Evaluation of Geology and Water Well Data Associated with the EPA Hydraulic Fracturing

Retrospective Case Study, Bradford County, PA

Deborah Watkins, P.E. and Thomas Cornuet, P.G. July 24, 2012

12M-0159

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Background Information

Hydrogeology and Historical Water Quality in Bradford Co., PA

Historical and Baseline Groundwater Data Evaluation

Study Well Evaluation

Conclusions

Discussion Topics for Today’s Presentation

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EPA is conducting a retrospective hydraulic fracturing study in Bradford and Susquehanna Cos. - During the first sampling event, EPA collected samples from

37 groundwater locations in October and November of 2011 - A second sampling event was conducted in April 2012; data are

currently being evaluated and are not included in this presentation

A third party contractor collected split samples with the EPA for accessible sample locations; many sample locations could not be accessed because:

- EPA deemed confidential - Property owner would not allow access

Certified commercial laboratories used EPA approved analytical methods

Background Information

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Objective: - Evaluation of analytical data for 15 Bradford Co, PA groundwater

sample locations to determine if they have been impacted by unconventional shale gas development

Scope: - Evaluate hydrogeology and summarize historical water quality data

in Bradford Co.

- Compare EPA Study Well data to historical water quality and available pre-drill/baseline data sets

- Identify exceedances of EPA and PADEP water quality screening criteria for historical and baseline data sets

Presentation: - Provides a brief overview of evaluation including methane

WESTON Evaluation

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Hydrogeology and Historical Water Quality

in Bradford Co, PA

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Bradford County Geology

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Prepared prior to commercial unconventional shale gas development in Bradford Co.

A comprehensive study of the hydrogeology and groundwater quality of Bradford, Potter, and Tioga Cos. conducted by the USGS beginning in 1983

Describes hydrogeologic conceptual model and provides a large and thorough historical/background database of water quality data for unconsolidated stratified drift glacial deposits and the Lock Haven and Catskill bedrock formations

Bradford Co. Hydrogeology and Geochemistry USGS Report (Williams et al, 1998)

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Catskill Formation : 9 EPA split sample locations Lock Haven Formation: 6 EPA split sample locations

Devonian-age interbedded shale, siltstone, and sandstone

Catskill underlies much of the uplands of Bradford Co. and Lock Haven underlies most of the major valleys

Lock Haven water typically considered hard and often naturally high in arsenic, barium, chloride, iron, manganese, sodium, and TDS

Catskill and Lock Haven Formations

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Restricted groundwater flow zones: - Naturally occurring

- Water quality is affected by aquifer formation geochemistry, water residence time, recharge, and depth of occurrence

- Highly mineralized or poor water quality (often Na-Cl or Na-HCO3 water types)

- Often exhibits elevated hydrogen sulfide and methane concentrations

Typically found in major stream and river valleys, mostly in Catskill and Lock Haven bedrock formations

Water quality typically contains barium, chloride, iron, manganese, radium, sodium, strontium, and TDS which commonly exceed screening criteria

Bradford Co. Hydrogeology “Restricted Groundwater Flow Zones”

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Historical and Baseline Groundwater Data Evaluation

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Database No. of Wells* Sample Dates Classifications**

National Water Information System (NWIS) – inorganics

169 1935-2006 Catskill, Lock Haven Formations

National Uranium Resource Evaluation (NURE) - inorganics

160 October 1977 Catskill, Lock Haven Formations

USGS Water Resources Report 68 (Wms 1998) - inorganics

108 1935-1986 Detailed geologic classifications***

Baseline Data (near sample locations) – inorganics and BTEX

3,773 9/17/2009 – 1/10/2012

Divided into Central, Eastern, and

Western Regions

Databases

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*Includes only wells in Bradford Co. in the Catskill and Lock Haven Formations. **Geologic units assigned based on bedrock occurrence; geographic regions used for

retrospective study wells. ***Includes Catskill Formation, Lock Haven Formation, stratified drift (confined

and unconfined), and restricted flow zone.

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Baseline Sampling Program Near Retrospective Wells

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PA Statewide Groundwater Information System (PAGWIS) query cross referenced 83% of NWIS wells

PA Geologic Survey (PGS) spatial query used to classify remaining wells (17% of NWIS; all of NURE)

PGS spatial query used to identify wells potentially within stratified drift (within stratified drift footprint and < 120 feet deep)

If depth not known, defaulted to bedrock formation

Geologic Classification for NURE, NWIS, and Study Wells

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Screening Levels for Select Parameters

Parameter PADEP Act 2* EPA MCL EPA SMCL EPA

Regional**

Aluminum (mg/L) 0.2 15.5

Arsenic (mg/L) 0.01 0.01 0.000045

Chloride (mg/L) 250

Iron (mg/L) 0.3 10.9

Lead (mg/L) 0.005 0.015***

Lithium (mg/L) 0.073 0.031

Manganese (mg/L) 0.3 0.05 0.322

pH (pH units) 6.5-8.5

TDS (mg/L) 500

Turbidity (NTU) 5

Total Coliform (col/100 ml) 1

*Residential use wells < 2,500 mg/l TDS **Screening levels for tap water (chronic) ***Action level

