89–010 

Calendar No. 614 

111TH CONGRESS REPORT " ! SENATE 2d Session 111–328 

INLAND EMPIRE PERCHLORATE GROUND WATER PLUME 

ASSESSMENT ACT 

SEPTEMBER 27, 2010.—Ordered to be printed 

Mr. BINGAMAN, from the Committee on Energy and Natural 

Resources, submitted the following 

R E P O R T 

[To accompany H.R. 4252] 

The Committee on Energy and Natural Resources, to which was 

referred the Act (H.R. 4252) to direct the Secretary of the Interior 

to conduct a study of water resources in the Rialto-Colton Basin in 

the State of California, and for other purposes, having considered 

the same, reports favorably thereon without amendment and recommends that the Act do pass. 

PURPOSE

The purpose of H.R. 4252 is to direct the Secretary of the Interior 

to conduct a study of water resources in the Rialto-Colton Basin in 

the State of California, and for other purposes. 

BACKGROUND AND NEED

Perchlorate is both a naturally occurring and man-made chemical. Most of the perchlorate manufactured in the United States is 

used as the primary ingredient of solid rocket propellant and is 

also used in the manufacture of pyrotechnics and roadside flares. 

Perchlorate-containing chemicals are increasingly being discovered 

in soil and groundwater. Over the last several years the Environmental Protection Agency has been studying the impact of perchlorate in water and its impacts on both adults and children. Perchlorate is a regulated drinking water contaminant in California, 

with a maximum contaminant level of 6 micrograms per liter. 

Perchlorate has been detected in 20 water supply wells at concentrations above the California action level of 4 parts per billion 

in the Rialto-Colton Basin. The basin is the source of water for 


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thousands of San Bernardino County residents. The introduction of 

perchlorate into the Rialto-Colton Basin can he traced to the B.F. 

Goodrich Site, a 160-acre area in Rialto, once used for construction 

of rockets and fireworks. The other source of contamination is the 

San Bernardino Landfill. In September 2008, the Environmental 

Protection Agency proposed adding the B.F. Goodrich Site to the 

Superfund National Priorities List. 

H.R. 4252 proposes a study of the complicated geological formation surrounding the contamination in order to understand how to 

best clean up the existing contamination. Before a comprehensive 

cleanup plan can be developed, additional data must he collected 

at source sites and regionally. Although information through EPA 

and other monitoring wells exists, information gaps still remain 

that must be resolved prior to finalizing and implementing an effective cleanup plan to restore the aquifer. 

LEGISLATIVE HISTORY

H.R. 4252, sponsored by Representative Baca, passed the House 

of Representatives by voice vote on March 18, 2010. The Subcommittee on Water and Power held a hearing on H.R. 4252 on 

June 9, 2010. At its business meeting on July 21, 2010, the Committee on Energy and Natural Resources ordered H.R. 4252 favorably reported without amendment. 

COMMITTEE RECOMMENDATION

The Committee on Energy and Natural Resources, in open business session on July 21, 2010, by voice vote of a quorum present, 

recommends that the Senate pass H.R. 4252. 

SECTION-BY-SECTION ANALYSIS

Section 1 identifies the short title of the bill as the ‘‘Inland Empire Perchlorate Ground Water Plume Assessment Act or 2010’’. 

Section 2 authorizes the Secretary of the Interior, acting through 

the United States Geological Survey, and in coordination with the 

State of California, and other federal agencies, to conduct a study 

of the water resources of the Rialto-Colton Basin in the State of 

California. The study shall include a characterization of the extent 

of perchlorate in the area groundwater and an identification of potential source areas. At the conclusion of the study, the Secretary 

of the Interior shall report to the Senate Committee on Energy and 

Natural Resources and the House Natural Resources Committee. 

COST AND BUDGETARY CONSIDERATIONS

The following estimate of costs of this measure has been provided 

by the Congressional Budget Office: 

H.R. 4252—Inland Empire Perchlorate Ground Water Plume Assessment Act of 2010 

H.R. 4252 would direct the U.S. Geological Survey to conduct a 

study of water resources in the Rialto-Colton Basin located east of 

Los Angeles, California. The study would identify the location of 

aquifers in the basin, evaluate the impact of perchlorate contamination in the basin, and include analysis of other related water 

issues in the basin. Based on information from the U.S. Geological 


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Survey and assuming appropriation of the necessary amounts, 

CBO estimates that implementing H.R. 4252 would cost $4 million 

over the next two years. 

