dynamics in numerical models (Scanlon et al., 2003; Hartmann et al., 2014): Studies of the Edwards Aquifer revealed spatial and temporal variations in aquifer properties and processes. These have long been issues for groundwater models that are important for quantitative understanding the aquifer system.
• Managing aquifers in the context of evolving Texas water law and administrative policies (Hardberger, 2019; Payne et al., 2019): Management practices need to evolve not only as laws and policies evolve but also as our understanding of the aquifer’s endangered species, conduit flow systems, and basic hydrogeology evolves. For instance, intra- and inter-aquifer connections and delineation of recharge areas continue to be topics of research.

The regional water planning groups have identified and recommended several water management strategies (George et al., 2011). These include drilling new wells to meet increased water demand, constructing small dams along streambeds to enhance aquifer recharge, and reallocating supplies from irrigation to municipal users. They have also recommended expanding existing aquifer storage and recovery (ASR) facilities, such as the one that stores water from the Edwards Aquifer in the Carrizo-Wilcox Aquifer in southern Bexar County.

Finally, the adaptation of new technologies will be needed for future characterization, development, and management of the aquifer. These include:

• new ASR projects (Smith et al., 2017; Deeds and Blumberg, 2019) in the underlying Trinity Aquifer and the brackish/saline Edwards Aquifer;
• desalination of brackish water including from the bad-water zone (Mancha and Walker, 2019);
• surface geophysics to characterize the system (Saribudak, 2019);
• tracer testing for define flow paths more accurately (Johnson et al., 2019);
• multiport wells to understand vertical variations in hydraulic properties (Smith and Hunt, 2019); and,
• the use of DNA in characterization of aquifer ecology (Devitt, 2019).

Continued hydrogeologic study, including detailed aquifer vulnerability mapping and flow path delineation, is needed to improve understanding of the Edwards Aquifer and how it can meet the demands of society. Water laws and management policies must be able to adapt to meet these challenges in light of growing knowledge of the Edwards Aquifer and growing demand for water.