2001

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER

Comparative Water-Quality Assessment of the 

Hai He River Basin in the People’s

Republic of China and Three Similar Basins

in the United States

By Joseph Domagalski1, Zhou Xinquan2, Lin Chao2, Zhi Deguo2, Fan Lan Chi2, Xu Kaitai3, Lü Ying3,

Luo Yang2, Liu Shide3, Liu Dewen2, Guo Yong2, Tian Qi4, Liu Jing2, Yu Weidong5,

Robert Shedlock6, and Donna Knifong1

1U.S. Geological Survey, Sacramento, California, United States

2Hai He River Water Conservancy Commission, Tianjin, People’s Republic of China

3Tangshan Water Resources Bureau, Tangshan, People’s Republic of China

4Ministry of Water Resources, Beijing, People’s Republic of China

5Zhangweinan Canal Management Bureau, Dezhou, People’s Republic of China

6U.S. Geological Survey, Baltimore, Maryland, United States

1647

NATIONAL WATER-QUALITY ASSESSMENT PROGRAM

Prepared in cooperation with the

Ministry of Water Resources, People’s Republic of China

Hai He River Water Conservancy Commission

Tangshan Water Resources Bureau
 U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

 U.S. GEOLOGICAL SURVEY

The use of firm, trade, and brand names in this report is for 

endorsement by the U.S. Government.

For sale by U.S. Geological Survey, Information Services

Box 25286, Federal Center

Denver, CO 80225

Library of Congress Cataloging in Publications Date

identification purposes only and does not constitute

 Charles G. Groat, Director

Comparative water-quality assessment of the Hai He River basin in the People’s

Republic of China and three similar basins in the United States / by Joseph Domagalski

... [et al.]. ; prepared in cooperation with U.S. Geological Survey, Sacramento, 

California, United States ... [et al.[.

 p. cm. -- (U.S. Geological Survey professional paper ; 1647)

 Includes bibliographical references.

 ISBN 0-607-97600-4

 1. Water quality--China--Hai He River Watershed. 2. Water quality--Delmarva Peninsula.

 3. Water quality--California--Sacramento Valley. 4. Water quality--California--San

 Joaquin Valley. I. Domagalski, Joseph L. II. Geological Survey (U.S.) III. Series.

TD302.H25 C65 2001

363.738--dc21

 2001053177
FOREWORD

The U.S. Geological Survey (USGS) is committed 

to serve the Nation with accurate and timely scientific information that helps enhance and protect the overall quality of 

life, and facilitates effective management of water, biological, energy, and mineral resources. Information on the quality of the Nation’s water resources is of critical interest to 

the USGS because it is so integrally linked to the long-term 

availability of water that is clean and safe for drinking and 

recreation and that is suitable for industry, irrigation, and 

habitat for fish and wildlife. Escalating population growth 

and increasing demands for the multiple water uses make 

water availability, now measured in terms of quantity and 

quality, even more critical to the long-term sustainability of 

our communities and ecosystems.

The USGS implemented the National Water-Quality 

Assessment (NAWQA) Program to support national, 

regional, and local information needs and decisions related 

to water-quality management and policy. Shaped by and 

coordinated with ongoing efforts of other Federal, State, and 

local agencies, the NAWQA Program is designed to answer: 

What is the condition of our Nation’s streams and ground 

water? How are the conditions changing over time? How do 

natural features and human activities affect the quality of 

streams and ground water, and where are those effects most 

pronounced? By combining information on water chemistry, physical characteristics, stream habitat, and aquatic life, 

the NAWQA Program aims to provide science-based 

insights for current and emerging water issues. NAWQA 

results can contribute to informed decisions that result in 

practical and effective water-resource management and 

strategies that protect and restore water quality.

Since 1991, the NAWQA Program has implemented 

interdisciplinary assessments in more than 50 of the 

Nation’s most important river basins and aquifers, referred 

to as Study Units. Collectively, these Study Units account 

for more than 60 percent of the overall water use and population served by public water supply, and are representative 

of the Nation’s major hydrologic landscapes, priority ecological resources, and agricultural, urban, and natural 

sources of contamination. 

Each assessment is guided by a nationally consistent 

study design and methods of sampling and analysis. The 

assessments thereby build local knowledge about waterquality issues and trends in a particular stream or aquifer 

while providing an understanding of how and why water 

quality varies regionally and nationally. The consistent, 

multi-scale approach helps to determine if certain types of 

water-quality issues are isolated or pervasive, and allows 

direct comparisons of how human activities and natural processes affect water quality and ecological health in the 

Nation’s diverse geographic and environmental settings. 

Comprehensive assessments on pesticides, nutrients, volatile organic compounds, trace metals, and aquatic ecology 

are developed at the national scale through comparative 

analysis of the Study-Unit findings. 

The USGS places high value on the communication 

and dissemination of credible, timely, and relevant science 

so that the most recent and available knowledge about water 

resources can be applied in management and policy decisions. We hope this NAWQA publication will provide you 

the needed insights and information to meet your needs, and 

thereby foster increased awareness and involvement in the 

protection and restoration of our Nation’s waters. 

The NAWQA Program recognizes that a national 

assessment by a single program cannot address all waterresource issues of interest. External coordination at all levels is critical for a fully integrated understanding of watersheds and for cost-effective management, regulation, and 

conservation of our Nation’s water resources. The Program, 

therefore, depends extensively on the advice, cooperation, 

and information from other Federal, State, interstate, Tribal, 

and local agencies, non-government organizations, industry, 

academia, and other stakeholder groups. The assistance and 

suggestions of all are greatly appreciated.

Robert M. Hirsch

Associate Director for Water
Editor’s Note

This report is based on a research study in the People’s Republic of China. The report was edited for an 

international technical audience and for Chinese readers with English as a second language (ESL). For example, 

the term “Tangshan study area” is used prior to defining “Tangshan study unit,” which is used thereinafter to 

denote the specific Tangshan area under study. The term “physiographic provinces” was changed to 

“physiographic regions” to prevent possible miscommunication with the Chinese geographic term “Provinces.” 

Other similar assessments were made during the language editing phase of the editorial process.

The style used for site names and well locations in the area studied outside the United States—the 

Tangshan region of the People’s Republic of China—was taken from unpublished data and from correspondence 

with the Chinese coauthors. The “Atlas of the People’s Republic of China,” produced and published in the 

People’s Republic of China (see the “Xiudong” listing in the References Cited section at end of this report), was 

used to verify spellings of Chinese cities, rivers, and other geographic features. Style editing included 

appropriate use of syntax of Chinese phrases, diacritical marks, and syllable boundary markers (for example, 

“the two-syllable “Xi’an” for two Chinese characters is distinguished from the single syllable “xian” for a single 

Chinese character). In some places in the report, “People’s Republic of China” was respectfully replaced with 

“China” to reduce repetition or because of limited space such as in table cells; the United States of America is 

referred to in shortened fashion as well.

Some USGS standards for style of illustrations have been customized as well. In the bar graph figures—

figures 30, 31, 32, and 33—the Legend, or Explanation box, does not include the word “Explanation.” This word 

was eliminated to maintain consistency with the boxes of similar figures in which “Explanation” is not required 

when the box appears within the illustration, as with figures 21–25 and 34–36. In the “Piper diagrams” (figures 

13–20), the term “trilinear graph” replaces the term “Piper diagram.” Some slight variation in graphical elements 

on maps of areas in the People’s Republic of China and the United States is the result of different digital sources.

The References Cited section includes no references pertaining to Chinese data on the study because, 

though available, this information has not been published in the international scientific literature. 

Representatives from various water agencies in the People’s Republic of China (Hai He River Water 

Conservancy Commission, Tangshan Water Resources Bureau, and the Chinese Ministry of Water Resources) 

have worked extensively with the U.S. Geological Survey on the content of this report. This collaboration is 

noted in the authorship on the title page.
Contents V

CONTENTS

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Description of Study Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Hai He River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Delmarva Peninsula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

San Joaquin Valley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Sacramento Valley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Comparison of Study-Unit Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Design of Ground-Water Well Networks for Joint Agreement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Methods and Sample Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Natural Water Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Oxygen and Hydrogen Isotopes in Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Dating of Ground-Water Recharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Assessment of Water-Quality Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Gray Pattern Method of Water-Quality Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Chemical Signatures of Ground Water Affected by Agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Principal Component Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Nitrate and Detection Frequency of Pesticides in Ground Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Comparison of Nitrate Use in Study Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Physical and Chemical Factors Related to the Detection Frequency of Nitrate . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Pesticides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

FIGURES

1–12. Maps showing:

1. People’s Republic of China including the Hai He River Basin and the Tangshan study area . . . . . . . . . . . . 2

2. United States including the Delmarva Peninsula, the Sacramento River Basin, and the 

San Joaquin–Tulare Basins study units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3. Hai He River Basin and Tangshan study area in the People’s Republic of China. . . . . . . . . . . . . . . . . . . . . . 5

4. Tangshan study area, or “study unit,” and locations of wells, transects for detailed investigations, 

county boundaries, and physiographic regions, People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . 6

5. Geomorphic regions of the Tangshan study unit, People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . 7

6. Physiographic regions of the Delmarva Peninsula, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

7. Hydrogeomorphic regions and locations of well networks of the Delmarva Peninsula, United States . . . . . 10

8. Physiographic regions of the San Joaquin–Tulare Basins, California, United States . . . . . . . . . . . . . . . . . . . 12

9. General geohydrologic cross section through the central part of the San Joaquin Valley, 

California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

10–11. Maps showing:

10. Physiographic regions of the Sacramento River Basin, California, United States . . . . . . . . . . . . . . . . . . . . . 14

11. Locations of wells in the San Joaquin Valley, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

12. Locations of wells in the Sacramento Valley, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
VI Contents

13–20. Trilinear graphs of:

13. Major element chemistry of Tangshan ground water, People’s Republic of China . . . . . . . . . . . . . . . . . . . . 21

14. Water chemistry of the Luan He River, People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

15. Major element chemistry of ground water of the Delmarva Peninsula, United States . . . . . . . . . . . . . . . . . . 23

16. Ground water of the western San Joaquin Valley, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . 24

17. Ground water of the southern San Joaquin Valley, California, United States . . . . . . . . . . . . . . . . . . . . . . . . 25

18. Ground water of the eastern San Joaquin Valley, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . 26

19. Subunit ground water, Sacramento, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

20. Rice land-use ground water, Sacramento, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

21–36. Graphs showing:

21. Boxplots of specific conductance for wells within each study unit in the People’s Republic of China 

and the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

22. Boxplots of specific conductance for wells in various physiographic regions of the 

Tangshan study unit, People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

23. Boxplots of specific conductance for wells in various regions of the San Joaquin Valley, 

California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

24. Boxplots of pH for wells within each study unit in the People’s Republic of China 

and the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

25. Boxplots of iron concentration for various zones within study units or for an entire study unit, 

People’s Republic of China and the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

26. Stable isotopes δ deuterium (2H) versus δ18O of ground water in the San Joaquin Valley, 

California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

27. Stable isotopes δ deuterium (2H) versus δ18O of ground water in the Sacramento Valley and 

of the Sacramento River at Colusa, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

28. Stable isotopes δ deuterium (2H) versus δ18O of ground water in the Tangshan study unit 

and of the Qinglong and Luan He Rivers, People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

29. Water levels measured in May and September 1996, Tangshan study unit, People’s Republic of China . . . 34

30. Boxplots of gray scores (gray matrix calculations) for study-unit wells in the People’s Republic of China 

and the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

31. Boxplots of nitrate concentrations in ground water for various zones within study units or for an 

entire study unit in the People’s Republic of China and the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

32. Boxplots of total dissolved solids concentrations in ground water for various zones within study units 

or for an entire study unit in the People’s Republic of China and the United States . . . . . . . . . . . . . . . . . . . 40

33. Boxplots of calcium concentrations in wells with low and high nitrate in the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

34. Boxplots of sulfate concentrations in wells with low and high nitrate in the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

35. Boxplots of pH in wells with low and high nitrate in the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

36. Boxplots of iron concentrations in wells with low and high nitrate in the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

37, 38. Maps showng:

37. Geomorphology and range of principal component 2 values for wells of the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

38. Range of principal component 2 values for wells of the Delmarva Peninsula study unit, United States . . . 46

39–43. Graphs showing:

39. δ15N and δ18O in nitrate for select wells of the Tangshan study unit, People’s Republic of China . . . . . . . . 48

40. Nitrate concentration versus well depth for wells of the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

41. Nitrate concentration versus water level below land surface for wells of the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

42. Nitrate concentration versus iron concentration for wells of the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Contents VII

43. Nitrate concentration versus total dissolved solids concentration for wells of the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

44. Locations of wells and corresponding levels of nitrate concentrations for the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

45. Boxplots of nitrate concentrations by Chinese name designation for wells of the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

TABLES

1. Comparison of geographic and hydrologic characteristics of the four study units in the 

People’s Republic of China and the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2. Results of stable isotope analyses—δ deuterium and δ18O in water—for wells of the Tangshan study unit, 

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

3. Results of dating analyses for wells of the Tangshan study unit, People’s Republic of China . . . . . . . . . . . . . . . . 34

4. Classification of representative values of National Standards of Groundwater Quality in the 

People’s Republic of China, and of primary and secondary standards of the 

U.S. Environmental Protection Agency in the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

5. Gray matrix summary for upper aquifer (plain region) of the Tangshan study unit, 

People’s Republic of China, May 1996 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6. Gray matrix summary for upper aquifer (plain region) of the Tangshan study unit, 

People’s Republic of China, May 1996 data, without coliform analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

7. Gray matrix summary for upper aquifer (plain region) of the Tangshan study unit, 

People’s Republic of China, September 1996 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

8. Gray matrix summary for lower aquifer (plain region) of the Tangshan study unit, 

People’s Republic of China, May 1996 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9. Gray matrix summary for lower aquifer (plain region) of the Tangshan study unit, 

People’s Republic of China, September 1996 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

10. Gray matrix summary for aquifer of the mountain region of the Tangshan study unit, 

People’s Republic of China, May 1996 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

11. Gray matrix summary for aquifer of the mountain region of the Tangshan study unit, 

People’s Republic of China, September 1996 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

12. Gray matrix summary for aquifer of the coastal region of the Tangshan study unit, 

People’s Republic of China, May 1996 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

13. Gray matrix summary for aquifer of the coastal region of the Tangshan study unit, 

People’s Republic of China, September 1996 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

14. Gray matrix summary for aquifer of the Delmarva Peninsula study unit, United States . . . . . . . . . . . . . . . . . . . . . 37

15. Gray matrix summary for upper aquifer of the western region of the San Joaquin Valley study unit, California, 

United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

16. Gray matrix summary for lower aquifer of the western region of the San Joaquin Valley study unit, California, 

United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

17. Gray matrix summary for upper aquifer of the southern region of the San Joaquin Valley study unit, California, 

United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

18. Gray matrix summary for lower aquifer of the southern region of the San Joaquin Valley study unit, California, 

United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

19. Gray matrix summary for the unassigned aquifer of the southern region of the San Joaquin Valley study unit, 

California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

20. Gray matrix summary for the eastern aquifer of the San Joaquin Valley study unit, California, United States . . . 37

21. Gray matrix summary for aquifer of the Sacramento subunit area of the Sacramento Valley study unit, 

California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
VIII Contents

22. Gray matrix summary for the aquifer of the rice land-use study area of the Sacramento Valley study unit, 

California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

23. Results of principal component analyses of chemical data from the Tangshan study unit,

People’s Republic of China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

24. Results of principal component analyses of chemical data from the Delmarva Peninsula study unit, 

United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

25. Results of principal component analyses of chemical data from the western region of the 

San Joaquin Valley study unit, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

26. Results of principal component analyses of chemical data from the southern region of the

San Joaquin Valley study unit, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

27. Results of principal component analyses of chemical data from the eastern region of the

San Joaquin Valley study unit, California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

28. Results of principal component analyses of chemical data from the Sacramento Valley study unit, 

California, United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

29. Comparison of nitrate use in counties of study units within the People’s Republic of China 

and the United States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

30. Usage or generation of manure in counties of study units within the People’s Republic of China and the

United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

31. Nitrogen content of manure from various animals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Contents IX

CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATIONS

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F = (1.8)°C + 32

Sea level: In this report “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD

of 1929)—a geodetic datum derived from a general adjustment of the first-order level nets of both

the United States and Canada, formerly called Sea Level Datum of 1929.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 25°C).

Concentrations of chemical constituents in water are given in either milligrams per liter (mg/L) or

micrograms per liter (μg/L).

1 megagram = 1 metric ton = 1 tonne = 1,000 kilogram

Abbreviations and Acronyms

μg/L, microgram per liter

μm, micrometer

μS/cm, microsiemens per centimeter

pCi/L, picocurie per liter

CFC, chlorofluorocarbon

DBCP, 1,2-dibromo-3-chloropropane

δ, delta

EPA, U.S. Environmental Protection Agency

GIS, Geographic Information System

H, hydrogen

2H, deuterium

3H, tritium

3He, helium-3

N, nitrogen

NAWQA, National Water-Quality Assessment (Program)

O, oxygen

p, level of statistical significance

per mill, parts per thousand

PRC, People’s Republic of China

RASA, Regional Aquifer Systems Analysis

ρ, Spearman’s rho

U.S., United States

USGS, U.S. Geological Survey

yr, year

Multiply By To obtain

cubic meter (m3) 0.0008107 acre-foot 

kilogram (kg) 2.205 pound avoirdupois

kilometer (km) 0.6214 mile 

megagram (Mg) 1.102 ton (2,000 lb)

megagram per square kilometer (Mg/km2) 2.855 ton (2,000 lb) per square mile

meter (m) 1.094 yard 

 milligram per liter (mg/L) 8.345 pound per million gallon

millimeter (mm) 0.03937 inch

square hectometer (hm2) 2.471 acre

square kilometer (km2) 0.3861 square mile
Introduction 1

Comparative Water-Quality Assessment of the Hai He 

River Basin in the People’s Republic of China and Three 

Similar Basins in the United States

By Joseph Domagalski, Zhou Xinquan, Lin Chao, Zhi Deguo, Fan Lan Chi, Xu Kaitai, Lü Ying, Luo Yang, 

Liu Shide, Liu Dewen, Guo Yong, Tian Qi, Liu Jing, Yu Weidong, Robert Shedlock, and Donna Knifong

ABSTRACT

Ground-water quality with respect to nitrate, 

major inorganic constituents, pesticides, stable isotopes, and tritium was assessed in the agricultural 

Tangshan region in the Hai He River Basin of the 

People’s Republic of China and compared with 

three similar regions in the United States: the 

Delmarva Peninsula of the states of Delaware, 

Maryland, and Virginia; and the San Joaquin and 

Sacramento Valleys of the state of California. 

These four regions are considered similar with 

respect to size, land use, or climate. Although the 

Tangshan region has been in agricultural production for a much longer time, probably several centuries, than the three regions of the United States, 

the widespread use of synthetic fertilizers and 

other soil amendments probably started at a similar 

time in all four regions. Median nitrate concentrations were found to be similar in the four regions in 

most instances, and those median concentrations 

were below the American nitrate drinking water 

standard of 10 milligrams per liter; however, 

higher concentrations, and a greater range of concentrations, were evident for the Tangshan region. 

In some water samples collected from a shallow 

aquifer in Tangshan, nitrate concentrations 

exceeded the Chinese standard of 20 milligrams 

per liter, whereas few comparative samples collected in the United States exceeded that standard. 

In Tangshan, recently recharged (early 1960s) 

water that was detected in wells drilled as deep as 

150 meters was found to correlate with the elevated 

nitrate concentrations. Relatively low nitrate, 

which is indicative of natural water, was measured 

in older water of deeper wells. In addition to elevated nitrate concentrations, the agricultural area of 

the Tangshan region has been affected by an 

increase in the concentrations of total dissolved 

solids and iron. The increase in total dissolved 

solids of the Tangshan study unit could not be 

attributed to any one process. Increases in iron concentrations may be partly attributable to the widespread application of animal wastes and sewage as 

fertilizer, which could deplete oxygen concentrations in ground water and lead to dissolution of iron 

from various minerals. In contrast to the United 

States, pesticides were not detected in aquifers of 

the Tangshan region, which could be attributed to 

lower pesticide use in the People’s Republic of 

China. Alternatively, pesticide use may be increasing in the People’s Republic of China, but the 

pesticides would not yet have been detected in 

ground water because of the lag in travel time from 

soil horizons to the aquifer.

INTRODUCTION

In 1986, the U.S. Geological Survey (USGS) initiated a pilot program, the National Water-Quality 

Assessment (NAWQA), designed to assess the current 

water-quality conditions, to identify trends, and to 

describe the natural and anthropogenic factors affecting 

water-quality conditions on regional and national levels. Full-scale implementation of the NAWQA Program 

began in 1991. The goals and design of the NAWQA 

Program are described by Hirsch and others (1988) and 

by Gilliom and others (1995). The NAWQA Program 
2 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

EXPLANATION

Tangshan study area

Hai He River Basin boundary

People's Republic

of China

MONGOLIA

NORTH KOREA

RUSSIA

PAKISTAN

INDIA

NAPAL

BHUTAN

TAJIKISTAN

0 500 MILES

0 500 KILOMETERS

Urumqi

Lanzhou

Xi'an

Tangshan

Taian

Chengdu

Chongqing

Shenyang

Jilin

Harbin

Changchun

Guiyang

Hangzhou

Guangzhou

Nanjing

Huainan

Tianjin

Tayauin

Dezhou

Beijing

Ji'nan

Shanghai

Shaozing

Dalian

Hong Kong

Taipei

Wuhan

Bohai

YELLOW 

SEA

EAST CHINA

SEA

SOUTH CHINA

SEA

OS LA

RA IN

NAY M

VIET NAM

KJRGYZSTAN

KAZAKHSTAN

map data: Environmental Systems Research Institute, 1998

has successfully described and identified the extent and 

causes of nitrate and other contamination in ground 

water and surface water on regional and national levels. 

