eChapters

Since the last decade discussion regarding ecology is being heard. A campaign with a great planning has launched by holding seminar conferences and meets. The ecological problem became a matter of tremendous panic and anxiety. Not only in India but also in entire world this problem is being discussed through all school, colleges and universities on international scale all over world, since it became universal issue now a days. The word ecology was not known to the people 20 years ago, never the less it became familiar even among the villages today. The people in villages are making thorough study of the subject. The experts of ecology from all over the world have been surprised to learn the exhaustive study of the same done by the Indian scholars. We have instituted a separate ministry to look after the environmental problems. The activities injurious to environment are prohibited. An act is there to restrict antienvironmental deeds what made scientists all over the world to take this matter so seriously. Does it mean that the very existence of mankind has been jeopardized by it Let us see what our ancient literature say about the ecology and pollution.

Introduction

The natural hazards like floods, cyclones, droughts, landslides and earthquakes are not rare or unusual phenomenon. India is among the world’s most disaster prone areas and a large part of the country is exposed to such natural hazards, which often turn into disasters causing significant disruption of socio-economic life of communities leading to loss of life and property. It would not be considered as a disaster unless it resulted in actual damage to human life or property. According to data accumulated over past 25 years, natural disasters in Asia accounts for about 40% of the world’s total disasters while the death toll ratio is about 50% and the number of people affected is about 90%. The latter figure is about 2.2 times the ratio of number of occurrences in Asia. The figures vary widely over the decades, a result that can be attributed to a few particularly terrible disasters. Such as the 1976 Tangshan Earthquake in China, which killed about 250,000, and a series of severe cyclones that hit Bangladesh in 1970 with a death toll of about 500,000. The death toll resulting from wind and flood disasters jumped by an order of magnitude in the 1990s. But this sudden increase affected Asia’s ratio to the world total by about 15 percentage points because there was a worldwide surge in this type of disaster. Clearly, there is an extreme concentration of victims of such disasters in Asia, Another substantial increase is clear in the value of damage caused by typhoons and cyclones; it is now running at 10 times the level of the 1980s. Again, however, the ratio has remained almost unchanged, at about 40%, because hurricanes in Central and North America account for more than 50% of the world total (51.2%, 58.5%, and 54.4% in the 1970s, 1980s, and 1990s,respectively). It is sadly worth noting that there has been conspicuous growth in the absolute value of damage in both Asia and the Americas.

Introduction

Disaster is defined as a serious disruption of the functioning of a community or a society causing widespread human, material, economic or environmental losses, which exceed the ability of the affected community or society to cope using its own resources (ISDR 2002).

Disaster in Global context - The impact of natural disasters in terms of human and economic losses has risen in recent years, society in general has become more vulnerable to natural disasters. Those usually most affected by natural and other disasters are the poor and socially disadvantaged groups in developing countries as they are least equipped to cope with them (IFRC 2001).

Introduction

Natural Disasters are inevitable, and Indian subcontinent is prone to all type of Natural Disaster either it is flood, drought, cyclone, earthquakes, tsunami or forest fires etc. Disasters can be classified in several ways. A possible sub-division of disaster is: (i) Natural Disasters; (ii) Human made disasters; (iii) Human induced disasters. Another sub-division is related to the main controlling factors leading to a disaster. These may be meteorological, geomorphological/geological, ecological, technological, global environmental and extra terrestrial. Another useful distinction that can be made between disasters is regarding their duration of impact and the time of forewarning. Some disaster strikes within a short period with devastating outcomes; others have a slow onset period with equally or more serious repercussions. According to the available statistics 60% of the total area of Indian subcontinent is venerable to seismic activity of varying intensities, 16% of the country’s total area is drought prone. In India 68% of total sown area of the country is drought prone. Coastal areas of India is exposed to tropical cyclones, tsunami in recent years and among all the disaster occur in the country, River floods are the most frequent and often the most devastating.

Introduction

Disasters are the natural and man made extreme events which exceeds the tolerable magnitude of any event, where adjustment is difficult. These events are catastrophic and results in the loss of life and property on a huge scale. These abnormal events form the headlines to the newspapers and media a world and national level.

These processes are beneficial to the human beings because they form the earth and habitable planet for the evolution of life. However, these processes within a short time limit forms, hazardous and such activities adversely affect the human beings and human related activities on a very large scale.

Amongst the three important types of disasters viz. natural, anthropogenic and technological, the first and the foremost natural disaster mainly includes the geological atmospheric and other related natural types viz. floods, earthquakes, cyclones, tsunamis etc.

