Hydrologic Modeling to Evaluate the Impact of Hydraulic Fracturing on Stream Low Flows: Challenges and Opportunities for a Simulation Study

Hydraulic fracturing (fracking) has been increasing in the eastern part of Ohio for the last few years leading to the increased stress on water resources, particularly on the hydrological low flows. Yet, evaluation of the various impacts of fracking on stream low flows using appropriate tools is still a challenging issue, even though significant progress has been achieved in recent decades to advance the scientific tools and techniques for watershed modeling. While various existing watershed models are capable of addressing water resource issues, each model is unique and the appropriate selection of model depends upon several factors. Therefore, the objective of this study are: (i) to review the current state of art for various available watershed models, including their potential capability, in order to conduct a study related to hydraulic fracking and (ii) to present a case study using best selected model application. Our review indicated that the Soil and Water Assessment Tool (SWAT) is one of the most competent models to assess water issues related to the fracking process at various spatial and temporal scales. The SWAT model incorporating hydraulic fracking is presented in a series of steps: (i) in the first step, the preparation of input data for water use and hydraulic fracking is discussed, including detail calibration and validation of the SWAT model for this study; (ii) in the second step, a case study is presented to evaluate the impact of hydraulic fracking with stream low flows by analyzing the current fracking trend in watershed; (iii) finally, issues and challenges related to data availability and sources of water withdrawal is presented. The SWAT model was calibrated and validated both for daily and monthly scales for 9 various locations of the watershed, with a monthly Nash-Sutcliffe efficiency varying from 0.49 to 0.88 for calibration and from 0.55 to 0.86 for validation. Analysis indicates that fracking practices have nominal impact on annual flows, with modest impact on seven days lows flows, especially at the localized scale, varying in the range of 5.2 to 10.6%.