Impact of hydraulic fracturing induced landscaping change on regional surface water quality in eastern Ohio

Abstract

The impacts of unconventional exploration of oil and gas in eastern Ohio on local landscape and regional surface water quality were studied. The landscaping alteration associated with unconventional exploration resulted in deforestation and increased the impervious and developed land areas on regional scale. It accelerated the movement of water and sediment across the landscape causing a deterioration in surface water quality. A total of ten surface water sampling sites were selected along surface streams in two Ohio counties where hydraulic fracking oil and gas exploration boom was observed in the past decade. Drainage areas were delineated around each sampling site using USGS StreamStats online tool. Land use and land cover were investigated for each delineated drainage area for 2013 and 2019 to study the changes in landscaping patterns. Forest land areas have maintained their steady percentage (with less than ±1% changes) in the majority of the investigated drainage basins since 2013; during the same period, developed land areas have increased by a range of 1.5% to 4.7%. Additionally, landscaping fragmentation was studied using FRAGSTATS to assess the class-level fragmentation of the forested land. Forest patch number within the drainage areas were not observed with significant variations since 2013, which suggest a minor or neglectable deforestation within the region. Surface water sampling were carried out in 2018 and 2019 by collecting surface water samples from two streams and one reservoir. Eleven water quality parameters, including pH, dissolved oxygen, total suspended solids, conductivity, nitrate, Ba, Sr, Ca, and etc., were analyzed onsite and in the lab. Principal Component Analysis showed elevated impacts on water quality in the upstream sampling sites near the unconventional oil and gas well drilling fields. Strong positive correlations (coefficient values close to +0.9) were reported between developed land percentage and metal element concentrations, as well as forestry patch number and turbidity.