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Sole Source Aquifer Designation of the Troutdale Aquifer System; Clark County, WA

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

 
[Federal Register: September 6, 2006 (Volume 71, Number 172)]
[Notices]
[Page 52541-52544]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06se06-62]

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ENVIRONMENTAL PROTECTION AGENCY
[FRL-8217-2]
 
Sole Source Aquifer Designation of the Troutdale Aquifer System; 
Clark County, WA

AGENCY: Environmental Protection Agency.
ACTION: Notice of Final Determination.

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SUMMARY: Notice is hereby given that pursuant to Section 1424(e) of the 
Safe Drinking Water Act (42 U.S.C. 300h-3(e), Pub. L. 93-523), and in 
response to a petition from a group of Clark County residents (two 
private groups and 8 individuals), the U.S. Environmental Protection 
Agency (EPA) Region 10 Administrator has determined that the Troutdale 
aquifer system, in Clark County, Washington, is a sole or principal 
source of drinking water, and that if contaminated, would create a 
significant hazard to public health. As a result of this action, all 
Federal financially-assisted projects proposed over the designated 
aquifer system will be subject to EPA review to ensure that they do not 
create a significant hazard to public health.

DATES: This determination shall be promulgated for purposes of judicial 
review at 1 p.m. eastern time on September 20, 2006.

ADDRESSES: The information upon which this determination is based is 
available to the public and may be inspected during normal business 
hours at the EPA Region 10 Library, 1200 Sixth Avenue, Seattle, 
Washington 98101, or on the EPA Web site at: 
http://yosemite.epa.gov/r10/water.nsf/Sole+Source+Aquifers/Program.

FOR FURTHER INFORMATION CONTACT: Martha Lentz, Hydrogeologist, Office 
of Environmental Assessment, OEA-095, Environmental Protection Agency, 
Region 10, 1200 Sixth Avenue, Seattle, Washington 98101, 206-553-1593.

SUPPLEMENTARY INFORMATION:

I. Background

    Section 1424(e) of the Safe Drinking Water Act states:

    If the Administrator determines, on his own initiative or upon 
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 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 EPA Region 10 Drinking Water Section received a draft sole 
source aquifer (SSA) petition in early November 2005 from a group of 
Clark County residents, who represent both individuals and private 
public interest groups. The petitioners were:

The Columbia Riverkeeper,
The Rosemere Neighborhood Association,
Dvija Michael Bertish,
Dennis Dykes,
Thom McConathy,
Nathan Reynolds,
Karen Kingston,
Coleen Broad,
Richard Dyrland,
Dean Swanson.

    A final petition was presented to EPA on November 29, 2005. On 
December 28, 2005, EPA sent a letter to the petitioners acknowledging 
that the agency considered the petition complete, and that the 
technical review process would begin.
    In January 2006 EPA met with the petitioners to discuss expanding 
the aquifer system boundary to include more of the geologic formations. 
There was agreement to extend the boundary, and the petitioners agreed 
to provide updated values for population and drinking water use data. 
On January 17, 2006 the petitioners provided the adjusted water use and 
population data to EPA.
    In February of 2006, the Troutdale aquifer system review was 
completed and the area appeared to meet all criteria for SSA 
designation. The legal and technical basis for the proposal was 
outlined in an EPA publication titled: ``Draft Support Document for the 
Sole Source Aquifer Designation of the Troutdale Aquifer System''. 
After a technical peer review and public

[[Page 52542]]

comment period, a final publication was compiled titled: ``Final 
Support Document for the Sole Source Aquifer Designation of the 
Troutdale Aquifer System''.

