Poolesville Area Aquifer System, Lower Western Montgomery County, Maryland
Mid-Atlantic Sole Source Aquifers
- Supplementary Information
AGENCY: Environmental Protection Agency.
SUMMARY: The Regional Administrator of Region III of the U.S. Environmental Protection Agency (EPA) has determined that the portion of the Piedmont aquifer system that underlies Poolesville and the surrounding area in lower western Montgomery County, Maryland (denominated as "Poolesville Area Aquifer System") is the sole or principal source of drinking water for this area and if the aquifer system were contaminated would create a significant hazard to public health. This determination is in response to a petition submitted by a citizen group, For A Rural Montgomery (FARM), requesting that the Administrator of EPA make a determination under Section 1424(e) of the Safe Drinking Water Act, 42 U.S.C. 300h-3(e), as amended, that the Poolesville Area Aquifer System is a sole or principal source of drinking water for the area. As a result of Sole Source Aquifer (SSA) designation, federal financially assisted projects in the designated area will be subject to EPA review pursuant to section 1424(e) to ensure that these projects are designed and constructed so that they do not contaminate this aquifer so as to create a significant hazard to public health. The Poolesville Area SSA adds an additional area to the existing Maryland Piedmont SSA area, previously designated by EPA in 1980 (45 FR 57165, 08/27/80). The Maryland Piedmont SSA includes seven surface water drainage basins which underlie northwestern Montgomery County, and extend into minor portions of Frederick, Carroll and Howard Counties, MD. The addition of the Poolesville Area Aquifer System to the existing SSA will extend the Maryland Piedmont SSA from State Route 28 (approximate boundary) to the Potomac River, between Little Monocacy River and Seneca Creek's confluence with the Potomac River.
EFFECTIVE DATE: This determination shall become effective February 23, 1998.
ADDRESSES: The data upon which these findings are based are available to the public and may be inspected during normal business hours at the U.S.
Environmental Protection Agency--Region III, Drinking Water Branch, 841 Chestnut Building, Philadelphia, PA 19107. [Information is out-of-date.]
FOR FURTHER INFORMATION CONTACT:
Barbara Smith, Drinking Water Branch, U.S. EPA-III at the address above or at (215) 566-5786, e-mail: firstname.lastname@example.org. [Information is out-of-date.]
Section 1424(e) of the Safe Drinking Water Act, 42 U.S.C. 300h-3(e), states:
If the Administrator determines, on his own initiative or petition, that an area has an aquifer which is the sole or principal drinking water source for the area and which, if contaminated, would create a significant hazard to public health, he shall publish notice of that determination in the Federal Register. After the publication of any such notice, no commitment for federal financial assistance (through a grant, contract, loan guarantee, or otherwise) may be entered into for any project which the Administrator determines may contaminate such aquifer through a recharge zone so as to create a significant hazard to public health, but a commitment for federal financial assistance may, if authorized under another provision of law, be entered into to plan or design the project to assure that it will not so contaminate the aquifer.
In December 1996, EPA Region III received a petition from FARM, requesting the designation of the aquifer system underlying the Poolesville area as a sole source aquifer under Section 1424(e) of the SDWA. EPA reviewed the petition and supporting documentation and began gathering available data to make a determination. EPA opened the official public comment period on the petition on June 18, 1997 and announced a public hearing in a local paper, to be held in Poolesville. EPA conducted the public hearing on July 24, 1997 at the Poolesville Elementary School. The public comment period closed on August 31, 1997. EPA received eleven letters from a variety of people, mostly representatives of local citizen groups, eight of which expressed support for the SSA designation, two expressed opposition to designation and one letter requested more information and a public hearing. Twenty-seven people attended the public hearing and 19 people presented statements, all in support of designation.
II. Basis for Determination
Among the factors considered by the Regional Administrator as part of the review and technical verification process for designating an area under Section 1424(e) were:
1. The aquifer system underlying the Poolesville area supplies the service area population with 50% or more of its drinking water needs.
2. There are no economical alternative drinking water source or combination of sources to supply the designated service area.
3. The EPA has found that FARM has appropriately delineated the boundaries of the aquifer project review and service area.
