Columbia and Yorktown - Eastover Multi-aquifer System - Accomack and North Hampton Counties
Mid-Atlantic Sole Source Aquifers
- Supplementary Information
AGENCY: Environmental Protection Agency.
SUMMARY: In response to a petition from the Bi-County Ad Hoc Citizens Committee on Oversight, notice is hereby given that the Regional Administrator of Region III of the U.S. Environmental Protection Agency (EPA) has determined that the Columbia and Yorktown-Eastover Multiaquifer System satisfies all determination criteria for designation as a sole source aquifer, pursuant to Section 1424(e) of the Safe Drinking Water Act. The following findings were made in accordance with the designation criteria: the Columbia and Yorktown-Eastover Multiaquifer System supplies more than 50% of the water needs for the communities within the service area boundaries; there are no viable alternative sources of sufficient supply; the boundaries of the designated area and the project review area have been reviewed and approved by the EPA; and, if contamination were to occur, it would pose a significant public hazard and a serious financial burden to the communities within the aquifer service area. As a result of this action, the EPA may review, suggest modifications to, or withhold funding for, any federally financially assisted projects proposed for construction within the Columbia and Yorktown-Eastover Multiaquifer System that may pose an adverse risk of ground water contamination.
DATES: This determination shall become effective May 9, 1997.
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, Water Protection Division, 841 Chestnut Building, Philadelphia, PA 19107. [Information is out-of-date.]
FOR FURTHER INFORMATION CONTACT: Barbara M. Smith, Drinking Water Branch, (215) 566-5786. [Information is out-of-date.]
Section 1424(e) of the Safe Drinking Water Act, 42 U.S.C., section 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.
The Sole Source Aquifer designation process consists of four phases, as outlined in the "Sole Source Aquifer Designation Petitioner Guidance": Phase I--Petition Preparation, Phase II--Initial Petition Review/Determination of Completeness, Phase III--Detailed Review/Technical Verification, and Phase IV--Designation Determination.
In August 1992, EPA Region III received a petition from the Bi-County Ad Hoc Citizens Committee on Oversight, requesting the designation of the Columbia and Yorktown-Eastover Multiaquifer System as a sole source aquifer under Section 1424(e) of the SDWA. EPA returned the petition following an initial review with a "Notice of Deficiencies" to be corrected prior to further consideration by EPA. On July 28, 1993 a revised petition was submitted to EPA which was determined to be complete. EPA determined that the Bi-County Ad Hoc Citizens Committee on Oversight's petition fully satisfied the first three phases of the designation process and announced a public hearing on the petition on December 15, 1993. EPA conducted a public hearing in Onley, Virginia on January 25, 1994. The public comment period on the petition closed on February 22, 1994.
II. Basis for Determination
Among the factors considered by the Regional Administrator as part of the detailed review and technical verification process for designating an area under Section 1424(e) were:
1. The Columbia and Yorktown-Eastover aquifers are high-yielding aquifers which the service area population relies on for more than 50% of its drinking water needs.
2. There exists no viable economical alternative drinking water source or combination of sources to supply the designated service area.
3. The EPA has found that the Bi-County Ad Hoc Citizens Committee on Oversight has appropriately delineated the boundaries of the aquifer project review area.
4. While the quality of the Columbia and Yorktown-Eastover aquifer's ground water is considered to be good, it is highly vulnerable to contamination due to its geological characteristics and possible land-use activities. The designated area is a multiaquifer system with a surficial aquifer (Columbia aquifer) consisting of shallow sand and gravel deposits and a deeper confined aquifer (Yorktown-Eastover aquifer) which is recharged by water from the surficial aquifer. The shallow nature of the surficial aquifer allows contaminants to be rapidly introduced into the ground water with minimal assimilation. It is this high vulnerability to contamination, especially on the central "spine" of the peninsula, coupled with the aquifer's value as the principal source of drinking water for the residents served, that could pose a significant public health hazard.
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 Yorktown-Eastover Multiaquifer System boundary is based on hydrological principles and EPA's interpretation of available data.
III. Description of the Columbia and Yorktown-Eastover Multiaquifer System Designated Area and Project Area
The Columbia and Yorktown-Eastover Multiaquifer System is part of the Atlantic Coastal Plain physiographic province. The designated and project area of the Columbia and Yorktown-Eastover Multiaquifer System underlies the political boundaries of Accomack and Northampton Counties (known as the Eastern Shore of Virginia), located on the southern tip of the Delmarva Peninsula. The designated/project area (Accomack and Northampton Counties) is approximately 695 square miles in surface area. The topography of the two counties is generally low-lying and near sea level with elevations ranging from sea level to 50 feet above mean sea level.
The Atlantic Coastal Plain physiographic province in Virginia consists of an eastward-thickening wedge of unconsolidated sediments. The sediments were deposited on a crystalline bedrock platform which has subsided since early Cretaceous time. The sediments consist of gravels, sands, clays and varying amounts of shell material. The sediments were deposited from early Cretaceous time to the Holocene period from the ancient Appalachian mountain chain to the west and can be classified as continental, coastal or marine deposits.Due to the presence of salt water at depth only the Columbia and Yorktown- Eastover aquifers constitute the freshwater system on the Eastern Shore. The Yorktown-Eastover aquifer is further subdivided into an upper, middle and lower aquifers, bounded by confining units. The aquifer materials of the Yorktown-Eastover aquifer generally consist of shelly sands while the confining units are silts and clays. The Columbia aquifer on the Eastern Shore of Virginia is an unconfined aquifer above the upper Yorktown confining unit and consists of sandy unconsolidated deposits.
