United States-Mexico Transboundary Aquifer Assessment Act
PL 109-448 (S.214), enacted 12/22/2006

120 STAT. 3328
PUBLIC LAW 109–448—DEC. 22, 2006
Public Law 109–448
109th Congress
An Act
To authorize the Secretary of the Interior to cooperate with the States on the
border with Mexico and other appropriate entities in conducting a hydrogeologic
characterization, mapping, and modeling program for priority transboundary
aquifers, and for other purposes.
Be it enacted by the Senate and House of Representatives of
the United States of America in Congress assembled,
SECTION 1. SHORT TITLE.
This Act may be cited as the ‘‘United States-Mexico
Transboundary Aquifer Assessment Act’’.
SEC. 2. PURPOSE.
The purpose of this Act is to direct the Secretary of the Interior
to establish a United States-Mexico transboundary aquifer assess-
ment program to systematically assess priority transboundary
aquifers.
SEC. 3. DEFINITIONS.
In this Act:
(1) AQUIFER.—The term ‘‘aquifer’’ means a subsurface
water-bearing geologic formation from which significant quan-
tities of water may be extracted.
(2) IBWC.—The term ‘‘IBWC’’ means the International
Boundary and Water Commission, an agency of the Department
of State.
(3) INDIAN
TRIBE.—The term ‘‘Indian tribe’’ means an
Indian tribe, band, nation, or other organized group or
community—
(A) that is recognized as eligible for the special pro-
grams and services provided by the United States to
Indians because of their status as Indians; and
(B) the reservation of which includes a transboundary
aquifer within the exterior boundaries of the reservation.
(4) PARTICIPATING STATE.—The term ‘‘Participating State’’
means each of the States of Arizona, New Mexico, and Texas.
(5) PRIORITY TRANSBOUNDARY AQUIFER.—The term ‘‘priority
transboundary aquifer’’ means a transboundary aquifer that
has been designated for study and analysis under the program.
(6) PROGRAM.—The term ‘‘program’’ means the United
States-Mexico transboundary aquifer assessment program
established under section 4(a).
(7) RESERVATION.—The term ‘‘reservation’’ means land that
has been set aside or that has been acknowledged as having
been set aside by the United States for the use of an Indian
42 USC 1962
note.
42 USC 1962
note.
42 USC 1962
note.
United States-
Mexico
Transboundary
Aquifer
Assessment Act.
Dec. 22, 2006
[S. 214]
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120 STAT. 3329
PUBLIC LAW 109–448—DEC. 22, 2006
tribe, the exterior boundaries of which are more particularly
defined in a final tribal treaty, agreement, executive order,
Federal statute, secretarial order, or judicial determination.
(8) SECRETARY.—The term ‘‘Secretary’’ means the Secretary
of the Interior, acting through the Director of the United States
Geological Survey.
(9) TRANSBOUNDARY AQUIFER.—The term ‘‘transboundary
aquifer’’ means an aquifer that underlies the boundary between
a Participating State and Mexico.
(10) TRI-REGIONAL
PLANNING
GROUP.—The term ‘‘Tri-
Regional Planning Group’’ means the binational planning group
comprised of—
(A) the Junta Municipal de Agua y Saneamiento de
Ciudad Juarez;
(B) the El Paso Water Utilities Public Service Board;
and
(C) the Lower Rio Grande Water Users Organization.
(11) WATER RESOURCES RESEARCH INSTITUTES.—The term
‘‘water resources research institutes’’ means the institutes
within the Participating States established under section 104
of the Water Resources Research Act of 1984 (42 U.S.C. 10303).
SEC. 4. ESTABLISHMENT OF PROGRAM.
(a) IN GENERAL.—The Secretary, in consultation and coopera-
tion with the Participating States, the water resources research
institutes, Sandia National Laboratories, and other appropriate
entities in the United States and Mexico, and the IBWC, as appro-
priate, shall carry out the United States-Mexico transboundary
aquifer assessment program to characterize, map, and model pri-
ority transboundary aquifers along the United States-Mexico border
at a level of detail determined to be appropriate for the particular
aquifer.
(b) OBJECTIVES.—The objectives of the program are to—
(1) develop and implement an integrated scientific approach
to identify and assess priority transboundary aquifers,
including—
(A) for purposes of subsection (c)(2), specifying priority
transboundary aquifers for further analysis by assessing—
(i) 
the 
proximity 
of 
a 
proposed 
priority
transboundary aquifer to areas of high population den-
sity;
(ii) the extent to which a proposed priority
transboundary aquifer would be used;
(iii) the susceptibility of a proposed priority
transboundary aquifer to contamination; and
(iv) any other relevant criteria;
(B) evaluating all available data and publications as
part of the development of study plans for each priority
transboundary aquifer;
(C) creating a new, or enhancing an existing,
geographic information system database to characterize the
spatial and temporal aspects of each priority transboundary
aquifer; and
(D) using field studies, including support for and
expansion of ongoing monitoring and metering efforts, to
develop—
42 USC 1962
note.
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120 STAT. 3330
PUBLIC LAW 109–448—DEC. 22, 2006
(i) the additional data necessary to adequately
define aquifer characteristics; and
(ii) scientifically sound groundwater flow models
to assist with State and local water management and
administration, including modeling of relevant ground-
water and surface water interactions;
(2) consider the expansion or modification of existing agree-
ments, as appropriate, between the United States Geological
Survey, the Participating States, the water resources research
institutes, and appropriate authorities in the United States
and Mexico, to—
(A) conduct joint scientific investigations;
(B) archive and share relevant data; and
(C) carry out any other activities consistent with the
program; and
(3) 
produce 
scientific 
products 
for 
each 
priority
transboundary aquifer that—
(A) are capable of being broadly distributed; and
(B) provide the scientific information needed by water
managers and natural resource agencies on both sides of
the United States-Mexico border to effectively accomplish
the missions of the managers and agencies.
