TIER 1 DRAFT ENVIRONMENTAL IMPACT STATEMENT

Geologic 

Resources

7.7

7. Affected Environment, Environmental Consequences, and Mitigation Strategies

Tier 1 Draft EIS Page | 7.7-1

7.7 GEOLOGIC RESOURCES

7.7.1 Introduction

Understanding geologic features can influence design and construction practices because certain 

geologic features are considered resources while others are considered potential hazards (see 

Section 7.7.1.1). 

This chapter identifies geologic resources that are intersected by the Representative Routes of the 

Tier 1 Draft Environmental Impact Statement (Tier 1 Draft EIS) Action Alternatives. Appendix E, 

Section E.07, provides both the effects-assessment methodology that was used to evaluate geologic 

resources and hazards and the data supporting the analysis.

7.7.1.1 Definition of Resource

Geologic resources and hazards are defined below and include descriptions of the different types of 

geologic resources and hazards assessed in this Tier 1 Draft EIS:

4 Geologic Resourcesinclude sole source aquifers, naturally occurring minerals, and active/inactive 

mines.

1

– Sole source aquifers: Sole source aquifers are aquifers that supply at least 50 percent of the 

drinking water consumed in the area overlying the aquifer. The U.S. Environmental Protection 

Agency (EPA) regulates disturbances to these sole source aquifers. 

– Mineral resources: Construction of tunnels in areas with known mineral resources may 

require additional studies to evaluate potentially unstable foundations in mined areas or 

potential subsurface constraints such as abandoned or filled mines or tunnels. There may also 

be impacts to active mining or mineral operations that could require compensation to the 

owner(s) of those operations.

4 Geologic Hazards include seismic hazards (active geologic faults or fractures), karst terrain 

(characterized by sinkholes and caves), unstable soils (landslide susceptibility), naturally occurring 

asbestos, and acid producing soils.

– Seismic hazards: Seismic hazards are typically associated with a geologic fault or fracture.

Areas requiring tunnels or bridges may be especially susceptible to such hazards.

– Karst terrain: Areas with karst terrain are susceptible to sinkholes, groundwater 

contamination, and erosion resulting from water drainage.

– Landslide susceptibility: Construction and tunneling in areas that are susceptible to landslides 

may be challenging from an engineering perspective in order to incorporate design principles 

that minimize hazards to workers during construction and the future utilization of the corridor 

itself.

 

1 Inactive mines were not included in the analysis because of the lack of complete and timely data. The Tier 2 

process would perform additional analysis.
7.7. Geologic Resources

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– Naturally occurring asbestos: Without the proper protection and engineering controls,

excavating or tunneling in areas containing naturally occurring asbestos formations can be 

dangerous to the health and safety of site workers. Excavating in areas with naturally 

occurring asbestos is subject to U.S. Department of Labor–Occupational Safety and Health 

Administration (OSHA) regulations to minimize exposure to workers. Excavating in areas with 

naturally occurring asbestos typically requires engineering controls, site worker training and 

awareness, site monitoring, and regulatory interaction and reporting, which can increase the 

construction cost and duration in these areas.

– Acid producing soils: Certain unconsolidated soils and sediments in the Atlantic coastal plain 

could contain minerals that may produce enough acidity to degrade concrete and steel 

structures to the point of failure. Surface water run-off containing acidic discharges could also 

degrade the environment. Locating and identifying acid producing soils is necessary to 

properly design structures and to mitigate against any potential negative consequences 

during the construction process.

Appendix E, Section E.07, provides more-detailed definitions of geologic resources and hazards. 

7.7.1.2 Effects-Assessment Methodology

The Federal Railroad Administration (FRA) developed an effects-assessment methodology for each of 

the resources examined in this Tier 1 Draft EIS. The effects-assessment methodology defines each 

resource and data source, and explains how the Affected Environment was defined and established 

and how the effects on each resource were evaluated and reported. Table 7.7-1 summarizes key 

factors associated with the effects-assessment methodology for examining effects on geologic 

resources and construction constraints caused by geologic hazards.