Introduction

Earthquakes are the most destructive among all the natural hazards. Most of the time, they occur without any warning, which makes them most feared and unpredictable natural phenomena. Globally, on an average two earthquakes of magnitude 8 are known to occur every year. Some of the countries like Japan, China and United States have suffered several damaging earthquakes in the past. India has also experienced a number of high intensity earthquakes in the recent past and more than 650 earthquakes of magnitude >5.0 have been reported in India since 1890. Sixty-nine earthquakes in Delaware (U.S.A.) have been documented or suspected since 1871. Refer to Baxter (2000) for more details about the DGS Seismic Network and for documentation of earthquakes. In the 1930s Charles Richter developed a magnitude scale (Richter scale) which was an objective way of discriminating between large and small shocks using the seismic wave amplitude recorded by seismographs (Richter, 1958).

Introduction

The state of Maharashtra now again reels under the scarcity of water. Geologically, major part of the state is covered by Deccan basaltic flows. This basaltic terrain, as such, has been labelled notorious as far as the availability of groundwater is concerned. Uncertain availability of groundwater in the terrain is due to heterogeneity in the nature of piles of basaltic flows which adversely affects the geohydrological characters of the rocks.

The area understudy is unfortunately, a part of basaltic terrain in which no storage structures like major dams or medium projects have been constructed across the existing rivers. Consequently, the irrigation in the area and domestic needs of the people solely depend on whatever water is available in the existing dug wells. The wells do not suffice the need of the people because the percolation of water in the wells is not adequate in major part.

Introduction

On 26^th December 2004, the Indian coastline experienced the most devastating tsunami in recorded history. The tsunami was triggered by an earthquake of magnitude Mw 9.3 at 3.316ºN, 95.854°E off the coast of Sumatra in the Indonesian Archipelago at 06:29 hrs making it the most powerful in the world in the last 40 years. In recent years increasing the vulnerability to natural disasters of developing countries is a major reason for concern. The potential loss of human lives and property due to natural hazards is very high in the urban areas of these countries. The Information obtained from conventional tsunami hazard maps does not always provide sufficient data for users .needs. The difficulty in presenting more significant information on tsunami hazard maps in conventional paper format is due to the limited available physical space of that format. Printing more information on such paper maps tends to confuse rather than provide more needed information to users. Furthermore, these kinds of maps provide little opportunity for users to ask for additional information, to determine the relationships between different kinds of information and important quantitative analyses. Furthermore, Tsunami hazards have important temporal attributes. Presenting these attributes on the map; e.g. the sequence of volcanic eruptions in a region or the frequency of tsumani in a particular area during a particular period of time is very difficult.

Introduction

The Rispana river is a order of stream forming a tributary of Ganga. Its watershed covers an area of approximately 53.6 Km in the northern part of Dehradun city lies between 78^º30’ to 78^º15⁰’ longitude and 30^º15’ to 30^º 30’ latitude in top sheet No is 1/3. The area is covered in IRS - IC Pan of 13 Jan 1998 and LISS-III of 7 March 1997.

The Doon Valley is enriched with numerous seasonal and perennial streams. Which forms the lifetime or the inhabitants . The Rispana river is the part of the Ganga system of Drainage of the valley. The river originates from the Mussoorie hills, which are full of natural springs. The droplets from the springs collect and form numerous streamlets and these streamlets are joined to be these and they form the famous Shekhar Falls (north of Shahanshai Ashram about 5 Km away). Then the Rispana flows along Rajpur road over the Doon Gravels and then river passes through the tiny hamlets Nalapani, Raipur, Chanderroad, Defence colony, Amwala, Tapowan, Dandadhoran Adohiwala, Dalanwala, Gujram, Ajabpur and finally its contribute the water to the suswa River which intern joins the Ganga.

Introduction

The Himalayan Moutains that is relatively a younger formation and geologically a very complex occupies most of the Arunachal Pradesh. The mountain terrain covers an area of about 86000 sq. km with elevation ranging from 400 to 6000 m above mean sea level (Satapathy and Dutta 1999). The wet tropical and sub-tropical climate which prevails in most part of the Arunachal Pradesh, there is usual phenomenon of erosion and land degradation by the action of water. It is estimated by the application of USLE for Arunachal Pradesh that the total amount of about 669.35 million tones of soil is eroded annually with an average rate of 90.7 tonnes /ha/year (Singh, 1999).