The climate for the region is temperate with an average rainfall of 43 inches. The total recharge to the Columbia aquifer is estimated to be 257 Mgal/day. Although most of this recharge is eventually discharged to either the Atlantic Ocean or the Chesapeake Bay, an estimated 11 Mgal/day leaks through the first confining unit into the upper portion of the Yorktown- Eastover aquifer. Most of the recharge to the confined Yorktown-Eastover aquifer takes place in a narrow zone along the center of the peninsula called the spine. Generally, patterns of vertical flow are downward in the spine area and upward in the coastal areas. Natural ground water flow patterns have been subsequently altered by ground water development. Under pumping conditions ground water flow directions are similar to prepumping directions, however downward leakage from the Columbia aquifer increases and the area of recharge becomes larger.
Nearly all drinking water on the Eastern Shore of Virginia is derived from groundwater as there are no surface water bodies capable of supplying a large quantity of water. Most residents obtain their drinking water from private wells since the percentage of housing units in Accomack county having water supplied by a public water system is listed at 31% (out of 15,840 units) in the most recent U.S. Census data; for Northampton county the figure is 12% (out of 6,183 units). Municipal wells are usually completed in the Yorktown- Eastover aquifer system, typically with multi-screened wells. Total ground water use was estimated to be 5 million gallons per day (Mgal/d) by the U.S. Geological Survey and using records contained within the EPA Federal Data Reporting System. A population of approximately 52,000 is served by public water supply systems (which rely on ground water). Withdrawals by private wells from the Columbia were estimated to be at least 1.7 Mgal/day. Other large ground water withdrawals include those for industry and irrigation.
The quality of ground water in Accomack and Northampton counties is generally good, but both the highly permeable nature of the aquifer material and the shallow depths to the water table reduce the capacity for contaminant attenuation, making the aquifer vulnerable to contamination from point and nonpoint sources. The Columbia aquifer is especially vulnerable to potential sources of contamination. Ground water data collected for the surficial aquifer on Delmarva peninsula indicates ground water quality has been affected by human activities. These impacts include statistically significant increases in dissolved minerals, elevated nitrate levels and pesticide residue detections.
Use of alternative supplies of water outside the aquifer is economically and technically infeasible due to the difficulties and costs of transporting water from either mainland Virginia or northerly portions of the Delmarva peninsula. In addition, excess alternative ground water supplies in nearby portions of mainland Virginia are unlikely to be available, as shown by current difficulties in obtaining additional water for Virginia Beach, VA.
Local government has acted to protect the water quality of ground water in Accomack and Northampton counties through formation of the Eastern Shore of Virginia Ground Water Steering Committee in 1990. State government has also acted to protect ground water on the Eastern Shore through designation of the Eastern Shore groundwater management area in 1976, among other actions. The petitioner believes that a Sole Source Aquifer Designation would augment ground water protection efforts by providing a forum for public education and by increasing awareness about the importance and vulnerability of the aquifer which underlies the two counties.
The designated project review area will consist of both Accomack and Northampton Counties, VA but does not include Tangier Island, VA (located in the Chesapeake Bay, off shore from the peninsula), and Chincoteague Island, VA (located in the Atlantic Ocean, just off shore from the peninsula). There are no streamflow source zones for this designation. Maps of the designated area are available from EPA Region III at the above address.
IV. Information Utilized in Determination
The information utilized in this determination includes: the petition submitted to the EPA Region III by the Bi-County Ad Hoc Citizens Committee on Oversight, 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. A Support Document for this designation contains more detailed information on ground water usage, potential sources of drinking water and vulnerability of the aquifer to contamination and will be placed in the libraries of Accomack and Northampton counties. The Support Document is also available from EPA Region III.
V. Project Review
The EPA Region III Ground Water Protection Section 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 the EPA will be notified of proposed commitments by federal agencies to projects which could potentially impact the Columbia and Yorktown-Eastover Multiaquifer 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 the EPA's review will attempt to complement and support state and local ground water protection measures. Although the project review process cannot be delegated, the 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 Columbia and Yorktown-Eastover Multiaquifer System Project Review Area.
VI. Discussion of Public Comments
EPA issued a public notice (December 15, 1993) to request comments and announced the proposed designation and a comment period. A public hearing was held (January 25,1994) at Nandua High School in Onley, Virginia. The public comment period closed on February 22, 1994.
EPA received 29 written comments during the public comment period. Of these, 25 were in support of the designation and 4 were opposed. Fifteen people spoke at the public hearing held at Nandua High School in Onley, Virginia on January 25, 1994. Of the speakers, 11 supported the designation, two opposed it and two neither supported nor opposed the designation. The public's written and oral comments are fully addressed in EPA's Responsiveness Document and Support Document. Both of these documents will be placed on file at the main library and are also available upon request at the above address.
VII. Economic and Regulatory Impact
Pursuant to the provisions of the regulatory Flexibility Act (RFA), 5 U.S.C. 605(b), I hereby certify that the attached rule 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 Columbia and Yorktown-Eastover Multiaquifer System sole source aquifer 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 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 affect of $100 million of 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 Columbia and Yorktown-Eastover Multiaquifer System in the area of Northampton and Accomack County. 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 Columbia and Yorktown-Eastover Multiaquifer System located in Accomack and Northampton Counties, Virginia. As a result of this 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.
Dated: March 26, 1997.
W. Michael McCabe,
Regional Administrator, U.S. Environmental Protection Agency--Region III.