Table 7.7-1: Effects-Assessment Methodology Summary: Geologic Resources

Resource

Affected 

Environment Type of Assessment Outcome

Geologic 

Resources

3,000-footwide swath

centered along 

Representative 

Route for each 

Action 

Alternative

§ Presence/Absence: Seismic hazards; sole source 

aquifers; karst terrain; naturally occurring 

asbestos; acid producing soils; landslide 

susceptibility

§ Number of Resources: mineral resources: 

producer, occurrence, plant, inactive producer;*

active mines

Identification of the 

presence of geologic 

resources within the 

Affected Environment

and intersected by the 

Representative Routes.

Source: NEC FUTURE Geologic Resources Effects-Assessment Methodology, Appendix E, Section E.07, 2014

* A plant is a facility that processes raw minerals. A producer, either past or present, is a location where a raw mineral is/was 

produced from (e.g., mine, ore bank, pit)

7.7.2 Resource Overview

The southern portion of the Study Area can be geographically characterized by a mix of low-lying 

areas and gentle changes in topography that transition to higher elevations and sharper changes in 

topography in the north. Notable geologic features in the Study Area include the Chesapeake Bay, 

Long Island Sound, and Appalachian Mountains.
7. Affected Environment, Environmental Consequences, and Mitigation Strategies

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With regard to Environmental Consequences, the Action Alternatives may affect geologic resources, 

but geologic hazards may also affect decisions about the location, design, and construction methods 

for any of the Action Alternatives. Effects would depend on the type of geologic resource or hazard 

present and construction method proposed. Depending on construction type, effects would be 

generally associated with earth-moving construction activities such as drilling, boring, and earth 

removal. For example, tunneling would have a higher likelihood of affecting a geologic feature (such 

as sole source aquifers) than at-grade construction activities. However, given the level of detail 

regarding construction activities and alignments being analyzed for this Tier 1 Draft EIS and 

generalized locations of the geologic resources and hazards, the FRA did not identify site-specific 

effects. 

Although different types of geologic resources and hazards (as defined in Section 7.7.1.1) are present 

within the Affected Environment and within the footprint of the Action Alternatives, only certain 

resources and hazards are highlighted in this section. The resources and hazards highlighted may 

present significant regulatory challenges, potential associated safety issues, and engineering costs 

related to construction, or other potential geographic conflicts that would need to be assessed.

Appendix E, Section E.07, includes an inventory of the larger set of geologic features (listed by state 

and county) within the Affected Environment and that are intersected by the existing NEC and Action 

Alternatives.

7.7.3 Affected Environment 

The FRA analyzed the Affected Environment for the existing Northeast Corridor and each Action 

Alternative for the existence and/or occurrence of geologic resources and geologic hazards. 

Appendix E, Section E.07, notes these geologic features by state and county.

Notable resources within the Affected Environment include sole source aquifers, naturally occurring 

asbestos, karst terrain, and soils associated with moderate or high landslide susceptibility. The former 

two resources are notable to highlight within the Affected Environment because they may represent 

significant regulatory challenges. The latter two resources are notable to highlight within the Affected 

Environment due to potential associated safety issues and engineering costs related to construction.

Sole source aquiferssupply drinking water to many areas within the Affected Environment and occur

in the following locations:

4 States of Delaware and Pennsylvania

4 Mercer and Middlesex Counties, NJ 

4 Queens and Kings Counties, NY 

4 New London County, CT 

4 Washington and Kent Counties, RI

4 Bristol and Norfolk Counties, MA

Existing NEC and all Action Alternatives

4 Nassau and Suffolk Counties, NY

Alternative 3

(New York City to Hartford via Long 

Island)
7.7. Geologic Resources

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Naturally occurring asbestos exists in soils within the Affected Environments of the existing NEC and 

all Action Alternatives in Baltimore City, MD, and Hudson County, NJ. 

