eChapters

The research setting is an important component of the research methodology. Research setting refers to the detailed information of an area where the study was conducted. The research setting can be seen as the physical, social, and cultural site in which the researcher conducts the study. In qualitative research, the participants are observed in their natural environments with a primary focus on meaning-making. The study area generally consists of a particular geographical area viz. a state, district, block, or gram panchayat area selected according to the benefit of the investigator who possesses adequate knowledge regarding the location, communication facility, the period of study, the availability of resources, etc. of the locality so that he can easily approach every corner of the area for data collection. Additionally, to comprehend people’s knowledge, attitudes, and behaviour more easily, investigators must have a fundamental understanding of their socio-demographic backgrounds. It is the environment within which studies are run that has important consequences for experimental design, the type of data that can be collected and the interpretation of results.

Arsenic contamination of groundwater is a form of groundwater pollution that is often due to naturally occurring high concentrations of arsenic in deeper levels of groundwater. The Ganges Delta’s usage of deep tube wells for water delivery has raised awareness of the issue because it has led to widespread arsenic poisoning in significant numbers of people. During the weathering of rocks and minerals, which is followed by subsequent leaching and runoff, arsenic (As) is released into the soil and groundwater. Additionally, anthropogenic sources can transfer it into the soil and groundwater. Six West Bengal districts with a combined area of 34000 km2 and a population of 30 million have been determined to have groundwater levels of arsenic over the WHO maximum allowable limit of 0.05 mg l1. (Alam et al.,2002)

At present, 37 administrative blocks by the side of the river Ganga and adjoining areas are affected. Areas affected by arsenic contamination in groundwater are all located in the upper delta plain and are mostly in the abandoned meander belt. More than 800 000 people from 312 villages/wards are drinking arsenic-contaminated water and amongst them, at least 175 000 people show arsenical skin lesions. Thousands of tube well water in these six districts have been analysed for arsenic species. Hair, nails, scales, urine, and liver tissue analyses show elevated concentrations of arsenic in people drinking arsenic-contaminated water for a longer period. Arsenic comes from a geological source. Only a few soil strata have high arsenic contents, which are determined to be linked to iron-pyrites according to investigations of bore hole silt. Arsenical skin lesions in various areas cause a variety of societal issues. (Das et al.,1996)

Arsenic contamination is one of the serious concerns for public health throughout the world. During the weathering of rocks and minerals, which are followed by subsequent leaching and runoff, arsenic (As) is released into the soil and groundwater. Additionally, human sources can transfer it into the soil and groundwater. Depending on the geological settings, geochemistry, and geo-environmental conditions of an aquifer, different aquifers may have different adsorption and desorption processes, arsenic species, Eh, pH, solid phase dissolutions, and precipitations. Therefore, rigorous geochemical investigation for an adequate understanding of arsenic geochemistry under different hydrogeological and geo-environmental conditions of aquifers is essentially required for evolving sustainable solutions. All of the arsenic affected river plains have river routes originated from the Himalayan region. Arsenic in groundwater contamination has far-reaching consequences including its ingestion through the food chain, which are in the form of social disorders, health hazards and socioeconomic dissolution besides its sprawling movement, and exploitation of groundwater. Food crops produced with arsenic tainted water are marketed to other locations, including areas where people may eat the tainted food and be exposed to arsenic. The arsenic contamination of groundwater is a form of groundwater pollution which is due to naturally occurring high concentrations of arsenic in deeper levels of groundwater.

Introduction to GIS

QGIS (Quantum GIS) is an open-source Geographic Information System (GIS) software has been used to showcase various exercises pertaining to viewing, editing, analyzing, and printing of the geospatial data. QGIS helps to allow the users to easily access and manage geographic data stored in folders on local disks or relational databases available on the user’s network. QGIS supports raster, vector, and mesh layers. QGIS also allows using data from external sources with the help of web services such as Web Map Service (WMS) and Web Feature Service. QGIS is a constantly developing software as anyone can add new features or update existing tools. Newer versions of QGIS are frequently released on the official website. It is a cross-platform software that can be installed in Windows, Linux, and MacOS.