Enacting the legislation would not affect direct spending or revenues; therefore, pay-as-you-go procedures do not apply. 

H.R. 4252 contains no intergovernmental or private-sector mandates as defined in the Unfunded Mandates Reform Act and would 

impose no costs on state, local, or tribal governments. 

On March 3, 2010, CBO provided a cost estimate for H.R. 4252 

as ordered reported by the House Committee on Natural Resources 

on February 24, 2010. The two versions of the legislation and 

CBO’s cost estimates are similar. 

The CEO staff contact for this estimate is Aurora Swanson. The 

estimate was approved by Theresa Gullo, Deputy Assistant Director for Budget Analysis. 

REGULATORY IMPACT EVALUATION

In compliance with paragraph 11(b) of rule XXVI of the Standing 

Rules of the Senate, the Committee makes the following evaluation 

of the regulatory impact which would be incurred in carrying out 

H.R. 4252. 

The bill is not a regulatory measure in the sense of imposing 

Government-established standards or significant economic responsibilities on private individuals and businesses. 

No personal information would be collected in administering the 

program. Therefore, there would he no impact on personal privacy. 

Little, if any, additional paperwork would result from the enactment of H.R. 4252, as ordered reported. 

CONGRESSIONALLY DIRECTED SPENDING

H.R. 4252, as ordered reported, does not contain any congressionally directed spending items, limited tax benefits, or limited tariff 

benefits as defined in rule XLIV of the Standing Rules of the Senate. 

EXECUTIVE COMMUNICATIONS

STATEMENT FOR THE RECORD, U.S. GEOLOGICAL SURVEY, 

DEPARTMENT OF THE INTERIOR

Madam Chairwoman and members of the Subcommittee, 

I appreciate the opportunity to provide the Department of 

the Interior’s views regarding U.S. Geological Survey 

(USGS) scientific capability relevant to the Inland Empire 

Perchlorate Ground Water Plume Assessment Act of 2009 

(H.R. 4252). 

USGS SCIENCE IN SUPPORT OF GROUNDWATER MANAGEMENT

AND CONTAMINANTS

The USGS serves the Nation by providing reliable scientific information to describe and understand the Earth; 

minimize loss of life and property from natural disasters; 

manage water, biological, energy, and mineral resources; 

and enhance and protect our quality of life. The specific 

mission of the USGS California Water Science Center is to 


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collect, interpret, and provide unbiased and timely scientific information of the highest quality for the responsible planning, use, and management of California’s water 

resources in cooperation with local, State, and other Federal agencies. Scientific issues related to the occurrence 

and movement of groundwater and contaminants, such as 

perchlorate, fall within the scope of the USGS mission. 

PERCHLORATE ISSUES IN RIALTO-COLTON AND THE ‘‘INLAND

EMPIRE’’ 

The Rialto-Colton Basin is located in western San 

Bernardino County in California, about 60 miles east of 

Los Angeles in the upper Santa Ana River watershed (the 

Inland Empire). The Rialto-Colton Basin is bounded on the 

northeast by the Bunker Hill and Lytle Creek Basins and 

on the southwest by the Chino and North Riverside Basins. Groundwater presently constitutes about 79 percent 

of the drinking-water supply in the Inland Empire. Perchlorate has been detected in the main water-producing 

aquifers within the Rialto-Colton and adjacent basins and 

has contaminated water in more than 20 production wells 

that supply the communities within the Rialto-Colton 

Basin and surrounding area. 

Perchlorate (ClO4) has both synthetic and natural 

sources. Synthetic perchlorate is a residual of the manufacture and use of rocket propellants, fireworks, flares and 

other pyrotechnic devices. Minor concentrations of natural 

perchlorate has been measured in mined Chilean nitrate 

fertilizers. Perchlorate is extremely soluble and is carried 

in groundwater without retardation or absorption. The two 

major sources of synthetic perchlorate in the area are San 

Bernardino County’s Mid-Valley Sanitary Landfill and a 

160-acre site near the landfill. These two sites were used 

for storage and destruction of perchlorate-containing compounds such as explosives, propellants, and pyrotechnic 

devices. Chilean nitrate fertilizer was commonly used in 

the Basin in the early part of the 20th century. In addition, imported water from the Colorado River contains 

measurable perchlorate and also may be a source of perchlorate in the Inland Empire. Recent data collected by the 

USGS indicates that low levels of perchlorate have accumulated naturally in unsaturated zones in arid and semiarid areas of the southwestern United States, such as the 

Mojave Desert, likely as a result of atmospheric deposition. 

