eChapters

After precipitation, run-off and surface water storage in lakes and man-made reservoirs, the next steps in the hydrological cycle are infiltration through the unsaturated zone and groundwater dynamics in the saturated zone. Well-established applications of isotopes in groundwater hydrology are

Water vapour changes to the liquid water through condensation process. Condensation is the direct cause of the various forms of precipitation. It occurs as a result of changes in air volume, temperature, pressure or humidity. Water vapour can also be converted directly into the solid form through a process called sublimation. The latent heat expended in evaporation is liberated in the process of condensation. Four mechanisms may lead to condensation.

15.1 Fuel Cell

Fuel cell is a electrochemical device that convert chemical energy of a reaction directly into electrical energy. The basic physical structure of a fuel cell consists of an electrolyte layer in contact with a porous anode and cathode on either side. A schematic representation of a fuel cell with the reactant or product gases and the ion conduction flow directions through the cell is shown in Fig. 15.1

Soil Erosion As a Process
 
Soil erosion is a three stage process, namely (1) detachment, (2) transport, and (3) deposition of soil. Different energy source agents determine different types of erosion. There are four principal sources of energy: physical, such as wind and water, gravity, chemical reactions and anthropogenic, such as tillage. Soil erosion begins with detachment, which is caused by break down of aggregates by raindrop impact, sheering or drag force of water and wind. Detached particles are transported by flowing water (over-land flow and inter-flow) and wind, and deposited when the velocity of water or wind decreases by the effect of slope or ground cover. Processes like dispersion, compaction and crusting, accelerate the natural rate of soil erosion. These processes decrease structural stability, reduce soil strength, exacerbate erodibility and accentuate susceptibility to transport by overland flow, interflow, wind or gravity. These processes are accentuated by soil disturbance (by tillage, vehicular traffic), lack of ground cover (bare fallow, residue removal or burning) and harsh climate (high rainfall intensity and wind velocity).

Introduction

Salinity in India is a major issue affecting the sustainability of irrigated as well as non-irrigated areas particularly in the states of Rajasthan, Gujarat, Haryana, Uttar Pradesh, West Bengal and Orissa. Salt affected soils are unproductive unless excess salts are reduced or removed. These soils occur most extensively in arid and semi-arid climates, but these soils are also found in coastal sea areas where soils are unundated by ocean or sea water. Soils are said to be saline if they contain an excess of soluble salts and sodic or alkali if they contain an excess of sodium salts. Again soils are said to be saline-sodic or saline-alkali if they contain appreciable amounts of both soluble salts and sodium. The impact of salinity manifests itself in several ways. As the salinity increases, not only does the productivity decline but sensitive crops also go out of cultivation and are replaced by salt-tolerant, low value crops and other plant species.

India is an agricultural country. The geographical area of India is about 328 mha out of which 147 mha of land under cultivation and 84-mha land is under irrigation. The population is increasing at an alarming rate that requires producing more food for the growing population. This problem can be solved either by increasing the land under irrigation or using different soil water conservation techniques. It is well known fact that during rainfall a considerable amount of water goes to sea due to high rate of runoff. It is highly needed to trap as much as water falling in the form of rainfall and recharge the groundwater so that it is made available for irrigation purposes.

Agricultural land drainage is adopted for removal of excess surface and subsurface water, either from irrigation or rainfall in order to improve the profitability of land use.  Drainage also plays a role in removal of salts from the root zone. Therefore, land drainage is closely linked to irrigation in arid and semi arid regions. India has a long history of practicing irrigation and drainage in its semi arid irrigated regions. During the ancient times in the Indus Valley dams and drainage system were built for cultivation of different crops. The earlier experience of drainage was more concerned with surface drainage because from time immemorial India has been experiencing floods of varying magnitudes.