Karst terrain occurs within the Affected Environment in Baltimore and Harford Counties, MD, within 

Alternative 3.

Soils associated with moderate or high landslide susceptibility occur within the Affected 

Environments of the existing NEC and all Action Alternatives in Washington, D.C., and Prince 

George’s, Anne Arundel, Howard, and Baltimore Counties, MD. Additionally, these soils occur within 

the Affected Environment of Alternatives 2 and 3 in Hartford County, CT, and Suffolk County, NY, in 

the New York City to Hartford via Long Island route option of Alternative 3.

7.7.4 Environmental Consequences

This analysis highlights where certain geologic resources and hazards—including sole source aquifers, 

soils associated with moderate and high landslide susceptibility, naturally occurring asbestos, and 

karst terrain—intersect with the existing NEC and the Representative Route for each Action 

Alternative. These four geologic resources and hazards may present significant regulatory challenges 

or potential associated safety issues and engineering costs related to construction. Appendix E, 

Section E.07, includes an inventory of a larger set of geologic features (listed by state and county) 

that are intersected by the existing NEC and Action Alternatives.

Table 7.7-2 and Table 7.7-3 present areas where the Representative Routes intersect sole source 

aquifers and soils associated with moderate or high landslide susceptibility. The potential exists for 

the existing NEC and all the Action Alternatives to encounter these geologic resources and hazards. 

In addition, karst terrain exists only in Harford County, MD, within the Representative Route of 

Alternative 3, and no soils that contain naturally occurring asbestos exist within the existing NEC or 

Representative Routes of any of the Action Alternatives.

Table 7.7-2: Environmental Consequences: Representative Route – Geologic Resources

Geography

Geologic 

Resource/Hazard Existing NEC Alternative 1* Alternative 2* Alternative 3*

D.C. Landslide Susceptibility X X X X

MD Landslide Susceptibility X X X X

DE Sole Source Aquifer X X X X

PA Sole Source Aquifer X X X X

NJ Sole Source Aquifer X X X X

NY Sole Source Aquifer X X X X

CT Sole Source Aquifer X X X X

Landslide Susceptibility X X X

RI Sole Source Aquifer X X X X

MA Sole Source Aquifer X X X X

Source: NEC FUTURE team, 2015

X = Presence of resource and potential effects within the Representative Route; effects would be subject to Tier 2 analysis.

Blank cell = No presence and no effects identified for listed geologic resource or hazard for specified alternative.

* All Action Alternatives assume improvements to the existing NEC; therefore, the data presented include the Environmental 

Consequences inclusive of improvements to the existing NEC and any new route option or off-corridor route associated with 

each Action Alternative.
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Table 7.7-3: Environmental Consequences: Representative Route of Alternative 3 Route 

Options – Geologic Resources

Geography

Geologic 

Resource/Hazard

Existing 

NEC

Alternative 3

D.C. to 

NYC

New York City to 

Hartford

Hartford to Boston

via Central 

Connecticut

via Long 

Island 

via 

Providence

via 

Worcester

D.C. Landslide Susceptibility X X — — — —

MD Landslide Susceptibility X X — — — —

DE Sole Source Aquifer X X — — — —

PA Sole Source Aquifer X X — — — —

NJ Sole Source Aquifer X X — — — —

NY Sole Source Aquifer X — X X — —

CT

Sole Source Aquifer X — X X X X

Landslide Susceptibility X — X X X X

RI Sole Source Aquifer X — — — X X

MA Sole Source Aquifer X — — — X X

Source: NEC FUTURE team, 2015

X = Presence of resource and potential effects within the Representative Route; effects would be subject to Tier 2 analysis.

Blank cell = No presence and no effects identified for listed geologic resource or hazard for specified alternative.

— = Not applicable within that alternative/route option.