Perchlorate contamination is of concern to water managers because of the importance of groundwater in this region. Water managers need to know the source, fate, and 

transport of perchlorate within the Rialto-Colton Basin 

and adjacent basins in order to effectively mitigate the 

contamination. Major uncertainties facing water managers 

include: (1) the source(s) of perchlorate in specific wells; (2) 

the hydrologic and geologic controls on the migration of 

perchlorate within the Rialto-Colton Basin; (3) the effectiveness of the Rialto-Colton Fault as a barrier to perchlorate migration from the Rialto-Colton basin to the adVerDate Mar 15 2010 01:16 Oct 02, 2010 Jkt 089010 PO 00000 Frm 00004 Fmt 6659 Sfmt 6969 E:\HR\OC\SR328.XXX SR328

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jacent Chino and North Riverside basins; and (4) the potential vertical movement of perchlorate through longscreened wells. 

WHAT IS THE USGS DOING IN THE AREA?

The USGS has a long history of hydrologic work in the 

Rialto-Colton area and adjacent areas in the Inland Empire going back as far as the early 1900s. This work has 

been updated periodically and collectively forms the basis 

of our scientific understanding of the regional hydrogeologic setting, the movement of water within aquifers 

pumped for public supply, and water-quality issues in the 

area. The USGS operates an extensive groundwater-monitoring network providing the public with real-time information on water levels and water quality. The USGS has 

developed predictive models in the Rialto-Colton Basin 

(Woolfenden and Kadhim, 1997; Woolfenden and Koczot, 

2001) and the adjacent Lytle Creek and Bunker Hill 

groundwater basins (Danskin and Freckleton, 1989; 

Danskin and others, 2006) to assist in the management of 

the water resources in the area. These models are based 

on the current scientific understanding of the geology and 

hydrology in the area, including the areal and vertical extent of aquifers, hydraulic properties, recharge and discharge of groundwater, and the interaction between 

groundwater and surface water. Most of the USGS research done in the Inland Empire has been in cooperation 

with local water management agencies such as the San 

Bernardino Valley Municipal Water District under the 

auspices of the USGS Cooperative Water Program. In the 

past five years, about 70 percent of the cost of these studies has been borne by local agencies. 

In recent years, the USGS has been working with local 

water agencies to help them understand the sources, distribution, and migration of perchlorate in the Inland Empire. A recent study completed as part of the USGS 

Groundwater Ambient Monitoring and Assessment 

(GAMA) Program (Belitz and others, 2003) sampled 99 

drinking water wells throughout the Inland Empire and 

identified perchlorate in about 67 percent of the wells at 

the reporting level of 0.5 micrograms per liter (μg/L); about 

10 percent had perchlorate concentrations in excess of the 

California maximum contaminant level of 6 μg/L, but no 

well had concentrations in excess of the EPA health reference level (Kent and Belitz, 2009). Woolfenden (2008) 

used a particle-tracking model to determine the susceptibility of an aquifer to perchlorate contamination in the Rialto-Colton Basin. Izbicki (2008) collected wellbore flow 

and depth-dependent water-quality data from a public supply well near Highland, CA located in the northern part of 

the Inland Empire. Water-quality and isotopic data indicated that the source of perchlorate was Chilean nitrate 

fertilizer. 

The USGS is participating in a 2-year study funded by 

the Department of Defense Environmental Security TechVerDate Mar 15 2010 01:16 Oct 02, 2010 Jkt 089010 PO 00000 Frm 00005 Fmt 6659 Sfmt 6969 E:\HR\OC\SR328.XXX SR328

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nology Certification Program (ESTCP) to apply state-ofthe-art chemical and multiple-isotope techniques to identify the source of perchlorate within the Inland Empire. A 

total of 25 wells will be sampled and analyzed for perchlorate, perchlorate isotopes, and other tracers in the Rialto-Colton Basin and Chino Basin adjacent to the RialtoColton Fault. Data collected in this study are intended to 

help identify the areal and vertical extent of perchlorate 

contamination near the margin plumes in areas having 

high background perchlorate concentrations from fertilizer 

or other sources. An important component of this new 

work is to investigate the impact of well-bore flow on the 

vertical distribution of perchlorate within aquifers. 