Introduction

Rainfall is one of the climatic variables that varies very highly spatially and temporally. Understanding this micro-level variation is a crucial indicator for planning future water requirements and preparing for management strategies. Numerous researchers have delved into the distribution, variability, and trends of rainfall across diverse spatial scales, ranging from global to regional and basin levels. Nair et al. (2014) analyzed the rainfall trend and seasonality index for Kerala state in India over the last 100 years. The rainfall trend was found to be decreasing significantly in almost all the regions of the state. Nischitha et al. (2013) provide insights into the spatial and temporal variability of daily monsoon rainfall in the Tunga and Bhadra River basins in Karnataka state. Paradkar et al. (2019) evaluated the pattern of weekly rainfall by using statistical parameters such as mean, standard deviation, skewness, and kurtosis for five stations in Pratapgarh district.

Geographical Information System (GIS) proved to be an effective tool in handling information and analyzing rainfall patterns, providing visual representations, and facilitating the decision-making process (Kadir et al. (2016) and Rao et al. (2017)). Anand et al. (2020) analyzed the long-term spatial and temporal trends of rainfall in the Lower Bhavani basin in Tamil Nadu, India using GIS and statistical methods. Earls et al. (2007) compared different interpolation methods such as Inverse Distance Weighting, Spline, and Kriging (ordinary and universal) to generate a 30 m representation of the rainfall data. Spatial interpolation techniques perform differently and their evaluation should not rely solely on quantitative assessment. Wu & Hung (2016) compared the performance of three spatial interpolation techniques i.e., IDW, kriging, and spline using quantitative assessment, 2D visualization, and 3D visualization. IDW and kriging performed similarly in terms of quantitative assessment, while spline performed worse. IDW and spline performed similarly in 2D visualization, while kriging showed different behavior. Kriging was observed to be an inexact interpolation in 3D visualization, while spline tended to create extreme values along the edges of the study area. Some studies discovered that the accuracy of Kriging in the study area is higher than that of IDW or Thiessen interpolations (Earls et al. 2007; Song et al. 2008; Chen et al. 2010). GIS applications have the capability to integrate spatial data and non-spatial data like rainfall and to visualize, model, and analyze how rainfall distribution varies across space and over time, providing insights into climate change, water resource management, agricultural planning, and disaster management. The present study aims to analyze annual rainfall data pertaining to Kerala state in the GIS environment.

Introduction

Climate change and human activities have emerged as significant factors affecting water resources in diverse regions (Kumar et al. 2022; Haddeland et al. 2014). The escalation in human water consumption for domestic and industrial purposes enhanced by the impacts of climate change has resulted in an overall decline in water availability (Liu et al. 2017; Paul et al. 2021). Rising temperatures and altered precipitation patterns directly influence water availability for ecosystems and agriculture potentially leading to greater evapotranspiration rates, intensified rainfall events, and prolonged droughts (Sharannya et al. 2021; Myers et al. 2023). Furthermore, urbanization, deforestation, and agricultural practices alter landscapes, affecting water resources in these areas.

Water shortages pose threats to ecosystem health, and socio-economic development and disrupt agricultural production (Piao et al. 2010). Thus, ensuring sustainable and efficient water usage necessitates accounting for water usage and quantifying it in a changing environment. To comprehensively assess the significance of water resources in the environment, Falkenmark (1995) introduced the concept of blue water (BW) and green water (GW) water, particularly for managing water resources in water-stressed regions. Green water refers to the portion of precipitation that infiltrates into the unsaturated soil layer and is subsequently utilized by plants through transpiration and soil evaporation. In fact, “blue water” represents surface and groundwater flow in rivers, lakes, and aquifers (Abate et al 2024; Sharannya et al. 2021). While numerous studies have investigated the spatial and temporal variation of BW and GW using the Soil and Water Assessment Tool (SWAT) (Feng et al. 2021; Li et al. 2009; Lyu et al. 2019), fewer publications have focused on assessing these variations and uncertainties at the basin scale under varying climate scenarios (Sharma et al. 2023). Hydrological models such as SWAT, serve as valuable tools for simulating past and future hydrological changes in the watersheds using projected climate data. SWAT specifically can simulate both blue and green flows at the watershed scale.

