| dc.description.abstract | The Eagle Ford (EF) Shale Play has been under intensive development for oil and natural gas production since 2011. This region is a major energy supplier to the United States and worldwide, currently producing over 1.2 million barrels of oil and over 7 billion cubic feet of natural gas per day. However, with the average volume of a single hydraulic fracture job increasing from 17,000 m^3 of water in 2011 to over 37,000 m^3 per treatment in 2017, this new water demand in a water scarce region is a growing concern for south-central Texas. Although the water used in hydraulic fracturing (HF) Texas accounts for less than 1% of total, statewide water consumption, water supplies are distributed unevenly so that many regions of Texas were under water stress prior to the start of fracking. Owing to energy development, the region has experienced extensive declines in water levels in wells of up to 60 meters in areas of the western play since hydraulic fracturing initially commenced in 2009 (Scanlon, 2014). This addition of a new, competing groundwater-using sector has residents concerned about their water security. Their wells, which supply local households, agriculture, municipalities and other industries, tap the same aquifers as the fracking water supply wells. Although water is increasingly transferred long distances in Texas, this transportation is energy consumptive, expensive and politically unpopular. This leads to a competitive advantage, economically and politically, in using local groundwater. Groundwater pumping for hydraulic fracturing tends to occur in spatially concentrated areas over short, but intense time periods. Therefore, conflicts may still arise when drawdown in the water level in wells of neighboring groundwater users are caused by the new pumping activity. Understanding how this short-term, localized pumping for fracking causes the propagation of hydraulic head drawdown throughout the aquifer, thereby impacting other users, is integral in determining the economic impacts of water production to all sectors, such as agriculture, manufacturing, and livestock, to name some. These costs may range from increased pumping costs, replacing damaged pumps, well deepening, or securing and transferring water from new sources. Combining the FracFocus Database, a registry required by the state for producers to report frac chemicals and volumes used at all well sites, with spatial analysis and groundwater modelling, to estimate the effects of transient drawdown can aid in the planning and use of groundwater resources in the region so that all sectors of society and industry can continue production with minimal competition. This study undertakes a straightforward approach to estimate this localized, ephemeral drawdown in the principal aquifers utilized for fracking in the EF using publicly available data. Although groundwater is critical to several sectors of the economy in Texas, there is a gap in knowledge regarding how an aquifer responds to pumping for fracking across a large region- on a local scale This is because, unlike other sectors which pump at relatively steady rates, the pumping at any given location to supply water for nearby fracking is short-lived. By utilizing basic hydrogeologic principles in a transparent method, this study provides a module that predicts the impacts from this short-lived pumping and estimates the pumping cost impacts imposed on other sectors. This study identified key stakeholders impacted by transient drawdown from HF pumping and estimated their additional pumping costs in response to these times. Although drawdown was found to disproportionately impact well owners over the region, it was not always the determining factor in maximum cost impacts. Of the six Groundwater Conservation Districts (GCDs), or Underground Water Conservation District (UWCD), included in this study, wells in Wintergarden and McMullen GCD experienced the greatest drawdown impacts from groundwater pumping to supply HF operations, at approximately 200 and 300 m in the most extreme cases, respectively. However, the greatest additional pumping cost over the study period in these cases were found to impact a small number of well owners residing in McMullen GCD and Gonzales UWCD, totaling approximately $200 each. The framework and results from this module could be added to a transdisciplinary model developed by the Water-Energy-Food (WEF) nexus of professionals who are working to enhance efficiency within all domains. While water need/demand is a rigorously studied subject in the realm of WEF research, the surbsurface geologic and hydraulic constraints are commonly unaccounted for. With this modeling approach we hope to bridge this subsurface knowledge gap and give professionals from all backgrounds a method for assessing groundwater competition between all sectors. | en |