RIALTO-COLTON BASIN, CALIFORNIA WATER-RESOURCES

STUDY

The key issues of concern identified in H.R. 4252 are: 

A. The delineation, either horizontally or vertically, 

of the aquifers in the Rialto-Colton Basin within the 

State, including the quantity of water in the aquifers; 

B. the availability of groundwater resources for 

human use; 

C. the salinity of groundwater resources; 

D. the identification of a recent surge in perchlorate 

concentrations in groundwater, whether significant 

sources are being flushed through the vadose zone, or 

if perchlorate is being remobilized; 

E. the identification of impacts and extents of all 

source areas that contribute to the regional plume to 

be fully characterized; 

F. the potential of the groundwater resources to recharge; 

G. the interaction between groundwater and surface 

water; 

H. the susceptibility of the aquifers to contamination, including identifying the extent of commingling 

of plume emanating within surrounding areas in San 

Bernardino County, California; and 

I. characterization of surface and bedrock geology, 

including the effect of the geology on groundwater 

yield and quality. 

The USGS has the capability to complete a 2-year study 

to address the issues of concern presented in H.R. 4252 for 

the Rialto-Colton Basin. The tasks required are within the 

scope of the USGS mission and expertise and could be accomplished under existing authorities. 

H.R. 4252 focuses on perchlorate issues in the RialtoColton Basin; however, perchlorate is a concern throughout the Inland Empire. If requested, the USGS could consider options for studying this issue throughout the region. 

CONCLUSION

The USGS has the scientific capacity to address issues 

of concern identified in H.R. 4252, a strong working relationship with many of the people currently working on 


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groundwater quality issues in California’s Inland Empire, 

and a reputation for providing unbiased information. 

The problem of groundwater quality affecting drinking 

water supplies is not unique to communities in Rialto-Colton or the Inland Empire. Perchlorate is an issue throughout the southwestern U.S. Therefore, methods developed to 

understand the perchlorate contamination in the RialtoColton could be useful to water managers in other basins. 

We note, however, that the activities called for in H.R. 

4252 are already authorized by existing authorities. Any 

study conducted to fulfill the objectives of the bill would 

need to compete for funding with other Administration priorities. 

Thank you, Madam Chairwoman, for the opportunity to 

present the views of the Department on H.R. 4252. I will 

be happy to answer any questions you or the other Members may have. 

REFERENCES

Belitz, Kenneth, Dubrovsky, N.M., Burow, K.R., 

Jurgens, Bryant, and Johnson, Tyler, 2003, Framework for 

a ground-water quality monitoring and assessment program for California: U.S. Geological Survey Water Resources Investigations Report 03–4166. 

Belitz, Kenneth, Hamlin, S.N., Burton, C.A., Kent, R.H., 

Fay, R.G., and Johnson, Tyler, 2004, Water Quality in the 

Santa Ana Basin, California: U.S. Geological Survey Circular 1238. 

Danskin, W.R. and Freckleton, J.R., 1989, Groundwater-flow modeling and optimization techniques applied 

to high-ground-water problems in San Bernardino, California: U.S. Geological Survey Open File Report 89–75. 

Danskin, W.R., McPherson, K.R., and Woolfenden, L.R., 

2006, Hydrology, description of computer models and evaluation of water-management alternatives in the San 

Bernardino area, California: U.S. Geological Survey Open 

File Report 2005–1278. 

Izbicki, J.A., 2008, Determining the source of contamination to long-screened wells: East Valley Water District 

2008 Water Quality Conference, October 2008. 

Kent, Robert, and Belitz, Kenneth, 2009, Ground-water 

quality data in the Upper Santa Ana Watershed Study 

Unit, November 2006 to March 2007: Results from the 

California GAMA Program: U.S. Geological Survey Data 

Series 404. 

Woolfenden, L.R., and Kadhim, Dina, 1997, Geohydrology and water chemistry in the vicinity of the RialtoColton fault, San Bernardino County, California: U.S. Geological Survey Water Resources Investigations Report 97– 

4012. 

Woolfenden, L.R., and Koczot, K.M., 2001, Numerical 

simulation of ground-water flow and assessment of the effects of artificial recharge in the Rialto-Colton Basin, San 

Bernardino County, California: U.S. Geological Survey 

Water Resources Investigations Report 00–4243. 


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Woolfenden, L.R., 2008 Aquifer susceptibility to perchlorate contamination in a highly-urbanized environment: 

IAHS Publ 324, pp. 156–163. 

CHANGES IN EXISTING LAW

In compliance with paragraph 12 of rule XXVI of the Standing 

Rules of the Senate, the Committee notes that no changes in existing law are made by H.R. 4252, as ordered reported. 

Æ 


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