Hard Rock Region Research Articles

Groundwater: resource evaluation, augmentation, contamination, restoration, modeling and management

Foreword.- Preface.- 1. Application of GIS and Remote Sensing Techniques in Identification, Assessment and Development of Groundwater Resources.- 2. Electrical Resistivity Methods for Borehole Siting in Hardrock Region.- 3. Parameterization of Goundwater Aquifer System.- 4. Applicatrion of Geo-statistics in Hydrosciences.- 5. Augmentation of Groundwater Resources through Aquifer Storage and Recovery (ASR) Method.- 6. Environmental Impact Assessment, Remediation and Evolution of Fluoride and Arsenic Contamination Process in Groundwater.- 7. Characterization of Fracture Properties in Hard Rock Aquifer System.- 8. Groundwater Models and Their Role in Assessment and Management of Groundwater Resources and Pollution.- 9. Model Calibration and Issues Related to Validation, Sensitivity Analysis, Post-audit, Uncertainty Evaluation and Assessment of Prediction Data Needs.- 10. Groundwater Development and Management of Coastal Aquifers (including Island Aquifers) through Monitoring and Modeling Approaches.- 11. Management of Groundwater Resources.- Index.

Reliability of Resistivity Method of Prospecting Groundwater in Hard Rock Region

A study was conducted to determine the reliability of electrical resistivity method of ground water explorations at 'farmers' field in under hard rock region in Rahuri Tahsil of district Ahmednagar (Maharashtra). In this method, vertical electrical soundings with Schlumberger array were carried out at forty locations in the area. The data gathered from this method at each sounding were interpreted by curve break method for finding the depth of soil formations. The interpreted data were compared with the actual observations recorded during the drilling process at 15 locations. The method was found effective in hard rock areas, as the average deviation between observed and estimated depth of water bearing strata was found to be 13.45 per cent. The reliability of this method was found 73% for selecting the site for irrigation water and 87% for determining the depth of water bearing formation.

Integrated studies for characterization of lineaments used to locate groundwater potential zones in a hard rock region of Karnataka, India

An integrated study was carried out to investigate the subsurface geological conditions in a hard rock environment, with the aim of identifying zones with groundwater resource potential. The study, in Bairasagara watershed, Karnataka, India, considered geomorphology, water level, resistivity imaging, self potential, total magnetic field and susceptibility. The signatures due to lineaments have been clearly identified and their role in groundwater movement has been documented. Synthetic simulation methods were used to model the electrical response of the lineament using finite differential modeling scheme. The inverted image of the field data is compared with the synthetic image and iteration were performed on the initial model until a best match was obtained resulting on the generation of the calibrated resistivity image of the subsurface. Resistivity imaging revealed that the dykes are weathered/fractured to a depth of 6–8 m and are compact at deeper levels, and that they behave as barriers to groundwater movement, yet facilitate a good groundwater potential zone on the upgradient side. The results of magnetic surveys were utilized in differentiating granites and dolerite dykes with an insignificant resistivity contrast. Geomorphological expression alone cannot reveal the groundwater potential associated with a lineament. However, characterizing the nature of the feature at depth with integrated geophysical methods provides essential information for assessing that potential.

Integrated studies for characterization of lineaments used to locate groundwater potential zones in a hard rock region of Karnataka, India

Integrated studies for characterization of lineaments used to locate groundwater potential zones in a hard rock region of Karnataka, India

Localization of water bearing fractured zones in a hard rock area using integrated geophysical techniques in Andhra Pradesh, India

Knowledge of the existence of fracture zones, their extent, intensity and direction is very useful for assessing groundwater in hardrock regions and in this context geophysical methods are widely accepted as a powerful means of study. In the modern era of exploration, application of the Resistivity Imaging technique gives a new opportunity for groundwater study in hardrock regions. Exploration surveys were conducted at one of the important sites in Maheshwaram watershed, Andhra Pradesh, India with a multielectrode resistivity imaging system. To reduce the ambiguity of geophysical interpretation some complementary geophysical studies like ground Magnetic and VLF were also carried out.

