Current and Future Water Demand of the Texas Oil and Gas and Mining Sectors and Potential Impact on Aquifers

The Texas mining industry, in addition to oil and gas, produces mostly lignite coal and aggregates (sand and gravel and crushed rocks). Operations always involve water, either as an aid in extraction or as a byproduct. A recent study compiled current water use in the various sectors of the mining industry and made projections for the next 50 years. The study concerned the upstream segment of the oil and gas industry (drilling, hydraulic fracturing, waterfloods), the aggregate industry (washing included but no further processing), the coal industry (pit dewatering and aquifer depressurizing), and other substances mined in a fashion similar to that of aggregates (industrial sand, lime, etc.), as well as through solution mining. Overall, in 2008, the industry used ~160 thousand acre-ft (kAF), including 35 kAF for hydraulic fracturing and ~21 kAF for other purposes in the oil and gas industry. The coal and aggregate industries used 20 kAF and 71 kAF, respectively. Mining of industrial sand dominates the remainder. Approximately three-fourths of the water used is consumed, and approximately two-thirds of the water consumed is groundwater. Projection estimates call for a steady increase in water use in coal and aggregate production and a sharp increase, followed by a slow decrease, in the oil and gas industry. Operators favor surface water when it is plentiful, but groundwater is a more drought-proof source. Because the various segments of the energy industry are spread out across the state, they impact many different aquifers. Mining withdrawals represent only ~1% of total withdrawals at the state level but can be much higher locally and compete with other uses, such as municipal usage or irrigation.