Introduction

Groundwater resources are under stress globally due to various reasons including increasing water demand, impending climate change, industrialization, land use/land cover changes, etc. Adequate sustainable development strategies have to be adopted for the management of groundwater resources. Irrespective of the developmental status of countries all over the world, groundwater serves as a crucial resource for meeting fundamental needs. However, increasing population, water demand, surface water contamination, and recent patterns of climate unpredictability have caused increasing reliance on groundwater as reported by several researchers (Adimalla and Taloor 2020; Aladejana et al. 2020; Cuthbert et al. 2019; Green 2016; Hamed et al. 2018; Jasrotia et al. 2019; Khalaj et al. 2019; Li 2016; McGill et al. 2019; Morsy et al. 2017; Taloor et al. 2020).

Even in India, water scarcity has been reported in many parts, though the country receives relatively higher rainfall. However, the rainfall pattern has changed over the last few years. The country has been experiencing significant spatiotemporal changes in rainfall patterns, leading to fewer rainy days and more extreme rainfall, which many studies have attributed to global climate change and anthropogenic influences. The rainfall variability has substantial impacts on water availability, agricultural productivity, and welfare of the 1.2 billion people in India because agriculture in India feeds about 17.2% of the global population and more than 56% of the agricultural land is rain-fed. Rapid and heavy patterns of rainfall result in the draining of most of the rainfall as surface runoff particularly on higher slopes, and reaches the surface water bodies, thereby reducing the infiltration and subsequent groundwater recharge. These variations in rainfall have ultimately affected the groundwater behavior and availability in many river basins.

Introduction

Watershed management has emerged as an important research area in recent years. Understanding the morphology of the catchment is one of the widely used methods for watershed management. Morphometry is the measurement and mathematical analysis of the configuration of the earth’s surface, shape, and dimension of its landforms (Agarwal 1998; Obi Reddy et al., 2002). The study of watershed is very useful in drainage basin evaluation, silt erosion control, flood frequency analysis, watershed prioritization, natural resources management, and conservation (Waikar and Nilawar, 2014). The significance of morphometric analysis is highlighted in the basins that are either un-gauged or difficult to access. The morphometry is usually analyzed through measurement of linear, aerial, relief, gradient of channel network, and contributing ground slope of the basin (Magesh et al., 2012). The hydrological behavior of a basin can be easily determined through the areal parameters (Mahala, 2020.) The evolutionary history of any basin can be best understood through the implication of different relief morphometric measures of drainage basin (Sharma and Sarma, 2013).

GIS and RS techniques are proven convenient methods for morphometric characterization of sub-watersheds and prioritization of watersheds. As the satellite images provide a synoptic view of a large area, the RS and GIS methods become very useful in the analysis of drainage basin morphometry (Rai et al., 2017). Thus, the morphometric analysis using spatial techniques has emerged to be the fast and efficient method as compared to most of the conventional methods (Rao et al., 2010) such as manual extraction of drainage network and assigning the stream order from a published Survey of India topographic map. The present study aims at using remote sensing and GIS technology to compute various parameters of morphometric characteristics of the Chaliyar River basin.

Introduction

The term “Remote Sensing” was coined in 1950s by Ms. Evelyn Pruitt, a geographer with the U.S. Office of Naval Research, and the term is now commonly used to describe as the science and art of identifying, observing, and measuring an object on the earth surface, without having any direct contact. This process involves the detection and measurement of radiation of different wavelengths reflected or emitted from distant objects or materials through which they may be identified and categorized by class/type, substance, and spatial distribution (National Aeronautics and Space Administration—NASA). Remote sensing technology has been widely applied in various applications such as water resources, agriculture, geological studies, forestry, land use, resource exploration, etc.

Elements of Remote Sensing

The remote sensing process involves an interaction between the incident radiation and the targets of interest, exemplified by the use of imaging systems in which the following seven elements are involved; however, remote sensing also involves sensing of emitted energy and using non-imaging sensors

Definition of Disaster

A disaster can be defined as a sudden or catastrophic event that causes significant damage, destruction, and disruption to human life, property, or the environment. Disasters can be natural, such as earthquakes, hurricanes, floods, wildfires, or they can be human-made, including industrial accidents, terrorist attacks, or technological failures.

Disasters often result in the loss of lives, injuries, displacement of people, infrastructure damage, and the interruption of essential services like electricity, water, and communication systems. They can have long-lasting impacts on communities, economies, and the environment.

