Chandra Groundwater Geophysics in Hard Rock

1. Auflage 2015
ISBN: 978-0-203-09367-2
Verlag: CRC Press
Format: PDF
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 384 Seiten

In hard rock terrain, shallow water wells generally have a poor to moderate yield. Sinking wells deeply to tap yielding fracture zones often backfires, because the borehole may miss the saturated fracture zones at depths. A wrong approach to groundwater exploration in hard rock has therefore often led to unnecessary recurring expenditures and waste of time, something that could have been avoided by a systematic and proper geophysical approach. The combination of various geophysical techniques with environmental conditions is essential to constrain the interpretation and reduce uncertainties in this respect. This book presents the approach to groundwater exploration in hard rocks, various geophysical techniques and combinations to be used, interpretation of data with case studies and drilling results and the preparation of different utility maps.

Zielgruppe

Professionals and Researchers in Hydrogeology, Water Resources, Exploration Geophysics (well boring, oil exploration), Soil Engineering (crop science, agricultural sustainability) as well as in Rock, Mining,Environmental and Geological Engineering, Construction & General Civil Engineering (excavations, large civil engineering projects). Advanced Students in the above-mentioned disciplines will also find this publication useful.

Autoren/Hrsg.

Chandra, Prabhat Chandra

Fachgebiete

• Geowissenschaften Geologie Bodenkunde, Sedimentologie
• Technische Wissenschaften Umwelttechnik | Umwelttechnologie Umwelttechnik
• Geowissenschaften Umweltwissenschaften Umwelttechnik
• Naturwissenschaften Physik Angewandte Physik Geophysik
• Geowissenschaften Geologie Hydrologie, Hydrogeologie
• Geowissenschaften Geologie Geophysik