Geo-electrical exploration for groundwater in a hard rock region of Hyderabad, India

Geo-electrical exploration for groundwater in a hard rock region of Hyderabad, India

Seismic imaging of steep dips with low fold data: Case studies for Broken Hill and the Lachlan Fold Belt

In hard rock regions, a large range of stacking velocities is required to correctly stack reflectors of different dips. Typically, horizontal reflectors stack at 6000 m/s, whereas reflectors with dips of 60° stack at 12,000 m/s. For high fold (vibrator) data, correct stack of conflicting dips can be achieved by dip moveout (DMO) correction. However, for lower fold (dynamite) data, the sparse offset distribution complicates application of DMO. An alternative technique involves producing stacks with different stacking velocities and stacking these stacks. This technique was applied to two seismic reflection data sets, low fold dynamite data from Broken Hill and high fold vibrator data from the Lachlan Fold Belt. The Lachlan data set was used as both full 60/120 fold and reduced 10/20 fold. Velocity analysis, both analytical and empirical, was carried out to determine the range of stacking velocities. Stacking velocity increases with dip angle (cos-1q), but the velocity range across which an event stacks coherently increases more rapidly (approximately cos-3q for velocities typical of hard rock). The most critical area for analysis is the first two seconds of data, due to greater sensitivity of NMO to stacking velocity. The optimum number of stacks is an important consideration, based on the number of stacks in which an event contributes coherently to the sum The Broken Hill stack data showed simultaneous imaging of horizontal and dipping events. For the Lachlan reduced fold data set, horizontal and moderate to steeply dipping events were stacked successfully, although not as well as the post-DMO stack of the full fold data. The technique has some problems at the shallowest levels, where the stack can be degraded due to time shifts of events in the individual stacks, but is a useful tool for low fold seismic data typical of older regional profiles.

Characterization of an aquifer system in the Upper Palar Basin: a case study

Hydrodynamics of the groundwater flow regime in hard rock regions, and its quantification, are not yet fully understood. This is mainly a result of several uncertainties involved in quantifying the hydrogeological parameters. Numerical techniques are potential tools in interpreting hydrogeological parameters in hard rock regions. Such a study was carried out in the Palar River Basin, Tamilnadu (India), where pumping tests carried out on large diameter wells were interpreted using a numerical technique.

CALIBRATION AND VALIDATION OF A CONCEPTUAL DISTRIBUTED FUNCTION MODEL FOR AN INDIAN CATCHMENT

ABSTRACT The present paper aims at studying the suitability of conceptual distributed parameter rainfall—runoff model under Indian condition by applying it to the catchment of hard rock region. The model is tested using the Malaprabha catchment data for five years. The results obtained show that the model can be used for Indian conditions by deriving some of the parameter values from catchment. The model predicts the rise and fall, and the magnitude of the runoff from the catchment quite accurately.

Selection of Appropriate Pumping Systems for Bore Wells in The Deccan Basalt of India

In India, groundwater resources from the hard-rock regions in general and from the Deccan Volcanic Province in particular are being obtained from 115-mm, 152-mm and 165-mm diameter bore holes (commonly known as bore wells). With no definite criteria for pump selection, these bore wells are either overdeveloped or underutilized, and the groundwater resources are thereby being mismanaged. PUMPS is a computer program that helps select a proper pumping system on a bore well in the Deccan basalt, taking into account the productivity of the bore well and considering a stabilized drawdown above the main aquifer tapped by the bore well. This method of pump selection has yielded encouraging results and all the bore wells with pumping systems installed using PUMPS have proven to be effective in providing the required yields without overstressing the aquifers.

Q and Site Amplification Factors of Hard-Rock Region in the Kitakami Massif, Northeastern Japan.

We observed three explosions along a 60 km profile in the central part of the Kitakami massif, northeastern Honshu, Japan. Explosion sites and most of the observation sites were located on hard-rock outcrops. Using P-wave first arrivals, the average QP along ray paths and site amplification factors were determined for the frequency range between 6 and 30 Hz based on the amplitude spectra decay with distance. QP increased proportional to fn (n_??_0.9). The difference in amplification factors among hard-rock sites was as much as a factor of five for frequencies lower than 12 Hz and became large at higher frequencies. QS and S-wave site amplification factors were obtained only for 5 and 7.5 Hz. QS was slightly larger than QP, but the difference was not significant. S-wave site amplification factors were more variable than those of P-wave among the stations.