II. Basis for Determination

    Among the factors to be considered by EPA in connection with the 
designation of an area under Section 1424(e) are: (1) Whether the 
aquifer is the area's sole or principal source of drinking water, and 
(2) whether contamination of the aquifer would create a significant 
hazard to public health.
    EPA Region 10 follows EPA guidance which interprets the statutory 
language of ``sole or principal'' as meaning that the aquifer must 
supply at least 50 percent of the drinking water for the area. 
Furthermore, there should be no alternate drinking water source(s) 
which can physically, legally, and economically supply all those who 
depend upon the aquifer for drinking water, should it become 
contaminated. In addition, aquifer boundaries should be delineated 
based on sound hydrogeologic principles and the best available 
scientific information.
    Although designation determinations are largely based on science-
based criteria, the Regional Administrator may also consider the 
overall public interest and net environmental and public health 
benefits in making a sole source aquifer determination.
    On the basis of information available to this Agency, the Region 10 
Administrator has made the following findings:
    (1) The aquifer system is the principal source of drinking water 
(approximately 99.4%) for the people in the Troutdale aquifer system 
area and there are no alternate sources which can physically, legally, 
and economically supply all those who depend upon the aquifer for 
drinking water, should it become contaminated. Potential alternate 
sources considered include surface water, alternative aquifers, and an 
intertie with the Portland Water Bureau. None of these drinking water 
sources are considered by EPA to be feasible replacements for the 
entire aquifer system due to economic barriers or because these sources 
are not consumed or utilized for domestic purposes in significant 
quantities.
    (2) Contamination of the aquifer system would create a significant 
hazard to public health. The aquifer system is vulnerable to 
contamination because recharge occurs essentially over the entire area, 
the aquifer is highly permeable, and there are many human activities 
that have released, or have the potential to release, contaminants to 
the aquifers. The Washington Department of Ecology (WDOE) currently 
lists 204 active cleanup and 12 Federal Superfund sites in the proposed 
aquifer service area. These sites are known to have been contaminated 
and are undergoing cleanup. Many of these sites include plumes of 
groundwater contamination. WDOE also lists 625 hazardous waste 
generators, and 609 underground storage tanks in this area.
    ? Superfund sites--12
    ? Active state cleanup sites--90
    ? Active voluntary and independent cleanup sites--114
    ? LUST sites--185
    ? Hazardous waste sites--625
    ? UST sites--609
    Other sources of contamination include untreated or poorly treated 
storm water and septic systems. There are about 7,000 septic systems 
within the City of Vancouver's sewer service area. There are tens of 
thousands of additional septic systems outside the city discharging to 
the aquifer. The county is experiencing rapid growth which increases 
the threat to the quality of the aquifer as well as increases the 
demand for potable water.
    Because the aquifer system is vulnerable to contamination and 
restoring groundwater quality can be difficult or even impossible; and 
because the aquifer system is the principal source of drinking water 
for the area and there are no other sources which can economically 
supply all those who depend upon it for drinking water; EPA believes 
that contamination of the aquifer system would pose a significant 
hazard to public health.
    These findings are based on information from various sources 
including the petition, EPA guidance, U.S. Geological Survey reports, 
and public comments.

III. Description of the Troutdale Aquifer System

    The following is a summary of information from the Support Document 
available upon request from EPA Region 10, or from the EPA Web site. 
Much of the hydrogeological information in the Support Document is 
taken from the petition and from ``Description of the Groundwater Flow 
System in the Portland Basin, Oregon and Washington'', U.S. Geological 
Survey (USGS) Water Supply Paper 2470-A, by McFarland, William D. and 
David S. Morgan, 1996A.
    The petitioned area is within Clark County, Washington, which is a 
part of the southernmost boundary of the state, along the Columbia 
River. The geography is characterized by flat-lying alluvial lands 
along the Columbia River and its tributaries. These alluvial lands are 
interrupted by low, rolling hills and/or buttes with benches and hilly 
areas that rise to meet the foothills of the Cascade Range to the east 
and the northeast. The altitude of the land surface ranges from 
approximately 10 feet along the Columbia River to about 3,000 feet in 
the foothill of the Cascade Range. The Columbia River flows westward 
out of the Columbia River Gorge, past the City of Vancouver, 
Washington, where it flows northward. The tributaries to the Columbia 
River that drain Clark County include the North and East Forks of the 
Lewis, Little Washougal, Washougal, and Lake Rivers. Major creeks are 
Cedar, Salmon, Burnt Bridge, and Lacamas Creeks.
    The geologic units of the Troutdale aquifer system are all 
lacustrine and fluvial sediments of the upper and lower members of the 
Troutdale Formation, other consolidated sand and gravel aquifer units, 
and overlying unconsolidated alluvium and flood deposits. These aquifer 
system units overlie volcanic and marine sedimentary rocks that are 
commonly known as the ``older rocks'' unit. The older rocks unit is 
minimally productive as an aquifer and is therefore not included in the 
aquifer system being considered for sole source designation.
    Sedimentary units of the aquifer system include eight hydrogeologic 
units comprising the Portland Basin aquifer system. From youngest to 
oldest, these hydrogeologic units are (1) The unconsolidated 
sedimentary aquifer, (2) the Troutdale gravel aquifer in the Troutdale 
Formation, (3) confining unit 1, (4) the Troutdale sandstone aquifer in 
the Troutdale Formation, (5) confining unit 2, (6) the sand and gravel 
aquifer, and (7) older rocks. The eighth unit is an undifferentiated 
fine-grained sediment deposit that occurs in the basin where the 
Troutdale sandstone and the sand and gravel aquifer are absent or where 
there is insufficient information to characterize the aquifer units 
within the lower Troutdale member.
    The quality of groundwater in the proposed aquifer service area is 
generally good with some exceptions. Dissolved-solids concentrations 
ranged from 12 to 245 milligrams per liter, with a median concentration 
of 132 milligrams per liter. Most waters can be characterized as soft 
to moderately hard. Concentrations of nitrate as nitrogen exceeded 1.0 
milligram per liter throughout the Vancouver urban area, and were as 
large as 6.7 milligrams per liter (Maximum Contaminant Level (MCL) is 
10 milligrams per liter). Potential nitrate sources are septic