This success is attributed to a uniform approach to 

study design, through understanding of the hydrological factors that affect contaminant concentrations and 

transport in aquifers and rivers, and to an adherence to 

strict quality control practices in the field and laboratory. Currently, the NAWQA Program is focusing on 

nonpoint sources of contamination, including nitrogen 

fertilizer and pesticides. To address these contamination problems in ground water, studies are designed on 

various spatial scales. Three types of ground-water 

studies are used in NAWQA ground-water investigations. The first is a study-unit survey whereby a randomly selected population of wells, in a defined part of 

a study unit and normally within a continuous aquifer 

system, is sampled for natural water and contaminant 

chemistry. The second is the land-use survey, which targets specific types of land uses within an aquifer setting. The third is the flow-path study, which addresses 

ground-water and surface-water interactions. 

As a result of a rapidly developing economy and 

intensive agricultural land-use practices, some areas of 

the People’s Republic of China have shown evidence of 

ground-water and surface-water quality degradation. In 

the People’s Republic of China, water quality and availability can affect future economic growth, and the lack 

of clean water can have serious consequences for 

human health and agricultural production. To help 

address and better understand these problems, as well 

as to provide a framework for effective management, a 

cooperative research project was initiated in 1995 to 

utilize parts of the NAWQA approach to study the reasons for nitrate and other agricultural contamination 

problems within the region surrounding the city of 

Tangshan in the Hai He River Basin (Zhang, Suo Zhu, 

Hai He River Water Conservancy Commission, written 

commun., 1996) of the People’s Republic of China (fig. 

1). This project, hereinafter referred to as the “joint 

agreement,” included an assessment of nitrate and other 

water-quality constituents of an agricultural region 

north of the city of Tangshan along with a comparative 

assessment of three similar agricultural regions of the 

United States—the Delmarva Peninsula, the San 

Joaquin–Tulare Basins, and the Sacramento River 

Basin (fig. 2). The joint agreement was designed to 

introduce methodologies of ground-water assessment 

not widely available in the People’s Republic of China, 

such as stable isotope chemistry and methods of dating 

Figure 1. People’s Republic of China including the Hai He River Basin and the Tangshan study area (Xiudong, 1989). 
Introduction 3

ground-water recharge. At the time of the writing of the 

joint agreement, the stable isotope and dating studies 

were considered to be among the most important work 

elements of the agreement. The joint agreement was 

also designed to introduce water-quality scientists in 

the People’s Republic of China to the methods of landuse analysis using a Geographic Information System 

(GIS). It was anticipated that a similar approach to 

study design would allow for a direct comparison of the 

geochemical and hydrological conditions in the four 

study areas, and that this comparison would benefit 

researchers and scientists both in the United States and 

in the People’s Republic of China.

Although information was available on the 

chemistry of ground water in the Tangshan region, 

information about Tangshan’s ground-water flow system was scarce. Whereas the general direction of flow 

of predevelopment ground water was known or 

assumed, little was known about the effect of agricultural development and pumpage on the flow system and 

the areas of the aquifer that were most susceptible to 

contamination. Knowledge of the age distribution of 

ground water, and possibly the use of stable isotopes, 

could enable scientists and water managers of the 

People’s Republic of China to determine these effects 

and to plan effective control strategies to protect water 

quality. 

Three dating methods, tritium (3

H), tritium/ 

helium-3 (3

H/3He), and the chlorofluorocarbons 

(CFCs), were selected—in the joint agreement—to 

determine the age of recently recharged (less than 50 

years) ground water. 3

H analysis is used to determine if 

recharge occurred before or after the 1950s (Plummer 

and others, 1993). 3

H/3He analysis provides better temporal resolution than 3

H, especially for recharge that 

occurred in the decade after the 1950s. CFCs are 

organic compounds used as refrigerants and are globally distributed in the atmosphere. The partitioning of 

CFCs in rainwater is known, and the amounts of specific CFCs in the atmosphere, as a function of time, are 

known or have been calculated (Plummer and others, 

1993). CFC analyses can provide even better temporal 

resolution on recharge date, but the method does not 

work for all ground-water systems. The method works 

best for sandy aquifers where dissolved oxygen is 

present. Complicating factors that arise when using 

CFC analysis include microbial degradation of the 

CFCs or contamination of the ground water with excess 

San Francisco

Los Angeles

New York

Washington, D.C.

Delmarva Peninsula

Study unit

Sacramento River Basin

San Joaquin–Tulare Basins

EXPLANATION

ATLANTIC

OCEAN

PACIFIC

OCEAN

map data: Environmental Systems Research Institute, 1998

0 500 MILES

0 500 KILOMETERS

Figure 2. United States including the Delmarva Peninsula, the Sacramento River Basin, and the San Joaquin–Tulare Basins study units. 

Other NAWQA study units are shown by the solid contours for comparison.
4 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

CFCs, as happens near landfills. Therefore, a combination of dating techniques was used for the Tangshan 

region. 

Stable isotope studies were restricted to hydrogen and oxygen isotopes (ratio of 2

H to 1H, and the ratio 

of 16O to 18O) in water molecules, and nitrogen (ratio of 14N to 15N) and oxygen (ratio of 16O to 18O) isotopes in 

nitrate molecules. These isotopes can be related to precipitation and ground-water recharge flow paths and to 

the type or source of nitrogen in ground water (Coplen, 

1993). 

The purpose of this report is to compare data and 

interpretations of ground-water chemistry and agricultural contaminant chemistry for the Tangshan region of 

the People’s Republic of China and three study units in 

the United States: Delmarva Peninsula, which includes 

parts of the states of Delaware, Maryland, and Virginia; 

and the San Joaquin and Sacramento Valleys in the central region of the state of California. This report presents new data collected in the Tangshan region during 

1996 and 1997, and also includes a reexamination of 

data previously published for the three regions of the 

United States. The original data on the United States 

regions, or “study units,” were collected between 1985 

and 1997.

DESCRIPTION OF STUDY UNITS

The following sections describe the general environmental and land-use characteristics of the study 

units chosen for this joint agreement.

Hai He River Basin

The Hai He River Basin (figs. 1 and 3) is located 

in the northern part of the People’s Republic of China 

(35°N to 41°N, and 112°E to 120°E). The basin consists 

of mountains and plateaus in the northern and western 

parts, and the North China Plain in the eastern and 

southern parts. The Hai He River Basin belongs to the 

semihumid climate in the monsoon region of the East 

Asia warm Temperate Zone (Edmonds, 1998). The 

winters are dry and cold, with low rainfall in the spring 

and heavy rainfall in the summer. The average annual 

precipitation is 548 mm, about 80 percent of which falls 

during June to September. The Hai He River Basin is 

composed of two large river systems: the Hai He River 

system and the Luan He River system. The Hai He 

River system includes the Hai He River and several 

major tributaries, and part of the South Grand Canal, a 

major canal. The Luan He River system includes the 

Luan He River and several tributaries. The Hai He 

River Basin includes two very large cities—Beijing and 

Tianjin—and numerous other cities, including 

Tangshan. The drainage basin is 318,800 km2

, of which 

189,000 km2 is mountainous and the remainder is plain 

(Lin Chao, Hai He River Water Conservancy Commission, written commun., 1998). The basin population is 

118 million people and there are 110 million square 

hectometers of farmland (Lin Chao, Hai He River Water 

Conservancy Commission, written commun., 1998). 

The cropping patterns in the Tangshan study unit are 

diverse, and the major crops are wheat, rice, corn, sorghum, cotton, and peanuts. The population density is 

370 people per square kilometer. Water resources, 

which are deficient in the basin, average 40.4 billion 

(40.4  109

) cubic meters per year (Lin Chao, Hai He 

River Water Conservancy Commission, written commun., 1998). Surface runoff is 26.4 billion cubic 

meters. The average surface water per capita use is 251 

m3/yr (Lin Chao, Hai He River Water Conservancy 

Commission, written commun., 1998). This can be 

compared to a per capita usage in the United States 

(based on data collected in 1990) of 9,913 m3

/yr (Population Action International, 2000). As a result of the 

large population and the large amount of land in agriculture, water resource projects have been constructed 

to control floods, improve drainage, and provide for 

irrigation and water supply. Serious water contamination problems also exist in the basin. The annual 

amount of wastewater is about 4.71 billion megagrams, 

about 4 billion megagrams of which is discharged into 

rivers (Lin Chao, Hai He River Water Conservancy 

Commission, written commun., 1998). The combined 

problems of water shortage and water contamination 

limit economic and agricultural development.

The region chosen for the ground-water investigation, hereinafter called the “Tangshan study unit,” is 

located within an area known as the North China Plain, 

about 160 km southeast of Beijing (fig. 3) (Xiudong, 

1989). The 13,472 km2 study unit is about 130 km from 

east to west and 150 km from north to south, and has 

180 km of coastline. The study unit slopes from the 

front of the mountain region southward to the Bohai 

Sea, resulting in a general predevelopment direction of 

ground-water flow to the ocean (Zhang, Suo Zhu, Hai 

He River Water Conservancy Commission, written 

commun., 1996). Three physiographic regions are 

defined for this study: the mountain region of the north, 

the plain region in the center, and the coast region to the 

south (fig. 4) (Xiudong, 1989). The mountain region 

covers 4,620 km2

, the plain region 4,884 km2, and the 

coast region 3,968 km2

. Several geomorphic zones are 

recognized (fig. 5) within these physiographic regions. 

The Tangshan study unit is characterized by the monsoon climate of the Asian warm Temperate Zone, with 

cold winters and hot wet summers. The average annual 

temperature is 10.5°C (Zhang, Suo Zhu, Hai He River 

Water Conservancy Commission, written commun., 
Description of Study Units 5

1996). Annual precipitation decreases from 750 mm in 

the northern mountain region to 600 mm in the southern plain. The average precipitation in the study unit is 

645 mm, most of which falls between June and September (Zhang, Suo Zhu, Hai He River Water Conservancy 

Commission, written commun., 1996). The Luan He 

River is the largest river in the study unit and has perennial flow. The study unit also includes many smaller 

rivers with seasonal or very low base flow. All rivers 

flow into the Bohai Sea from the north, southwest, and 

southeast. Water resources development is very important in the study unit, which includes 162 reservoirs 

with a total storage capacity of 4,361 billion cubic 

meters (Lin Chao, Hai He River Water Conservancy 

Commission, written commun., 1998). 

Geologically, the Tangshan study unit lies at the 

corner of the North China Platform (Yang and others, 

1986). This area has a complex geologic history, 

including folding and faulting of the nearby mountains. 

The area is also influenced by distant tectonic processes, including the movements of the Himalaya 

Mountains, which raised the mountains of the 

Tangshan study unit during the Cenozoic era. Movement along faults has resulted in serious earthquakes, 

including a devastating impact on the city of Tangshan 

during the 1970s. In the east, the bedrock comprises 

Archaean metamorphic and igneous rock (Yang and 

others, 1986). The mineralogy includes feldspars, 

quartz, and dolomite. The western and middle areas of 

the study unit have arenaceous rocks of the Permian, 

Figure 3. Hai He River Basin and Tangshan study area in the People’s Republic of China.

0

0

50

50

100 KILOMETERS

100 MILES

116

113

39

41

37

119

People's Republic 

 of China

B O HAI S E A

gding He

H River

e River Da

Yunhe (Grand Canal

Zhang H

Tangshan study area

Hai He River Basin boundary

EXPLANATION
6 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Figure 4. Tangshan study area, or “study unit,” and locations of wells, transects (T1 through T4) for detailed investigations, county 

boundaries, and physiographic regions, People’s Republic of China. A well group consists of two or more wells. Well sites show the regional 

identifier (Ben1, Lao1, Nan1, etc.), which corresponds to the Chinese naming convention.

0

0

20

20

40 MILES

40 KILOMETERS

LUAN XIAN

QIANAN

LUANAN

TANGHAI

FENGRUN

ZUNHUA

QIANXU

YUTIAN

LAOTING

11845

3910

118

4020

Well site—Color indicates site selected for more 

 detailed water-quality sampling, including dating 

 of ground water or isotope studies. Includes regional 

 identifier.

 Well-group location

 Single-well location

Transect and identifier— Approximate line 

 of detailed investigation

 T1

 T2

 T3

 T4

Physiographic region

 Mountain

 Plain

 Coastal

map data: 

base: Hai He River Water Conservancy Commission, 

 original map scale 1:400,000, publication data unavailable

TANGSHAN

FENGNAN

 T4

T3

T2

T1

Luan6

Luan5

Shan15

Shan14

Shan9

Shan7

Shan6

Shan17

Shan18

Shan13 Shan16 Shan12

Shan11

Shan8

Luan4

Luan1 Luan3

Luan2

Shi5

Shi6

Lao7

Lao6

Lao2 Lao4

Lao1

Lao3

Ben6

Ben7

Ben5 Ben8

Nan2

Nan1

Run4 Run7

Run6 Run3 Yu7

Yu6

Yu4

Yu3

Shan5

Shan2

Shan4

Shan1 Shan3

Yu1 Yu5

Yu2

Run2

Run1

Run5 Shi1

Shan10

Shi2

Shi4

Xian3

Xian5

Xian6 Xian7

Xian8 Xian9

Xian2

Xian1

Nan4

Nan5

Ben4

Ben2

Lao5

Lao8

Ben3 Ben1

Nan3

Xian4

EXPLANATION
Description of Study Units 7

Figure 5. Geomorphic regions of the Tangshan study unit, People’s Republic of China. Well sites show the regional identifier (for example, 

Ben1, Lao1, and Nan1), which corresponds to the Chinese naming convention.

Run5

3

Run7

L

La

Ben7

en8

Run6

Well site accompanied by regional identifier

Boundaries

Tangshan study unit boundary

Boundary between coastal and plain

 physiographic regions

Boundary between plain and mountain 

 physiographic regions

Coastal deposits below sea level

Geomorphology

Other coastal deposits

Reservoirs

Slight highland on flood basin

Old flood basin

Flood plain

Natural levee or dike

Flat land

Slightly sloped land

Old riverbed highland

Slight highland

Area formed by collapsed

 or destroyed levee or dike

Alluvial area

Terrace

Sloped land, slope less than 3 degrees

Sloped land, slope greater than 3 degrees

Valley

Low hill, height less than 50 meters

High hill, height 50 to 300 meters

Low mountain, height 300 to 1,000 meters

EXPLANATION

0

0

20

20

40 MILES

40 KILOMETERS

118

11845

map data: 

base: Hai He River Water Conservancy Commission, 

 original map scale 1:400,000, publication data unavailable 

geomorphology: Hai He River Water Conservancy Commission, 

 orginal map scale and publication date unavailable
8 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Mississippian, and Pennsylvanian Periods and tuffs of 

the Tertiary Period. The western parts of the study unit 

also include Ordovician limestone. The southern part of 

the study unit includes primarily coastal deposits. The 

surficial deposits of the plain area are composed of 

primarily Quaternary deposits, including gravels, 

sands, clayey sands, and clays. 

Four aquifer systems are recognized in the Tangshan study unit, Aquifers 1–4. Aquifers 1 and 2 are 

shallow and have good recharge characteristics, 

whereas aquifers 3 and 4 are deeper and separated from 

the overlying aquifers by clayey sand or clay layers, 

although those layers are probably not continuous 

(Zhang, Suo Zhu, Hai He River Water Conservancy 

Commission, written commun., 1996). Aquifer 1 is not 

continually saturated under the present conditions of 

recharge and water use and has generally been lost as a 

water-producing unit. The thickness of Aquifer 1 is 

20–140 m. The thickness of Aquifer 2 is 40 to 240 m. 

The sediments are alluvial, diluvial, or lacustrine. 

Aquifer 3 is about 20 to 140 m thick. The sediments are 

composed of alluvial, diluvial, and marine sediments. 

Aquifer 4 is about 10 to 20 m thick. All of the upper 

sedimentary material is from the Quaternary period and 

is composed mainly of alluvial, diluvial, or lacustrine 

sediments. Information on the saturated thickness of 

these aquifers was provided by the Hai He River Water 

Conservancy Commission (Lin Chao, Hai He River 

Water Conservancy Commission, written commun., 

1998).

Delmarva Peninsula

The general environmental setting of the Delmarva Peninsula has been described in Hamilton and 

others (1993). The Peninsula has an oval shape that 

extends about 241 km north to south and about 113 km 

east to west at its widest point and its physiography 

consists mostly of the Coastal Plain with a small 

amount of the Piedmont upland in the north (fig. 6). The 

Delmarva Peninsula is a flat to gently rolling upland, 

which is flanked by low plains that slope toward the 

Chesapeake Bay, the Delaware Bay, and the Atlantic 

Ocean. Tidal wetlands are located close to the coastline. 

A wedge of unconsolidated sediments, which 

thickens to the south and east, underlies the Delmarva 

Peninsula. The thickness of the sediment varies considerably: it is more than 2,400 m along the Atlantic Coast 

of Maryland, whereas no sediment is located along the 

boundary of the Coastal Plain and Piedmont upland 

physiographic regions (fig. 6). The sediments range 

from Cretaceous to Quaternary (Holocene) in age and 

are comprised primarily of sand, clay, silt, gravel, and 

variable amounts of shells. The wedge of sediments is 

underlain by Precambrian igneous and metamorphic 

rocks, and sedimentary rocks of the Cretaceous Period. 

Previous studies in Cushing and others (1973) identified a series of nine confined aquifers and associated 

confining units, whereas Harsh and Laczniak (1990) 

identified only six confined aquifers and associated 

confining units. In either case, the series of confined 

aquifers is overlain by an extensive surficial aquifer that 

is under unconfined conditions in most of the study 

unit. This surficial aquifer is the focus of the waterquality studies for this study unit because it supplies 

water to the confined underlying aquifers and also 

because it is used extensively. About one half of the 

643,000 m3 of water that is pumped daily from wells is 

withdrawn from the surficial aquifer. 

A description of the surficial aquifer of the 

Delmarva Peninsula has been provided in Hamilton and 

others (1993). Previous authors who also have reported 

on this aquifer include Rasmussen and others (1955), 

Jordan (1962, 1964), Hansen (1966), Cushing and 

others (1973), Owens and Denny (1978, 1979a,b), 

Denny and others (1979), Owens and Minard (1979), 

Hansen (1981), Bachman (1984), Owens and Denny 

(1984), Mixon (1985), and Andres (1986). Briefly, the 

sediments that compose the surficial aquifer represent 

several time-stratigraphic units, and those sediments 

were deposited in fluvial, estuarine, and marine and 

marginal marine environments. Most investigators consider the deposits to be from the Pleistocene Epoch. The 

mineralogy of these sediments consists of quartz sand 

and varying amounts of plagioclase, orthoclase, feldspars, and glauconitic sand. Minor amounts of heavy 

minerals are also present.

The Delmarva peninsula includes primarily one 

major physiographic region, the coastal plain, but comprises seven hydrogeomorphic regions within the plains 

(described in Hamilton and others, 1993): the poorly 

drained upland, the well-drained upland, the surficial 

confined region, the poorly drained lowland, the finegrained lowland, the inner coastal plain, and “other” 

(fig. 7). Knowledge of these hydrogeomorphic regions 

is critical in understanding major element chemistry 

and contaminant transport. The surficial aquifer has 

been described as “under water table conditions 

throughout most of the study unit” (Hamilton and 

others, 1993, p. 8). The shallow water table is about 

0–3 m below land surface in the central uplands. The 

water table is deeper in the well-drained uplands (as 

deep as 12 m below land surface). The flow in the surficial aquifer is from local water-table highs to streams 

and the coast. The ground-water flow paths are generally shorter than a few kilometers (Hamilton and others, 

1993). Within these regions, agriculture is the major 

land use, woodlands constitute about 31 percent of the 

land area, and residential or urban development 

constitutes about 13 percent.

The average annual precipitation for the 

Delmarva Peninsula is 1,143 mm/yr. More than half of 
Description of Study Units 9

Figure 6. Physiographic regions of the Delmarva Peninsula, United States. Includes state and county boundaries.

0

0

20

20

40 KILOMETERS

40 MILES

Coastal Plain

Physiographic region

Piedmont Upland

CHESAPEAKE BAY

ATLA

NTIC OCEAN

DELAWARE BAY

Chest

Cambridge

Eastville

Cape Charles

Rehoboth

Beach

y

SO

NORTHAMPTON NORTHAM

DORCHESTER

38

39

EXPLANATION

map data: U.S. Geological Survey, 1981a,b; 1983 c,e,f,g; 1984a,b,e,i; 1999
10 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Figure 7. Hydrogeomorphic regions and locations of well networks of the Delmarva Peninsula, United States. Includes county boundaries.

0

0

20

20

40 MILES

40 KILOMETERS

76

39

38

EXPLANATION

Surficial confined 

Hydrogeomorphic region

Inner coastal plain

Well-drained upland

Fine-grained lowland

Poorly drained lowland

Poorly drained upland

Other

Areal well network

Transect well network

NEW

CASTLE

CECIL

KENT

CAROLINE

SUSSEX

WICOMICO

WORCESTER

ACCOMACK

SOMERSET

NORTHAMPTON

TALBOT

DORCHESTER

QUEEN

ANNES

KENT

map data: Hamilton and others, 1993.