For better yield irrigation water must be free from soluble salts and from concentration of specific chemical substances that may hazard to soil with respect to salinity, sodicity, alkalinity and toxicity. Water analytical data which helpful to predict the magnitude of the effect of irrigation water on soil and plant growth under specific environmental circumstances so irrigation water must be analyzed for EC, pH, Na+, Ca⁺⁺, Mg⁺⁺, Cl^-, CO₃–, HCO₃-  and SO₄.^– 

Abstract

The anomalies observed in the reverine systems have been demonstrated to be the potential tool in deciphering the tectonically active zones. Such various drainage anomalies viz: radial drainages, anomalous compressed meanders, eyed drainage and the youthful floodplains observed in Annamali – Palani - Varushanad hill ranges of the Western Ghats of Tamil Nadu show that the N-S and NE-SW trending faults are tectonically active in the recent years.

Abstract

The Remote Sensing and the followed up field based investigations show that the Tamil Nadu coast, India, is facing series of geoenvironmental problems due to tectonic movements and morphodynamic processes. Such problems pose a challenge to the engineering geologists. The paper discusses such challenging engineering geological problems and plausible remedial measures.

Importance

Drought is a climatic anomaly characterized by deficient supply of moisture, which may result from sub-normal, untimely and unevenly distributed rainfall. Among the various hazards of nature, drought is one of the major disasters because it brings innumerable miseries to the mankind. Almost every year some part or the other of the country suffers from such calamities. Drought is a recurring phenomena and its occurrence cannot be avoided. However, its impact can be minimized through application of science and technology by developing drought management plans.

The Gujarat state is located on the north-west of India between 20^o6' N and 24^o42' N latitude and 60^o24' E to 74^o24' longitude. The climate of Gujarat is semi-arid tropical . the summers are very hot, the winter season is uncertain and irregular. The Arabian sea and Gulf of cambay have a moderating effect on the climate of the coastal areas of the state.

The state has a coastline of 1600 km (27% of the country) out of which Saurashtra and Kutch has about 1125 km long coastal line. The total coastal cropped area of the state is 8.75 lakh ha (9.11% of total cultivated area) spread over three agro-climatic regions of the state, out of which 91% comes under arid and semiarid climate type (Table 1). The important crops of the region are groundnut, bajara, sorghum, cotton, and wheat. The ground water availability is also scare. In the state recently the soil degradation through salinity has caught hold over 1.2 m ha of land, of which, about 0.3 m ha occurs in the coastal area. About 1125 km long coastal line is in Saurashtra and Kutch which comprises about 0.1079 m ha of saline land which needs to be treated for salinity reduction.
 

Agriculture is world’s single largest employer and probably the most weather dependent of all human activities.  Climate and its variability have been and continue to be, the principal source of fluctuations in global food production. Throughout history, extreames of heat and cold, droughts and floods, and various form of violent weather have wretched havoc on the global agricultural production. With the unprecedented increase in population over past few decades, clearly the mankind faces undertaking task to ensure food and nutritional security for all, considering reduced per capita land, reduced availability of water, depleting biodiversity and need to preserve ecology and environment. In India, of the total geographical area of 328 m ha, about 175 m ha (53 % of total) are categorized as degraded land, of which 150 m ha are subjected to serious water and wind erosion (Singh et al. 1981). Crops are sown in about 180 m ha annually. Since it seems very much impossible to bring more area under cultivation we need to achieve greater efficiency in the natural resources use while conserving the environment by placing greater emphasis on understanding and exploiting climatic resources for the benefits of agriculture.

Participation means different things to different people. They way participant is defined largely depends upon the context and back ground in which participation is applied. While the Economic Commission for Latin America (1973) considers contribution by the people to public programmes to the complete exclusion of any involvement in the decision making process as participation. Cohem and Uphoff (1977) maintain that participation tools includes the peoples involvement in the entire decision making process. Like Cohem & Uphoff, FAO (1982) emphasizes participation in all the decision making processes but by the people’s organization and through self organized action. Paul (1987) introduces the concept of enhancement of well-being in terms of values cherished by the communities as being the ultimate objective of participation.