7.7.4.1 Stations

New stations would likely affect geologic resources or encounter geologic hazards more than 

modified stations. Table 7.7-4 presents proposed new stations or modified existing stations that 

geographically coincide with resources and hazards that may present significant regulatory 

challenges, potential associated safety issues, and engineering costs related to construction, or other 

potential geographic conflicts that would need to be assessed. The resources include sole source 

aquifers and mineral resources. The hazards include soils associated with moderate or high incidence 

of landslide occurrences, naturally occurring asbestos, and karst terrain. As shown in Table 7.7-4, no 

effects associated with naturally occurring asbestos or karst terrain would occur as a result of new 

stations or modifications to existing stations.

7.7.5 Context Area 

Conditions within the Context Area are similar to those described for the Affected Environment. In 

addition to the geologic resources and hazards described in Section 7.7.3, a sole source aquifer exists 

in Fairfield County, CT, only in the Context Area of Alternative 3 (New York City to Hartford via Central 

Connecticut route option). Soils potentially containing naturally occurring asbestos also exist within 

the Context Area in Delaware, Philadelphia, and Bucks Counties in Pennsylvania.
7.7. Geologic Resources

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Table 7.7-4: Environmental Consequences: Stations – Geologic Resources

State County

Station 

ID/Type Station Name

Geologic 

Resource/Hazard Alt. 1 Alt. 2 Alt. 3

MD

Anne 

Arundel

5/Existing Odenton Landslide Susceptibility X X X

6/New BWI Airport Landslide Susceptibility 

Mineral Resources X

Baltimore 

City 11/New Baltimore Downtown Mineral Resources X

DE New Castle 28/New Edgemoor Sole Source Aquifer X X X

PA

Delaware 32/Existing Chester

Sole Source Aquifer

X X X

34/New Baldwin X X X

Philadelphia

44/New Philadelphia Airport X X

46/New Philadelphia Market 

East X

Bucks 53/Existing Cornwells Heights X X X

NJ Mercer 61/Existing Princeton Junction Sole Source Aquifer X X X

NY

Queens 144/Existing Jamaica

Sole Source Aquifer

X

145/New Jamaica H.S. X

Nassau 146/New Nassau Hub X

Suffolk 148/New Suffolk Hub X

149/Existing Ronkonkoma X

CT Hartford 164/New Hartford (New) Landslide Susceptibility X X

RI Washington 123/Existing Westerly Sole Source Aquifer X X X

Source: NEC FUTURE team, 2015

X = Presence of resource and potential effects within the Representative Route; potential effects subject to Tier 2 analysis.

Blank cell = No presence and no effects identified for listed geologic resource or hazard for specified alternative.

H.S. = high speed
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7.7.6 Potential Mitigation Strategies 

Programmatic mitigation measures could include design considerations, alternative construction 

methods, and slope/soil stabilization measures. Depending on the affected geologic resource, specific 

mitigation measures could include the following:

4 Sole Source Aquifers – Develop Stormwater Pollution Prevention Plan and/or Spill Pollution 

Prevention Plan.

4 Landslide Susceptibility – Use engineered slopes and fill material.

4 Seismic hazards – Mitigate seismic motion through design consideration and enforcement of 

seismic building codes during construction.

4 Acid Producing Soils – Use engineered fill material, add soil amendments to correct acidity of soil.

4 Naturally Occurring Asbestos – Follow OSHA regulations to minimize exposure to workers;

engineering controls, site worker training and awareness, site monitoring, and regulatory 

interaction and reporting.

4 Karst terrain – Karst terrain assessment, design consideration, construction engineering.

4 Mineral resources – Provide/construct alternative access to physically avoid the mineral 

resource.

7.7.7 Subsequent Tier 2 Analysis 

Tier 2 analyses would determine the presence and type of geologic resources to a higher level of 

detail, as well as assess the need for and identify mitigation measures and design and construction 

methods that would avoid or minimize effects. Coordination with the EPA and the U.S. Geological 

Survey may be warranted when more site-specific effects are known.