 U.S. Geological Survey, 1981a,b; 1983c,e,f,g; 1984a,b,e,i; 1999
Description of Study Units 11

this precipitation falls as rain during the spring and 

summer, but most of the recharge from the surface to 

the surficial aquifer occurs in the winter and spring 

nongrowing seasons when evapotranspiration is low. 

Much of the agricultural land in the Delmarva Peninsula is used for soybeans and corn, which are used for 

poultry feed (Hamilton and others, 1993; Shedlock and 

others, 1999). In addition to grain crops, other crops 

such as fruits, vegetables, and nursery stock are grown 

for local and regional markets. Large poultry farms are 

found across the peninsula, which is one of the leading 

production areas of broiler chickens in the United 

States (Hamilton and others, 1993; Shedlock and others, 1999).

San Joaquin Valley

The San Joaquin Valley is the low-lying part of 

what is commonly referred to in the USGS as the San 

Joaquin–Tulare Basins (two separate basins that combine to form a larger basin). The San Joaquin–Tulare 

Basins are composed of three major physiographic 

regions—the Coast Ranges, the San Joaquin Valley, 

and the Sierra Nevada (fig. 8). The San Joaquin Valley, 

which is part of the Central Valley of California (fig. 8), 

is subdivided into three physiographic regions: the 

western fans, basin deposits, and eastern fans. Because 

most of the ground-water use, and potential impacts on 

ground water, occur within the valley’s physiographic 

region, that part of the study unit was selected for 

detailed investigation. The valley, which consists of the 

San Joaquin and Sacramento Valleys, is a structural and 

topographic trough more than 805 km long. The San 

Joaquin Valley is the lower two-thirds of the Central 

Valley (fig. 8). A low east-west trending structural high 

in the valley floor just south of the Kings River area 

separates the southern part of the San Joaquin Valley 

into an area dominated by closed drainage. The climate 

in the San Joaquin Valley is Mediterranean with mild 

winters and hot summers. The average annual precipitation ranges from 127 to 406 mm (Page, 1986), most 

of which falls from November to April. As a result of 

the small amount of precipitation, ground-water 

recharge probably is almost exclusively acquired from 

infiltration of irrigation water. Most of the valley floor 

is irrigated. 

A generalized geohydrologic section through the 

central part of the San Joaquin Valley is shown in 

figure 9. The regional freshwater aquifer system is in 

the Tulare Formation of the Pliocene and Pleistocene 

Epochs and in more recently deposited overlying alluvium. Because the Tulare Formation and overlying 

alluvium are lithologically similar, it is difficult to distinguish the boundary between them (Davis and others, 

1959; Page, 1986), and so, it is not shown in figure 9. 

The Corcoran Clay Member of the Tulare Formation is 

an areally extensive fine-grained lacustrine deposit 

throughout the western part of the valley and the 

western part of the southern valley. It is used in this 

report to define the boundary of an upper and lower 

zone of the regional aquifers. The part of the Tulare Formation above the Corcoran Clay Member consists of 

Coast Ranges sediments on the west that interfinger 

eastward with sediments derived from the Sierra 

Nevada.

Alluvial, Pleistocene nonmarine, and other nonmarine deposits of the eastern part of the valley were 

derived primarily from the weathering of granitic intrusives of the Sierra Nevada, with fewer contributions 

from sedimentary and metasedimentary rocks of the 

foothills. The Sierran deposits are primarily highly 

permeable, medium to coarse-grained sands with low 

total organic carbon. The deposits generally are coarsest near the upper parts of the alluvial fans in the eastern 

part of the valley and finest near the valley trough. The 

depth to ground water below land surface varies greatly 

in these deposits (6 to 61 m). The combination of 

coarse-grained deposits and the relatively shallow 

water table results in a high potential for transport of 

nitrate or pesticides in irrigated areas of the eastern part 

of the valley (Domagalski and Dubrovsky, 1991, 1992). 

The alluvial deposits of the western part of the 

valley tend to be of finer texture relative to those of the 

eastern part of the valley because of their origin in the 

Coast Ranges. The Coast Ranges to the west of the San 

Joaquin Valley are a complex mixture, consisting primarily of marine shales with smaller amounts of continental sediments and volcanic rocks. Ground water is 

less than 6 m below land surface over much of the 

western part of the valley, particularly in the lower parts 

of the alluvial fans. The unsaturated zone is primarily 

fine grained in these areas. 

The southern part of the valley has closed drainage except in the wettest years, and lacustrine sediments have been deposited in the lowest topographic 

areas. These fine-grained sediments may tend to inhibit 

the transport of agricultural chemicals such as nitrate 

and pesticides. Stream-channel deposits of coarse sands 

are present along the San Joaquin River and its major 

east-side tributaries. In the valley trough, flood-basin 

deposits of varying extent flank the stream-channel 

deposits. The flood-basin deposits are interbedded 

lacustrine, marsh, overbank, and stream-channel sediment deposits generated by the numerous sloughs and 

meanders of the major rivers. The soils that have developed on these deposits generally are clays with low permeability (Davis and others, 1959). The stream-channel 

and flood-basin deposits are variable in nature with generally shallow water tables. The potential for contaminant transport may be high in places where the coarsetextured deposits are present.
12 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Figure 8. Physiographic regions of the San Joaquin–Tulare Basins, California, United States.

CALIFORNIA

Sacramento River Basin

San Joaquin–Tulare Basins

Sacramento Valley

San Joaquin Valley

38

121120

36

35

37

EXPLANATION

Western fans

Physiographic region

Drainage-basin boundary

Basin deposits

Eastern fans

Coast Ranges

Sierra Nevada

San Joaquin Valley:

Central Valley

PACIFIC OCEAN

0

0

20 40

20 40

MILES

KILOMETERS

San Joaquin

River

map data: Fenneman and Johnson, 1946. California Division of Mines and Geology, 1958; 

 1959; 1964; 1965a,b; 1966; 1967; 1969. U.S. Geological Survey, 1978a. Page,1986

Stockton

Modesto

Fresno

Merced

Bakersfield
Description of Study Units 13

Crystalline basement complex

of the Sierra Nevada

Corcoran Clay Member

of the Tulare Formation

Sierra Nevada sediments

Sierra Nevada sediments

UPPER ZONE

LOWER ZONE

Coast Ranges

sediments

Coast Ranges sediments

San Joaquin River 

? ?

? ?

?

WEST EAST

Depth with respect to sea level, meters –100

100

150

200

250

–50

50

Sea

level

–150

–200

–250

Approximate position of water table

? Queried where uncertain

EXPLANATION

Approximate boundary between sediments of 

Coast Ranges and Sierra Nevada 

0

0

5

5

10 MILES

10 KILOMETERS

(Vertical scale greatly exaggerated)

The San Joaquin Valley probably has the most 

diversified agricultural economy of the four regions 

included in this report. In 1987, about 10 percent of the 

total agricultural production in the United States came 

from California, of which 49 percent, or $6.82 billion 

(in United States dollars), was generated in the San 

Joaquin Valley (Gronberg and others, 1998). Major 

products are livestock and livestock products 

(35 percent), fruits and nuts (33 percent), cotton 

(13 percent), vegetables (6.5 percent), hay and grains 

(6 percent), and other crops (6.5 percent) (Gronberg 

and others, 1998).

Sacramento Valley

The Sacramento Valley is the low-lying part of 

the Sacramento River Basin (fig. 10). The Sacramento 

River Basin comprises six physiographic regions: the 

Great Basin, the Middle Cascade Mountains, the 

Klamath Mountains, the Coast Ranges, the Sierra 

Nevada, and the Sacramento Valley (fig. 10) (Domagalski and others, 1998). The Sacramento Valley is the primary region within the Sacramento River Basin where 

most of the ground-water use and potential effects on 

ground water occur. The Sacramento Valley is the 

northern one-third of the Central Valley. Page (1986) 

has described the geology of the Sacramento Valley as 

part of the northwestward-trending asymmetricstructural trough of the Central Valley that has been 

filled with sediment as much as 16 km in depth. The 

ages of the sedimentary rocks and deposits in the 

Sacramento Valley range from the Jurassic Period to the 

Quaternary Period (Holocene Epoch) and include 

marine and continental rocks and deposits. Much of the 

valley is classified as continental rocks and deposits that 

range from the Pliocene Epoch to Holocene Epoch, 

which are a heterogeneous mix of generally poorly 

sorted clay, silt, sand, and gravel. The valley also 

includes beds of claystone, siltstone, sandstone, and 

conglomerate. River and flood-basin deposits are also 

an important part of the valley’s geology. The river 

deposits consist of gravel, sand, silt, and minor amounts 

of clays; the flood-basin deposits consist of clay, silt, 

and some sand deposited during flood stages of the rivers. The foothills of the Sierra Nevada and Cascade 

Mountains flank the eastern side of the valley. Those 

physiographic regions are composed of volcanic, 

marine, granitic, and continental rocks. The valley is 

flanked on the western side by rocks of the Coast 

Ranges, which are principally marine deposits. The 

Natural Resources Conservation Service (name 

changed from the “Soil Conservation Service” in 

Figure 9. General geohydrologic cross section through the central part of the San Joaquin Valley, California, United States (modified slightly 

from Davis and others, 1959). 
14 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Figure 10. Physiographic regions of the Sacramento River Basin, California, United States (from Domagalski and others, 1998).

39

40

41

123

122

121

map data: 

Fenneman and Johnson, 1946. U.S. Geological Survey, 1972; 1975a,b; 1976a,b,c,d; 1978b,c,d; 

1979a,b,c; 1980; 1983a,b,d; 1984c,d,f,g,h. Steeves and Nebert, 1994

0 20 40 60 MILES

0 20 40 60 KILOMETERS

EXPLANATION

Great Basin

Physiographic region

Middle Cascade Mountains

Sierra Nevada

Klamath Mountains

Sacramento Valley 

 (northern Central Valley)

Coast Ranges

Sacramento 

River Basin 

CALIFORNIA

PACIFIC OCEAN

Sacramento River

Redding

Chico

Colusa

Sacramento
Design of Ground-Water Well Networks for Joint Agreement 15

October 1994) has described the soils of the Sacramento Valley (Soil Conservation Service, 1993). Most 

of the soils are clay with very slow or moderately slow 

infiltration rates. Because of the regional extent of these 

clay soils, rice cultivation is a major agricultural practice in the Sacramento Valley. Fruits and nuts also are 

grown in the Sacramento Valley, but production is limited to regions with well-drained soils, primarily near 

river channels. Row crops, including corn and tomatoes, are also produced. Although clay soils are widespread throughout the Sacramento Valley, no major 

confining layers of clays, such as those that characterize parts of the San Joaquin Valley, occur in the Sacramento Valley. The aquifer of the Sacramento Valley 

resides under unconfined conditions in most of the 

valley (Page, 1986).

The average annual precipitation in the Sacramento River Basin is 914 mm/yr, with most of the precipitation in the form of rain or snow during November 

through March. The precipitation in the Sacramento 

Valley (fig. 10) is less than that of the overall basin, and 

the average annual precipitation measured in Sacramento is 472 mm/yr. Most of that precipitation falls 

also as rain during November through March. More 

rain falls in the mountainous regions, especially in the 

northern part of the basin.

Comparison of Study-Unit Characteristics

A comparison of geographic and hydrologic 

characteristics of the four study units is shown in 

table 1. The study units generally are in about the same 

range of latitude. The greatest differences are the variation in the amount of precipitation, the amount of irrigation water, and the density of population. The 

Delmarva Peninsula has the greatest amount of precipitation and, because a significant percentage of the 

annual precipitation falls during the growing season, 

there is less of a need for irrigation water. The Asian 

monsoon influences the weather of the Tangshan study 

unit, where most of the precipitation falls between June 

and September. Although Tangshan’s precipitation 

coincides with its growing season, annual rainfall 

varies, and usually a significant amount of irrigation 

water is still needed. In contrast, little or no rain falls in 

the San Joaquin and Sacramento Valleys during the 

growing season, and as a result, successful agriculture 

in this region requires irrigation water. 

DESIGN OF GROUND-WATER WELL NETWORKS 

FOR JOINT AGREEMENT

The overall design of the study was to characterize the regional ground-water quality in the Tangshan 

region of the People’s Republic of China and to 

compare the water quality with that of similar areas in 

the United States. Unfortunately, it was not logistically 

possible or necessary to design the sampling strategy 

for the joint agreement such that all sampling would 

take place at the same general time. In fact, sampling 

for two of the study units of the United States—the 

Delmarva Peninsula and the San Joaquin Valley—took 

place prior to the actual design of the joint agreement 

for international study. Participants of the study determined that the basic concept of the NAWQA study-unit 

survey (Gilliom and others, 1995) would be the principal guidance for well selection and data analysis. The 

study unit survey relies primarily on the sampling of 

existing wells and, wherever possible, on the interpretation of existing data collected by other agencies or 

programs. Wells are selected using a grid-based random 

sampling approach (Scott, 1990; Alley, 1993). As mentioned, the ground-water well networks for study units 

in the United States were designed for specific studies, 

including but not limited to NAWQA, and had been 

sampled previously. The design for the joint agreement 

followed the criteria of these earlier studies as closely 

as possible. In all cases, the design of the ground-water 

networks was regional in scope. All well networks were 

designed to obtain water-quality data for a regional 

ground-water system in agricultural areas, and all study 

designs for these well networks included water-quality 

sampling for nitrate and other nutrient compounds. 

However, only the well networks of the San Joaquin 

Valley and the Tangshan aquifer system included samplings of a shallow well and a deep well in most chosen 

locations. Therefore, whereas comparisons can be 

made of the surficial aquifers in all four study units, 

comparisons of deeper aquifers can only be made for 

those in the San Joaquin Valley and the Tangshan study 

units.

The wells of the Delmarva Peninsula were sampled in 1989 and 1990, the wells of the San Joaquin Valley were sampled during 1985 through 1988, and those 

of the Sacramento Valley were sampled in 1996 and 

1997. The wells of the Tangshan aquifer had two samplings for water quality. These were completed in May 

and September 1996 in order to obtain data prior to and 

following the rainy season, respectively. Much of the 

data analysis and interpretation for this study used the 

data from the May sampling, which included more 

comprehensive chemical analyses. 

The design of the water-quality network for the 

Delmarva Peninsula is discussed in detail in Hamilton 

and others (1993). That study was part of the pilot program for the design of study-unit surveys for NAWQA. 

The Delmarva network consisted of two components: 

an aereal network and a transect network (fig. 7). The 

authors of this report decided that the two networks 

would be combined to provide better regional coverage 

of ground-water quality for this joint study.
16 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

The design of the San Joaquin Valley network is 

described in Domagalski and Dubrovsky (1991). Those 

wells were sampled as part of the Regional Aquifer 

Systems Analysis (RASA) Program of the USGS. The 

basic design of the San Joaquin Valley RASA study 

was to sample a set of wells spaced randomly to evenly 

throughout the San Joaquin Valley, thereby approximating the general guidance for design of a NAWQA 

study-unit survey (fig. 11). The design of the San 

Joaquin Valley study most closely approximates that of 

the Tangshan study because shallow and deep wells 

were sampled through most of both study units. 

A general discussion of the design of the Sacramento Valley well network is given in Domagalski and 

others (1998). That well network included a study of a 

part of the Sacramento Valley (Sacramento subunit survey) and an agricultural (rice) land-use survey (fig. 12). 

The well network was based on the NAWQA guidance 

for well selection in a study unit. Because of the areally 

extensive nature of rice agriculture in the Sacramento 

Valley, the authors decided to combine two well networks for data interpretation to provide greater spatial 

coverage. However, the water-quality characteristics 

and interpretation of the water quality of the subunit 

survey and rice wells are discussed separately. 

The well network for the Tangshan aquifer is 

shown in figure 4. A total of 111 wells, used for irrigation and domestic water, were sampled. Water-quality 

samples were also collected at three river sites—two on 

the Luan He River and one site on the Qinglong He 

Table 1. Comparison of geographic and hydrologic characteristics of the four study units in the People’s Republic of China and the United 

States

[hm, hectometer; km, kilometer; m, meter; mm, millimeter; na, not available; yr, year; °C, degree Celsius] 

1

DE, Delaware; MD, Maryland; VA, Virginia.

2

Precipitation is shown as either the average or the range.

Country: People's Republic

of China United States

Study unit: Tangshan 

(Hai He River Basin)

San Joaquin 

Valley

(California)

Sacramento

Valley

(California)

Delmarva Peninsula 

(DE, MD, VA)1

Geographic range:

Latitude 39°03′–40°35′ 35°–38°30′ 38°–40°30′ 37°–30°40′

Longitude 117°30′–119°18′ 120°–120°30′ 120°30′–122°20′ 75°–76°20′

Area (km2

) 13,472 31,216 16,392 15,540

Precipitation2

 (mm/yr) 645 127–380 350–640 1,140

Evaporation (mm/yr) 1,585 1,245 1,245 na

Drought index (evaporation/

precipitation)

2.456 9.8–3.3 3.6–1.9 na

Air temperature, °C (mean, 

highest, lowest)

10, 39.6, –22.07 16.5, 43.9, –8.9 16, 45, –7.8 13.4, 38.5, –20

Aquifer characteristics (single 

or multilayer)

Multilayer Multilayer Single Single

Thickness of the main aquifer 

(m)

10–50 730–2,740 730 30.5 for surficial 

aquifer

Depth of ground water (m) 7.5 6 or greater 6 or greater 6.1

Average annual recharge 

amounts of ground water 

(m3

/yr)

169,000 1,850,222,700 

(combined for San Joaquin and Sacramento 

Valleys)

6,315,456,000

Ground-water use

(104

m3/km2/yr)

14.1 25.8 20.1 1.5

Utilization coefficient of ground 

water (exploitation amount/

recharge amount)

Slightly greater than 

one

Greater than one Less than one Less than one

Area of farmland (km2) 5,806 30,000 13,072 7,459

Proportion of farmland (farmland area/total land)0.431 0.96 0.79 0.48

Irrigation water (m3/hm2) 44,275 4,540 5,080 na

Monitoring well amounts 111 178 59 103

Density of population 

(people/km2

)

512 87 134 45
Design of Ground-Water Well Networks for Joint Agreement 17

Figure 11. Locations of wells in the San Joaquin Valley, California, United States. Includes county boundaries. 

0

0

20 40 60

20 40

MILES

60 KILOMETERS

EL DORADO

SACRAMENTO

AMADOR

ALPINE

SAN 

 JOAQUIN

CALAVERAS

TUOLUMNE

STANISLAUS MARIPOSA

MERCED

MADERA

FRESNO

KINGS

TULARE

KERN

EXPLANATION

San Joaquin Valley floor

 Upper aquifer, western valley

 Upper aquifer, southern valley

 Lower aquifer, western valley

 Lower aquifer, southern valley

 Eastern valley

 Unassigned aquifer, southern valley

San Joaquin–Tulare basins study-unit boundary

San Joaquin Valley sampling site—See

 figure 9 for zones

35

36

37

38

121120

map data: 

U.S. Geological Survey, 1978a. Charles Johnson, U.S. Bureau of Reclamation, unpub. data (county boundaries, scale 1:24,000), 1993
18 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Figure 12. Locations of wells in the Sacramento Valley, California, United States. Includes county boundaries.

0 20 40 60 MILES

0 20 40 60 KILOMETERS

SISKIYOU

MODOC

SHASTA

LASSEN

TEHAMA

PLUMAS

GLENN

BUTTE SIERRA

NEVADA

YUBA

SUTTER

COLUSA

LAKE

NAPA

YOLO

SOLANO

SACRAMENTO

PLACER

EL DORADO

39

40

123

122

121

41

Well sites

 Rice land use

 Sacramento subunit survey 

EXPLANATION

Sacramento Valley floor

Yolo Bypass

Sacrament o

River

map data: 

U.S. Geological Survey, 1972; 1975a,b; 1976a,b,c,d; 1978b,c,d; 1979a,b,c; 1980; 1983a,b,d; 1984c,d,f,g,h. 

Charles Johnson, U.S. Bureau of Reclamation, unpub. data (county boundaries, scale 1:24,000), 1993. Steeves and Nebert, 1994
Natural Water Chemistry 19

River—to compare the chemistry of river water with 

that of ground water. The lower Luan He River was the 

only site sampled for major inorganic constituents, and 

all three sites were sampled for hydrogen and oxygen 

isotopes. At most locations, both a shallow and a deeper 

well were sampled. Four ground water transects were 

selected for detailed analysis by stable isotopes or 

dating analysis. Transects 1 and 2 (lines T1 and T2 

shown in fig. 4) were sampled in June 1996, and the 

analyses included stable isotopes and dating. Water 

samples were also collected for the analysis of pesticides at select wells along those transects. Not all of the 

wells were sampled for all three types of dating 

methods because of logistics difficulties or because not 

all of the wells were suitable for this type of sampling. 

At the very least, samples for tritium (3

H) were collected. Transects 3 and 4 were sampled in September 

1996 for stable isotopes to provide a better spatial resolution of the distribution of deuterium and oxygen isotopes in ground water. Water-quality technicians of the 

Hai He River Water Conservancy Commission or 

Tangshan Water Resources Bureau collected waterquality samples in May and September 1996. The May 

sampling occurred prior to the Asian monsoon season 

and the September sampling afterwards. In that way, 

the effects on water quality of very recently recharged 

water could be examined.