Summary

The main greenhouse gases (GHGs) that have caused the global climate change or global warming are carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O). CO₂ is the principal anthropogenic GHG that affects the earth’s radiative balance. It is the reference gas against which other GHGs are measured and therefore has a Global Warming Potential (GWP) of 1. CH₄ and N₂O have a GWP of 21 and 310, respectively. CO₂ is responsible for most of the enhanced greenhouse effect of more than 50%, CH₄ for about 10-15% and N₂O for about 8%. The global atmospheric concentrations of CO₂, CH₄ and N₂O have increased since 1750. While CO₂ increased from a pre-industrial value of 280 ppm to 379 ppm in 2005, CH₄ increased from 715 ppb to 1774 ppb and N₂O increased from 270 ppb to 319 ppb during the same period. Rich countries and large developing countries account for most of global CO₂ emissions (China 23.5%, USA 18.27%, India 5.83%, Russia 5.72%, Japan 4.04% and European Union 13.98%). A new climate agreement called ‘Warsaw International mechanisms (November 2013) on loss and damage’ agreed to help the poor countries to cope with loss and damage from heatwaves, droughts, floods, typhoons, desertification and rising sea levels. The Warsaw agreement also includes a set of decisions to help developing countries to reduce GHG emissions from deforestation and degradation of forests which is backed by pledges of US$280 million financing by the United States, Norway and the United Kingdom. Projections for global average temperature rise is in the range of 1.1-6.4°C; a doubling of CO₂ (from pre-industrial 280 ppm) and average sea level rise is in the range of 0.18-0.59 m (Meehel et al. 2007) and 0.5–2.4 m (Brown et al. 2013). Hot extremes, heat waves and heavy precipitation events will continue to become more frequent. Projected data show that there is an increasing global trend in the rise of average temperature in all countries, regions or sub-zones; a decreasing trend in average precipitation in most sub-tropical areas and an increasing trend of precipitation in most of the tropical and high latitudes.

Summary

Climate change (floods, droughts, rise of temperature and sea level) can directly impact the incidence of water related diseases through effects on water temperature and precipitation frequency and intensity. This chapter focuses on some common water quality related diseases that may enhance due to climate change such as arsenicosis, cholera, cyanobacterial toxins, dengue, diarrhoea and malaria. Arsenicosis is the disease caused by arsenic (As) contamination. As poisoning via groundwater has become a worldwide problem with 21 countries experiencing As groundwater contamination including Bangladesh, India, and China. In Bangladesh, out of 64 districts, As levels in 60 districts have exceeded WHO recommended guidelines of 10 µg/L and in 51 districts it exceeded Bangladesh recommended guidelines of above 50 µg/L. Chronic exposure to As has been linked to carcinogenic effects in both humans and animals. These include cancer of the various skins and internal organs (lung, bladder, liver and kidney) and reproductive and developmental effects; cardiovascular disease; reduced intellectual function in children and mortality. Alternate floods and droughts (due to climate change) have been found associated with the release of As and contamination of groundwater in Bangladesh, therefore may increase the risks of the disease due to rise of extreme events such as floods and droughts. Cholera is a diarrhoeal disease caused by the bacterium Vibrio cholerae. In 2012, WHO reported 245, 3931 cases of cholera in 48 countries, with more than 3,034 deaths with a case-fatality rate (CFR) of 1.2%. The highest cases were from Africa, followed by Latin America and Asia. The epidemic of cholera is reported to be linked strongly with climate change. Changes in temperature, salinity, rainfall and abundance of phytoplankton have been shown to cause an impact on distribution and survival of V. cholerae. In Bangladesh, cholera (cholera-toxin producing strain of V. cholerae) outbreaks are related to plankton blooms and rise of sea temperature.