4. While the quality of the area's ground water is considered to be good, it is vulnerable to contamination due to the relatively thin soil cover and rapid movement of ground water in fractured rock, coupled with increasing development and other land uses. Thin soil cover may allow contaminants to be rapidly introduced into the ground water with minimal assimilation into the soil. Rapid movement of ground water through fractured rock can allow contaminants to spread quickly, once introduced. Clean up of contaminated fractured aquifers is usually difficult to achieve and an expensive, long term effort. The designated area is underlain primarily by a fractured nonmarine sedimentary rock aquifer system, with some localized diabase intrusions. The aquifer system also includes an area of phyllite, terrace and alluvial deposits.
5. Definable Aquifer Boundaries: EPA guidance allows designations to be made for entire aquifers, hydrologically connected aquifers (aquifer systems), or part of an aquifer if that portion is hydrologically separated from the rest of the aquifer. The Poolesville Area Aquifer System boundary is based on accepted hydrological principles and EPA's interpretation of available data.
III. Description of the Aquifer System That Underlies the Designated Poolesville Area
The aquifer system underlying the Poolesville area is within the Piedmont Lowland physiographic province. The designated area extends the southwestern boundary of the existing SSA, called the Maryland Piedmont Aquifer, from State Route 28 (approximate boundary) to the Potomac River, between Little Monocacy River and Seneca Creek's confluence with the Potomac River. The designated area encompasses the surface area, as well as the underlying formations. The topography of the area is gently rolling, cut by streams and small tributaries. The area's climate is moderate and somewhat humid.
Precipitation that has not evaporated, transpired or drained as runoff from the area recharges the underlying aquifer system with water.
The Poolesville area is underlain primarily by nonmarine sedimentary conglomerates, sandstones, siltstones and shales which have been locally intruded by diabase. These fractured rocks of Triassic age are part of the Newark Group, largely the New Oxford formation. The area northeast of Poolesville is underlain by phyllite crystalline rock of early Paleozoic age (approximate age) and underlies the Barnesville, Beallsville and Jerusalem area. The phyllitic rocks are foliated and fractured. Located west of Poolesville towards the Potomac River, are terrace deposits of Tertiary age, comprised of unconsolidated sediments that are not used for ground water supply. Alluvial sediments of Quaternary age occur along the Potomac River valley and some of the major tributaries, but also are not used for ground water supply.
All drinking water (except commercially obtained bottled water) in the Poolesville area is ground water, supplied by the underlying aquifer system.
Poolesville residents are served by public water supply wells, and residents outside of Poolesville Township obtain their drinking water from private wells.
The quality of ground water underlying the Poolesville area is generally good, but both the relatively thin soil cover and rapid movement of ground water in fractured rock reduce the capacity for contaminant attenuation, making the aquifer vulnerable to contaminates from point and nonpoint sources.
The only alternative sources of water (other than the existing supply of ground water from the Poolesville Area Aquifer System) to be considered include surface water sources, or ground water that is extracted outside the SSA area and transported to the Poolesville area, or a combination of the two. The two most likely scenarios in the event that the area's ground water was made unusable, are that the area would be served by extending water mains from Washington Suburban Sanitary Commission's (WSSC) existing distribution system, or by building local intakes and treatment facilities on the Potomac River and supplying the area. A third option is less likely and that would include pumping ground water from areas outside the SSA and delivering the water to the SSA area. All of the above options, and any others not discussed here, are economically infeasible due to the difficulties and costs of constructing water mains, distribution lines and pumping stations through out the entire designated area. Whereas the Town of Poolesville has the water infrastructure in place (wells, treatment, storage and distribution lines) and could probably be connected to the nearest WSSC distribution line for an affordable price, the area outside of Poolesville, that relies on individual wells and has no water distribution system in place, could not afford the massive expense involved in laying distribution pipes to each farm, home, business and school in the designated area. Houses and farms are located farther apart in the areas outside of Poolesville, and could not be put on a distribution system in an economically feasible way.