Governments, organizations, and communities implement disaster preparedness, response, and recovery strategies to mitigate the effects of disasters, protect lives and property, and facilitate the rebuilding and restoration of affected areas.

Remote sensing can be a useful tool in engineering geological investigations, particularly in the identification and characterization of geological features and hazards.

Some of the ways that remote sensing can be used in engineering geological investigations include:

Geological mapping: Remote sensing data can be used to create detailed maps of the geological features in an area, including rock formations, faults, and folds. This information can be used to identify potential hazards, such as landslides and rockfalls, and to plan engineering projects accordingly.

Landslide detection and monitoring: Remote sensing data, such as satellite imagery, can be used to detect landslides and monitor their movement over time. This information can help engineers to design and implement appropriate stabilization measures.

Ground deformation monitoring: Remote sensing techniques, such as Interferometric Synthetic Aperture Radar (InSAR), can be used to detect ground deformation caused by geological processes such as subsidence, uplift, and faulting. This information can be used to identify potential hazards and plan engineering projects accordingly.

Remote Sensing in Oil Exploration

Remote sensing plays a significant role in the oil exploration industry. It refers to the use of sensors and instruments to gather information about the Earth's surface and its environment from a distance. This information can be used to locate and evaluate oil and gas deposits.

There are different remote sensing techniques used in oil exploration, including

Seismic surveys: This technique involves creating sound waves underground and recording their reflection to determine the subsurface structure. It is commonly used in oil exploration to locate potential oil and gas deposits.

Magnetic surveys: This technique uses a magnetometer to measure the magnetic field of the Earth's surface. Magnetic anomalies can indicate the presence of underground geological structures that may contain oil or gas deposits.

Gravity surveys: This technique involves measuring variations in the Earth's gravitational field, which can indicate the presence of underground geological structures.

Remote Sensing in Mineral Exploration

Remote sensing is a powerful tool used in mineral exploration to study and identify minerals and mineral deposits from a distance. This technology allows geologists to gather information about the Earth's surface and subsurface without having to physically access the site. Here are some ways remote sensing is used in mineral exploration:

Mapping Geology: Remote sensing can be used to map geology by identifying surface features associated with mineral deposits. Geologists use images collected by remote sensing satellites and aircraft to create detailed maps of the geology and topography of a region. These maps can help identify areas that are likely to contain mineral deposits.

Mineral Identification: Remote sensing can help identify specific minerals by analyzing the reflectance or absorption patterns of light. Different minerals have unique spectral signatures that can be detected by remote sensing instruments. By analyzing these signatures, geologists can identify the type and abundance of minerals present in an area.

Geomorphological mapping is the process of creating detailed maps that illustrate the physical features of the Earth's surface, including landforms, soil types, vegetation, and water resources. These maps can be used to better understand the underlying geology and topography of a region, and can be used for a variety of purposes, such as land-use planning, environmental management, and geological hazard assessment.

Geomorphological maps are typically created using a combination of field observations, aerial photography, and remote sensing data. Field observations involve physically visiting a site and making detailed observations of the landforms, soil types, and vegetation. Aerial photography involves taking high-resolution photographs of the Earth's surface from an airplane or satellite, which can be used to create detailed maps of the area. Remote sensing data can also be used to create geomorphological maps, including data from satellites, radar, and LiDAR (Light Detection and Ranging) systems. These technologies allow scientists to gather data about the Earth's surface without physically visiting the site, and can provide highly accurate information about the topography, geology, and vegetation of an area. The resulting maps can be used for a variety of purposes, including land-use planning, natural resource management, and hazard assessment. For example, geomorphological maps can be used to identify areas of high risk for landslides, floods, or earthquakes, and can be used to develop strategies for managing these hazards.

Rock

A rock is a solid, naturally occurring substance composed of minerals or mineraloids. It is typically formed through geological processes, such as cooling and solidification of molten lava or magma, or by the deposition and compaction of sediment over time. Rocks are classified into three main types based on their origin: igneous, sedimentary, and metamorphic.

Igneous rocks: Formed from the cooling and solidification of molten lava or magma. Examples include granite, basalt, and obsidian.

Sedimentary rocks: Formed from the accumulation and compaction of sediment, such as sand, mud, or organic matter, over long periods. Examples include sandstone, limestone, and shale.