Innovations in the use and management of groundwater in hardrock regions in India

Empirical evidence emanating from many parts of India indicates that, because of their advantageous resource position and bureaucratic-political influence, owners of large farms have appropriated the gains of lift irrigation disproportionately more than small farmers. In this situation the use and management of groundwater — a CPR — calls for innovative institutional arrangements to improve accessibility to small farmers especially in water-scarce hardrock regions. For such institutional arrangements to emerge and succeed, appropriate policy prescriptions are required on several fronts, such as groundwater legislation, land reforms, pricing of water, electricity, and so on. The paper examines critically some of these innovative experiments in hardrock regions in India.

Vertical open fractures and shear‐wave velocities derived from VSPs, full waveform acoustic logs, and televiewer data

Fracture or stress‐related shear‐wave birefringence (or azimuthal anisotropy) from vertical seismic profiles (VSPs) is commonly observed today, but no attempt is made to fit the observations with observed in‐situ fractures and velocities. With data from a hard rock (limestones, dolomites, and anhydrites) region of Michigan, fast and slow shear‐wave velocities have been derived from a nine‐component zero offset VSP and compared to shear‐wave velocities from two full waveform acoustic logs. To represent the shear‐wave birefringence that affects the shear wave’s vertical propagation, a propagator matrix technique is used allowing a local measurement independent of the overburden layers. The picked times obtained by using a correlation technique have been corrected in the birefringent regions before we compute the fast and slow velocities. Although there are some differences between the three velocity sets, there is a good fit between the velocities from the shear‐wave VSP and those from the two logs. We suspect the formations showing birefringence to be vertically fractured. To support this, we examine the behavior of the Stoneley wave on the full waveform acoustic logs in the formations. In addition, we analyze the borehole televiewer data from a nearby well. There is a good fit between the fractures seen from the VSP data and those seen from the borehole.

Finite-element modelling of groundwater flow in hard rock regions containing a heat-emitting radioactive waste depository

The finite-element method is used to study the effect of various parameters on the groundwater flow field around a hypothetical radioactive waste depository in hard rock. From the flow field water transport times are calculated. It is shown that major fault zones in the vicinity of a depository have a substantial effect on water transport times; in some cases this may be advantageous. The effect of the natural geothermal gradient on water viscosity at depth is shown to be significant. A permeability decrease with depth is shown to have a marked effect on water transport times. The effects on water flow of depository heat output are also considered.

Inadequacies in theTechnique of Resistivity Method for Location of Waterwell Sites in Hard Rock Areas

Large scale exploratory work for groundwater in hard rock region of South India has been carried out by the authors during the last ten years, using electrical resistivity method. The standard methods of data interpretation were found to be inadequate in locating water well sites and determining the existence and depth of occurrence of water bearing fractures and joints. Wenner and Schlumberger type vertical electrical sounding (VES) curves were interpreted by matching against theoretical model curves and also by inverse slope method. The interpreted results were correlated with the actual driller's logs. No satisfactory correlation could be observed either between the geoelectrical interpreted layer boundaries and the layer boundaries from the wells or between the resistivity in the hard rock and the water yield. A more pragmatic approach to the problem is desirable to minimize the failures of wells in hard rock terrain.

Site Correction for Long Period Seismometers, Tiltmeters and Strainmeters

Summary Long-period horizontal seismometers, tiltmeters and strainmeters are influenced by inhomogeneous rock properties in the site region. These inhomogeneities interact with applied stress fields to create local strains and tilts that differ from those averaged over greater distances. These effects have been called strain-strain and strain-tilt coupling. For each instrument, the coupling is defined by three coefficients, so that for observations at a particular point a correction may be defined using a third-order tensor for seismometers and tiltmeters, and a fourth-order tensor for strainmeters. These tensors may be evaluated using instrumental data alone, either at tidal periods, or at seismic periods using properties of Rayleigh waves. Long-period seismometers and tiltmeters have usually been sited in specially constructed vaults in hard rock on the grounds that such sites give the lowest levels of background noise. The theory of the detection of seismic waves (see for example Rodgers 1968) implicitly assumes horizontal layering in the region of the site (including the earth-air interface) and no account is taken of lateral inhomogeneities that have dimensions small compared to the seismic wavelength being studied. Since these inhomogeneities do not affect the propagation of seismic waves it is assumed that they can be neglected in the region of a seismometer site. This is rarely satisfactory especially for a hard rock site (King 1971) since hard rocks are usually jointed and hard rock regions have pronounced topography. Topography, inhomogeneities due to fissures and the cavity formed by the seismometer vault all cause the strains associated with incoming seismic waves to produce local tilting; effects of this sort have been described in the tidal literature (Lecolazet & Wittlinger 1975; King & Bilham 1973; Lennon 8z Baker 1973; Itsueli et al. 1975; Harrison 1975) using terms such as ' cavity effect ' and ' topographic effect '. Attempts have been made to study the site effect with finite element models (Itsueli et al. 1975; Harrison 1975) using as input data the visible topography and cavity shape, and rock moduli inferred from geological and seismological information. This approach has two defects. The first is the practical problem of constructing and checking large three-dimensional finite element models. The second arises from the difficulty of obtaining the correct input data for the models. Published results (Itsueli et al. 1975) indicate that fracture patterns exist around excavations and it is

