Preface Hydrogeomorphology is the science relating to the geographical, geological and hydrological aspects of water bodies and changes to these in response to flow variations and to natural and human caused events such as heavy rainfall or channel straightening. The knowledge of hydrogeomorphology is important for planning and management activities concerned with the surface of the earth. The resource managers and planners for agricultural landuse need detailed, timely, accurate and reliable data on the extent, location and quality of land and water resources and climate characteristics. The hydrogeo-morphological processes comprise the physical and chemical interaction between the earth's surface and the natural processes acting upon it to produce landforms in association with their hydrological characteristics. This book is intended to serve as a guide to those who are concerned with various facets of hydrogeological and geomorphological studies - students, academic and the professional in diverse fields like geology, hydrogeology, geomorphology, irrigation and agricultural engineering and environmental management concerns. Others who will find the book useful are administrators, policy makers, economists whose interest in assessment studies are concerned with formation and evaluation of plans for development and management of the natural recourses. I have endeavored to present the readers with diverse backgrounds the basic principles, various methods and techniques of hydrogeomorphological analysis of the area i.e. the basin or watershed. Special emphasis has been laid on aspects dealing with morphometric analysis of the basin, geologic, structural and geomorphological control on the occurrence and movement of the groundwater. The whole book is divided into 12 chapters. The Chapter 1 gives the introduction and definition of hydrogeomorphology in association with the aspects of hydrogeological units, geology, climate and surface processes and groundwater movement. The chapter also discusses the hydrogeomorphology in practice and status of interdisciplinary research and relations in hydrogeomorphology. Chapter 2 is dealing with the general aspects of mechanism and processes, basic tools, methods of data collections, properties of earth materials, scales of explanation and dimensions of hydrogeomorphological units along with the hydrological cycle, water balance and water budget. The Chapter 3 deals, firstly with surface water resources including the streams and rivers, lakes and ponds and reservoirs and secondly with groundwater resources with reference to physical properties, chemical characteristics, quality parameters and biological characteristics. Chapter 4 deals with the classification of aquifers in to confined unconfined and perched aquifers along with the study of aquifer properties like porosity and permeability, specific yield and specific retention, groundwater flow and Darcy's law. The Chapter 5 presents the hydrological properties of igneous, sedimentary, metamorphic and unconsolidated rocks. Chapter 6 includes the hydrogeomorphological characters of uniclinal structures and hydrogeomorphic expressions of folds, faults, joints and lineaments.

The term hydrogeomorphology can be divided into three terms hydro- means water including both surface and groundwater; geo- means the earth and morphology- is the surface expression of the features in the form of landforms. This means that the hydrogeomorphology is dealing with the aspects of water, rocks and earth’s morphological features (land). Of these water and land are most important natural resources for human beings. Water is synonymous with life. This is a natural resource and an absolute necessity for the survival of the living beings. Human beings have an organic relationship with water. For living and livelihood, human beings solely depend upon the availability of water. They have an inalienable right on water. This is a community resource and cannot be made a tradable commodity, violating normative law of nature. Water is among the most precious gifts of nature to mankind. Most of the ancient towns of the world grew on the banks of the river, and some of the ancient civilizations are known by the names of rivers. Rivers have always been important sources of drinking water and the means of sustaining human, animal and plant life. Whenever one is dealing with water resources development and utilization, it has to be kept in mind that not only quantity of water but also quality of water is very important. The well being and development of our society is dependent on the availability of water.

Present day hydrogeomorphological research is the explanation of landscape and landforms: what they are, how they function and have developed with reference to the hydrological conditions. Research is a much more complex undertaking than giving names to landforms or even the study of processes, both in terms of what we mean by process and how explanations are approached. It is worthwhile examining some reasons for this, as it shows the increasing complexity of the subject and lead to ideas of how hydrogeomorphology can be studied. Here are some of the fundamentals required for hydrogeomorphological studies: Mechanism and Processes ‘Mechanism’ provides explanations in detail by describing physical or chemical effects. ‘Process’ signifies the integration of mechanisms in time. Thus, for example when we talk about ‘fluvial process’ or, more specifically, about the ‘mechanism of saltation’, then we have to discuss about the energy source and processes of carrying the material. A process can thus be viewed as the simultaneous operation of a set of specific mechanisms over a specific time period.