(c) DESIGNATION OF PRIORITY TRANSBOUNDARY AQUIFERS.—
(1) IN GENERAL.—For purposes of the program, the Sec-
retary shall designate as priority transboundary aquifers—
(A) the Hueco Bolson and Mesilla aquifers underlying
parts of Texas, New Mexico, and Mexico;
(B) the Santa Cruz River Valley aquifers underlying
Arizona and Sonora, Mexico; and
(C) the San Pedro aquifers underlying Arizona and
Sonora, Mexico.
(2) ADDITIONAL AQUIFERS.—The Secretary may, using the
criteria under subsection (b)(1)(A), evaluate and designate addi-
tional priority transboundary aquifers which underlie New
Mexico or Texas.
(d) COOPERATION WITH MEXICO.—To ensure a comprehensive
assessment of priority transboundary aquifers, the Secretary shall,
to the maximum extent practicable, work with appropriate Federal
agencies and other organizations to develop partnerships with, and
receive input from, relevant organizations in Mexico to carry out
the program.
(e) GRANTS
AND COOPERATIVE AGREEMENTS.—The Secretary
may provide grants or enter into cooperative agreements and other
agreements with the water resources research institutes and other
Participating State entities to carry out the program.
SEC. 5. IMPLEMENTATION OF PROGRAM.
(a) COORDINATION WITH STATES, TRIBES, AND OTHER ENTI-
TIES.—The Secretary shall coordinate the activities carried out
under the program with—
(1) the appropriate water resource agencies in the Partici-
pating States;
(2) any affected Indian tribes;
(3) any other appropriate entities that are conducting moni-
toring and metering activity with respect to a priority
transboundary aquifer; and
(4) the IBWC, as appropriate.
42 USC 1962
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120 STAT. 3331
PUBLIC LAW 109–448—DEC. 22, 2006
(b) NEW ACTIVITY.—After the date of enactment of this Act,
the Secretary shall not initiate any new field studies or analyses
under the program before consulting with, and coordinating the
activity with, any Participating State water resource agencies that
have jurisdiction over the aquifer.
(c) STUDY PLANS; COST ESTIMATES.—
(1) IN GENERAL.—The Secretary shall work closely with
appropriate Participating State water resource agencies, water
resources research institutes, and other relevant entities to
develop a study plan, timeline, and cost estimate for each
priority transboundary aquifer to be studied under the program.
(2) REQUIREMENTS.—A study plan developed under para-
graph (1) shall, to the maximum extent practicable—
(A) integrate existing data collection and analyses con-
ducted with respect to the priority transboundary aquifer;
(B) if applicable, improve and strengthen existing
groundwater flow models developed for the priority
transboundary aquifer; and
(C) be consistent with appropriate State guidelines
and goals.
SEC. 6. EFFECT.
(a) IN GENERAL.—Nothing in this Act affects—
(1) the jurisdiction or responsibility of a Participating State
with respect to managing surface or groundwater resources
in the Participating State;
(2) the water rights of any person or entity using water
from a transboundary aquifer; or
(3) State water law, or an interstate compact or inter-
national treaty governing water.
(b) TREATY.—Nothing in this Act shall delay or alter the
implementation or operation of any works constructed, modified,
acquired, or used within the territorial limits of the United States
relating to the waters governed by the Treaty Between the United
States and Mexico Regarding Utilization of Waters of the Colorado
and Tijuana Rivers and of the Rio Grande, Treaty Series 994
(59 Stat. 1219).
SEC. 7. REPORTS.
Not later than 5 years after the date of enactment of this
Act, and on completion of the program in fiscal year 2016, the
Secretary shall submit to the appropriate water resource agency
in the Participating States, an interim and final report, respectively,
that describes—
(1) any activities carried out under the program;
(2) any conclusions of the Secretary relating to the status
of priority transboundary aquifers; and
(3) the level of participation in the program of entities
in Mexico.
SEC. 8. AUTHORIZATION OF APPROPRIATIONS.
(a) IN GENERAL.—There are authorized to be appropriated to
carry out this Act $50,000,000 for the period of fiscal years 2007
through 2016.
(b) DISTRIBUTION OF FUNDS.—Of the amounts made available
under subsection (a), 50 percent shall be made available to the
water resources research institutes to provide funding to appro-
priate entities in the Participating States (including Sandia
42 USC 1962
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42 USC 1962
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120 STAT. 3332
PUBLIC LAW 109–448—DEC. 22, 2006
LEGISLATIVE HISTORY—S. 214:
SENATE REPORTS: No. 109–17 (Comm. on Energy and Natural Resources).
CONGRESSIONAL RECORD:
Vol. 151 (2005): July 26, considered and passed Senate.
Vol. 152 (2006): Dec. 6, considered and passed House, amended.
Dec. 8, Senate concurred in House amendment.
National Laboratories, State agencies, universities, the Tri-Regional
Planning Group, and other relevant organizations) and to imple-
ment cooperative agreements entered into with appropriate entities
in Mexico to conduct specific authorized activities in furtherance
of the program, including the binational collection and exchange
of scientific data.
(c) CRITERIA.—Funding provided to an appropriate entity in
Mexico pursuant to subsection (b) shall be contingent on that entity
providing 50 percent of the necessary resources (including in-kind
services) to further assist in carrying out the authorized activity.
SEC. 9. SUNSET OF AUTHORITY.
The authority of the Secretary to carry out any provisions
of this Act shall terminate 10 years after the date of enactment
of this Act.
Approved December 22, 2006.
42 USC 1962
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