Notes From Underground
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An update on source water protection and underground pollution control from the
U.S. Environmental Protection Agency (EPA) Pacific Southwest/Region 9, serving Arizona,
California, Hawaii, Nevada, Native American Tribes in the Region, and the Pacific Islands.
Fall 2002
EPA 909-N-02-003
IN THIS ISSUE:
Bentonite Plugging.
Sole Source Aquifer
Program
Class V Cesspools and
Motor Vehicle Waste
Disposal Wells Banned, but
What About Other Types...2
Tribal Corner 3
Upcoming
Conferences 4
NEW FROM EPA:
EPA's Water Office has a new look
on its Website. Go to
www.epa.gov/safewater to learn
more about how EPA, with its
many partners, protects public
health by ensuring safe drinking
water and protecting ground
water.
Protecting Drinking Water
Through Underground
Injection Control
Bentonite* Plugging - "Showing" Soon at a Well Near You
The full spectrum of underground injection control (UIC) well responsibilities includes
planning, drilling, construction, operation and maintenance, and lastly, plugging. When
considering environmental standards and concerns, the plugging phase is the most critical.
When the useful life of an injection well is over, a well owner/operator is required by Federal
regulation to properly plug and abandon the well. It should be plugged in a manner that will
be permanent and does not allow fluid movement between geologic formations. Properly
plugging an underground injection well is a concern shared by industrial groups and
regulatory agencies. A well is defined as any bored, drilled or a driven shaft whose depth is
greater than the largest surface dimension; or, a dug hole whose depth is greater than the
largest surface dimension, or, an improved sinkhole; or, a subsurface fluid distribution
system.
Conventional plugging for the deeper classes of UIC wells usually involves a rig and crew,
cementing equipment and other incidentals. The entire process can last several days and
the expense can add up in areas with many wells. Any cost-saving measures that are
environmentally sound have obvious benefits. While new techniques are few, there is one
that well owners/operators should know about. It uses compressed bentonite - in pellet form.
The bentonite pellets, which are shaped and sized like charcoal barbecue briquettes, are
dropped to free-fall down the well to form the bottom of the plug. A predetermined amount
of pellets is inserted into the well to settle and stack up to a point where the top of the plug
is formed. With time, the pellets hydrate and swell through hydration pressure to eliminate
any free space within the finished plug. A bridge plug or a similar device is placed in the well
for the next plug, followed by a prescribed amount of pellets, and so on until the last plug is
set at the top of the hole.
This method of using compressed bentonite has undergone numerous tests, including
efforts to assess its properties, behavior and performance under differing environmental
conditions. While these details are beyond the scope of this article, here is a partial list of
the advantages, disadvantages, limitations and possible applications.
Advantages:
Flexibility and adaptability to accommodate disturbances with minimal or no compromise.
Low permeability and good chemical stability.
Provides an economical alternative to other plugging options.
Plugs can be easily drilled for well re-entry.
"Protecting Drinking Water
Through Underground Injection
Control," is a pocket-sized guide
to the five classes of injection
wells and a list of regional/state
UIC contacts. For free copies,
contact Tony Capinpin at
capinpin.tony@epa.gov.
* Disclaimer: Any mention of trade names, products or
services does not constitute endorsement by EPA or
the federal government. Information presented is for
compliance assistance only. Each situation is unique.
Site-specific determinations should be made by qualified
professionals. All wells owners/operators must comply
withthefederalregulations40CFR§144.12and§146.10
when plugging and abandoning wells.
(continued on page 4)
Bentonite pellets being used to set a plug in a well.
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Sole Source Aquifer Program in EPA,
Pacific Southwest
Sole Source Aquifer designations are used by communities
to help prevent contamination of ground water from federally
funded projects. They also can serve as a mechanism to
increase public awareness of ground water protection. EPA's
Sole Source Aquifer (SSA) Program was established under
Section 1424(e) of the Safe Drinking Water Act (SDWA).
Sole Source Aquifer Designation. A sole source aquifer is
an underground water supply designated by the EPA as the
"sole or principal" source of drinking water for a specific area.
In order to be designated a sole source, an aquifer must
supply more than 50% of a community's drinking water and
it must be the only available local or regional source of
drinking water.
Federal regulations (40 CFR Part 149) to carry out the sole
source aquifer program were first proposed in 1977 for the
Edwards Underground reservoir in San Antonio, Texas.
