Thangarajan / Thangrajan Groundwater

Resource Evaluation, Augmentation, Contamination, Restoration, Modeling and Management
1. Auflage 2007
ISBN: 978-1-4020-5729-8
Verlag: Springer Netherland
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 372 Seiten, eBook

The demand for water resources is increasing day by day due to ever increasing population, mostly from developing countries. This has resulted in abstracting more water from the subsurface stratum and forcing the water managers to manage the limited groundwater resources in a more scientific way, which in turn needs a more sophisticated way of assessing the underground resource and manage it optimally. There is an urgent need to locate high yielding boreholes in the hard rock region by using geophysical methods. Electrical imaging technique in conjunction with remote sensing and geographical information system (GIS) technique has proved to be a potential tool for the purpose. Hydrodynamics of fractured aquifer system in hard rock region is not yet fully understood. The understanding of the groundwater pollution migration in porous and fractured aquifer system and the seawater intrusion in the coastal aquifer has to be improved further. Various aspects of groundwater modeling and in particular issues related to model calibration, validation and prediction has to be understood in much better way. One should integrate all the above issues for effective understanding of the assessment and management of groundwater resources. There is a need to have a comprehensive book to deal with all the above. My former colleague, Dr. M. Thangarajan, Retired Scientist-G, NGRI, Hyderabad, India has successfully edited a book on GROUNDWATER (Resource Evaluation, Augmentation, Contamination, Restoration, Modeling and Management) by inviting topics from various experts across the globe.

Zielgruppe

Research

Autoren/Hrsg.

Thangrajan, M.

Thangarajan, M.

Inhaltsverzeichnis

Application of GIS and Remote Sensing Techniques in Identification, Assessment and Development of Groundwater Resources.- Electrical Resistivity Methods for Borehole Siting in Hardrock Region.- Parameterization of Groundwater Aquifer System.- Application of Geostatistics in Hydrosciences.- Augmentation of Groundwater Resources through Aquifer Storage and Recovery (ASR) Method.- Environmental Impact Assessment, Remediation and Evolution of Fluoride and Arsenic Contamination Process in Groundwater.- Characterization of Fracture Properties in Hard Rock Aquifer System.- Groundwater Models and Their Role in Assessment and Management of Groundwater Resources and Pollution.- Model Calibration and Issues Related to Validation, Sensitivity Analysis, Post-audit, Uncertainty Evaluation and Assessment of Prediction Data Needs.- Groundwater Development and Management of Coastal Aquifers (including Island Aquifers) through Monitoring and Modeling Approaches.- Management of Groundwater Resources.

Leseproben

3 Parameterization of Groundwater Aquifer System (p. 61)

V.S. Singh

Scientist, National Geophysical Research Institute

Hyderabad-500007, India
PREAMBLE

In order to assess groundwater potential in any area, and/or to evaluate the impact of pumpage on the groundwater regime, it is essential to know the aquifer parameters. These are chiefly Transmissivity (T) and Storativity (S). These parameters are also vital for the management of the groundwater resources through the use of groundwater flow model.

These parameters are estimated either by means of in-situ test or performing test on aquifer samples brought in the laboratory. The applicability of the result from the laboratory test has limitations while in-situ tests give representative aquifer parameters.

The most common in-situ test is pumping test performed on wells, which involves the measurement of the fall and rise of water level with respect to time. The change in water level (drawdown/recovery) is caused due to pumping of water from the well. The change in water level with time is then interpreted to arrive at aquifer parameters.

Theis (1935) was first to propose a method to evaluate aquifer parameters from the pumping test on a bore well in a confined aquifer. Since then, several methods have been developed to analyze the pumping test data (time-drawdown) under different conditions. Before we describe these methods in detail, let us recall some of the definitions, which are frequently used.

WATER BEARING FORMATION

A geological formation, which can yield water in sufficient quantity to be of consequence as a source of supply is termed as aquifer. Such formations are porous and pores are interconnected (eg. sands). Some formations are porous but the interconnections between the pores are poor. These are termed as aquiclude (such as clay).

The formations which have interconnected pores but not sufficient enough to allow significant horizontal flow through them, are called aquitard (eg. silt). Although significant groundwater does not flow through them but under certain conditions induced vertical flow (leakage) can take place across them.

The formations, which do not have any pores or voids, are termed as aquifuge for example compact granite. Such rocks are impervious. The saturated rock formations in the nature form the aquifer under different conditions. For example, deposition of weathered material forms an aquifer. Under various conditions, various types of aquifers are formed which are described below.

Confined Aquifer

The completely saturated permeable formations when occur in between two impervious layers, the aquifer is termed as confined aquifer as shown in Fig. 1. In such aquifers the pressure of water is usually higher than that of the atmospheric pressure and therefore the water in the well stands above the top of the aquifer.

This water level is called piezometric surface. Unconfined Aquifer The permeable formation partly saturated with water, when rests over an impervious bed is called an unconfined aquifer (Fig. 2). The upper part of saturated zone is bounded by free water level called water table or phreatic level. The water level at the upper surface is at atmospheric pressure.

Über Autor(innen)

Dr. M. Thangarajan, formerly Scientist-G & Head, groundwater modeling group, at National Geophysical Research Institute (NCRI), Hyderabad, India, obtained his Master's in Physics at Madras University and PhD in Applied Geophysics from Indian School of Mines, Dhanbad, For more than three decades, he has carried out extensive research work in the assessment and management of groundwater resources through mathematical modeling. He has visited Botswana as modeling expert. Het is the member of IAH, IAHS, AGID and Geological Society of India. He has contributed over 125 research papers in national and international journals besides seminar proceedings. Author of the title "Regional Groundwater Modeling", he is also the co-editor of five other books.