The well network for the Delmarva Peninsula 

(fig. 7) had a total of 103 wells sampled in 1989 and 

1990. In the well network for the San Joaquin Valley 

(fig. 11), 178 wells were sampled. The wells of the 

western San Joaquin Valley were sampled in 1985, 

those of the southern part in 1986, and those of the eastern part in 1987. The 59 wells of the Sacramento Valley 

were sampled in 1996 and 1997. The well network of 

the Sacramento Valley is shown in figure 12.

METHODS AND SAMPLE ANALYSIS

The methodology chosen to collect water from 

ground-water wells for the study units of the United 

States conformed to established USGS procedures. 

Ground-water samples for the Delmarva study unit 

were collected according to the method in Hardy and 

others (1989), which called for the removal of standing 

water in the well by pumping at least three well-casing 

volumes of water and monitoring field-measured constituents such as temperature, pH, and specific conductance. After these field-measured constituents had 

stabilized, water samples were collected through noncontaminating equipment such as Teflon tubing. Water 

samples were filtered through 0.45 μm pore-size filters 

for dissolved constituents. Quality assurance and 

quality control practices for the Delmarva study were 

summarized in Jones (1987), Hardy and others (1989), 

and Koterba and others (1991). The purpose of the quality assurance and quality control practices was to 

ensure that accurate and representative water-quality 

data for each sampling network were acquired and to 

estimate the variability in selected water-quality constituents. These quality assurance and quality control 

practices included the cleaning of equipment used for 

sampling, collecting blank samples using the same procedures that are used for real water samples, and collecting replicate samples to determine variability 

caused by sampling or laboratory analysis. 

A similar strategy was used for collecting waterquality samples from wells in the San Joaquin Valley, 

which is summarized in Dubrovsky and others (1991). 

Sampling for wells in the Sacramento Valley conformed 

to guidance provided by the NAWQA Program 

(Koterba and others, 1995). Most chemical analyses of 

water collected from all wells in the United States were 

conducted by the USGS’s National Water Quality Laboratory in Arvada, Colorado, except for 3

H and 3H/3He 

analyses. Most of the analytical methods are described 

in Fishman and Friedman (1985). Some samples were 

analyzed for pesticides using the methods in Zaugg and 

others (1995). 

Radiochemical analyses were completed on 

many samples, including some collected in the People’s 

Republic of China. The dating methods were the 3

H, 

3

H/3He, and CFC methods. Stable isotope analyses 

were limited to deuterium (2H) to hydrogen (1H) ratio 

and oxygen 18 (18O) to oxygen 16 (16O) ratios, both in 

water molecules; and to nitrogen (14N to 15N ratio) and 

oxygen (18O to 16O ratio) isotopes in nitrate. 

Ground-water samples in the People’s Republic 

of China were collected from existing domestic or irrigation wells. For wells that were not operational, standing water was removed prior to sampling. Water 

samples were collected for field-measured constituents 

(pH, dissolved oxygen, specific conductance, and alkalinity), major elements, nutrients, metals, and in some 

cases, coliform bacteria, according to standard methods 

for the collection of water samples established by the 

People’s Republic of China. The samples were analyzed by the Hai He Basin Water Environmental 

Monitoring Center and the Tang-Qin Water Environmental Monitoring Center. A subset of samples collected in the People’s Republic of China was analyzed 

by the National Water Quality Laboratory of the USGS 

for comparison. The results showed that the two laboratories obtained similar results for major constituents, 

nutrients, and metals.

NATURAL WATER CHEMISTRY

Ideally, natural water chemistry is defined on the 

basis of ground-water samples collected from aquifer 
20 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

zones that have been unaffected by agricultural or other 

anthropogenic activities. In practice, it is difficult to 

determine whether any ground water in a large agricultural region has been unimpacted by agricultural chemicals. Even water with no measurable nitrate may 

indeed have had a major flux of nitrate that subsequently degraded by bacterial action under anoxic conditions. In previous studies of the Delmarva Peninsula, 

such as Hamilton and others (1993), ground-water 

concentrations at or below 0.4 mg/L of nitrate as N 

were indicative of natural water unaffected by agricultural activities. Hamilton and others (1993) used the 

results from a sufficiently large population of wells in 

the Delmarva Peninsula to define this background. A 

study of ground water throughout the United States 

(Madison and Brunett, 1984) suggests that nitrate as N 

concentrations below 0.2 mg/L are indicative of natural 

ground water in the United States and that nitrate as N 

concentrations generally between 0.2 to 3.0 mg/L or in 

some cases, slightly higher, indicate water that is 

affected by agricultural activities. There are no corresponding studies from China that document levels of 

natural ground-water nitrate concentrations, but it is 

reasonable to assume that they are also low. A threshold 

value of 0.5 mg/L of nitrate as N has been chosen as the 

value below which ground water can be assumed to be 

relatively unaffected by agriculture, at least with 

respect to nitrate within the Tangshan region. The situation in the San Joaquin Valley, especially the western 

region of the valley, is more complicated because of 

localized areas of naturally occurring nitrate (Sullivan, 

1978). 

It is beyond the scope of the present study to 

determine the sources of nitrate measured in the wells 

of the western San Joaquin Valley. Therefore, it is 

possible that some of the nitrate concentrations that 

were measured were not the result of agricultural 

activities. However, the nitrate levels measured in the 

lower aquifer of the western San Joaquin Valley tend to 

have nitrate concentrations less than 0.5 mg/L 

(median = 0.4 mg/L). Given these caveats, natural 

ground-water chemistry is defined in this study as water 

with a low nitrate concentration. The composition of 

ground water with nitrate as N less than 0.5 mg/L and 

with nitrate as N less than 3 mg/L are used to compare 

ground water across these study units as likely having 

been unimpacted or minimally impacted by agricultural activities, respectively. This range of values is 

used for comparative purposes for all study units of this 

investigation, although some of the higher nitrate concentrations measured in the western San Joaquin Valley 

may have resulted from natural sources. Water with 

nitrate concentrations greater than 3 mg/L are therefore 

assumed as likely to have been affected by the use of 

nitrogen fertilizer.

The natural water chemistry of the Tangshan 

aquifer can be characterized as calcium–magnesium–

carbonate water (fig. 13). The water of the Luan He 

River (fig. 14) is also a calcium–magnesium–carbonate 

type of water. The natural water chemistry of the 

ground water and the Luan He River is consistent with 

the mineralogy of the aquifer sediments, which include 

a mixture of igneous and carbonate rocks. Ground 

water of the Tangshan study unit tends to be close to saturation or supersaturated with respect to carbonate minerals. Natural sources of chloride and sulfate are not 

apparent in most of the aquifer system, except in the 

coastal zone where intrusion of salt water can lead to 

elevated concentrations of chloride and sulfate.

Hamilton and others (1993) have described the 

natural water chemistry of the surficial aquifer of the 

Delmarva Peninsula, noting that the water tends to be 

acidic and soft with low alkalinity, low sodium, and low 

specific conductance. The chemistry of the natural 

water tends to be primarily controlled by the chemical 

properties of rainfall and snowmelt, mineral dissolution, biological activity and its residence time in the soil 

zone and aquifer, and the nearby presence of saline 

water (Hamilton and others, 1993). Mineral dissolution 

may take place when the minerals of the soil and aquifer 

zones come in contact with water moving through the 

system, including meteoric water and irrigation water. 

The principle mineral of the aquifer is quartz with 

minor amounts of silicate minerals or clay minerals, as 

well as calcium carbonate from shells and shell 

fragments (Hamilton and others, 1993). 

The major element chemistry of the natural 

ground water of the Delmarva Peninsula is displayed in 

a trilinear graph in figure 15. The chemistry of natural 

ground water, unaffected by agriculture, is displayed as 

white squares in figure 15. The cation and anion chemistry of natural ground water of the Delmarva Peninsula 

is variable (fig. 15). Much of the natural water is dominated by bicarbonate as the principal anion, but the 

water also includes a considerable amount of sulfate 

and chloride, which can be attributed to the proximity 

of the Atlantic Ocean. The cation chemistry shows that 

most of the natural ground water is dominated by 

sodium plus potassium, but several ground-water samples also have high amounts of calcium and magnesium. Most of the ground water of the Delmarva 

Peninsula is undersaturated with respect to carbonate 

minerals.

The chemistry of natural water in the San Joaquin 

and Sacramento Valleys of California is complicated 

because of the contrasting physiographic regions surrounding the valley and different types of sediment that 

make up the aquifer materials. The chemistry of the San 

Joaquin Valley ground water is not expected to be the 

same for each location because the chemical composition of the recharge water is different for each location. 
Natural Water Chemistry 21

Trilinear graphs of ground water from wells sampled in 

the western, southern, and eastern parts of the valley are 

shown in figures 16 through 18. The western San 

Joaquin Valley is recharged principally by runoff from 

the Coast Ranges and from irrigation. The anion chemistry of the western San Joaquin Valley ground water is 

complex with all three types of waters present: bicarbonate, sulfate, and chloride dominated. The cation 

chemistry is mostly sodium with varying amounts of 

calcium and magnesium. Ground water of the southern 

San Joaquin Valley is recharged from a variety of 

sources, including the Coast Ranges, the Sierra 

Nevada, various streams, and irrigation. The anion 

chemistry is basically similar to that of the western San 

Joaquin Valley, but with a greater dominance of bicarbonate water. The cation chemistry of the natural 

ground water is generally similar to that of the western 

San Joaquin Valley. Ground water of the eastern San 

Joaquin Valley is recharged mainly from the Sierra 

Nevada runoff and from irrigation. The anion chemistry 

of the natural ground water is principally dominated by 

bicarbonate. The cation chemistry is different from that 

of the western and southern San Joaquin Valley in that 

calcium and magnesium tend to be the dominant ions. 

The ground water of the western San Joaquin Valley 

and much of the southern San Joaquin Valley tends to 

be close to saturation or supersaturated with respect to 

carbonate minerals, but the ground water of the eastern 

San Joaquin Valley tends to be undersaturated, reflecting the differences in chemistry of recharge water.

Hull (1984) recognized six hydrochemical facies 

throughout the Sacramento Valley. According to Hull 

Figure 13. Trilinear graph displaying major element chemistry of Tangshan ground water, People’s Republic of China. Each scale represents

percentage of total milliequivalents per liter. N, nitrogen.

20

40

60

80

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

HCO 20 40 60 80 3+CO3 80 60 40 20

Magnesium (Mg)

Sulfate (SO4)

Sodium (Na)+Potassium (K)

Carbonate (CO3)+Bicarbonate (HCO3)

Calcium (Ca)+Magnesium (Mg)

Sulfate (SO4)+Chloride (Cl)

Calcium (Ca) Chloride (Cl)

Ca

SO Mg 4

Na+K Cl

C A T I O N S A N I O N S

EXPLANATION

Nitrate concentration as N, in

 milligrams per liter

 Less than 0.5

 Greater than 0.5 to 3

 Greater than 3 to 10

 Greater than 10 to 20 

 Greater than 20 
22 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

(1984), the Sacramento subunit comprises two hydrochemical facies whereas the extent of the rice land-use 

study covers three hydrochemical facies. Under natural 

conditions, much of the recharge to the Sacramento 

subunit originates in the Sierra Nevada as dilute sodium 

or calcium bicarbonate water. Parts of the Sacramento 

subunit aquifer have areas with low dissolved oxygen 

and higher concentrations of chloride. The chemistry of 

the natural ground water of the Sacramento subunit is 

shown in figure 19. Bicarbonate is the dominant anion 

for most of the ground water sampled in the Sacramento Valley study with the exception of one well that 

has high chloride. The cation chemistry shows that the 

natural ground water is generally calcium and magnesium with varying amounts of sodium. The area of the 

Sacramento rice land-use study is on both sides of the 

Sacramento River and within three of the hydrochemical facies mentioned in Hull (1984). The area of the 

study unit to the west of the Sacramento River is likely 

to have higher concentrations of total dissolved solids, 

chloride, sulfate, and other constituents in ground water 

relative to the area east of the Sacramento River 

because of naturally occurring sources of these constituents in the Coast Ranges. The natural water chemistry 

of the ground water sampled for the Sacramento rice 

land-use study is shown in figure 20. More wells in the 

Sacramento rice study have higher sulfate and chloride 

composition than wells of the Sacramento subunit. 

The chemistry of the cations in the ground water of the 

Sacramento rice study is similar to that of the 

Sacramento subunit.

Figure 14. Trilinear graph displaying water chemistry of the Luan He River, People’s Republic of China. Each scale represents percentage of 

total milliequivalents per liter.

20

40

60

80

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

80 60 40 20 20 40 60 80

Magnesium (Mg)

Sulfate (SO4)

Sodium (Na)+Potassium (K)

Carbonate (CO3)+Bicarbonate (HCO3)

Calcium (Ca)+Magnesium (Mg)

Sulfate (SO4)+Chloride (Cl)

Calcium (Ca) Chloride (Cl)

Ca

SO Mg 4

HCO Cl 3+CO Na+K 3

C A T I O N S A N I O N S

EXPLANATION

Lower Luan He River
Natural Water Chemistry 23

Boxplots of specific conductance for the wells of 

each study unit are shown in figure 21. The ground 

water with the lowest specific conductance is that of the 

Delmarva Peninsula with a median specific conductance of 203 μS/cm. The sampled ground water of the 

San Joaquin Valley has the highest specific conductance with a median value of 704 μS/cm. The specific 

conductance of sampled ground water of the Sacramento Valley is most similar to that of the Tangshan 

study unit, with median specific conductances of 612 

and 625 μS/cm, respectively. Boxplots of specific conductance for wells of the three physiographic regions of 

Tangshan, including the upper and lower aquifer of the 

plain region, are shown in figure 22. The wells of the 

mountain region have the lowest median specific 

conductance, which is expected because most groundwater recharge is likely to occur under natural 

conditions in this region. The highest median specific 

conductance is shown for the wells of the upper aquifer 

of the plain region. That specific conductance is significantly higher than the specific conductance of the 

lower aquifer, which suggests that salts have been 

added to the water as a result of land use. The specific 

conductance of the wells of the coastal region are similar to that of the lower aquifer of the plain region. 

Whereas some of the ground water of the coastal region 

is known to have high salt content, the water in samples 

of this region are from parts of the aquifer that have not 

been affected by saltwater intrusion. 

Boxplots of specific conductance for wells of the 

various regions of the San Joaquin Valley, including the 

upper and lower aquifers of the western and southern 

San Joaquin Valley, are shown in figure 23. The highest 

median specific conductance is about 1,500 μS/cm for 

the lower western San Joaquin Valley ground water. The 

western San Joaquin Valley ground water has the 

Figure 15. Trilinear graph displaying major element chemistry of ground water of the Delmarva Peninsula, United States. Each scale 

represents percentage of total milliequivalents per liter. N, nitrogen.

20

40

60

80

20

40

60

80

60

40

20

80

60

40

20

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

80 60 40 20 20 40 60 80

Magnesium (Mg)

Sulfate (SO4)

Sodium (Na)+Potassium (K)

Carbonate (CO3)+Bicarbonate (HCO3)

Calcium (Ca)+Magnesium (Mg)

Sulfate (SO4)+Chloride (Cl)

Calcium (Ca) Chloride (Cl)

Ca

SO Mg 4

HCO Cl 3+CO Na+K 3

EXPLANATION

Nitrate concentration as N, in

 milligrams per liter

 Less than 0.5

 Greater than 0.5 to 3

 Greater than 3 to 10

 Greater than 10 to 0 

 Greater than 20 

80
24 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

highest specific conductance for several reasons. Some 

of the recharge to the aquifer originates within the 

Coast Ranges, and that recharge water is relatively high 

in total dissolved solids. Additionally, some parts of the 

western San Joaquin Valley have poor soil drainage. 

Irrigation over poorly drained soils in a semiarid environment can lead to high rates of evaporation, which 

leave behind salts. The median specific conductance for 

the other regions of the San Joaquin Valley are lower 

than those of the western San Joaquin Valley. Ground 

water of the eastern San Joaquin Valley tends to have 

the lowest specific conductance because the recharge 

originates from the Sierra Nevada, which has relatively 

low concentrations of total dissolved solids. 

 Boxplots of pH for the wells of each study unit 

are shown in figure 24. The lowest median pH (5.25) 

is for the Delmarva Peninsula. Because its aquifer 

mineralogy is dominated by quartz, a relatively insoluble mineral, the ground water pH is very similar to that 

expected for rain. 

Concentrations of iron in ground water provide 

information on the state of oxidation or reduction of the 

ground water. Iron is insoluble when oxidized, but is 

much more soluble in the reduced state. Boxplots of 

iron for the various zones of study units or for an entire 

study unit are shown in figure 25. The greatest range in 

iron concentrations for the Tangshan study unit is for 

the upper aquifer of the plain zone. The median iron 

concentration for that part of the aquifer is 290 μg/L. 

Median iron concentrations are below 250 μg/L in the 

lower aquifer of the plain zone and also in the mountain 

zone. Median iron concentrations of the coastal zone 

of the Tangshan study unit are similar to those of the 

upper aquifer of the plain zone. The higher iron

Figure 16. Trilinear graph of ground water of the western San Joaquin Valley, California, United States. Each scale represents percentage of 

total milliequivalents per liter. N, nitrogen.

20

40

60

80

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

Ca 80 60 40 20 Na+K 20 40 60 80 Cl

Magnesium (Mg)

Sulfate (SO4)

Sodium (Na)+Potassium (K)

Carbonate (CO3)+Bicarbonate (HCO3)

Calcium (Ca)+Magnesium (Mg)

Sulfate (SO4)+Chloride (Cl)

Calcium (Ca) Chloride (Cl)

Mg

HCO3+CO3

SO4

EXPLANATION

Nitrate concentration as N, in

 milligrams per liter

 Less than 0.5

 Greater than 0.5 to 3

 Greater than 3 to 10

 Greater than 10 to 20 

 Greater than 20 
Natural Water Chemistry 25

concentrations of the upper aquifer of the plain zone 

suggest that some processes are affecting the redox 

potential of the ground water, which is allowing the 

iron of the aquifer sediment to go into solution. Iron 

concentrations of the lower aquifer are expected to be 

highest because the deeper ground water is probably 

older and has had more time to undergo oxygendepleting reactions. The wide range and higher concentrations of iron in the upper aquifer suggest that oxygen 

is being removed from the ground water by some process, which may be related to the use of manure on agricultural land or to the input of sewage waste over the 

land surface. 

The ground water of the Delmarva Peninsula has 

a wide range of iron concentrations. The median concentration is only 24 μg/L, but the 90th percentile is 

close to 12,000 μg/L. Iron concentrations in the San 

Joaquin Valley tend to be lower than those measured in 

the Tangshan aquifer. The highest iron concentrations 

are in the western San Joaquin Valley and the lowest are 

in the eastern San Joaquin Valley. The aquifer of the 

eastern San Joaquin Valley is composed of coarser sediments relative to those of the western and southern San 

Joaquin Valley. Because of the coarser sediment, the 

aquifer is more open to the atmosphere, and hence the 

water has a greater amount of dissolved oxygen and less 

iron. Iron concentrations for the sampled wells of the 

Sacramento Valley are shown in figure 25. The median 

concentrations of iron in the ground water in the Sacramento subunit and the Sacramento rice zone (3.0 and 

4.2 μg/L, respectively) are similar, but a larger range of 

concentrations is present in the wells of the rice landuse study. In summary, iron concentrations tend to be 

highest in the ground water of the Tangshan and 

Figure 17. Trilinear graph of ground water of the southern San Joaquin Valley, California, United States. Each scale represents percentage 

of total milliequivalents per liter. N, nitrogen. 

20

40

60

80

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

80 60 40 20 20 40 60 80 Cl

Calcium (Ca)+Magnesium (Mg)

Sulfate (SO4)+Chloride (Cl)

Ca Na+K

Sulfate (SO4)

Calcium (Ca) Chloride (Cl)

HCO3+CO3

Sodium (Na)+Potassium (K)

Carbonate (CO3)+Bicarbonate (HCO3)

Mg SO4

Magnesium (Mg)

EXPLANATION

Nitrate concentration as N, in

 milligrams per liter

 Less than 0.5

 Greater than 0.5 to 3

 Greater than 3 to 10

 Greater than 10 to 20 

 Greater than 20 
26 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Delmarva aquifers, relative to the ground water of the 

other aquifers of this study.

OXYGEN AND HYDROGEN ISOTOPES IN WATER

Variations in stable isotopes in water and dissolved constituents originate from the natural variation 

in atomic mass and from fractionation in the environment. Isotope fractionation is defined as the partitioning of isotopes by physical or chemical processes in a 

manner proportional to the differences in masses 

(Coplen, 1993). Stable isotopes in water molecules— 

hydrogen (1

H), deuterium (2H), oxygen-16 (16O), and 

oxygen-18 (18O)—have long been used to help determine ground-water recharge or ground-water flow 

paths. The ratio of the isotopes is measured with a mass 

spectrometer. The ratios, expressed as δ notation, are 

given in parts per thousand (per mill). The principal 

fractionation mechanisms of stable isotopes are evaporation and precipitation. Lighter isotopes partition to 

water vapor, for example, leaving the heavier isotopes 

enriched in the remaining water. In contrast, rainwater 

is more enriched in heavier isotopes and becomes progressively lighter as clouds move over landmasses. Isotope ratios in rainwater can be measured and, thus, the 

pathways of ground-water recharge can be determined 

by measuring stable isotope ratios along ground-water 

flow paths. Stable isotope studies or analyses have been 

completed for wells of the San Joaquin Valley and Sacramento Valley study units from previous studies, but 

no stable isotope data are available for wells of the Delmarva Peninsula. This study reports on the first analyses of stable isotopes for the Tangshan study-unit 

ground water. 