Metamorphic rocks: Formed from the transformation of existing rocks under high temperature and pressure conditions. They undergo changes in mineral composition, texture, and structure. Examples include marble, slate, and gneiss.

Rocks serve as the building blocks of the Earth's crust and are an essential part of the geological processes that shape the planet. They can provide valuable information about Earth's history, including the formation of mountains, the movement of continents, and the presence of ancient life forms. Rocks are also used in various practical applications, such as construction, road building, and the production of minerals and resources.

Structural landforms are landforms that are created due to the underlying geological structures of the earth's crust. These structures can include folds, faults, and other features that have been formed due to the tectonic forces that have shaped the earth's surface over millions of years.

Examples of structural landforms include mountain ranges, plateaus, and rift valleys. Mountain ranges are formed due to the upliftment of the earth's crust along a fault line or due to the folding of the earth's crust. Plateaus are flat-topped landforms that are formed due to the upliftment of a large area of the earth's crust. Rift valleys are formed due to the stretching and pulling apart of the earth's crust along a fault line.

Denudational landforms, on the other hand, are landforms that are created due to the process of erosion and weathering. These landforms are formed due to the gradual wearing down of the earth's surface by natural forces such as wind, water, and ice.

Interpretation of Drainage Patterns Through Aerial Photographs

Aerial photographs can provide a useful tool for interpreting the drainage patterns of a landscape. Drainage patterns are formed by the natural movement of water across the land and the way in which it flows from high to low areas, creating channels and streams that eventually converge into larger rivers and bodies of water. Different types of drainage patterns can be identified through aerial photographs, which can help to understand the underlying geology and topography of the landscape.

Here are some of the different drainage patterns that can be identified through aerial photographs:

1. Dendritic pattern

This pattern resembles the branches of a tree and is the most common type of drainage pattern. It occurs in areas where the underlying rock or soil is uniform and has no preferred direction of erosion. The streams converge into larger rivers, which may flow in a particular direction.

India is a geologically diverse country with a wide variety of rock types. The major rock types found in India can be broadly classified into the following categories:

Igneous Rocks: These rocks are formed from the solidification of molten magma. They can be further divided into two types:

1. Plutonic (Intrusive) Igneous Rocks: Examples include granite, diorite, and gabbro. These rocks are formed deep within the Earth's crust and have a coarse-grained texture.
2. Volcanic (Extrusive) Igneous Rocks: Examples include basalt, andesite, and rhyolite. These rocks are formed on the Earth's surface from volcanic eruptions and have a fine-grained texture.

Sedimentary Rocks: These rocks are formed by the deposition and consolidation of sediments over time. They can be further divided into various types based on their composition and mode of formation:

1. Clastic Sedimentary Rocks: Examples include sandstone, shale, and conglomerate. These rocks are formed from the accumulation and lithification of fragments of pre-existing rocks.
2. Chemical Sedimentary Rocks: Examples include limestone, dolomite, and rock salt. These rocks are formed from the precipitation of minerals from water bodies.

Lithological interpretation of igneous rocks involves the identification and description of the different types of rocks that form as a result of the cooling and solidification of magma or lava. Igneous rocks can be classified based on their mineral composition, texture, and the way they formed. Here are some of the common types of igneous rocks and their characteristics:

1. Basalt

Basalt is a dark-colored, fine-grained rock that forms from the rapid cooling of lava. It is typically composed of minerals such as pyroxene, plagioclase feldspar, and olivine.

Basalt is a common extrusive igneous rock formed from the rapid cooling of basaltic lava. It is typically dark in color, ranging from black to dark gray, and has a fine-grained texture. Basalt is composed mainly of plagioclase and pyroxene minerals, with smaller amounts of olivine, magnetite, and other minerals.

Basalt is found in many parts of the world, including the oceanic crust, volcanic islands, and some continental regions. It is also used as a construction material, such as in road paving, because of its durability and resistance to weathering. Additionally, basalt fiber is used in various applications, including reinforcing materials in composites, insulation, and other industrial uses.

Basalt in India: Basalt is a type of igneous rock that is commonly found in India. It is a dark-colored, fine-grained rock that is rich in iron and magnesium minerals.