Surface Water Resources Surface water is a general term describing any water body which is found flowing or standing on the surface, such as streams, rivers, ponds, lakes and reservoirs. Surface water originates from various combinations of sources: Direct precipitation - rainfall which falls directly in the surface water body; Surface runoff - rainfall which has fallen onto the surrounding land and that flows directly over the surface into the water body; Interflow - excess soil moisture which is constantly draining into water body; and Water table discharge - where there is an aquifer below the water body and the water table is high enough, the water will discharge directly from the aquifer into the water body. The quality and quantity of surface water depends on a combination of climate and geological factors. The recent pattern of rainfall, for example, is important in enclosed water bodies such as lakes and reservoirs where water is collected over a long period and stored. The water storage in streams and rivers is in a constant stage of movement and depend on the weather conditions.

An aquifer is a geologic formation, a part of a formation, or a group of formations that will yield water. The quantity of ground water that an aquifer will yield to wells depends partly on its thickness, extent, continuity, and homogeneity, and partly on its physical properties of permeability and porosity. Groundwater is stored in subsurface void spaces below the water table. The geologic material that stores, transmits, and yields groundwater to wells and springs are called aquifers. The key word here is yields. To be an aquifer, it must store and transmit water at rates fast enough to supply reasonable amounts to wells and springs. Therefore, not all groundwater is stored in an aquifer. Productive aquifers can be comprised of sand and gravel, sandstone, limestone and dolomite, or basalt flows, whereas fractured igneous or metamorphic rocks are only marginal aquifers. The classifications of aquifer are given below:

Groundwater exists at many places beneath the surface of the earth. It is normally hidden from view but, on occasion, can be seen flowing from springs and wells or seeping into tunnels. Certain properties of the various geologic materials control the ability of groundwater to enter into, move through, be stored in, or be extracted from the ground. Therefore, an understanding of geology is necessary in order to gain an understanding of groundwater found within a particular area of investigation. A basic part of the study of the geology of an area includes the preparation of a map showing surfacial exposures of each rock type. Interpretation of the map facilitates the study of the underground configuration, characteristics, and physical properties of these materials. This, in turn, enables the evaluation of groundwater storage, movement, and yield, as well as the identification of areas of ground water quality problems, recharge, and extraction. The fundamental unit of a geologic study is the geologic formation. A formation has been defined as any assemblage of rocks, which have some character in common, whether of origin, age, or composition. In this sense, the term “rock” is defined as any naturally occurring part of the earth’s crust, made up of aggregate of minerals and includes hard, dense granite, lava ash, clay, sand, and even loose-uncohesive soil.

Application of the principal of geomorphology provides information, which will be of value in predicating the geometry of aquifers. On weathering and erosion, many geological formations develop landforms that are distinctive in respect of slope continuity of outcrops and symmetry of valley flanks. The surface topographic features of bedrocks can some times be extrapolated to reasonable depths to predict the thickness of alluvium or aeolian sands occurring as valley fill deposits, by treating slope profile as mathematical curves for which equations similar to regression equations can be found (Doornkamp and King, 1971). The influence of tectonic movements and resultant structural features on landform is of paramount importance for hydrogeomorphologists. The control of structure on landforms and hydrogeological processes are being discussed here. The structural geology concerns with the features such as uniclinal or inclined beds, folds, faults and joints. Of these the structural features like faults, fractures, joints etc appear as linear feature. Linear features on the surface of the earth have attracted the attention of geologists for over one hundred years. This interest has grown most rapidly since the introduction of aerial photographs into geological studies. Geologists have recently proven that various structural features perceived in remotely sensed images are reliable indicators of geologic resources (Caran et al, 1982). These structures have been used in many applications: petroleum and mineral exploration (Blanchet, 1957); nuclear energy facility siting (Seay, 1979); geothermal assessments (Woodruff et al, 1982); and water resource investigations (Lattman and Parizek, 1964). Lattman and Parizek (1964) established a relationship between the occurrence of groundwater and fracture traces for carbonate aquifers, and in particular zones of localized weathering and increased permeability and porosity underlying these structures.