Submarine Topography near Noto Peninsula

This paper is a study of the features of the cultivated land, and that of the subareal and submarine topography of Noto peninsula, which is the only large peninsula that juts out on the Japan sea. 1. A Morphological Study of the Features of the Cultivated Land. (No. 6, p p. 399-411.) This land is divided into ten part saccording to type of the feature and the patterns of both rice and dry fields. I. Plane cultivated land. A. The Rice field type. This spreads out as “Oti” graben in the NW part of Fig. 2. B. The “Uti-ura” marine terrace type (see photo. 4, Fig. 5). C. The Former salt field type (see photo. 1.) The level of the rice field is almost equal to sea level, 50 years ago they were salt fields but now rice fields. D. The “Soto-ura” marine terrac type (see phot. 3). This type prevaids on the eastern part of the northern coast. E. The Dry field type in the western part of the northern coast. This plane has a steep sea cliff 20-100m. II. Massive cultivated land F. The “Isurugi-goisi” type. This massive rice field, Fig. 2 is intimately related to a land-slide Fig. 3. G. The Scattered type. These small massive rice field belong to “Einzeldorf” or “Weiler” on a number of upheaval planes. H. The Corrie-like type. (see Fig. 9.) This is developed on hard rock region. III. Linear cultivated land I. The Branching rice field type. (see Fig. 4, 5, 8.) The Valley bottom has a gentle slope, with much water and thick sediments, and the other part is not easy to irrigate, so that this type has developed. J. The Chaining rice field type. As the result of intermittent upheavs there are many knick-points as show in Fig 10 at which point the Linear rice fields are cut or closed. 2. A Geomorphologieal Study of Subareal and Submarine Topography. (No. 7_??_8, p p. 477_??_490, 546_??_556.) The Noto Peninsula consists of two groups of Tertiary fault blocks. The first group, which forms the main part of this peninsula, are from south to north, the “Sekidosan” block, “Oti” graben, “Bijosan” block, “Sirahama-Takahama” graben, “Musigamine” block, “Takatumeyama” block, and “Nisiura” block. Since this group is an elevated land related to the “Kaga” mountain region, which is the southern great block of the first group, these blocks have many points in common. That is, they have a marine erosion surface under 400m, and there is between the two blocks a clear fault or graben, while the trend of the blocks, and that of the fault or graben is NE-SW, which gradurally becomes NNE-SSW, and finally N-S. These changes are on account of the time that elapsed between the move-ment of the two elevations the first and second groups. The second group, which is related to the “Hida” mountain block, lying east of the “Kaga” block, consists of two fault blocks and three submarine banks, mamely, from south to north, the “Hatibuse-” and “Suzu” blocks, “Nanatu-sima” and “Yomeguri” banks, and the “Hegura-sima” bank. The trend of this group is NE-SW. The height of the two blocks is higher than the former, and the flat plane on the top of this block mountain has a very small area, although there are many other small flat planes on the various levels. Usually, the slope is steep on the north side and gentle to the south, and both coasts have marine terraces of two or three levels, that are higher on the northern coast. That block which situated north of the first group and west of the second group has both characteristics. The flat planes of the first group seem to be the surfaces of a marine erosion of the same stage, while the planes at various levels of the second group seem to be the surfaces of marine erosion at several stages.