Local government has acted to protect the ground water quality in Poolesville by starting a Wellhead Protection program in cooperation with the Maryland Department of the Environment. The petitioner group believes that a Sole Source Aquifer designation would augment local ground water protection efforts, and assist in preserving the rural and natural resources of the area.
IV. Information Utilized in Determination
The information utilized in this determination includes: the petition and supporting document submitted to the EPA Region III by FARM, letters received during the public comment period, and public comments received during the public hearing. In addition, much of the information has been derived from published literature on the hydrogeology and water resources of the region.
This information is available to the public and may be inspected at the address listed above. The petition and support document, the transcript of the public hearing and EPA's response summary to public comment are available in the Poolesville Public Library, in Poolesville, MD.
V. Project Review
EPA Region III is working with the federal agencies most likely to provide financial assistance to projects in the project review area. Interagency procedures and Memoranda of Understanding will be developed through which EPA will be notified of proposed commitments by federal agencies to projects which could potentially impact the Poolesville Area Aquifer System. The EPA will evaluate such projects, and where necessary, conduct an in-depth review, including soliciting State and local government and public comments when appropriate. Should the Regional Administrator determine that a project may contaminate the aquifer through its recharge zone so as to create a significant hazard to public health, no commitment for federal financial assistance may be entered into for that project. However, a commitment for federal financial assistance may, if authorized under another provision of law, be entered into to plan or design the project to ensure that it will not contaminate the aquifer. Included in the review of any federal financially- assisted projects will be the coordination with state and local agencies and the project's developers. Their comments will be given full consideration and EPA's review will attempt to complement and support state and local ground water protection measures. Although the project review process cannot be delegated, EPA will rely to the maximum extent possible on any existing or future state and/or local control measures to protect the quality of ground water in the Poolesville Area Aquifer Review Area.
VI. Economic and Regulatory Impact
Pursuant to the provisions of the Regulatory Flexibility Act (RFA), 5 U.S.C. 605(b), I hereby certify that this designation will not have a significant impact on a substantial number of small entities. For purposes of this Certification, the "small entity" shall have the same meaning as given in Section 601 of the RFA. This action is only applicable to projects with the potential to impact the Poolesville Area Aquifer System SSA as designated.
The only affected entities will be those businesses, organizations or governmental jurisdictions that request federal financial assistance for projects which have the potential for contaminating the Sole Source Aquifer so as to create a significant hazard to public health. EPA does not expect to be reviewing small isolated commitments of financial assistance on an individual basis, unless a cumulative impact on the aquifer is anticipated; accordingly, the number of affected small entities will be minimal.
For those small entities which are subject to review, the impact to today's action will not be significant. Most projects subject to this review will be preceded by a ground water impact assessment required pursuant to other federal laws, such as the National Environmental Policy Act (NEPA) as amended 42 U.S.C. 4321, et seq. Integration of those related review procedures with sole source aquifer review will allow EPA and other Federal agencies to avoid delay or duplication of effort in approving financial assistance, thus minimizing any adverse effect on those small entities which are affected.
Finally, today's action does not prevent grants of federal financial assistance which may be available to any affected small entity in order to pay for the redesign of the project to assure protection of the aquifer.
Under Executive Order 12866, EPA must judge whether a regulation is "major" and therefore subject to the requirement of a Regulatory Impact Analysis.
This regulation is not major because it will not have an annual effect of $100 million or more on the economy, will not cause any major increase in costs or prices and will not have significant adverse effects on competition, employment, investment, productivity, innovation, or the ability of United States enterprises to compete in domestic or export markets. Today's action only affects the Poolesville Area Aquifer System in Western Montgomery County, MD. It provides an additional review of ground water protection measures, incorporating state and local measures whenever possible, for only those projects which request federal financial assistance.
This determination affects only the Poolesville Area Aquifer System located in Western Montgomery County, MD. As a result of this Sole Source Aquifer determination, all federal financially-assisted projects proposed in the designated area will be subject to EPA review to ensure that they do not create a significant hazard to public health. Once designated, the Poolesville Area Aquifer System will become part of the existing MD Piedmont SSA area.
Dated: January 14, 1998.
Thomas C. Voltaggio,
Acting Regional Administrator, U.S. Environmental Protection Agency--Region III.