Geomorphometric analysis is the measurement of the threedimensional geometry of landforms and has traditionally been applied to watersheds, drainages, hill slopes, beaches, and other groupings of terrain features. In particular basin morphometric parameters have received a lot of attention from hydrologists and geomorphologists since watersheds (catchments) have been used for analysis of various physical ecosystem processes, including soil erosion, deposition, runoff, stream discharge, sediment yield, sedimentation of streams, irradiation by sunlight, evaporation, evapotranspiration, and nutrient distribution. The study of morphometric parameters, which include variables such as average basin slope, the basin elongation ratio, compactness ratio, basin relief and stream density. Some parameters, such as slope length or stream sinuosity, can be used to represent both basin and hill slope, or basin and stream channel properties. The main task before geomorphologists is to use an ideal unit of the earth surface for the study of its landforms. The search for an ideal areal unit, within which the collection, processing, organization and interpretation of the data of the geometry of landform, particularly of erosional origin can be made has been the main aim of the geomorphologists right from Fennemen (1914), Horton (1932 and 1945), Strahler (1956 and 1957), Miller (1953), Chorley (1957), Schumm (1956), Shreve (1966), Singh (1981), Sarkar (1995), Schumm and Spitz (1996), Sharma and Amin (1996), Iqbaluddin et al (1997) and Raj et al (1999).

The beginning of the 20th century was heralded by methodological revolution in geomorphological studies brought in by Davis (1899). His classical model of geographical cycle defined by him ‘ as a period of time during which and uplifted landmass undergoes its transformation by the process of land sculpture ending into a low featureless plain (peneplain)’ dominated the geomorphological investigations all over the world throughout 1st half of the 20th century. The statistical techniques by Horton (1932 and 1945) brought quantitative revolution in the field of geomorphology when he presented quantitative analysis of morphometric characteristics of fluvially originated drainage basin. Post 1950 geomorphology has undergone vast change in the methods and approaches to the study of landforms, conceptual framework, paradigm and thrust areas of study. The most outstanding contribution to the advancement of geomorphological knowledge in this period is the adoption of quantitative approach based on deductive scientific method to the study of landforms and processes at short spatial and temporal scales (Strahler, 1956 and Schumm, 1956). Several attempts have been made in the world in past to classify large territories and landforms into morpho-units. Valuable contributions pertaining to landform analysis have been summarized below: Joerg (1914) subdivided North America into natural regions, Fenneman (1914) established physiographic boundaries and gave physiographic divisions of the United States, whereas Anderson (1941) gave physiographic divisions of Columbia plateau. Howard and Spock (1940) and Weaver (1965) presented the excellent ways of classification of the landforms while Wood and Snell (1960) applied the quantitative systems for the classification of the landforms. However, Linton (1951) and Hammond (1954 and 1965) gave techniques for mapping delineating small scale and large-scale landforms.

Water is a primary source of life and sustains all human activities such as domestic needs, agriculture, industries etc. The allocation and management of water resources is becoming a difficult task due to increasing demands, decreasing supply and diminishing quality. This calls for judicious use of water resources. The geomorphology describes the environment in which the hydrological processes operate. A strong mutual correlation exists between geomorphological variables and hydrological characteristics. Such relationship can be applied to both surface and groundwater regime. Thus the linking of geomorphological parameters with hydrological characteristics of the basin provides a simple way to understand the hydrogeomorphological behaviour of different basins and particularly of un-gauged basins. During the last few years various applications of hydrogeomorphology with reference to the Geographic Information System (GIS) and various other techniques have emerged as an extensively effective tool for analyzing and prioritizing natural resource management alternatives. Because natural resource management problems are spatial in nature the GIS technology provides a tool for defining the extent of the problem, and facilitates the design and implementation of alternative management strategies. The GIS is used to estimate the hydrogeomorphological parameters of the watershed, which can be used in watershed planning and management at micro and macro levels. The results of the study can be utilized to infer the hydrological features like runoff potential, infiltration and groundwater recharge of the region. Some of the applications of hydrogeomorphological studies are described below:

New techniques and approaches to groundwater studies are always in deep concern with the hydrogeomorphologists. The designing of new techniques or adapting existing techniques with better enhancement to solve practical problems in the study of groundwater are of central concern. One of the recent technical developments include the mathematical model of groundwater flow that has become the most widely used computer-based model in the groundwater industry. Techniques to identify and date recently recharged water that is useful in characterizing the susceptibility of hydrogeologic environments to contamination are utilized by various research groups all over the world. Geophysical methods for determining the hydraulic properties of fractured rocks gained the importance in the hydrogeomorphic studies. Predicting the movement of water and contaminants through fractured rocks has been one of the most challenging problems in hydrogeomorphology. Besides conventional and above mentioned techniques the techniques discussed in this chapter are Remote Sensing, Geographical Informational system (GIS), Global Positioning System (GPS), Digital Elevation Model (DEM), Groundwater Information System (GWIS), Digital Surface Terrain Modelling (DSTM), Multicriteria evaluation (MCE) and Thermal Infra Red (TIR) Mapping and Microwave Data.

Common groundwater investigations include necessary considerations of the system’s influx sources, flow regime, discharge points and geomorphological characteristics of the area. Often, hydrogeomorphological mapping of an area is required as to determine these characteristics. The primary data can be acquired from the survey of India toposheet map and the satellite images. The secondary data set includes the satellite imageries, the preparation of digital elevation model (DEM) and digitized precipitation maps. The first step in the procedure of hydrogeomorphological mapping is to calculate the watershed/basin area, which serves as a mask to define the area of interest. The watershed/basin calculation relies on the digital elevation data and assumes that topographic aspect (dip direction of the cell surface) completely controls the extent to which surface flow emanating from each point in the study area can reach the low point in the valley. The calculation of the potential annual recharge of the aquifer combines techniques described above with data for recharge areas, DEM aspect, and precipitation. First, the catchment area of the recharge zones must be calculated in a process similar to the watershed analysis, returning the area associated with the catchment coded as “1”. A simple multiplication overlay with the precipitation data and the catchment areas yields a result giving the amount of precipitation for each catchment cell. Before using the precipitation data, we converted it to meters so as to keep units consistent. The precipitation amounts within the catchment area (i.e. each cell value) are to be summed, yielding the amount of water available for influx into the groundwater system. Finally precipitation per year data can be acquired. Identifying surface areas of groundwater discharge is based on the observation that such areas provide a relatively constant source of moisture, which is readily exploited by vegetation in semi-arid region. Thus areas with year-round green vegetation are assumed to be indicators of discharge. The relative amount of vegetation in a scene can be estimated by calculating a vegetation index (Reddy et al, 1989 and Tucker 1979).

The world is head98ing towards a water crisis. Africa and West Asia are likely to be worst affected by water scarcity, but with increasing population, water may fall short even in the other parts of the world. According to the recent UN report, the supply of clean and fresh water is depleting at such an alarming rate in some regions, that within 30 years, about two third of population will suffer moderate to severe water stress. In hydrogeomorphological context of social environment the water is an essential natural resource for sustaining life. The available water resources are under tremendous pressure due to increased demands. The time is not far when water, which is the free gift of nature, will become a scare commodity. Therefore, conservation and preservation of water resources are urgently required to be done at priority basis. Water management has always been practiced in our communities since ancient times. But such practices have faded away during the past few decades mainly due to lack awareness. Hydrogeologists feel that the water harvesting practices must be urgently implemented to overcome the problem of water crises. In India the Ministry of water Resources is endeavouring to make rainwater harvesting a part of every day life in villages and cities as a people’s movement. Hydrogeomorphological aspect of social environment include (a) Social - Cultural -Administrative Consideration (b) Education and Training in Hydrogeology for Professionals and Technicians (c) Education for Farmers and Women (d) Education for Masses. These are described as below:

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