hf-report20121214

Study of the Potential Impacts of Hydraulic Fracturing
on Drinking Water Resources: Progress Report December 2012
Water Resources. The average precipitation in Bradford County is 33 inches per year. Summer
storms produce about half of this precipitation; the remainder of the precipitation, and much of the
ground water recharge, occurs during winter and spring (PADEP, 2012). Surface water in the study
area is part of the Upper Susquehanna River Basin. The main branches of the Susquehanna River
flow to the south, while the smaller tributaries are constrained by the northeast-southwest
orientation of the Appalachian Mountains. Stratified drift aquifers and the Loch Haven and Catskill
bedrock formations serve as primary ground water drinking sources in the study area. Glacial till is
also tapped as a drinking water source at some locations (Williams et al., 1998). These resources
provide water for domestic use, municipal water, manufacturing, irrigation, and hydraulic
fracturing.
The stratified drift aquifers in Bradford County occur as either confined or unconfined aquifers. The
confined aquifers in the study area are composed of sand and gravel deposits of glacial, ice-contact
origin and are typically buried by pro-glacial lake deposits; the unconfined aquifers are composed
of sand and gravel deposited by glacial outwash or melt-waters. Depth to ground water varies
throughout Bradford County and ranged from 1 to 300 feet for the wells sampled in the study. The
median specific capacity of confined stratified drift aquifers is 11 gallons per minute per foot; the
median specific capacity of unconfined stratified drift aquifers is 24 gallons per minute per foot
(Williams et al., 1998). The specific capacity of wells completed in till or bedrock is typically 10
times lower than in the stratified drift aquifers.
Ground water in the study area is generally of two types: a calcium bicarbonate type in zones of
unconfined flow and a sodium chloride type in zones of confined flow. Data from Williams et al.
(1998) show that water wells completed in zones with more confined flow contain higher TDS
(median concentration of 830 milligrams per liter), dissolved barium (median concentration of 2.0
milligrams per liter), and dissolved chloride (median concentration of 349 milligrams per liter)
compared to zones with unconfined flow. This is also true for concentrations of iron and manganese
in the study area. Table 53 presents a summary of median and maximum concentrations of
inorganic parameters in Bradford County ground water, based on the study conducted by Williams
et al. (1998).
Table 53. Background (pre-drill) water quality data for ground water wells in Bradford County, Pennsylvania (Williams
et al., 1998).
Parameter
Median Concentration
(milligrams per liter)
Pre - Drill Data
Maximum Concentration
(milligrams per liter)
Number of
Samples
Arsenic 0.009 0.072 16
Barium 0.175 98 50
Chloride 11 3,500 93
Iron 0.320 15.9 95
Manganese 0.120 1.03 77
TDS 246 6,100 102
pH (pH units) 7.25 8.8 102
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