These regulations guided EPA in subsequent SSA
designations. At present, there are nine sole source aquifers
in EPA's Pacific Southwest/Region 9 (see map below).
Geographic locations approximate.
Scotts Valle1
Campo-Cottonwoc|d_
Santa Cruz - Av
co Bisbee
Molokai
o
(Guam (not pictured)
A sole source aquifer designation can be requested by
submitting a petition to EPA. A petition must contain sufficient
technical information for EPA to evaluate whether the aquifer
meets criteria for designation. A petition can be submitted
by any individual, corporation, association, federal, state or
local agency. The SSA Designation Petitioner Guidance
document provides more information about preparing and
submitting a petition, and is available from EPA Regional
Offices.
The determination of aquifer boundaries can be challenging.
These boundaries should include the surface area above the
aquifer and its recharge area. Some sole source aquifers are
extremely large and can cross state lines. For example, the
Eastern Snake River Aquifer covers 10,000 square miles and
includes portions of Idaho, Nevada, Utah and Wyoming.
Use of a Sole Source Aquifer Designation. A SSA
designation provides an additional level of federal protection
that benefits all users of the aquifer, not just the petitioners.
According to the Safe Drinking Water Act (SDWA), projects
that receive federal financial assistance are subject to EPA
review and approval. The SSA program requires that all
development projects receiving federal financial support (loans
or grants) that are located in designated SSA areas must be
assessed by EPA for their potential to degrade ground water
quality in the SSA.
If a project does have such potential, it must be modified, or
federal funding can be denied. EPA's Pacific Southwest/
Region 9 reviews approximately 50 such projects each year.
Projects have included slaughter houses, amusement parks,
and bridge replacements.
When area-wide drinking water source protection is the goal,
sole source aquifer status is an important factor in planning.
Partnerships builtduring the petition and project reviewprocess
can be utilized in local team-building efforts which are a crucial
part of protection planning.
For more information. Contact Hillary Hecht, EPA Pacific
Southwest/Region 9 Ground Water Office at 415-972-3530 or
email hecht.hillary@epa.gov or visit www.epa.gov/safewater/
ssanp.html.
Class V Cesspools and Motor Vehicle
Waste Disposal Wells Banned, but What
About OtherTypes?
EPA has determined that existing Federal Underground
Injection Control (UIC) regulations are adequate to prevent
certain Class V (Five) wells from endangering underground
sources of drinking water, so no new rulemaking is necessary
at this time. Examples include industrial, storm water,
agricultural drainage and large-capacity septic systems. The
Federal requirements do not preclude a State or local
government from establishing more stringent requirements.
EPA published its Final Determination on the Class V Rule in
the Federal Register, June 7, 2002 (www.access.gpo.gov/
(continued on page 3)
U.S. EPA Pacific Southwest/Region 9 Notes From Underground, Fall 2002, Page 2
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Continued from page 2: No new Class V regulations
su_docs/fedreg/frcont02.html). This determination addresses
all Class V well types not included in the December 7, 1999
rule affecting large-capacity cesspools and motor vehicle
waste disposal wells.
EPA's UIC program will continue to collect inventory
information, conduct inspections, educate facility owners and
operators on their obligations under the UIC regulations, and
assess injection practices. The outcome of any given
assessment may be authorization by rule, a request for
additional information, requiring the facility to apply for a
general, area, or site specific permit, or requiring closure of a
well. This determination does not preclude future action under
EPA's UIC authority if the agency determines that additional
regulatory action is needed.
For general information about the UIC program, go to
www.epa.gov/safewater/uic, contact the Safe Drinking Water
Act Hotline at 1-800-426-4791, or email Hotline-
sdwa@epa.gov. For specific to EPA's Pacific Southwest/
Region 9, contact Elizabeth Janes at 415-972-3537, or email:
janes.elizabeth @ epa.gov.
Examples of Worst Management
Practices for Class V wells.
Wrong: Used oil runs
into Class V shallow
disposal well,
accelerated by steam
cleaner and soap.
Below: Dirty parts leak oil, fuel, and metals onto sandy soil, in an
area exposed to storm water. Soil and ground water contamination
is the likely result.