Figure 18. Trilinear graph of ground water of the eastern San Joaquin Valley, California, United States. Each scale represents percentage of 

total milliequivalents per liter. N, nitrogen.

20

40

60

80

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

Calcium (Ca)+Magnesium (Mg)

Sulfate (SO4)+Chloride (Cl)

Sulfate (SO4)

Carbonate (CO3)+Bicarbonate (HCO3)

SO4

Sodium (Na)+Potassium (K)

Mg

Magnesium (Mg)

Ca Na+K 80 60 40 20 20 40 60 80 Cl

Calcium (Ca) Chloride (Cl)

C A T I O N S A N I O N S

HCO3+CO3

EXPLANATION

Nitrate concentration as N, in

 milligrams per liter

 Less than 0.5

 Greater than 0.5 to 3

 Greater than 3 to 10

 Greater than 10 to 20 

 Greater than 20 
Oxygen and Hydrogen Isotopes in Water 27

The greatest variation in the distribution of stable 

isotopes is in the San Joaquin Valley ground water 

(fig. 26) where they vary for several reasons. Precipitation in that region generally results from winter storms 

that originate over the Pacific Ocean. Rain with heavier 

isotopes falls on the Coast Ranges, and rain that is relatively depleted in the heavier isotopes falls on the valley floor and the Sierra Nevada. The rain with the 

lightest isotopes falls on the Sierra Nevada. Groundwater recharge to the San Joaquin Valley aquifer originates from Coast Ranges runoff, precipitation on the 

valley floor, runoff from the Sierra Nevada, recharge 

from the San Joaquin River and its tributaries, and irrigation. Irrigation is currently the primary source of 

ground-water recharge to the aquifer of the San Joaquin 

Valley (Domagalski and Dubrovsky, 1991, 1992). 

Irrigation water is provided by local rivers, water 

imported from northern California, and ground water. 

Irrigation also affects the stable isotope pattern in that 

partial evaporation of the irrigation water leads to 

enrichment in the heavier isotopes. The isotope ratio 

patterns for the eastern, western, and southern San 

Joaquin Valley generally overlap because of the complexity of recharge and other factors that affect the stable isotope patterns (fig. 26). Because of the wide 

variation in stable isotope ratios of ground water, the 

use of stable isotope data has aided in the interpretation 

of previous studies on contaminant chemistry of the San 

Joaquin Valley ground water (Deverel and Fujii, 1988) 

and has helped researchers to understand ground 

water–surface water relations (Phillips and others, 

1991). In those cases, stable isotope data were useful 

Figure 19. Trilinear graph of subunit ground water, Sacramento, California, United States. Note: Red circles are not shown here because 

ground water with nitrate greater than 20 milligrams per liter was not detected. Each scale represents percentage of total milliequivalents 

per liter. N, nitrogen.

20

40

60

80

80

60

40

20

80

60 40

20

20

40

60

80

Ca 80 60 40 20 Na+K 20 40 60 80

Sodium (Na)+Potassium (K)

Magnesium (Mg)

Calcium (Ca) Chloride (Cl)

C A T I O N S A N I O N S

HCO Cl 3+CO3

Sulfate (SO4)

Carbonate (CO3)+Bicarbonate (HCO3)

SO Mg 4 20

40

60

80

20

40

60

80

80

60

40

20

80

60

40

20

Calcium (Ca)+Magnesium (Mg)

Sulfate (SO4)+Chloride (Cl)

EXPLANATION

Nitrate concentration as N, in

 milligrams per liter

 Less than 0.5

 Greater than 0.5 to 3

 Greater than 3 to 10

 Greater than 10 to 20 

 
28 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

because waters originating from different sources, or 

geochemical processes related to natural phenomenon, 

such as evaporation, could clearly be distinguished 

because of the range in values of stable isotope ratios. 

The same types of weather patterns described for 

the San Joaquin Valley also affect precipitation in the 

Sacramento Valley, and so the heaviest isotopes are 

found in runoff from the Coast Ranges and the lightest 

in rainfall from the Sierra Nevada and Cascade Mountains. The isotope ratio of the Sacramento River does 

not vary much because the flow is regulated by releases 

from large reservoirs that collect snowmelt runoff from 

high mountains, principally in the northern part of the 

basin and within the Sierra Nevada. The ratio of deuterium is close to –80 per mill and of 18O is close to 

–11.5 per mill. These ratios of the San Joaquin River 

are similar because most of the flow of the San Joaquin 

River originates as runoff from the Sierra Nevada. Isotope patterns are more variable for streams that drain 

the Coast Ranges and tend to be heavier than those of 

the Sacramento and San Joaquin Rivers. Stable isotopes 

were used by Davisson and Criss (1993) to map 

recharge of irrigation water to municipal wells in a 

region west of Sacramento, California. Davisson and 

others (1993) were able to document the extent of 

ground-water recharge to the surficial aquifer of the 

lower Sacramento Valley from the large rivers (Sacramento and American Rivers) using stable isotope data. 

In these cases, the difference in isotope abundances was 

sufficiently great to allow mapping of isotope contours.

Figure 20. Trilinear graph of the rice land-use ground water, Sacramento, California, United States. Note: Red circles are not shown here

because ground water with nitrate greater than 20 milligrams per liter was not detected. Each scale represents percentage of total 

milliequivalents per liter. N, nitrogen.

20

40

60

80

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

80

60

40

20

80

60

40

20

20

40

60

80

Sodium (Na)+Potassium (K)

Magnesium (Mg)

Sulfate (SO4)

Carbonate (CO3)+Bicarbonate (HCO3)

SO Mg 4

Ca 80 60 40 20 Na+K 20 40 60 80

Calcium (Ca) Chloride (Cl)

C A T I O N S A N I O N S

HCO Cl 3+CO3

Calcium (Ca)+Magnesium (Mg)

Sulfate (SO4)+Chloride (Cl)

EXPLANATION

Nitrate concentration as N, in

 milligrams per liter

 Less than 0.5

 Greater than 0.5 to 3

 Greater than 3 to 10

 Greater than 10 to 20 

 
Oxygen and Hydrogen Isotopes in Water 29

Agricultural practices may affect the isotope pattern of ground water underlying the rice fields of the 

Sacramento Valley (fig. 27). Because standing water is 

on the rice fields during the hottest part of the year, 

evaporation of water results in some fractionation. The 

isotope pattern for water underlying the rice fields tends 

to deviate from the global meteoric water line, a clear 

indication of the effect of evaporation.

Stable isotope samples were collected from 

ground water along four selected transects of the 

Tangshan study unit. Those transects were chosen to 

provide general information on the regional distribution of stable isotope ratios in this aquifer system. 

Transect 1 was closest to the Luan He River and was 

chosen to show how similar the stable isotopes of the 

ground water system are to those of the largest river. 

Transect 2 is located near ephemeral streams, such as 

the Qinglong He River, and was chosen to contrast the 

stable isotopes of that stream with those of nearby 

ground water. Transects 3 and 4 were chosen to obtain 

greater aerial coverage over the study unit. The stable 

isotope pattern of ground water in the Tangshan study 

unit (fig. 28 and table 2) varies less than that of the San 

Joaquin and Sacramento Valleys. This pattern is especially true in the mountain and plain regions where stable isotopes in ground water are very similar to those of 

the upper and lower Luan He River. Ground water of 

the coastal region has more variability, which is to be 

expected because seawater has infiltrated the ground 

water system. The 18O ratio in the wells sampled in the 

mountain and plain regions, and that of the Luan He 

River, tend to be close to –8 to –8.5 per mill and the 

deuterium ratio is close to –60 per mill. One sampling 

site, near the Luan He River (location Lao6), was different. The shallow well (LaoQ6) was slightly enriched 

in the heavier isotopes, but the deeper well (LaoS6) was 

more depleted in the heavier isotopes. This was the 

closest sampling point to the Luan He River. The difference in isotope values may reflect changes in the isotopic chemistry of the Luan He River over time, 

especially prior to the construction of reservoirs. The 

stable isotopes of the Qinglong He River were relatively enriched in the heavier isotopes. This enrichment 

would be expected for an ephemeral stream owing to 

evaporation. The wells of the upper aquifer sampled 

closest to the Qinglong He River (sites Ben3 [wells 

BenQ3-1, BenQ3-2, and BenQ3-3] and Ben4) are 

slightly enriched in the heavier isotopes, suggesting 

that some recharge of partially evaporated stream water 

occurred. 

The general uniformity of isotope ratios 

observed in most of the wells of the mountain and plain 

regions and the Luan He River probably results from 

the precipitation pattern. Rainfall originates over the 

Figure 21. Boxplots of specific conductance for wells within each 

study unit in the People’s Republic of China and the United States.

Figure 22. Boxplots of specific conductance for wells in various 

physiographic regions of the Tangshan study unit, People’s Republic 

of China.

Tangshan

study area

Delmarva Peninsula

San Joaquin Valley

Sacramento Valley

0

500

1,000

1,500

2,000

2,500

Specific conductance, in microsiemens per 

centimeter at 25 degrees Celsius

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

(112)

(103)

(179)

(59)

Tangshan mountain region

Tangshan coastal region

Tangshan Upper Aquifer Plain region

Tangshan Lower Aquifer Plain region

(15)

(43)

(50) (9)

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

0

500

1,000

1,500

2,000

2,500

Specific conductance, in microsiemens per 

centimeter at 25 degrees Celsius
30 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Pacific Ocean. Rain with a similar pattern of stable 

isotopes falls over the plain and mountain regions. 

Because most of the ground-water recharge comes 

from mountain runoff and meteoric input over the 

mountain and plain areas, the stable isotope pattern 

is very similar throughout. As a result, stable isotopes are not as useful a tool, on a regional pattern, 

to help determine ground-water flow paths for the 

mountain and plain regions of the Tangshan aquifer 

system. However, stable isotopes may be useful in 

local scale studies, such as near the ephemeral 

streams or within the coastal region in studies related 

to seawater intrusion, but that is beyond the scope of 

the present study.

DATING OF GROUND-WATER RECHARGE

Methods for dating ground-water recharge 

have been used extensively in the San Joaquin Valley, and more recently in the Sacramento Valley, to 

interpret the relative age of ground water with depth 

and to relate the detection frequency of various 

ground water contaminants to the age of ground 

water. For example, Domagalski and Dubrovsky 

(1991, 1992) showed that pesticide residues in 

ground water of the San Joaquin Valley were 

present only in relatively recent water (water 

with detectable 3

H). Older ground water (3H 

below detection limit) had no detectable pesticide residues. Knowledge of the depth distribution of recent water in an aquifer provides a 

good understanding of which part of the aquifer may be susceptible to contamination from 

recent land-use practices. Ground water with 

detectable 3

H is defined for this study as having been recently recharged (from the 1950s to 

the present).

Prior to this study, there had been no 

measurements of 3

H or any attempts to establish the age of ground water in the Tangshan 

aquifer study unit. Results of dating analyses 

from this study are shown in table 3. The wells 

selected for these analyses are located along 

two transects shown in figure 4. The samples 

were collected in June 1996. 3

H or CFC can be 

detected to a well depth of 150 m. Ground 

water sampled from well depths of 212 and 

230 m did not have measurable 3

H. Those two 

samples were collected from the coastal aquifer. The zone of 3

H-free water is probably at or 

below 150 m below land surface in this aquifer 

system. Ground water sampled in the lower 

aquifer of the plain region, at various depths, 

all had measurable 3

H or CFC, which suggests 

Figure 23. Boxplots of specific conductance for wells in various 

regions of the San Joaquin Valley, California, United States.

Figure 24. Boxplots of pH for wells within each study unit in the 

People’s Republic of China and the United States.

3

4

5

6

7

8

9

pH, in standard units

(111)

(103)

(177)

(59)

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

Tangshan study area

Delmarva Peninsula

San Joaquin Valley

Sacramento Valley

Upper western San Joaquin Valley

Lower western San Joaquin Valley

Upper southern San Joaquin Valley

Lower southern San Joaquin Valley

Eastern San Joaquin Valley

1,000

500

0

1,500

2,000

2,500

3,000

3,500

4,000

4,500

Unassigned southern San Joaquin Valley

(25)

(25)

(42)

(8)

(14)

(63)

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

Specific conductance, in microsiemens per 

centimeter at 25 degrees Celsius
Assessment of Water-Quality Conditions 31

that recently recharged water is present to a depth of at 

least 130 m and perhaps as deep as 150 m in the lower 

aquifer of the plain region. 

Water with undetectable 3H, such as that collected 

from wells Xian5 and Xian9, also could not be dated by 

the 3

H/3He method. There was not close agreement of 

the ages obtained from the CFC and the 3

H/3He methods, which might be expected because the methods do 

not work for all ground-water systems. In particular, the 

CFC method does not work for ground-water systems 

devoid of dissolved oxygen. Parts of the ground-water 

system of the Tangshan aquifer are devoid of dissolved 

oxygen as indicated by the high concentrations of dissolved iron measured at several wells. Therefore, the 

3

H/3He method provides a more reliable age for this 

ground water system.

The implication for the Tangshan aquifer system 

is that recent water is present in relatively deep parts of 

the aquifer, within approximately 150 m below land 

surface, which suggests that the ground water 

system is rapidly recharged either areally by 

meteoric water (during the Asian monsoon) or 

by infiltration from rivers, irrigation, or some 

combination. Water levels measured prior to 

and after the monsoon season in 1996 are 

shown in figure 29. Ground water levels were 

generally closer to land surface in September 

1996 relative to May 1996 because the levels 

for September were measured just after the 

rainy season (fig. 29). Subsequent pumping of 

ground water helps to draw the recently 

recharged water to deeper levels. Soil contaminants, or contaminants present at shallow 

water levels, such as nitrate, can then be transported to deeper parts of the aquifer system.

ASSESSMENT OF WATER-QUALITY 

CONDITIONS

Water-quality conditions, with respect 

to the suitability of ground water as a source 

of drinking water for each study unit, were 

assessed on the basis of standards or methods 

used in the People’s Republic of China and 

water-quality criteria specified in the Safe 

Drinking Water Act of the United States. In 

the United States, emphasis is given to 

meeting standards specified for each constituent that is regulated by the Safe Drinking 

Figure 25. Boxplots of iron concentration for various zones within 

study units or for an entire study unit, People’s Republic of China and 

the United States. The red line indicates drinking- water standard of 

China and secondary drinking-water standard of the U.S. 

Environmental Protection Agency. 

10

0

100

1,000

10,000

100,000

Iron concentration, in micrograms per liter

(18)

(39)

(44) (9)

(103)

(25)

(25)

(43)

(14)

(8)

(63)

(31)

(28)

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

San Joaquin Valley, upper western aquifer

San Joaquin Valley, lower western aquifer

San Joaquin Valley, upper southern aquifer

San Joaquin Valley, lower southern aquifer

San Joaquin Valley, unassigned aquifer

San Joaquin Valley, eastern aquifer

Sacramento subunit 

Tangshan mountain region

Tangshan Upper Aquifer Plain region

Tangshan Lower Aquifer Plain region

Tangshan coastal region

Delmarva Peninsula

Sacramento rice land use

Figure 26. Stable isotopes δ deuterium (2H) versus δ18O of ground 

water in the San Joaquin Valley, California, United States. H, 

hydrogen; O, oxygen; δ, delta. Position of the global meteoric water 

line from Drever (1982).

–120

–110

–100

–90

–80

–70

–60

–50

–40

–30

–20

–20 –18 –16 –14 –12 –10 –8 –6 –4 –2 0

Western San Joaquin Valley

Eastern San Joaquin Valley

Southern San Joaquin Valley

Global meteoric water line

δ Deuterium, in per mill

δ 18O, in per mill
32 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Water Act of the U.S. Environmental Protection 

Agency (EPA). When even a single standard is 

exceeded, there may be sufficient cause to stop the 

delivery of water supplied by a community well. For 

example, numerous wells in the San Joaquin Valley 

have been shut down because concentrations of the pesticide 1,2-dibromo-3-chloropropane (DBCP) exceeded 

the standard. Meeting individual standards is also 

important for the regulation of drinking water quality in 

the People’s Republic of China. In addition, the suitability of ground water as a source of drinking water is 

assessed using a broader method of classification called 

the “gray pattern method.” The results of the gray 

matrix calculations are presented to show the range of 

conditions in these aquifers.

Gray Pattern Method of Water-Quality 

Assessment

To classify the water with respect to a set of 

chosen water-quality constituents, the gray pattern 

method assesses the weights of contaminant concentrations, relative to both the National Standards of 

Groundwater Quality established by the People’s 

Republic of China and to boundary values of various 

water classes. The assessment of overall water quality 

according to a set of standards allows water-quality 

managers in the People’s Republic of China to prioritize decisions about the suitability of water for various 

uses. A set of 21 water-quality constituents regulated by 

National Standards of Groundwater Quality of the 

People’s Republic of China was selected for this study. 

Scientists and water-quality specialists of the Hai He 

River Basin’s Water Conservancy Commission, the 

Tangshan Water Resources Bureau, and the Ministry of 

Water Resources of the People’s Republic of China 

determined that the 21 water-quality constituents listed 

in table 4 are the most important for the protection of 

ground-water quality in the Tangshan study unit. The 

boundary values of class 3 water, as shown in table 4, 

are the closest analogy to primary drinking water standards as understood in the United States. These are set 

for individual constituents. When applicable, the primary and secondary water standards of the EPA are also 

shown in table 4. Primary standards are enforceable 

standards that must be met by all public drinking water 

systems to which they apply. Secondary standards are 

nonenforceable, but are maintained to protect public 

welfare and to ensure a supply of pure, wholesome, and 

potable water. Some states require that all new wells or 

sources of drinking water meet the secondary standards.

The classes of water, according to the method in 

the People’s Republic of China, represent a gradient of 

concentrations for each water-quality constituent, indicating suitability for drinking water to nonsuitability of 

the water. Class 1 water is of highest quality, whereas 

class 5 represents extremely poor water quality. The 

boundary values of class 3 (table 4) are most analogous 

to American drinking water primary standards. Note 

that the boundary value of class 3 for nitrate is set at 

Figure 27. Stable isotopes δ deuterium (2H) versus δ18O of ground 

water in the Sacramento Valley and of the Sacramento River at 

Colusa, California, United States. H, hydrogen; O, oxygen; δ, delta. 

Position of the global meteoric water line from Drever (1982).

Figure 28. Stable isotopes δ deuterium (2

H) versus δ18O of ground 

water in the Tangshan study unit and of the Qinglong and Luan He 

Rivers, People’s Republic of China. H, hydrogen; O, oxygen; δ, delta. 

Position of the global meteoric water line from Drever (1982).

–120

–110

–100

–90

–80

–70

–60

–50

–40

–30

–20

–20 –18 –16 –14 –12 –10 –8 –6 –4 –2 0

δ Deuterium, in per mill

Sacramento subunit 

Rice land use 

Sacramento River at Colusa

Global meteoric

 water line

δ 18O, in per mill

–120

–110

–100

–90

–80

–70

–60

–50

–40

–30

–20

–20 –18 –16 –14 –12 –10 –8 –6 –4 –2 0

δ Deuterium, in per mill

Upper zone of plain aquifer

Lower zone of plain aquifer

Mountain aquifer

Coastal aquifer

Luan He River

Qinglong He River

Global meteoric 

 water line

δ 18O, in per mill
Assessment of Water-Quality Conditions 33

20 mg/L. The primary (enforceable) American drinking water standard for nitrate is 10 mg/L as N. 

The gray pattern method first calculates a pollution index for each constituent relative to the boundary 

value of the class 3 drinking-water standard. Water with 

water-quality constituent concentrations less than the 

boundary values of class 3 water shown in table 4 are 

ranked low, but as water quality greatly exceeds the 

boundary values, the ranks are correspondingly higher. 

Even a single “exceedance” (that is, a value that 

exceeds the standard) can result in water of overall 

class 5 if the measured concentrations are very high, 

that is, if they exceed class 5. A summation of the relative amounts of exceedances and the corresponding 

factor for each constituent are then calculated, and the 

matrix of calculations is referred to as the “gray dependency pattern.” The output from the gray model is a 

comprehensive score. Water samples with class of 3 or 

higher indicate serious water-quality problems or that 

one or more standards have been exceeded. An examination of the detailed matrix then can provide information on which specific parameter or group of parameters 

contributed to the ranking. 