[[Page 52543]]

systems and fertilizers. According to the 1990 Census, there are more 
than 31,000 septic systems in Clark County. An analysis of limited 
historical data indicates that nitrate concentrations may be decreasing 
in the southwestern part of the county around the Vancouver urban area. 
A slight increase in nitrate concentrations was noted in rural areas. 
Nitrate concentrations correlated with sulfate concentrations (r = 
0.61), indicating similar sources for the two. Volatile organic 
compounds have been detected in wells in the Vancouver urban area. 
Compounds identified included tetrachloroethene, 1,1,1-trichloroethane, 
and other solvents. Atrazine and 2,4-D have also been detected in well 
water. Trace elements and radiochemical constituents were present only 
at small levels, indicating natural sources for these constituents.
    The Troutdale aquifer system boundaries are represented by rivers 
and the geologic boundary between the aquifer system units and the 
older rocks unit. The Columbia River forms the southern and western 
boundaries of the proposed Troutdale aquifer system. The northern 
boundary follows the North Fork of the Lewis River from its confluence 
with the Columbia River, east to the confluence of Cedar Creek. Cedar 
Creek is used as the northeast boundary because its location is the 
closest geographic representation of the geologic boundary between the 
Troutdale unit and the older rocks unit, and the creek also most likely 
acts as a local ground water divide for the upper parts of the aquifer 
system. The aquifer boundary follows Cedar Creek east where the 
boundary turns southeast and follows the mapped geologic contact 
between the Troutdale Formation and the older rocks unit. The eastern 
boundary follows the geologic contact south to the Little Washougal 
River, and then follows the Little Washougal River to its confluence 
with the Washougal River. The boundary then follows the Washougal River 
south to Woodburn Hill, where it turns northwest and follows the 
geologic contact along a small outcrop of the older rocks unit. The 
boundary follows the geologic contact through the City of Camas, and 
meets the Columbia River. In the northern part of the area, the aquifer 
system boundary is drawn around Bald Mountain, which is excluded from 
the aquifer system because it is composed of the older rocks unit. 
Please see the Support Document for a more detailed hydrogeologic 
description.

IV. Project Reviews

    The Safe Drinking Water Act authorizes EPA to review proposed 
Federal financially-assisted projects which have the potential to 
contaminate a designated SSA. Federal assistance may be denied if EPA 
determines that a project may contaminate the SSA through its recharge 
zone so as to create a significant hazard to public health. Outright 
denial of Federal funding is rare as most projects pose limited risk to 
ground water quality or can be feasibly modified to prevent ground 
water contamination. Proposed projects that are funded entirely by 
state, local, or private concerns are not subject to SSA review by EPA.
    EPA does not review all possible Federal financially-assisted 
projects, but tries to focus on those projects which pose the greatest 
risk to public health. Memorandums of Understanding have been developed 
between EPA and various Federal funding agencies to help identify, 
coordinate, and evaluate projects. EPA relies to the maximum extent 
possible on existing local and state mechanisms to protect SSAs from 
contamination. Whenever feasible, EPA coordinates project reviews with 
local and state agencies that have a responsibility for ground water 
protection. Their comments are given full consideration in the Federal 
review process.