Tribal
Corner
Who Regulates UIC Wells on Tribal Lands? The 1986
Safe Drinking Water Act (SDWA) enables federally-recognized
tribes to assume primacy for the UIC program. For tribes that
do not obtain UIC primacy, EPA directly carries out the
program and regulates these types of wells.
What is Underground Injection? Underground injection is
the technology of placing fluids underground through wells or
other similar conveyance systems. The fluids may be water,
wastewater or water mixed with chemicals.
Goal of the UIC Program: To protect public health by
preventing injection wells from contaminating Underground
Sources of Drinking Water.
Common Types of Wells on Tribal Lands in EPA's Pacific
Southwest/Region 9: Class V wells are the most common
wells located on tribal lands in our region. Most of these Class
V wells are shallow large-capacity (serves at least 20 persons)
on-site wastewater disposal systems. In general, Class V
wells include drywells, cesspools, and septic systems with
tanks and leach fields. Class V wells can also be deep
injection wells.
Federal Minimum Requirements for UIC wells. EPA's
requirements cover the siting, construction, operation,
maintenance, monitoring, testing, and closure of injection
wells. Fluids cannot be injected if they may cause a public
water system to violate drinking water standards, endanger
an underg round sourceof drinking water or otherwise adversely
affect public health. All operational injection wells require
authorization under general rules or specific permit. Inventory
information must be submitted to EPA's Ground Water Office
for UIC wells on tribal lands. Inventory information includes:
1) Facility name and location; 2) Name and address of legal
contact; 3) Ownership of property; 4) Nature and type of
injection well; 5) Operating status of injection well.
For more information or to obtain inventory forms.
Contact Lisa Penaska, Ground Water Office Tribal Contact,
at 415-972-3544 or visit www.epa.gov/safewater/uic.html.
***********
Source Water Assessment and Protection
The Water Education Foundation, through a grant from EPA,
produced a source water assessment and protection guidance
document, Protecting Drinking Water: A Workbook for Tribes
(July2000). Copies are available on request or at www.water-
ed.org/specialprojects.asp.
U.S. EPA Pacific Southwest/Region 9 Notes From Underground, Fall 2002, Page 3
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Continued from Page 1 - Bentonite Plugging
Disadvantages:
Cannot be set by pumping or be "squeezed", they can only
be placed.
Placement must involve a deliberate technique due to a
potential of premature bridging.
Poor compressive strength.
Pressure limitations.
Limitations. EPA regulations (40 CFR §146.10) require
operators of Class I and II wells to plug wells using cement as
the plugging agent. This prohibits the use of compressed
bentonite as the sole plugging agent. EPA's UIC Technical
Workgroup is conducting an examination of this method and
may revise its guidance in the future.
Other Applications. Compressed bentonite may be an
option for plugging Class III and V wells, which are usually
shallow, situated in low-pressure environments expected to
be geologically calm and freeof disturbances. Othercandidates
may include the shallow well groups of public and private
drinking water wells and those used in EPA's CERCLA
(Superfund) or RCRA (waste) programs, in addition to some
oil and gas production wells. Check applicable regulations
first.
For more information. Contact George Robin at 415-972-
3532, or email robin.george@epa.gov.
Upcoming Events
September 16-19, 2002: UIC Annual Inspector Training
Course in Denver, CO. For information, contact Kate Rao
at rao.kate@epa.gov.
September 18 - 19, 2002: Groundwater Resource
Association Annual Conference, "Sustaining Groundwater
Resources: The Critical Vision" in Newport Beach, Calif.
For information, visit www.grac.org.
September 21 -25,2002: Ground Water Protection Council
(GWPC) Annual Forum in San Francisco, Calif. For
information, go to www.gwpc.org.
October 23-25, 2002: 10th Annual Region 9 Tribal
Conference in Reno, Nevada co-hosted with the Pyramid
Lake Paiute Tribe. For information, contact Lisa
Penaska at penaska.lisa@epa.gov.
November 12-13, 2002: Groundwater Resources
Association Conference, "Nitrates in California
Groundwater" in Fresno, Calif. For information, visit
www.grac.org.
June 2-3, 2003: EPA National Source Water Protection
Conference in Washington, D.C. For information,
contact Kate Rao at rao.kate@epa.gov.
Notes From Underground
U.S. EPA, Pacific Southwest/Region 9
Ground Water Office, WTR-9
75 Hawthorne Street
San Francisco, CA 94105
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