The 21 constituents that were used to assess the 

quality of ground water according to the National 

Standards of the People’s Republic of China were total 

dissolved solids, chloride, sulfate, total hardness, 

ammonia, nitrite, nitrate, chemical oxygen demand 

(permanganate index), cyanide, arsenic, phenol, chromium (VI), mercury, cadmium, lead, copper, iron, fluoride, manganese, zinc, and coliform bacteria. The 

coliform bacteria measurements were completed only 

Table 2. Results of stable isotope analyses—δ deuterium and δ18O in water—for wells of the Tangshan study unit, People’s Republic of 

China

[na, not applicable; O, oxygen; per mill, parts per thousand; Q, shallow well; S, deep well; δ, delta]

Well

name

Date

sampled Transect Aquifer zoneor river

δ deuterium

(per mill)

δ18O

(per mill)

LuanQ5 23 June 1996 1 Plain upper –60.2 –8.21

LuanS5 23 June 1996 1 Plain lower –60.7 –8.75

LaoQ1 24 June 1996 1 Plain upper –61.7 –8.41

LaoS1 24 June 1996 1 Plain lower –61 –8.19

LaoQ6 24 June 1996 1 Plain upper –58 –7.86

LaoS6 24 June 1996 1 Plain lower –75 –9.61

Xian9 24 June 1996 1 Coastal –76.2 –9.91

Xian9-1 24 June 1996 1 Coastal –49.1 –5.93

Shan15 23 June 1996 2 Mountain –61 –8.62

LuanS1 23 June 1996 2 Plain lower –60.7 –8.51

BenQ3-1 23 June 1996 2 Plain upper –56.4 –7.6

BenS3 22 June 1996 2 Plain lower –60.3 –8.06

BenQ4 25 June 1996 2 Plain upper –55.8 –7.68

BenS4 25 June 1996 2 Plain lower –60 –8.3

Xian5 25 June 1996 2 Coastal –75.8 –9.55

Shan9 23 June 1996 3 Mountain –63.2 –8.72

Shan10 16 September 1996 3 Mountain –60.3 –8.42

ShiS2 3 October 1996 3 Plain lower –60.6 –8.37

NanQ2 3 October 1996 3 Plain upper –59.7 –8.49

NanS2 3 October 1996 3 Plain lower –58.2 –7.86

Xian3 4 October 1996 3 Coastal –60.5 –8.07

RunS1 3 October 1996 4 Plain lower –59.3 –8.22

RunQ2 24 September 1996 4 Plain upper –59.9 –8.45

RunS2 16 September 1996 4 Plain lower –63 –8.45

YuQ7 16 September 1996 4 Plain upper –58.9 –8.33

YuS7 10 September 1996 4 Plain lower –58.2 –8.01

RunS4 25 September 1996 4 Plain lower –61.2 –8.45

Xian1 16 September 1996 4 Coastal –71.1 –9.62

Upper Luan He River 23 June 1996 na River –63.4 –8.65

Lower Luan He River 24 June 1996 na River –65 –8.68

Qinglong He River 25 June 1996 na River –47.6 –5.91
34 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

for the wells of the upper aquifer (plain region) and 

only for the May 1996 sampling. The gray matrix summaries for the wells of the Tangshan study unit are 

shown in tables 5 through 13. The number of wells for 

each classification is shown in tables 5 through 13, and 

for each case, a median classification is presented. In 

each case, the median classification refers only to that 

individual grouping.

The highest median gray matrix results (table 5) 

were calculated for the upper aquifer (plain region) of 

the Tangshan study unit for the May 1996 sampling. 

May 1996 was the only time—and the wells selected 

during this time were the only wells—for which a complete set of coliform bacteria data was available. When 

the gray matrix is calculated without the coliform data, 

the result is a lower median gray matrix score (table 6). 

The median classification drops from 4.19 to 3.68, 

which indicates that coliform bacteria significantly 

degrades the water quality of the upper aquifer. The 

May 1996 score, without coliform data, is very similar 

to the median score calculated for the September 1996 

sampling of the upper aquifer in the plain region. This 

similarity indicates that general water quality conditions did not change appreciably following the monsoon season. A total of 29 out of 39 wells of the upper 

aquifer (plain region) of the Tangshan study unit, sampled during May 1996, were scored in class 3 on the 

basis of this gray matrix classification. Exceedances of 

total dissolved solids, total hardness, ammonia, nitrate, 

and coliform bacteria contributed to these high scores. 

A total of 28 out of 39 wells of the upper aquifer (plain 

region) of the Tangshan study unit, sampled in September 1996, were scored in class 3 on the basis of this gray 

matrix classification. Therefore, even without the 

coliform analyses, most wells of the upper aquifer were 

in a relatively high classification, which indicates poor 

water-quality conditions. The median classification for 

each sampling of the upper aquifer was a value corresponding to class 3 or higher water. 

Water quality of the lower aquifer (plain region) 

of the Tangshan study unit is better because fewer 

ground-water samples were in the highest rating 

(poorest water quality). The median classification was 

slightly below that of an overall class 3 water. Although 

the gray matrix calculations suggest that the water of 

the lower aquifer is of higher general quality relative to 

that of the upper, some serious water-quality problems 

are still present. The constituents that contributed to the 

higher rankings were ammonia, nitrate, iron, 

manganese, and total hardness. 

Table 3. Results of dating analyses for wells of the Tangshan study unit, People’s Republic of China

[The3

H/3He results column shows samples tested for dating on the basis of years elapsed since recharge. CFC, chlorofluorocarbon; 3H,

tritium; 3

H/3He, tritium/helium-3; L, liter; m, meters; pCi, picocuries; Q, shallow wells; S, deep wells. —, sample not taken]

1

Recharged before 1960.

Well name Well depth (m) Aquifer zone 3H (pCi/L) 3H/3He results CFC recharge date (period)

LuanQ5 27 Plain upper 34.2 — —

LuanS5 48 Plain lower 46.46 — Early 1970s

LaoQ1 21 Plain upper 34.7 6.08 Early 1960s or older

LaoS1 80 Plain lower 21.8 — —

LaoS6 150 Plain lower — — Mid-1940s

Xian9 212 Coastal 0 Old water1 —

Shan15 25 Mountain 98.79 7.36 Mid-1980s

LuanS1 130 Plain lower 38.75 20.71 —

BenQ3-1 13 Plain upper 97.6 — —

BenS3 60 Plain lower 6.53 20.56 Mid-1960s

BenQ4 20 Plain upper 35.8 — —

BenS4 120 Plain lower 10.2 — —

Xian5 230 Coastal 0 Old water1 —

Figure 29. Water levels measured in May and September 1996, 

Tangshan study unit, People’s Republic of China. 

10

0

15

5

20

25

30

35

40

45

50

0 5 10 15 20 25 30 35 40 45 50

Line of no water level change

Water level, in meters below land

 surface, measured September 1996

Water level, in meters below land surface, 

measured May 1996
Assessment of Water-Quality Conditions 35

As indicated by the gray matrix scores, water 

quality of the mountain region was considerably better 

than that of the aquifer of the plain region. Relatively 

few samples had scores in the higher classes. The 

source of ground-water recharge to the plain region 

lies, at least in part, in the mountain region. Water quality may be better in this region because of less intensive 

agriculture. However, as will be shown later, nitrate 

may be a developing problem for ground water in that 

region.

Water-quality problems are also evident for the 

coastal region as indicated by a median gray score 

above or near that of class 3 water. The water-quality 

constituents most responsible for the loadings are 

ammonia and nitrite, but not nitrate, iron, and 

manganese. 

The gray matrix summary of the Delmarva Peninsula ground water samples is shown in table 14. A 

total of 36 of 103 samples are of class 3 or higher. The 

presence of nitrate and iron contributed most to those 

higher water-quality class rankings. The median 

classification is that of class 2 water.

Gray matrix summaries for the San Joaquin 

Valley ground water are shown in tables 15 through 20. 

The upper and lower zones of the aquifer of the western 

San Joaquin Valley have relatively poor water quality as 

indicated by the gray matrix scores. Eighteen out of 25 

wells of the upper aquifer are in class 3 or higher, and 

14 out of 25 wells of the lower aquifer are in class 3 or 

higher. The water-quality constituents contributing to 

the higher gray matrix scores, for the upper and lower 

aquifer, are total dissolved solids, chloride, sulfate, total 

hardness, iron, and manganese. A total of 11 of 43 wells 

of the southern San Joaquin Valley, upper aquifer, had 

scores in class 3 or higher. The median score was lower 

than that of the western San Joaquin Valley. The lower 

aquifer of the southern San Joaquin Valley has much 

better water quality relative to that of the lower aquifer 

of the western San Joaquin Valley. Total dissolved 

solids, chloride, sulfate, and total hardness contribute to 

Table 4. Classification of representative values of National Standards of Groundwater Quality in the People’s Republic of China, and of

primary and secondary standards of the U.S. Environmental Protection Agency in the United States

[Values of constituents are in milligrams per liter, unless otherwise noted. Primary Standard: Enforceable standard that must be met for

drinking water. Secondary Standard: Nonenforceable, but recommended for drinking water. Class 1 to 5: Classification of water according

to a gradient of highly suitable (class 1) to highly unsuitable (class 5) with respect to the use of the water as a source of drinking water.

Boundary values of class 3: Analogous to an enforceable standard of the EPA. CaCO3, calcium carbonate; Cr, chromium; Cr+6, chromate

ion; EPA, U.S. Environmental Protection Agency; N , nitrogen; NH3, ammonia. —, no available standard]

Water-quality

constituent

People’s Republic of China United States

Class 1 Class 2 Class 3 Class 4 Class 5

Boundary 

values of 

Class 3

EPA primary 

standard

EPA secondary 

standard

Total dissolved solids 300 400 750 1,500 2,000 1,000 — 500

Chloride 50 100 200 300 350 250 — 250

Sulfate 50 100 200 300 350 250 — 250

Total hardness (as CaCO3) 150 225 375 500 550 450 — —

Ammonia (nitrogen as NH3) 0.02 0.02 0.11 0.35 0.5 0.2 — —

Nitrate (nitrogen as N) 2 3.5 12.5 25 30 20 10 —

Nitrite (nitrogen as N) 0.001 0.0055 0.015 0.06 0.1 0.02 1 —

Permanganate index 1 1.5 2.5 6.5 10 3 — —

Cyanide 0.001 0.0055 0.03 0.075 0.1 0.05 0.2 —

Arsenic 0.005 0.0075 0.03 0.05 0.05 0.05 0.05 —

Phenol 0.001 0.001 0.0015 0.006 0.01 0.002 — —

Chromium (as Cr+6) 0.005 0.0075 0.03 0.075 0.1 0.05 0.1 

as total Cr

—

Mercury 0.00005 0.00028 0.00075 0.001 0.001 0.001 0.002 —

Cadmium 0.0001 0.00055 0.0055 0.01 0.01 0.01 0.005 —

Lead 0.005 0.0075 0.03 0.075 0.1 0.05 0.015 —

Copper 0.01 0.03 0.525 1.25 1.5 1 — 1

Iron 0.1 0.15 0.25 0.9 1.5 0.3 — 0.3

Fluoride 1 1 1 1.5 2 1 4.0 —

Manganese 0.05 0.05 0.075 0.55 1 0.1 — 0.05

Zinc 0.05 0.275 0.75 3 5 1 — 5

Coliforms 3 3 3 52 100 3 — —
36 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Table 5. Gray matrix summary for upper aquifer (plain region) of the Tangshan study unit, People’s Republic of China, May 1996 data

Table 6. Gray matrix summary for upper aquifer (plain region) of the Tangshan study unit, People’s Republic of China, May 1996 data, without 

coliform analysis

Table 7. Gray matrix summary for upper aquifer (plain region) of the Tangshan study unit, People’s Republic of China, September 1996 data

Table 8. Gray matrix summary for lower aquifer (plain region) of the Tangshan study unit, People’s Republic of China, May 1996 data

Table 9. Gray matrix summary for lower aquifer (plain region) of the Tangshan study unit, People’s Republic of China, September 1996 data

Table 10. Gray matrix summary for aquifer of the mountain region of the Tangshan study unit, People’s Republic of China, May 1996 data

Table 11. Gray matrix summary for aquifer of the mountain region of the Tangshan study unit, People’s Republic of China, September 1996

data

Table 12. Gray matrix summary for aquifer of the coastal region of the Tangshan study unit, People’s Republic of China, May 1996 data

Table 13. Gray matrix summary for aquifer of the coastal region of the Tangshan study unit, People’s Republic of China, September 1996 data

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (39 total) 0 10 8 21

Median classification 4.19

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (38 total) 2 11 10 15

Median classification 3.68

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (39 total) 1 10 15 13

Median classification 3.65

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (45 total) 10 15 14 6

Median classification 2.71

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (45 total) 6 20 17 2

Median classification 2.8

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (18 total) 6 9 2 1

Median classification 2.085

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (18 total) 4 10 4 0

Median classification 2.17

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (9 total) 0 2 7 0

Median classification 3.4

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (9 total) 0 5 4 0

Median classification 2.98
Assessment of Water-Quality Conditions 37

the higher scores (class 3 or higher) of the 16 wells of 

the lower aquifer in the western San Joaquin Valley. 

Water quality of the unassigned aquifer of the southern 

San Joaquin Valley is similar to that of the lower aquifer 

of the southern San Joaquin Valley. A total of 8 out of 

63 wells of the eastern San Joaquin Valley were in class 

3 or higher (table 20). Water-quality constituents contributing to the class 3 scores are varied, but include 

total dissolved solids, nitrate, chloride, and sulfate. 

Total dissolved solids of the eastern San Joaquin Valley 

aquifer are lower than those of the western San Joaquin 

Valley; therefore, the gray matrix scores are 

correspondingly lower.

Gray matrix summaries of the Sacramento Valley 

show a marked difference between the subunit survey 

and the rice land-use survey (tables 21 and 22). The 

wells of the southeastern Sacramento Valley generally 

have good water quality. Only 3 wells out of 31 were in 

class 3 or higher. In contrast, 13 out of 28 wells of the 

rice land-use survey were in class 3 or higher. The 

water-quality constituents that contribute to the higher 

scores of the wells of the rice land-use survey are total 

dissolved solids, chloride, sulfate, total hardness, nitrite 

(in three wells), iron, and manganese. Nitrate is not a 

problem for the ground water of the rice land-use 

region.

Table 14. Gray matrix summary for aquifer of the Delmarva Peninsula study unit, United States

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (103 total) 38 29 5 31

Median classification 2.22

Table 15. Gray matrix summary for upper aquifer of the western region of the San Joaquin Valley study unit, California, United States

Table 16. Gray matrix summary for lower aquifer of the western region of the San Joaquin Valley study unit, California, United States

Table 17. Gray matrix summary for upper aquifer of the southern region of the San Joaquin Valley study unit, California, United States

Table 18. Gray matrix summary for lower aquifer of the southern region of the San Joaquin Valley study unit, California, United States

Table 19. Gray matrix summary for the unassigned aquifer of the southern region of the San Joaquin Valley study unit, California, United States

Table 20. Gray matrix summary for the eastern aquifer of the San Joaquin Valley study unit, California, United States

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (25 total) 4 3 9 9

Median classification 3.65

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (25 total) 1 8 12 4

Median classification 3.37

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (43 total) 16 16 6 5

Median classification 2.14

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (14 total) 8 5 0 1

Median classification 1.875

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (8 total) 4 2 2 0

Median classification 1.675

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (63 total) 39 16 8 0

Median classification 1.91
38 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Boxplots showing the results of the gray matrix 

rankings for all study units are shown in figure 30. The 

highest median ranking is for the wells of the upper 

aquifer of the plain region of the Tangshan study unit. 

The median is slightly less when recalculated without 

the coliform data. Coliform data were available only for 

the upper aquifer of the plain region of the Tangshan 

study unit and were not available for any other subunit, 

including those of the United States. The gray matrix 

rankings of the upper aquifer of the Tangshan plain 

region are similar to those of the western part of the San 

Joaquin Valley with respect to the median ranking and 

range of ranking, which suggests some similar or common water-quality problems, such as total dissolved 

solids and the oxidation potential of the water (elevated 

concentrations of iron and manganese). The wells of 

the eastern San Joaquin Valley have a much lower ranking because of the dilute nature of that water. The 

ground water of the eastern San Joaquin Valley is of 

better quality with respect to total dissolved solids, but 

its water quality has been degraded because of pesticides, especially DBCP (Domagalski and Dubrovsky, 

1991, 1992). 

The wells of the Delmarva Peninsula have the 

greatest range in gray scores. The median gray ranking 

is below those of the plain and coastal regions of the 

Tangshan study unit and also below that of the western 

San Joaquin Valley. Low total dissolved solids contribute to lower gray rankings for the Delmarva Peninsula 

whereas nitrate, iron, and manganese contribute to 

higher gray rankings. The wells of the Sacramento subunit survey provide a good representation of the quality 

of ground water actually used for consumption in that 

part of the Sacramento Valley. The gray matrix ranking 

for the Sacramento subunit indicates a very good water 

quality, and tests for pesticides and volatile organic 

chemicals showed that organic chemicals are either 

absent from the water or present only in extremely low 

concentrations. In contrast, the wells of the Sacramento 

rice land-use study rank much higher in the gray ranking because of higher concentrations of total dissolved 

solids and concentrations of iron and manganese, 

related to the oxidation–reduction potential of the 

water. This ranking suggests that the rice land use is 

affecting the quality of the shallow ground-water 

resource. 

Boxplots of nitrate concentrations for ground 

water in all study units are shown in figure 31. The 

Table 21. Gray matrix summary for aquifer of the Sacramento subunit area of the Sacramento Valley study unit, California, United States

Table 22. Gray matrix summary for the aquifer of the rice land-use study area of the Sacramento Valley study unit, California, United States

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0 to 4.0 4.0 to 5.0

Number of wells (31 total) 21 7 1 2

Median classification 1.72

Range of classification 1.0 to 2.0 2.0 to 3.0 3.0to 4.0 4.0 to 5.0

Number of wells (28 total) 3 12 7 6

Median classification 2.72

1

1.5

2

2.5

3

3.5

4

4.5

5

Gray scores

San Joaquin Valley, upper western aquifer

San Joaquin Valley, lower western aquifer

San Joaquin Valley, upper southern aquifer

San Joaquin Valley, lower southern aquifer

San Joaquin Valley, unassigned aquifer

San Joaquin Valley, eastern aquifer

Sacramento subunit

Tangshan mountain region

Tangshan Upper Aquifer Plain region

Tangshan Upper Aquifer Plain region, coliform not included

Tangshan Lower Aquifer Plain region

Tangshan coastal region

Delmarva Peninsula

Sacramento rice land use

(18)

(39) (39)

(45)

(9)

(103) (25)

(25) (43)

(14)

(8)

(63)

(31)

(28)

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

Figure 30. Boxplots of gray scores (gray matrix calculations) for 

study-unit wells in the People’s Republic of China and the United 

States.
Assessment of Water-Quality Conditions 39

boxplot representing the upper aquifer wells in the 

Tangshan plain region has the greatest range in nitrate 

concentrations and the highest concentration of all 

regions of the Tangshan study unit and all study units of 

the United States, but it does not have the highest 

median concentration. In fact, the median concentration of the Tangshan upper plain region is less than that 

of the mountain aquifer and the lower plain zone 

region. Over 25 percent of the wells sampled in the 

upper plain zone exceeded the Chinese standard for 

nitrate. Over 10 percent of the wells of the mountain 

region (mountain aquifer) and the lower aquifer (lower 

plain region) exceeded this standard. Only the wells of 

the coastal zone of the Tangshan study unit (coastal 

aquifer) have low nitrate concentrations. The wells 

sampled in the study units of the United States generally have a lower range of nitrate concentrations than 

wells in the plain region of the People’s Republic of 

China. Ten percent of the wells of the lower aquifer in 

the southern San Joaquin Valley exceed the Chinese 

standard. 

Figure 31 shows that nearly 25 percent of the 

wells of the Delmarva Peninsula and nearly 25 percent 

of the upper aquifer wells in the western San Joaquin 

Valley are close to or exceed the American standard 

(U.S. Environmental Protection Agency) for nitrate. 

Close to 25 percent of the samples collected in the 

eastern San Joaquin Valley also exceed the American 

nitrate standard. Relatively few samples of the ground 

water collected in the United States, from these studies, 

exceed the Chinese drinking-water standard for nitrate. 

As indicated by the gray matrix rankings, total 

dissolved solids is a problem for ground water in the 

People’s Republic of China and for some parts of the 

study units in the United States. Boxplots of total dissolved solids data in ground water for all of the study 

units are shown in figure 32. At least 25 percent of the 

wells sampled in the Tangshan upper plain region 

exceed the Chinese standard for total dissolved solids 

and about 50 percent of these same wells exceed the 

secondary standard of the EPA. The higher median concentrations of the upper aquifer relative to those of the 

lower aquifer, mountain aquifer, and coastal aquifer of 

the Tangshan study unit suggest that agricultural and 

other land-use activities have contributed to the total 

dissolved solids content of ground water. Because the 

aquifer mineralogy is the same for the upper and lower 

zones, the higher total dissolved solids concentrations 

cannot be explained on the basis of natural water–rock 

interactions. 

Ground water of the western San Joaquin Valley 

also has high total dissolved solids. Although some of 

the high dissolved solids can be attributed to natural 

processes, such as higher total dissolved solids content 

of the recharge water, some can also be attributed to 

agricultural activities, which have greatly affected the 

total dissolved solids content of the ground water in the 

western San Joaquin Valley. The western San Joaquin 

Valley has a long history of irrigation. Irrigation is 

required for successful agriculture in the San Joaquin 

Valley because little or no rain falls during the growing 

season. The soils of the western San Joaquin Valley 

tend to be poorly drained. Irrigation of crops and poor 

drainage in a semiarid environment lead to a high rate 

of evaporation of the irrigation water. Subsequent 

recharge can increase the salt loading to the aquifer and 

thereby increase the degradation of water quality with 

respect to total dissolved solids. In contrast, irrigation 

is not used as much in the Delmarva Peninsula, and rain 

or infiltration of stream water provides more recharge 

to the aquifers. As mentioned previously, the median 

concentration of total dissolved solids in the water samples of the Sacramento rice land-use study exceeds that 

 ̇

0

5

10

15

20

25

30

35

40

45

50

(18)

(39)

(45)

(9)

(103) (43)

(14)

(8)

(63)

China's drinking-water standard

Primary drinking-water standard of the 

U.S. Environmental Protection Agency

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

Nitrate concentration as N, in milligrams per liter

(25)

(25)

Tangshan mountain region

Tangshan Upper Aquifer Plain region

Tangshan Lower Aquifer Plain region

Tangshan coastal region

San Joaquin Valley, upper western aquifer

San Joaquin Valley, lower western aquifer

San Joaquin Valley, upper southern aquifer

San Joaquin Valley, lower southern aquifer

San Joaquin Valley, unassigned aquifer

San Joaquin Valley, eastern aquifer

Sacramento rice land use

Delmarva Peninsula

Sacramento subunit

(31)

(28)

Figure 31. Boxplots of nitrate concentrations in ground water for 

various zones within study units or for an entire study unit in the 

People’s Republic of China and the United States. N, nitrogen.
40 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

of the total dissolved solids of water samples collected 

in the Sacramento subunit survey. At least 50 percent of 

the samples of the rice land-use study exceed the secondary standard for total dissolved solids of the EPA. 