Inhaltsverzeichnis

1 Groundwater issues in hard rock & geophysics

1.1 Introduction

1.2 Trends in groundwater utilization

1.3 Necessity of managed aquifer recharge

1.4 Groundwater quality issues

1.5 Problems in groundwater development

1.6 Need for systematic investigation

1.7 Scope and essentiality of geophysical input

1.8 Geophysical deliverables

1.9 Prerequisite technical field-guidance

1.10 Interdisciplinary convergence

1.11 Cost-effectiveness vs technological development

2 Introduction to the hydrogeology of hard rock

2.1 Introduction

2.2 Weathered zone and fractures

2.3 Groundwater occurrences

2.3.1 Weathered zone aquifers in granitic terrain

2.3.2 Fractured zone aquifers in granitic terrain

2.3.2.1 Deeper fractured aquifers

2.3.3 Aquifers in metasediments

2.3.4 Aquifers in quartz reefs and dykes

2.3.5 Volcanic rock aquifers

2.4 Groundwater development

2.5 Groundwater quality

3 Introduction to geophysical investigations in hard rock

3.1 Introduction

3.2 Geophysical methods and physical property measurements

3.3 Applications of geophysical methods

3.3.1 Airborne geophysics

3.3.2 Surface geophysics

3.3.3 Borehole geophysics

3.4 Integration of methods

4 Planning of geophysical surveys

4.1 Introduction

4.2 Modeling geophysical response

4.3 Types of survey and coverage

4.4 Selection of method and equipment

4.5 Planning for field survey

4.5.1 General considerations for equipment

4.5.2 Access to the area

4.5.3 Area details and compilation of data

4.5.4 Survey parameter design

4.5.5 Surveying work for profile layout

4.6 Geophysical team size and responsibilities

4.7 Survey cost and time

4.8 Safety and precautions in field operations

4.9 Quality control

4.10 Deliverables

5 The magnetic method

5.1 Introduction

5.2 Basics

5.3 Instrument

5.4 Field procedures

5.4.1 Total magnetic field intensity measurement

5.4.1.1 Correction of data

5.4.2 Magnetic susceptibility measurement during field survey

5.5 Processing of data

5.5.1 Regional-residual anomaly separation

5.5.2 Reduction to pole

5.6 Interpretation

5.6.1 Estimation of depth to magnetic source

5.7 Identification of fractured zone

5.8 Aeromagnetics

5.8.1 Case studies

6 The electrical resistivity method

6.1 Introduction

6.2 Ranges of electrical resistivity in hard rock

6.3 Basics

6.4 Vertical electrical sounding

6.4.1 Electrode arrays

6.4.2 Depth of investigation

6.5 Resistivity profiling

6.5.1 Gradient array resistivity profiling

6.6 Resistivity imaging

6.7 Electrode arrays for investigating fracture/structure-induced anisotropy

6.8 Site selection in hard rock areas

6.9 Instrument and field accessories

6.10 Field layout, operation and data acquisition

6.10.1 Checks in field operations

6.11 Processing of data

6.12 Interpretation

6.12.1 Manual interpretation of vertical electrical sounding curve for layered-earth

6.12.1.1 Curve matching technique

6.12.1.2 Inverse slope method

6.12.2 Interpretation of sounding curve for bedrock depth

6.12.3 Interpretation of sounding curve for fracture detection

6.12.4 Detecting fractures from sounding curve by empirical methods

6.12.4.1 Curve-break method

6.12.4.2 Factor method

6.12.5 Computer based interpretations of sounding curves

6.12.6 Equivalence in layer parameters

6.12.7 Poor resolution or suppression of a geoelectrical layer

6.12.8 Depth-wise transition in resistivity

6.12.9 Effect of top soil conductivity

7 The self potential method

7.1 Introduction

7.2 Basics

7.3 Instrument

7.4 Field procedures

7.5 Processing of data

7.6 Interpretation

7.7 Case studies on effect of well pumping on SP

7.7.1 Changes in SP after 24 hrs pumping

7.7.2 Changes in SP after 1 hr pumping

7.7.3 Groundwater flow through cavernous limestone

8 The mise-a-la-masse method

8.1 Introduction

8.2 Basics

8.3 Instrument

8.4 Field procedures

8.5 Processing of data

8.6 Interpretation

8.7 Case studies

9 The frequency domain electromagnetic method

9.1 Introduction

9.2 Basics

9.3 Instrument

9.4 Field procedures

9.5 Processing of data

9.6 Interpretation

9.7 Delineation of saturated fractured zones

9.7.1 Case study from metasediments

9.7.2 Case studies from granitic terrain

10 The very low frequency electromagnetic method

10.1 Introduction

10.2 Basics

10.3 Instrument

10.4 Field procedures

10.5 Processing of data

10.6 Interpretation

10.7 Case studies

10.7.1 Granitic terrain

10.7.2 Metasediments

10.7.3 Basic dyke and quartz reef

11 The time domain electromagnetic method

11.1 Introduction

11.2 Basics

11.3 Instrument

11.4 Field procedures

11.5 Processing of data

11.6 Interpretation

11.6.1 Equivalence in electromagnetic sounding

11.6.2 Detectability and depth of investigation

11.7 Delineation of fractured zones in hard rock

11.8 Airborne electromagnetic surveys

11.8.1 Airborne TEM survey for groundwater in hard rock

12 The borehole geophysical logging methods

12.1 Introduction

12.2 Spontaneous potential

12.3 Single point resistance

12.4 Resistivity

12.5 Electromagnetic induction

12.6 Fluid conductivity

12.7 Temperature

12.8 Natural gamma radioactivity

12.9 Gamma-gamma (density)

12.10 Neutron

12.11 Caliper

12.12 Flowmeter

12.13 Acoustic

12.14 Borehole televiewer

12.15 Borehole radar

12.16 Nuclear magnetic resonance

13 Integrated geophysical survey

13.1 Introduction

13.2 Mapping of lineaments from satellite imagery

13.3 Airborne geophysical surveys

13.4 Geological and borehole information

13.5 Selected surface geophysical methods and techniques for integration

13.5.1 Seismic surveys

13.5.2 Passive seismic

13.5.3 Ground penetrating radar

13.5.4 Nuclear magnetic resonance measurement

13.5.5 Radon gas measurement

13.6 Integration of electrical and electromagnetic methods

13.7 Procedure for integrated field surveys

13.8 Case studies

13.9 Research studies and field experiments

14 Geophysical methods in management of aquifer recharge & groundwater contamination study

14.1 Introduction

14.2 Managed aquifer recharge

14.2.1 Geophysical investigations

14.2.1.1 Some managed aquifer recharge structures

14.2.1.2 Unsaturated zone characterization and monitoring recharge conditions

14.3 Groundwater contamination study

14.3.1 Geophysical investigations

14.3.1.1 Monitoring groundwater contamination

Über Autor(innen)

Dr. Prabhat C. Chandra, a professional groundwater geophysicist, was born in Varanasi, India in 1950. He received B.Sc. and M.Sc degrees in Geology and Geophysics from Banaras Hindu University (BHU) in 1970 and 1972 and was awarded the N.L. Sharma Gold Medal in Geology and first rank in Geophysics. Soon after, Dr. Chandra started his career as a groundwater geophysicist at the CSIR-National Geophysical Research Institute, Hyderabad (NGRI) India and in 1978 joined the Central Ground Water Board (CGWB), Govt. of India. His doctoral thesis was on groundwater geophysics. He superannuated in December 2010 at the age of 60 as Director, CGWB.

During his 38 year professional career he has had ample opportunity to work on a variety of groundwater issues in almost all the hydrogeological terrains of India including hard rock, coastal tracts, limestone, basalts, alluvium, desert, islands and hilly tracts. In view of the scarcity of groundwater in hard rock he took up the challenging geophysical investigations of delineating fracture zones in hard rocks which cover two thirds of the country. There are several papers and reports to his credit.

He was trained in groundwater management through an Indo-British Fellowship from the UK. He attended World Water Week, Sweden and visited the Hydro Geophysics Group (HGG), Aarhus University, Denmark for presentations on groundwater geophysics. At Allahabad University, Central University, Patna and the Indian School of Mines, Dhanbad, he taught hydrogeology and groundwater geophysics. After superannuation he worked as a consultant to The World Bank, New Delhi and as an expert to CSIR-NGRI along with experts from the U.S. Geological Survey (USGS) and HGG, Aarhus University, Denmark for aquifer mapping in pilot projects through heliborne geophysical surveys and as advisor to WAPCOS Ltd. Govt. of India for aquifer mapping of the National Capital Region through surface and borehole geophysical surveys.

The book ‘Groundwater Geophysics in Hard Rock’ is based on his vast experience in delineating the fracture zones in hard rocks, subsurface characterization and locating high yielding well sites.