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Parameters Historical USGS Databases

Baseline Database

Aluminum √ √ Arsenic √ √ Barium √ √ Chloride/TDS(1) √ √ Iron √ √ Lead √ √ Lithium Limited data √ Manganese √ √ pH √ √ Sodium √ √ Strontium(1) Limited data √ Turbidity Limited data √

Parameters that Frequently Exceeded Water Quality Screening Criteria in Historical and Regional Baseline Databases (pre 2006)

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(1) In the Restricted Flow Zone

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Region N

umbe

r of S

ampl

es

Num

ber o

f Det

ectio

ns

% o

f Det

ectio

ns

Max

imum

(mg/

L)

Mea

n (m

g/L)

Med

ian

(mg/

L)

Tota

l Num

ber >

3 m

g/L

Tota

l Num

ber >

7 m

g/L

Tota

l Num

ber >

20

mg/

L

Central Region 1965 526 26.8% 43.3 3.27 0.36 233 98 25

Eastern Region 570 157 27.5% 40.7 4.14 0.52 45 30 11

Western Region 1238 504 40.7% 72.1 4.12 0.70 274 125 30

Comparison of Baseline Methane Levels with Screening Levels of 3 mg/L, 7 mg/L, and 20 mg/L

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Study Well Evaluation

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Study well data included pre-drill baseline samples, additional post-drill samples, and EPA retrospective split samples

All study well data were compared to Applicable Water Quality Criteria

- Heavy Metals (As, Ba, Fe, Mn, etc.)

- Inorganics (Cl, TDS, Na, SO4, etc.)

- Organics (VOCs, SVOCs, etc.)

For 12 groundwater locations, post-drill data were compared to regional baseline data for those sample locations

For all 15 groundwater locations, available data were compared to historical USGS databases and regional baseline data

Study Well Parameters Evaluated

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Time Plot of Chloride - Property Owner E (115 ft. Well)

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Time Plot of Iron - Property Owner E (115 ft. Well)

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Time Plot of Manganese - Property Owner E (115 ft. Well)

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Time Plot of Sodium - Property Owner E (115 ft. Well)

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Time Plot of TDS - Property Owner E (115 ft. Well)

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Time Plot of Barium - Property Owner E (115 ft. Well)

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Time Plot of Methane - Property Owner G

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Time Plot of Methane - Property Owner H

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Time Plot of Methane – Property Owner I

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Conclusions

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The 15 groundwater sample locations do not appear to be impacted by natural gas drilling or production activities - For all 15 groundwater sample locations, water quality data was typical of

water quality concentrations in historical USGS databases and regional baseline data

- There are no significant increases in inorganic and other water quality parameters when comparing data from each of the 12 study wells with available baseline data

- There are no significant increases in dissolved methane when comparing data from each of the 12 study wells with available baseline data

- Few organics were detected - None of these are attributable to natural gas production activities or exceeded applicable drinking water standards

Similar to the historical/baseline databases, the15 sample locations contained aluminum, arsenic, barium, chloride, iron, lead, lithium, manganese, pH, sodium, strontium, and turbidity; in several instances, these naturally occurring concentrations exceeded EPA and/or PADEP screening criteria

Conclusions

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Boyer, EW, Swistock, BR, Clark, J, Madden, M and DE Rizzo, 2011. The Impact of Marcellus Gas Drilling on Rural Drinking Water Supplies, Center for Rural Pennsylvania, March 2012.

Focazio, MJ, Welch, AH, Watkins, SA, Helsel, DR and MA Horn, 2000. A Retrospective Analysis on the Occurrence of Arsenic in Ground-Water Resources of the United States and Limitation in Drinking-Water-Supply Characterizations, Water Resources Investigations Report 99-4270, USGS.

Low, DJ. and DG Galeone, 2007. Reconnaissance of Arsenic Concentrations in Ground Water from Bedrock and Unconsolidated Aquifers in Eight Northern-Tier Counties of Pennsylvania, Open-File Report 2006-1376, USGS.

Swistock, BR, Clemens, S and WE Sharpe, 2009. Drinking Water Quality in Rural Pennsylvania and the Effect of Management Practices, Center for Rural Pennsylvania, January 2009.

Watkins, DM, and TS Cornuet, 2012. Evaluation of Geology and Water Well Data Associated with the EPA Hydraulic Fracturing Retrospective Case Study, Bradford County, Pennsylvania, April 2012. http://www.chk.com/News/Articles/Documents/ 20120529_CHK_WestonStudy_BradfordPA.pdf

Williams, JE, Taylor, LE and DJ Low, 1998. Hydrogeology and Groundwater Quality of the Glaciated Valleys of Bradford, Tioga, and Potter Counties, Pennsylvania, PA Geological Survey and USGS, Water Resources Report 68.

Williams, JH, 2010. Evaluation of Well Logs for Determining the Presence of Freshwater, Saltwater and Gas above the Marcellus Shale in Chemung, Tioga, and Broome Counties, New York, USGS, Scientific Investigations Report 2010-5224.

References

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Thank You!

Questions?

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