The high total dissolved solids of the Tangshan aquifer 

cannot be explained by evaporative concentration of 

irrigation water because of a different climate. It also 

cannot be explained on the basis of water–rock interactions because the aquifer mineralogy does not contain 

salt deposits. The higher total dissolved solids may be 

attributed to a longer history of agricultural production 

in the Tangshan region relative to the San Joaquin 

Valley and other study units of the United States, or to 

the greater amount of animal and sewage wastes disposed on land within the Tangshan study unit.

Results of the gray matrix rankings indicate that 

iron concentrations are a water quality problem for 

some study units. Boxplots of iron concentrations for 

all study units are shown in figure 25. Iron concentrations that exceed the Chinese standard (0.3 mg/L) are 

present throughout the Tangshan study unit. The mountain region has the lowest relative iron concentration. 

Apparently, iron dissolves throughout the upper and 

lower parts of the plain and coastal aquifers in response 

to decreasing concentrations of dissolved oxygen. The 

only study unit in the United States with comparable 

iron concentrations is the Delmarva Peninsula. 

Chemical Signatures of Ground Water 

Affected by Agriculture

The water quality of the aquifers in the Tangshan 

study unit has been affected by agricultural activities, 

which have resulted in a redistribution of major ions, in 

addition to elevated nitrate concentrations, for the agriculturally affected waters relative to natural ground 

water (fig. 13). The trilinear graph shows that the water 

becomes more enriched in calcium and sulfate as nitrate 

concentrations increase. This enrichment can probably 

be attributed to the application of other chemicals in the 

applied fertilizers. Agricultural chemicals (fig. 15) also 

affected the natural ion chemistry of the Delmarva Peninsula as indicated by association with higher nitrate 

concentrations. Hamilton showed that the ground water 

that is affected by agricultural activities in the Delmarva Peninsula has significantly higher levels of calcium, magnesium, potassium, and chloride, in addition 

to nitrate (Hamilton and others, 1993). Because of the 

evaporative concentration of irrigation water prior to 

recharge, agriculture signatures of the western and 

southern San Joaquin Valley ground water, when 

arranged according to ranges in nitrate concentration, 

are not as evident as the signatures of Tangshan and the 

Delmarva Peninsula. There is no clear distinction of 

signatures for anions, but there appear to be slightly 

greater proportions of calcium and magnesium in agriculturally affected ground water (figs. 16 and 17). The 

agricultural signature of ground water of the eastern 

San Joaquin Valley is represented by slightly elevated 

chloride and sulfate (fig. 18). As mentioned previously, 

one signature of agriculturally affected ground water in 

the Sacramento Valley is elevated total dissolved solids. 

The increase in total dissolved solids is caused mainly 

by evaporative concentration, especially during the 

rice-growing season, as evidenced in the trilinear plot 

for the wells of the Sacramento rice land-use study 

(fig. 20). The cation chemistry tends to shift from a 

Figure 32. Boxplots of total dissolved solids concentrations in 

ground water for various zones within study units or for an entire 

study unit in the People’s Republic of China and the United States.

(18)

(39)

(45)

(9)

(103)

(25)

(25)

2,500

2,000

1,000

500

0

1,500

(43)

(14)

(8)

(63)

(31)

(28)

China's drinking-water standard

Secondary drinking-water standard 

of the U.S. Environmental 

Protection Agency

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

Tangshan mountain region

Tangshan Upper Aquifer Plain region

Tangshan Lower Aquifer Plain region

Tangshan coastal region

San Joaquin Valley, upper western aquifer

San Joaquin Valley, lower western aquifer

San Joaquin Valley, upper southern aquifer

San Joaquin Valley, lower southern aquifer

San Joaquin Valley, unassigned aquifer

San Joaquin Valley, eastern aquifer

Sacramento rice land use

Delmarva Peninsula

Sacramento subunit

Total dissolved solids, in milligrams per liter
Assessment of Water-Quality Conditions 41

calcium–magnesium water to a water with sodium as 

the most abundant cation. The shift probably results 

from precipitation of carbonate minerals such as calcite 

or aragonite.

The effects of agricultural land-use on major element chemistry can be further assessed by comparing 

the range in concentrations of individual water-quality 

constituents in ground water that have low nitrate concentrations with those that have high nitrate concentrations. Boxplots of calcium and sulfate concentrations in 

Tangshan study unit ground water with low nitrate (less 

than 0.5 mg/L as N) and high nitrate in ground water 

are shown in figures 33 and 34. The median calcium 

and sulfate concentrations in low nitrate wells are lower 

than those in high nitrate wells. The difference in medians for calcium was statistically significant at 

p = 0.0032 whereas the difference for sulfate was significant at p = 0.0013 using the nonparametric 

Mann–Whitney test. Evidence of geochemical processes that affect nitrate concentration can be seen by 

comparing the pH of ground water in samples from low 

and high nitrate wells (fig. 35). The difference in medians is statistically significant (p = 0.0004) by the 

Mann–Whitney test. It would be expected that iron concentrations might be higher in wells with low nitrate 

because of the oxidation state of the water. That is the 

case for the wells of the Tangshan study unit (fig. 36). 

The difference in medians is significant (p = 0.003) by 

the Mann–Whitney test (fig. 36). It is possible that iron 

dissolution and nitrate reduction may be partially linked 

by geochemical processes in the Tangshan aquifer. No 

other water-quality constituents, such as chloride, 

sodium, potassium, and magnesium, had statistically 

different concentrations in ground water of high or low 

nitrate in the Tangshan study unit. 

Agriculture is most likely to affect the major element chemistry of ground water when concentrations of 

the major elements in natural ground water are very 

low, as in the case of the Delmarva Peninsula. Hamilton 

0

20

40

60

80

100

120

140

160

180

Low nitrate water High nitrate water

(37)

(74)

Calcium concentration, in milligrams per liter

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

Low nitrate water High nitrate water

0

50

100

150

200

250

(37)

(74)

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

Sulfate concentration, in milligrams per liter

Figure 33. Boxplots of calcium concentrations in wells with low 

and high nitrate in the Tangshan study unit, People’s Republic 

of China.

Figure 34. Boxplots of sulfate concentrations in wells with low and 

high nitrate in the Tangshan study unit, People’s Republic of China.

Figure 35. Boxplots of pH in wells with low and high nitrate in the 

Tangshan study unit, People’s Republic of China.

7.0

7.2

7.4

7.6

7.8

8.0

8.2

8.4

8.6

8.8

9.0

Low nitrate water High nitrate water

pH, in standard units

(37)

(74)

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples
42 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

and others (1993) found that the concentrations of 

calcium, magnesium, potassium, and chloride were 

higher in waters affected by nitrate contamination relative to natural ground water. Those authors attributed 

the changes to the application of various fertilizers. 

Evaporative processes that occur after irrigation and 

prior to recharge affect the ground water of the Central 

Valley of California. Furthermore, it is more difficult to 

see changes in the major element chemistry of ground 

water in that region that can be attributed to fertilizer 

application.

Principal Component Analysis

Principal component analysis is a statistical technique that can help explain variation in large data sets 

of multiple components, such as the water chemistry of 

the study units. Principal component analysis will 

allow for the grouping of variables that may help to 

explain a process that is controlling the particular 

grouping observed. The following constituents were 

selected to represent the variables for principal component analysis for this study: total dissolved solids, 

sodium, potassium, calcium, magnesium, chloride, 

sulfate, fluoride, bicarbonate, nitrate, and iron. These 

constituents were measured in the ground water of all 

study units. Principal component analysis may provide 

reasons for the variation observed for these constituents. Principal component analysis requires a normally 

distributed data set. The water chemistry data from 

these study units are generally not normally distributed. 

Therefore, a log transform was applied to all data to 

approximate normality. Results of principal component 

analysis for the various study units are shown in tables 

23 through 28. The first two principal components are 

shown for each study unit because subsequent ones 

could not be attributed to any geochemical or anthropogenic process. The first two principal components 

explain between just under 60 percent to close to 

70 percent of the variation with this set of water-quality 

data. 

The first principal component is probably a general indication of the water chemistry that is attributed 

to recharge processes. The sign of the loadings is the 

same (tables 23 to 28) and of generally similar magnitude for major constituents of the ground water, such as 

total dissolved solids, magnesium, calcium, potassium, 

chloride, and sulfate. Two important points in interpreting the results of principal component analysis are the 

absolute values of the loadings and the positive or 

negative value of the results relative to one another. For 

example, all of the results for principal component 1 of 

the Tangshan study unit have the same sign, indicating 

that those water-quality constituents are affected by a 

similar process such as dissolution of minerals, which 

provides magnesium, calcium, sodium, chloride, and 

sulfate to the ground water. The second principal component shows that nitrate and iron concentrations are 

related but in opposite ways because of the change in 

sign, which is an indication of redox processes. As 

nitrate concentrations increase, iron concentrations 

tend to decrease, and as iron concentrations tend to 

increase, nitrate concentrations decrease. 

Principal component analysis can be obtained for 

each well under investigation. The individual variable 

range for the principal component 2 of the Tangshan 

study unit is shown on the geomorphology map in 

figure 37. The figure shows where the state of ground 

water is mainly under reducing or oxidizing conditions. 

The range of principal component 2 values is also 

shown for the Delmarva Peninsula in figure 38. Like the 

map of the Tangshan study unit, this map shows the 

locations where the state of ground water is under 

reducing conditions and where nitrate reduction may be 

removing some of the nitrate from the ground water.

The eastern San Joaquin Valley was the only 

location for this study that does not show an indication 

of iron dissolution or nitrate reduction. The lack of 

these two types of redox processes indicates that the 

ground water in this region is oxidizing, the iron concentrations are low, and the nitrate reduction is not an 

important process because nitrate reduction to nitrogen 

gas does not occur to a large extent. In the eastern San 

Joaquin Valley, the oxidizing condition is consistent 

with the sandy or coarse-grained texture of the aquifer 

materials, which allows for greater diffusion of oxygen 

to the ground water.

0

500

1,000

1,500

2,000

2,500

3,000

3,500

Iron concentraton, in micrograms per liter

Low nitrate water High nitrate water

(37)

(74)

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

Figure 36. Boxplots of iron concentrations in wells with low and 

high nitrate in the Tangshan study unit, People’s Republic of China.
Assessment of Water-Quality Conditions 43

Table 23. Results of principal component analyses of chemical data from the Tangshan study unit, People’s Republic of China

[N, nitrogen; —, loadings have absolute values of less than 0.30]

Water quality constituent Principal component 1 Principal component 2

Total dissolved solids –0.424 —

Magnesium –0.368 —

Calcium –0.361 —

Sodium –0.325 —

Potassium — —

Chloride –0.36 —

Sulfate –0.351 —

Fluoride — –0.494

Nitrate as N — 0.581

Bicarbonate — –0.305

Iron — –0.36

Percent variation explained 47.5 20.4

Cumulative percent variation explained 47.5 67.9

Table 24. Results of principal component analyses of chemical data from the Delmarva Peninsula study unit, United States

[N, nitrogen; —, loadings have absolute values of less than 0.30]

Water quality constituent Principal component 1 Principal component 2

Total dissolved solids 0.421 —

Magnesium 0.387 —

Calcium 0.382 —

Sodium — –0.341

Potassium 0.365 —

Chloride 0.405 —

Sulfate 0.303 —

Fluoride — —

Nitrate as N — 0.488

Bicarbonate — –0.401

Iron — –0.516

Percent variation explained 39.9 23.7

Cumulative percent variation explained 39.9 63.6

Table 25. Results of principal component analyses of chemical data from the western region of the San Joaquin Valley study unit, California, 

United States

[N, nitrogen; —, loadings have absolute values of less than 0.30]

Water quality constituent Principal component 1 Principal component 2

Total dissolved solids –0.429 —

Magnesium –0.4 —

Calcium –0.425 —

Sodium –0.334 –0.456

Potassium — —

Chloride –0.383 —

Sulfate — —

Fluoride — —

Nitrate as N — 0.424

Bicarbonate — —

Iron — –0.528

Percent variation explained 42.0 15.8

Cumulative percent variation explained 42.0 57.8
44 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Table 26. Results of principal component analyses of chemical data from the southern region of the San Joaquin Valley study unit, 

California, United States

[N, nitrogen; —, loadings have absolute values of less than 0.30]

Water quality constituent Principal component 1 Principal component 2

Total dissolved solids 0.42 —

Magnesium 0.356 —

Calcium 0.383 —

Sodium 0.302 0.456

Potassium 0.348 —

Chloride 0.325 —

Sulfate 0.375 —

Fluoride — 0.359

Nitrate as N — –0.353

Bicarbonate — —

Iron — 0.42

Percent variation explained 42.5 21.5

Cumulative percent variation explained 42.5 64.0

Table 27. Results of principal component analyses of chemical data from the eastern region of the San Joaquin Valley study unit, California, 

United States

[N, nitrogen; —, loadings have absolute values of less than 0.30]

Water quality constituent Principal component 1 Principal component 2

Total dissolved solids –0.431 —

Magnesium –0.308 –0.417

Calcium –0.397 —

Sodium –0.324 0.399

Potassium — –0.343

Chloride –0.342 —

Sulfate –0.371 —

Fluoride — 0.584

Nitrate as N — —

Bicarbonate –0.352 —

Iron — —

Percent variation explained 44.5 17.3

Cumulative percent variation explained 44.5 61.8

Table 28. Results of principal component analyses of chemical data from the Sacramento Valley study unit, California, United States 

[N, nitrogen; —, loadings have absolute values of less than 0.30]

Water quality constituent Principal component 1 Principal component 2

Total dissolved solids 0.427 —

Magnesium 0.376 —

Calcium 0.36 —

Sodium 0.368 —

Potassium — —

Chloride 0.264 —

Sulfate 0.402 —

Fluoride 0.154 —

Nitrate as N — –0.682

Bicarbonate 0.359 —

Iron — 0.566

Percent variation explained 48.2 14.1

Cumulative percent variation explained 48.2 62.3
Assessment of Water-Quality Conditions 45

Figure 37. Geomorphology and range of principal component 2 values for wells of the Tangshan study unit, People’s Republic of China.

More reducing

More oxidizing

Well site accompanied by regional identifier

Well-group location—Principal component

 2 values for shallow and deep wells at same

 group location

 Shallow well

 Deep well

Single-well location with principal component

 2 value

Principal component 2 value in wells

Boundaries

 Tangshan study unit

 Between coastal and plain physiographic regions

 Between plain and mountain physiographic regions

Coastal deposits below sea level

Geomorphology

Other coastal deposits

Reservoirs

Slight highland on flood basin

Old flood basin

Flood plain

Natural levee or dike

Flat land

Slightly sloped land

Old river bed highland

Slight highland

Area formed by collapsed

 or destroyed levee or dike

Alluvial area

Terrace

Sloped land, slope less than 3 degrees

Sloped land, slope greater than 3 degrees

Valley

Low hill, height less than 50 meters

High hill, height 50 to 300 meters

Low mountain, height 300 to 1,000 meters

EXPLANATION

map data: 

base: Hai He River Water Conservancy Commission, 

 original map scale 1:400,000, publication data unavailabl

geomorphology: Hai He River Water Conservancy Commission

 orginal map scale and publication date unavailable

–2.0 to –0.8

Greater than –0.8 to 0.2

Greater than 0.2 to 0.8

Greater than 0.8 to 2.5

L

Ben7

en8

n3

Run5

Run6

Run7

118

4020

11845

0

0

20

20

40 MILES

40 KILOMETERS

3910
46 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

Figure 38. Range of principal component 2 values for wells of the Delmarva Peninsula study unit, United States.

Principal component 2 values for well site

0

0

20

20

40 MILES

40 KILOMETERS

38

39

76

EXPLANATION

Surficial confined 

Hydrogeomorphic region

Inner coastal plain

Well-drained upland

Fine-grained lowland

Poorly drained lowland

Poorly drained upland

Other

–3.39 to –0.8

Greater than –0.8 to 0.25

Greater than 0.25 to 0.66

Greater than 0.66 to 2.3

NEW

CASTLE

CECIL

KENT

CAROLINE

SUSSEX

WICOMICO

WORCESTER

ACCOMACK

SOMERSET

NORTHAMPTON

TALBOT

DORCHESTER

QUEEN

ANNES

KENT

More reducing

More oxdidizing

map data: Hamilton and others, 1993.

 U.S. Geological Survey, 1981a,b; 1983c,e,f,g; 1984a,b,e,i; 1999
Nitrate and Detection Frequency of Pesticides in Ground Water 47

NITRATE AND DETECTION FREQUENCY OF 

PESTICIDES IN GROUND WATER

Comparison of Nitrate Use in Study Units

Nitrogen use data for each county in the study 

units were available for comparison of application 

amounts per given area. In each case, the most recent 

year of available nitrogen use data was used where a 

complete set of data was available.

A comparison of nitrate usage for counties 

within the four study units is shown in table 29. Data 

for study units of the United States were obtained from 

Battaglin and Goolsby (1995). Their data are based on 

documented sales, in each county, of fertilizers that are 

used primarily for agriculture. Therefore, the authors of 

this report assumed that all of the fertilizer that was purchased was used. The Hai He River Water Conservancy 

Commission obtained data for the Tangshan study unit 

through a similar process. On table 29, we see that 

nitrogen applications for some counties of the Central 

Valley of California are higher than those for the 

Delmarva Peninsula, but overall, the use is similar per 

unit area for the study units of the United States. The 

nitrogen usage in the counties of the Tangshan study 

unit is considerably higher than that of the study units 

of the United States by as much as a factor of 10, in 

some cases. Therefore, higher use of nitrogen fertilizer 

in this agricultural region of the People’s Republic of 

China is one possible explanation for the higher nitrate 

concentrations and for other agricultural contaminants 

found in the ground water of the Tangshan study unit. 

In contrast to nitrogen fertilizer, counties in the 

United States have a higher use or generation of manure 

than counties in the People’s Republic of China. The 

usage or generation of manure within the study units is 

shown in table 30. Data for the study units of the United 

States were obtained from Puckett and others (1998). 

Puckett and others (1998) based their estimates on the 

animal census of each county. Through a similar process, the Hai He River Basin’s Water Conservancy 

Commission obtained data for the counties of the 

Tangshan study unit. This generation of manure can be 

attributed to larger animal production facilities in the 

United States, especially cattle production. Manure is 

not necessarily used as an agricultural additive in the 

United States, but the generation of manure at animal 

operation centers represents a potential point source of 

nitrogen and other contaminants to ground water.

The amount of nitrogen in manure varies 

depending on the animal source. The nitrogen contents 

assumed for calculating possible nitrate effects from 

various animals are shown in table 31. The principal 

elements in manure are carbon, oxygen, and hydrogen. 

In all cases, nitrogen is a minor component of manure. 

The highest N content, 0.11 percent, is for broiler or 

other meat-type chickens, and the lowest, 0.028 percent, is for hogs, pigs, horses, and ponies. Although the 

N content in manure is relatively low, nitrate formed 

from the oxidation of manure can migrate to ground 

water. Six wells in the People’s Republic of China were 

sampled for nitrogen isotopes and oxygen isotopes in 

nitrate. Two of the wells (Shan15 and BenS3) had a 

clear signature of nitrogen from fertilizer because the 

values for δ15N were close to 5 per mill (fig. 39). Two 

wells showed a mixed source of the nitrate because the 

Table 29. Comparison of nitrate use in counties within study units in the People’s Republic of China and the United States 

[km2

, square kilometer; Mg, megagram]

Tangshan

study-unit

counties

Nitrogen

use, 1996

(Mg/km2)

Delmarva

study-unit

counties

Nitrogen use, 

1991

 (Mg/km2)

Sacramento Valley

study-unit

counties

Nitrogen use, 

1987

 (Mg/km2)

San Joaquin Valley

study-unit

counties

Nitrogen

use, 1987

(Mg/km2)

Laoting 59.1 Kent 5.3 Butte 2.4 Fresno 4.0

Zunhua 48.4 New Castle 3.0 Colusa 4.1 Kern 2.3

Fengnan 50.4 Sussex 3.1 Glenn 3.1 Kings 6.3

Fengrun 44.1 Caroline 4.9 Placer 0.2 Madera 2.4

TangHai 56.5 Cecil 2.7 Sacramento 2.5 Merced 4.8

Luannan 49.3 Dorchester 2.4 Solano 2.6 San Joaquin 7.4

Yutian 33.1 Kent 5.8 Sutter 7.9 Stanislaus 4.6

Qianxi 40.5 Queen Annes 5.2 Tehama 0.4 Tulare 2.9

Tangshan 36.0 Somerset 2.0 Yolo 4.8

Luan Xian 28.5 Talbot 4.9 Yuba 2.2

Qian’an 23.7 Wicomico 2.2

Worcester 2.0

Accomack 1.7

Northampton 2.9
48 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

δ15N values were close to 10. Finally, two wells had relatively high enrichment in δ15N, which is assumed to be 

from manure or sewage. Although an isotropic signature from two of the sampled wells indicated a source 

of nitrate from animal waste, this signature could also 

have come from sources of nitrate from human wastes 

or sewage. In the People’s Republic of China, sewage 

inputs to ground water are a possibility because not all 

rural areas have adequate wastewater treatment.