Introduction

Spatial variation structure of soil properties is a key input for digital soil mapping and generally determined through geostatistical techniques (Webster and Oliver 2007). In geostatistics, spatial variation is expressed by semivariogram ?(h) , which measures the average dissimilarity between data separated by a vector h. It is generally computed as half of the average squared difference between the components of data pairs:

Summary

Climate change can affect the quantitative and qualitative status of water resources by altering hydrological cycles, systems and through changes of water quality via chemical and biological contamination. Changes in these variables lead to impacts on all the socio-economic and environmental goods and services that depend on these variables directly or indirectly including water supply, damage to ecosystems, water dependent food production. The most dominant climate drivers for water quantity or water availability are precipitation, run-off and river flows, floods, droughts, snows, glaciers, sea level rise etc. The observed climate change related impacts on world’s water resources/water quantity include increased precipitation at high latitudes and temperate areas and decreasing trends at low latitudes. The annual run-off in some regions may experience increased run-off, such as in high latitudes and large parts of the USA, whereas there has been a decrease in run-off such as parts of West Africa, southern Europe and southernmost of South America. Floods have been the most reported natural disaster events in Africa, Asia and Europe than all other natural disasters and in case of Bangladesh, six extreme floods have occurred in the last two decades. More intense droughts have been reported from Australia, semi-arid and semi-humid regions, western USA and southern Canada, the Sahel. Precipitation is projected to increase at mid- and high latitudes, in the tropics, whereas precipitation is projected to decrease over many sub-tropical areas (North Africa, northern Sahara), tropical Central American (Caribbean) and the Mediterranean. In areas where evaporation rates are expected to increase it would lead to reduced river and stream run-off. In contrast, areas receiving higher precipitation would likely have higher lake and river levels and may experience floods. The annual stream flow in the Murray-Darling basin (Australia) is projected to fall by 10-25% by 2050 and 16-48% by 2100 which would have severe consequences on irrigated agriculture in the region. Rivers depending on the Himalayan glaciers such as the Indus, Ganges, Brahmaputra, Syr Darya and Amu Darya could face water shortages or river run-off due to retreat of glaciers, and this would cause dramatic impact on drinking water supplies, biodiversity, hydropower, industry, agriculture and ecosystems on which about 2.4 billion people in Asia depends. Globally, ground water is the source of one third of all freshwater withdrawals, supplying an estimated 36%, 42% and 27% of the water used for domestic, agricultural and industrial purposes, respectively. The demand for groundwater is likely to increase due to global increase of water use for irrigation and a decline in surface water quality and reduced summer flows in snow-dominated basins. It is projected that climate change (drought, floods) will affect groundwater recharge rates (e.g. floods would increase recharge, drought would decrease recharge).

Summary

Biodiversity (the variety of living things) is fundamental to ecosystem structures and functions, and provide the broad spectrum of goods and services that humans derive from natural systems such as food (e.g. fish), protection from disasters such as cyclones, storms, floods (e.g. mangroves) or maintenance of water quality. Species (biodiversity) respond to climate change either staying or moving out or dying out. For example, the rise of temperature as a consequence of climate change may cause some species to (a) stay in the same environment since they can tolerate to adapt to changes; or (b) may cause some species to move out in a suitable environment (e.g. some species to move pole ward, some up in elevation) or (c) some species (fish) to go deep to increased depths in the oceans to escape heat or warming or (d) may cause some species to die out or get extinct (species with restricted distribution, longer generation time will not be able to migrate or adapt to climate change). A pattern of range shifts such as pole wards and upwards has been documented in hundreds of species of plants and animals and is one of the strongest signals of biotic changes from global warming. These shifts result from two processes: cold-edge expansion and warm-edge contraction. There is now abundant evidence for local extinctions from contractions at the warm edges of species’ ranges or warm edge contraction because the species may have already reached the limits of their climatic tolerance. Investigations conducted reveals that many terrestrial and aquatic species are shifting their geographic ranges in response to rapid changes in temperature and precipitation regimes. For example, many terrestrial organisms are currently shifting in latitude or elevation in response to changing climate. It has been estimated that plants and animals have recently shifted to higher elevations at a median rate of 11.0 m per decade, and to higher latitudes at a median rate of 16.9 km per decade.

3.1. SOLID WASTE MANAGEMENT

Solid waste management includes the transportation, processing, recycling and disposal of our waste materials. We live in a disposable world in many ways with the modernization and convenience of our world we have cluttered it with our refuse.