V. Public Participation and Response to Comments

    The following is a summary of the information from the ``EPA 
Response to Public Comments Submitted on the Draft Support Document for 
the Sole Source Aquifer Designation of the Troutdale Aquifer System'', 
which is available on the EPA Region 10 Sole Source Aquifer Web site.
    EPA used various methods to notify and involve the public and 
others in the Troutdale Aquifer System SSA designation process. The 
outreach effort included briefings to local and State government, 
distribution of EPA facts sheets, placing information in local 
libraries, a public advertisement in the local newspaper, and posting 
all designation information on the EPA Region 10 Sole Source Aquifer 
Web site.
    A public comment period was in effect from March 1, 2006 to May 1, 
2006. EPA received 26 letters of support for the designation from a 
combination of individuals, public interest groups, Indian tribes, and 
public utilities. A letter from the City of Portland Bureau of Water 
Works suggested corrections to the Support Document regarding accurate 
wording of information about the Bureau of Water Works. A letter from 
the Board of Clark County Commissioners listed 7 questions for EPA to 
answer. In a follow-up letter, the Board questions the need for the 
designation and requests a written guarantee that EPA will only address 
technical aspects of federally-funded projects in the area, and not 
involve itself in local land use issues. A letter from the City of 
Vancouver questioned the need for the designation, and questioned the 
validity of the alternative source evaluation. There were no letters 
expressing strong opposition to the designation.
    The primary reason given for supporting the proposed action was a 
belief that designation would increase protection of the area's ground 
water. Many people cited concerns regarding historical and current 
ground water contamination of the aquifer system, indicating the high 
degree of aquifer vulnerability. Many cited the educational benefit 
that SSA status would have on the area's residents and on Clark County 
government on the source of the area's drinking water, and its value 
and the need for protection and conservation. Some people commented 
that protection of the area's ground water was important because there 
are no feasible alternate sources of drinking water.
    Two local governmental agencies questioned the need for the sole 
source, citing other ground water protection laws that are currently in 
effect. In response, there is no program in the State of Washington 
that designates an entire aquifer boundary for protection efforts. EPA 
has authority to review, and recommend mitigating measures to any 
federally-financially assisted project that is determined to be a risk 
to the ground water. No such review exists through any other program.
    One governmental agency expressed concern that special interests 
would exploit the designation which would lead to unnecessary project 
delays and the advancement of other agendas. In response, EPA's role, 
after designation, is to review federally-financially assisted projects 
proposed in the area, to make sure that they will not contaminate the 
aquifer. Project delays would only occur if it became necessary to 
incorporate mitigating measures to assure that the public's drinking 
water would be protected.
    One government agency believes that there are feasible alternative 
sources of drinking water for the area. In response, EPA considered and 
evaluated the potential costs of supplying the aquifer population with 
water from various rivers, Lake Vancouver, etc. * * * individually. We 
did not consider them collectively because if they were not feasible 
individually, then they would certainly not be economically feasible

[[Page 52544]]

collectively. It would cost considerably more to hook up everyone to 
not only a river source, but also to a lake source. When evaluating 
economic feasibility, the costs of supply lines running to every single 
household in the area must be included * * * this includes every 
household up in the foothills, out in the middle of the woods, and not 
just in the metropolitan areas. Although there may be a collection of 
alternative water supplies that could serve the City of Vancouver, this 
still does not meet the EPA guidance criteria for alternative sources, 
which states that it has to be shown that the alternative source could 
supply the entire population that lives over the aquifer. We requested 
information from the public that would show us if any such alternatives 
exist, but none were supplied to us.
    One government agency requested the EPA provide the technical basis 
for listing Salmon Creek and Lacamas Creek as losing stream reaches. In 
response, both creeks were measured as losing reaches by the U.S. 
Geological Survey in stream measurements made in 1996.
    One government agency expressed concern that EPA is unwilling to 
guarantee in writing that Federal agency Memorandums of Understanding 
(MOU's) will only address technical project elements and not diverge 
into non-technical issues such as land use or other local jurisdiction 
decisional concerns. In response, EPA creates MOU's with other Federal 
agencies to ensure that that EPA receives project information on all 
federally-financially assisted projects that are located in a Sole 
Source Aquifer and which have the potential to contaminate such 
aquifer. EPA's role is to review the projects and either approve as-is, 
or recommend changes in the project design that offer aquifer 
protection. Such recommended changes in project designs could have an 
indirect impact on local land use. EPA's direct role in local projects 
is solely the technical review of federally-financially assisted projects.

VI. Summary

    This determination affects only the Troutdale Aquifer System 
located in Clark County, Washington. 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: August 14, 2006.
Ron Kreizenbeck,
Acting Regional Administrator, Region 10.
[FR Doc. E6-14710 Filed 9-5-06; 8:45 am]
BILLING CODE 6560-50-P

 
 

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