Physical and Chemical Factors Related to the 

Detection Frequency of Nitrate

Nitrate concentrations versus well depths for the 

Tangshan study unit are shown in figure 40. These 

results are consistent with the isotope dating results; 

nitrate concentrations also are above those expected for 

natural ground water are present to a depth of 130 to 

140 m. Below that depth, nitrate concentrations tend to 

be below detection limits. Nitrate concentrations in 

older water, therefore, range from low to undetectable, 

and the higher concentrations are a result of a 

Table 31. Nitrogen content of manure from various animals (Puckett 

and others, 1998)

[kg, kilogram; N, nitrogen; Mg, megagram]

Animal (N content of manure in 

kg of N)/(Mg of manure)

Beef cows 0.315

Milk cows 0.4

Heifers and calves 0.31

Steers 0.315

Hogs and pigs 0.28

Sheep and lambs 0.45

Horses and ponies 0.28

Chickens (more than 3 months old) 0.83

Chickens (less than 3 months old) 0.62

Broilers and other meat-type chickens 1.1

Turkeys 0.74

Table 30. Usage or generation of manure in counties within study units in the People’s Republic of China and the United States 

[km2

, square kilometer; Mg, megagram]

Tangshan

study-unit

counties

Total manure,

1996 

(Mg/km2)

Delmarva

study-unit

counties

Total manure,

1992

(Mg/km2)

Sacramento Valley

study-unit

counties

Total manure,

1992 

(Mg/km2)

San Joaquin Valley

study-unit

counties

Total manure,

1992 

(Mg/km2)

Laoting 1,225.8 Kent 1,604.1 Butte 801.6 Fresno 3,575.8

Zunhua 1,831.1 New Castle 540.6 Colusa 495.2 Kern 1,266.7

Fengnan 1,623.7 Sussex 8,973.5 Glenn 2,905.6 Kings 7,990.9

Fengrun 3,133.5 Caroline 5,052.0 Placer 626.3 Madera 2,837.5

TangHai 158.5 Cecil 2,141.1 Sacramento 5,399.1 Merced 10,601.4

Luannan 1,753.0 Dorchester 2,023.7 Solano 2,498.6 San Joaquin 8,727.9

Yutian 1,165.1 Kent 2,873.8 Shasta 596.5 Stanislaus 13,824.5

Qianxi 1,806.1 Queen Annes 2,123.9 Sutter 992.4 Tulare 7,434.1

Tangshan 4,461.0 Somerset 6,212.5 Tehama 1,430.9

Luan Xian 4,240.2 Talbot 1,741.1 Yolo 1,163.6

Qian’an 3,066.1 Wicomico 8,042.8 Yuba 3,375.4

Worchester 5,922.9

Accomack 1,437.8

Northampton 18.5

Figure 39. δ15N and δ18O in nitrate for select wells of the Tangshan 

study unit, People’s Republic of China. N, nitrogen; O, oxygen; δ, delta.

0

5

10

15

20

25

0 2 4 6 8 10 12 14

LuanS5

LuanQ5

BenS4

BenQ3-1

BenS3 Shan15

15N, in per mill

18O, in per mill

Nitrogen from manure or sewage

Nitrogen from fertilizer

Mixed nitrogen source
Nitrate and Detection Frequency of Pesticides in Ground Water 49

combination of land use practices, hydrology, and 

geochemical processes. No linear relation of nitrate and 

well depth is apparent (fig. 40). The Spearman’s rho (ρ) 

or Spearman’s rank correlation, a nonparametric test, 

was used to determine whether a consistently decreasing trend of nitrate concentration correlated with well 

depth. A nonparametric test was required because the 

data were not normally distributed. Spearman’s rho is a 

test of the correlation between ranks of two variables, 

in this case nitrate concentrations and well depths. Values of ρ will be between –1 and 1. A negative value 

implies an inverse relation whereas a positive value 

indicates a positive relation. A value near zero indicates 

no correlation between the two variables. An absolute 

value of 1 implies a strong monotonic relation for the 

two variables. The value of ρ for the two variables (well 

depth and nitrate concentration) was –0.295, indicating 

a weak relation between well depth and nitrate concentration. Nitrate concentrations versus depth to water are 

shown in figure 41. The value of ρ for this pair of variables is 0.05, which indicates no relation between depth 

to water and nitrate concentration. It was not possible 

to plot nitrate concentration against the depth to the top 

of the screened intervals of individual wells because 

location of well screens is not known for the wells of 

the Tangshan study unit. The absence of a strong relation between nitrate concentrations and well depth is 

not unusual. The value of ρ for nitrate and well depth of 

the Delmarva Peninsula is –0.152, and the value for the 

wells of the San Joaquin Valley is –0.302. Similar 

results were obtained in an analysis of the eastern San 

Joaquin Valley by Burow and others (1998). Burow’s 

team suggested that factors other than well depth, such 

Nitrate concentrations versus total dissolved 

solids are plotted in figure 43. The calculation of ρ for 

this set of two variables is 0.317, which suggests a weak 

positive monotonic relation between the ranks of the 

two variables. Although nitrate seems to be weakly 

related to total dissolved solids, the relation is not statistically significant when compared with other tests. 

The median of total dissolved solids was tested in wells 

of low nitrate (less than 0.5 mg/L as N) and in wells of 

higher nitrate (greater than 0.5 mg/L as N) concentrations. The medians were assessed to be statistically similar (p = 0.27) when tested with the nonparametric 

Mann–Whitney test of medians. The p value associated 

Figure 41. Nitrate concentration versus water level below land 

surface for wells of the Tangshan study unit, People’s Republic of 

China. N, nitrogen.

0

10

20

30

40

50

60

70

80

0 5 10 15 20 25 30 35 40

Spearman's rho: 0.05

Nitrate concentration as N, milligrams per liter

Water level below land surface, in meters

as soil and sediment texture, may be more important in 

the distribution of nitrate in ground water of the eastern 

San Joaquin Valley.

Nitrate concentrations versus iron concentrations 

for the wells of the Tangshan study unit are shown in 

figure 42. As expected, most of the wells with higher 

nitrate concentrations also have low iron concentrations, but some have relatively high iron concentrations. In those wells, nitrate reduction is apparently not 

sufficient to reduce nitrate to relatively low levels. 

Those wells may be affected by a combination of nitrogen from fertilizer and sewage or manure. The value of 

ρ for the combination of nitrate and iron concentrations 

in the Tangshan study unit is –0.382, which suggests a 

weak monotonic relation between the two variables. 

Figure 40. Nitrate concentration versus well depth for wells of the 

Tangshan study unit, People’s Republic of China. N, nitrogen.

0

10

20

30

40

50

60

70

80

0 50 100 150 200 250

Spearman's rho: –0.295

Nitrate concentration as N, in milligrams per liter

Depth of well, in meters
50 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

with an observed value of a test statistic is the smallest 

level of significance that would have allowed the null 

hypothesis to be rejected. A value of p less than 0.05 

suggests that medians are different. Therefore, the relatively high p value of 0.27 suggests that the medians 

are statistically the same. Although nitrate and total dissolved solids are not strongly correlated, the total dissolved solids of the ground water in the plain region of 

the Tangshan study unit seem to have been affected by 

agricultural or other land-use practices. As mentioned 

previously, total dissolved solids (fig. 32) of the upper 

aquifer of the plain region are higher relative to other 

locations of the Tangshan study unit. This difference 

cannot be explained by water–rock interactions because 

of similar mineralogy; also, the deeper ground water 

would be expected to have a higher total dissolved 

solids content because of the longer time for mineral 

dissolution and equilibrium to occur. 

As part of this project, a collaborative laboratory 

and field study of ammonia and nitrate transport has 

been completed by the Hai He River Water Conservancy Commission and Tsinghua University (Xianbi 

Lue, written commun., 1998). Soil samples from 

Luannan County were collected for a laboratory scale 

simulation and a field experiment. The soil type in that 

part of Luannan County is fine sand with less than 

0.02 percent clay content. The results of those studies 

indicated that, while ammonia nitrogen is strongly 

adsorbed to soil particles, it is also rapidly oxidized to 

nitrate and then easily transported to deeper soil horizons. The collaborative team also showed that the use of 

nitrogen from manure results in a lower amount of 

nitrate transport. The experimental design also compared different water management scenarios. Nitrate 

transport was greatest during the rainy or monsoon 

season, and irrigation during the monsoon season 

resulted in the highest transport of nitrogen to deeper 

subsurface horizons. 

The locations of wells with corresponding levels 

of nitrate concentrations for the Tangshan study unit are 

shown in figure 44. Boxplots of nitrate concentrations 

of well by name designation in the Tangshan study unit 

are shown in figure 45. The wells of the Tangshan study 

unit have a name designation, which indicates a 

regional location, such as the Shan (mountain), or Xian 

(coastal) wells, or named as part of governmental entity, 

such as the Ben, Lao, Luan, Nan, Run, Shi, or Yu designations. The location that tends to have the most dense 

distribution of wells with high nitrate is in the western 

part of the study unit, where wells are labeled “Yu,” 

with decreasing concentrations of nitrate extending 

eastward to the locations where wells are labeled 

“Run.” A few locations in the mountain (Shan) region 

had samples that exceeded 10 mg/L of nitrate as N and, 

in some instances, even 20 mg/L. In contrast, wells of 

the Xian designation always tend to have low nitrate. 

Another cluster of wells with higher relative nitrate 

concentrations is the location where wells are labeled as 

“Luan” or “Ben.” The location of the Ben wells is 

where the variation in concentration is greatest. The 

median concentration of the Ben wells is relatively low, 

compared with the Yu wells. This great variation in the 

nitrate concentrations of the Ben wells, along with the 

relatively low median concentration in that area, suggests that land-use practices around individual wells 

may be most responsible for the outlying concentrations. The higher median concentrations of the Yu wells 

suggest that a combination of land use and hydrologic 

Figure 43. Nitrate concentration versus total dissolved solids 

concentration for wells of the Tangshan study unit, People’s 

Republic of China. N, nitrogen.

10

0

20

30

40

50

60

70

80

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000

Spearman's rho: 0.317

Nitrate concentration as N, in milligrams per liter

Total dissolved solids concentration, in milligrams per liter

10

0

20

30

40

50

60

70

80

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000

Spearman's rho: – 0.382

Nitrate concentration as N, in milligrams per liter

Iron concentration, in micrograms per liter

Figure 42. Nitrate concentration versus iron concentration for wells 

of the Tangshan study unit, People’s Republic of China. N, nitrogen.
Nitrate and Detection Frequency of Pesticides in Ground Water 51

Figure 44. Locations of wells and corresponding levels of nitrate concentrations for the Tangshan study unit, People’s Republic of 

China. Well location Ben3 has three shallow wells (Q1, Q2, and Q3); Ben1 has two shallow wells (Q1 and Q2); all others have either 

one shallow well or no shallow well. N, nitrogen

11845

118

4020

3910 EXPLANATION

Well-group location—Nitrate values for shallow 

 and deep wells at same group location. Includes 

 regional identifier.

Shallow well

Deep well

Single-well location with Nitrate value

Nitrate concentration as N in wells,

 in milligrams per liter

 Less than 0.5

 0.5 to 3.0

 Greater than 3.0 to 10

 Greater than 10 to 20

 Greater than 20

Physiographic region

 Mountain

 Plain

 Coastal

map data: 

base: Hai He River Water Conservancy Commission, 

 original map scale 1:400,000, publication data unavailable

 Tangshan study unit

 

Lao1

Lao2

Lao3

Lao4

Lao5

Lao6

Lao7 Lao8

Xian8 Xian9

Luan3

Luan1

Luan2 Luan4

Luan5

Luan6

Nan3

Shi4 Shi5

Shi6

Ben1

Ben2

Ben3

Ben4

Ben5

Ben6

Ben7

Ben8

Xian2

Xian3

Xian4

Xian5

Xian6

Xian7

Nan1

Nan2 Nan4

Nan5

Run2

Run3

Run4

Run5

Run6

Run7

Shi1

Shi2

Shan10

Xian1

Yu1

Yu2

Yu3

Yu4

Yu5

Yu6

Yu7

Run1

Shan7

Shan9

Shan1

Shan2

Shan3

Shan4

Shan5

Shan6

Shan8

Shan11

Shan12

Shan13

Shan14

Shan15

Shan16

Shan17

Shan18

0

0

20

20

40 MILES

40 KILOMETERS
52 Comparative Water-Quality Assessment of the Hai He River Basin, People’s Republic of China and Three Similar Basins, United States

factors may be responsible for the high nitrate concentrations of wells in that region. It has already been 

shown that the ground water in that region has low iron 

and probably contains dissolved oxygen. Those factors 

would tend to inhibit the reduction of nitrate. 

The distribution of nitrate in ground water may 

also be due to other important factors, such as well construction techniques, the texture of the unsaturated 

zone, climate, and ground-water pumpage. Some wells 

in the Tangshan study unit are perforated from near, or 

at, ground level, which allows water with high amounts 

of nitrate that is derived from the soil zone to directly 

infiltrate the well. Extremely high amounts of groundwater pumpage can result in the drawdown of water 

levels and the transfer of contaminants to deeper 

subsurface zones. The ratio of ground-water recharge 

to ground water use in the People’s Republic of China 

is near 1 or less than 1 depending on the strength of the 

Asian monsoon. The ratio of the Delmarva Peninsula is 

not known, but that region does not rely as heavily on 

irrigation water as do the Tangshan and California 

study units. In fact, rainfall is normally sufficient in the 

Delmarva Peninsula to support agriculture. The San 

Joaquin Valley is highly dependent on irrigation water, 

and its areas have serious ground-water overdraft problems (Gronberg and others, 1998). Although ground 

water is used for irrigation in the Sacramento Valley in 

some areas, irrigation water is normally provided from 

the Sacramento River. As previously mentioned, some 

regions of the Tangshan study unit, such as the Yu 

region, have several ground-water problems, including 

elevated nitrate, total dissolved solids, and coliform 

bacteria. These problems indicate either well construction problems or a highly vulnerable aquifer setting, or 

some combination of factors that is seriously degrading 

ground-water quality. Because a more detailed description of agricultural land-use management for the 

Tangshan study unit is beyond the scope of the current 

study, not all causative factors can be completely 

addressed here. Dating of the ground water in shallow 

and deeper zones and more thorough land-use analyses 

might be addressed in future studies.

Pesticides

Pesticides have been detected in the ground water 

of all three study units of the United States. Koterba and 

others (1993) reported on pesticides in the shallow 

ground water of the Delmarva Peninsula. The most 

commonly detected pesticides were organonitrogen and 

other herbicides, which are applied directly to the soil. 

These herbicides included atrazine, cyanazine, simazine, alachlor, metolachlor, and dicamba. These herbicides were generally present in concentrations below 

drinking-water standards. The detection frequency of 

these herbicides was most strongly correlated with 

corn, soybean, and small grains (winter wheat, barley, 

hay) grown in well-drained soils. Pesticides in ground 

water have affected the suitability of the ground water 

resource in parts of the San Joaquin Valley (Domagalski 

and Dubrovsky, 1991, 1992; Domagalski, 1997). The 

types of pesticides that are most frequently detected in 

the Central Valley of California and the Delmarva 

Peninsula are herbicides and soil fumigants; insecticides are only rarely detected. Herbicides and soil fumigants have a greater frequency of detection because 

they are applied directly to the soil and can migrate to 

ground water after rainfall or irrigation application, 

unless degradation reactions occur in the soil. Although 

herbicides or fumigants are frequently detected in 

ground water, only rarely are their concentrations above 

drinking-water standards. One exception is for the soil 

fumigant DBCP. Soil fumigants tend to be used more in 

the Central Valley of California relative to other agricultural regions of the United States because of the higher 

amount of fruit production in California. DBCP was 

used heavily in parts of the eastern San Joaquin Valley 

where orchards and vineyards are the principal land use 

(the use of DBCP was stopped in 1977). The EPA 

drinking-water standard for DBCP is set at 0.2 μg/L. 

Figure 45. Boxplots of nitrate concentrations by Chinese name 

designation for wells of the Tangshan study unit, People’s Republic 

of China. N, nitrogen. Shi Shan

Yu

Xian

Run

Nan

Ben

Lao

Luan

10

0

20

30

40

50

60

70

(6)

(18)

(14)

(9)

(11)

(10)

(19)

(16)

(8)

Nitrate concentration as N, in milligrams per liter

90th percentile

75th percentile

50th percentile

25th percentile

10th percentile

(n) Number of samples

Well name designation (regional location)
References Cited 53

DBCP was detected in 1,419 of 4,507 wells sampled 

between 1971 and 1988 with a median concentration 

near 2.0 μg/L or a factor of 10 greater than the drinkingwater standard (Domagalski, 1997). Other factors that 

contributed to the multiple detections of DBCP were 

high water solubility, high use in areas with coarsegrained soil texture, and a long environmental half-life. 

Few ground-water samples in the Tangshan study 

unit had been studied previously for the presence of 

pesticides. As a result, the collaborative team decided 

to sample wells of transects 1 and 2 (fig. 4) for pesticides. Samples were extracted in the People’s Republic 

of China, and the extracts were returned to the United 

States for analysis by mass spectrometry. Groundwater extracts were indistinguishable from blank 

extracts, indicating that pesticides were not present. 

However, samples were not available for wells of the Yu 

region, where high nitrate was found. Therefore, 

although no pesticides have been detected in one part of 

the study unit, sampling should be completed in other 

regions. Pesticide applications may not be as high in the 

People’s Republic of China as in the United States. 

That may be one explanation for the lack of pesticide 

detections in the ground water of the Tangshan study 

unit. Another possible explanation is that pesticides 

are present in the soil horizons, but have not yet been 

transported to the water table.

SUMMARY AND CONCLUSIONS

A regional assessment of ground-water quality in 

one region of the People’s Republic of China, the 

Tangshan region, showed that nitrate, total dissolved 

solids, iron, and other contaminants are affecting the 

recently recharged ground water. When compared with 

the ground water in similar agricultural regions of the 

United States, median nitrate concentrations tended to 

be similar, but the data from the Tangshan study unit 

showed a much greater range in concentrations. In the 

People’s Republic of China, the nitrate drinking water 

standard is set at 20 mg/L as N, whereas in the United 

States, the nitrate drinking water standard is set at

10 mg/L as N. Many wells in the regions under investigation in the United States exceeded the American 

(EPA) standard, but only a few wells in the United 

States exceeded the Chinese standard. The high values 

of nitrate concentrations in the Tangshan ground water 

were attributed to larger nitrate applications, to the 

application of animal wastes and sewage to agricultural 

land and to land near ground-water wells, to regional 

hydrology such as soil texture and oxidation–reduction 

processes, and possibly to well construction 

techniques. The use of dating techniques, especially the 

3

H/3He method, indicated that recently recharged water 

could be detected to depths as much as 150 m in the 

Tangshan study unit. The implication for that study unit 

is that agricultural contaminants could also be detected 

to those depths and that the drilling of deeper wells may 

be necessary, in some locations, to provide water of 

suitable quality. The western part of the San Joaquin 

Valley was shown to have some similar water quality 

problems, especially with respect to total dissolved solids. Total dissolved solids of the San Joaquin Valley are 

elevated mainly because of the evaporation of irrigation 

water in a semiarid environment. The climate of the 

Tangshan study unit is less arid than that of the San 

Joaquin Valley, and so the higher total dissolved solids 

content may be attributed less to evaporation and more 

to the longer period that the land has been in agricultural production, and to the greater amounts of land disposal of manure and animal wastes. Pesticides do not 

seem to be a current problem for this region of the 

ground-water system in the People’s Republic of China, 

but not all areas were sampled adequately to provide a 

full assessment. 

REFERENCES CITED

Alley, W.M., 1993, Ground-water-quality surveys, chap. 6 in

Alley, W.M., ed., Regional ground-water quality: New 

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Selected Series of U.S. Geological Survey Publications

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quarterly, annually, or at other regular intervals, depending on 

the need for current data. The MIS’s are published by commodity as well as by State. A series of international MIS’s is also 

available.

Published on an annual basis, Mineral Commodity Summaries is the earliest Government publication to furnish estimates 

covering nonfuel mineral industry data. Data sheets contain 

information on the domestic industry structure, Government 

programs, tariffs, and 5-year salient statistics for more than 90 

individual minerals and materials.

The Minerals Yearbook discusses the performance of the 

worldwide minerals and materials industry during a calendar 

year, and it provides background information to assist in interpreting that performance. The Minerals Yearbook consists of 

three volumes. Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Volume II, Area Reports: 

Domestic, contains a chapter on the minerals industry of each 

of the 50 States and Puerto Rico and the Administered Islands. 

Volume III, Area Reports: International, is published as four 

separate reports. These reports collectively contain the latest 

available mineral data on more than 190 foreign countries and 

discuss the importance of minerals to the economies of these 

nations and the United States.

Permanent Catalogs

“Publications of the U.S. Geological Survey, 1879–1961”

and “Publications of the U.S. Geological Survey, 1962–

1970” are available in paperback book form and as a set of 

microfiche.

“Publications of the U.S. Geological Survey, 1971–1981” is 

available in paperback book form (two volumes, publications 

listing and index) and as a set of microfiche.

Annual supplements for 1982, 1983, 1984, 1985, 1986, and 

subsequent years are available in paperback book form.