Arunachal Pradesh falls under upper Brahamaputra river system constituted by 10 major river basins. They are Tawang, Kameng, Dikrong, Subansiri, Siang, Sesseri, Dibang-Tellu, and Tirap-Tiso. In Arunachal Pradesh, Dikrong river is named after joining of two main rivers Pachin and Para . In the catchments of Dikrong river light textured unstable soils with the prevalent practice of Jhum Cultivation makes the entire catchments susceptible to erosion. In every monsoon the river Dilrong carries tremendous amount of silt, gravel, small boulder and causes flood in some parts of the catchments susceptible to erosion. Singh (1999) observed that loss rate through Dikrong River was 100.98 tones/ha/year. This indicates serious threat to soil resources and there is need for urgent treatment for sediment control in Dikrong river bash.

Introduction

Water preceded all forms of life on earth and is believed to be the very origin of all organic life forms. For ages water was forming oceans, separating landmasses and shaping the terrain. It further influenced the emerging atmosphere of the young planet. The first organism formed and began to evolve in the primeval oceans. Mankind entered into the scene several million years later. The history is rather too long and infinitely complex. Variety of models with different degrees of certitude and consensus attempt to cogently explain what could have happened. But in spite of all the differences on the course of evolution, there is a universal consensus that water played a decisive role in the changes.

Across the globe, mankind managed to establish different civilizations with dissimilar cultural and material advancements much later. But then invariably all civilizations considered water holy and water bodies were sacred places. Holy wells, springs, rivers, cenotaphs were held in awe all through human history. The mysterious properties of water are studied from time immemorial. And water indeed is a strange compound! Availability of water for consumption and agriculture has determined the zenith and nadir of surviving and extinct civilizations.

Ancient Indian temples as part of design, have a prominent sacred well or a pond with an associated purana/myth narrating the mystical properties of the theertha / waterbody. It is still is a living tradition. In the west wishing wells survive from remote antiquity.

Introduction

The science of hydrogeology is defined as hydrology with emphasis on geology. This chapter is to refresh your geology knowledge. The key words are highlighted to assist a quick review.

The Crust and its Composition

The thin outermost layer of the earth is called the crust and ranges in thickness from about 8 km under the oceans to about 25 km on land. It extends under both oceans and continents, and forms the source for all the soils, vegetation, and gases in the atmosphere.

The crust is primarily composed of two elements: silicon and oxygen which account for 75% of the earth’s crust. Note that these are the two elements found in quartz (e.g., sand), which suggests this is the most common of all minerals.

Introduction

Groundwater investigation has a long history. In the past a waterman in the village would walk around the investigation area with a Y shaped wooden fork and identify the location for digging the wells. Certain trees and organic landforms like termite mounds were considered as indicators. The native intelligence of local topography should have played a role in identifying potential location. Successful or otherwise the method can be said to lack scientific objectivity. The optimal groundwater surveying method is no doubt drilling. This method ensures that all necessary information is being brought up from the geological formations. However, in order to obtain a desired degree of information from the subsurface of an area, drilling alone is normally not a feasible alternative.

There are a number of efficient and inexpensive geophysical surveying methods available to the hydrogeologist. It is worth noting at this point that these are, without exception, indirect methods. This implies that no method measures directly what we are actually looking for. With geophysical surveys, the target features are therefore invariably associated features. This implies that unless we understand the water context of these features, our geophysical surveys will be less than meaningful.

Objective methods of investigating groundwater are discussed in this chapter.

Introduction

Normally, water is a liquid substance made of molecules containing one atom of oxygen and two atoms of hydrogen (H₂O). Pure water has no colour, no taste, no smell, turns to a solid at 0°C and a vapour at 100°C. Its density is 1 gram per cubic centimetre (1 g/cm₃), and it is an extremely good solvent.

An extraordinary property of water is its ability to dissolve other substances. There is hardly a substance known which has not been identified in solution in the earth's waters. Were it not for the solvent property of water, life could not exist because water transfers nutrients vital to life in animals and plants.

A drop of rain water falling through the air dissolves atmospheric gases. When rain reaches the earth, it affects the quality of the land, lakes and rivers.

Introduction

Wells are vertical shafts excavated or holes drilled in earth to the level of water table for extraction. Digging of wells is an age old practice. Shallow dug wells supported communities in the past. Well water is drawn to the ground manually or mechanically using variety of containers made of metal, leather, canvass and wood or a combination of them. Draught animals or electrical power are used to draw water for irrigation.

Water table (Fig.6.1) wells extend below the groundwater table and extract free water. Pumping water from these wells lowers the water level. The well first gains water from the water bearing material in its immediate proximity. Subsequently a cone of depression is formed in the immediate vicinity of the well. Water outside the cone of depression but with in the area of influence is diverted to replace the body of groundwater finding its way in to pumping well.

Introduction

Fresh water, a renewable but not an infinite resource, is becoming increasingly scarce. The amount available for use to the world today is almost the same as it was 4500 years ago but global demand has been increasing exponentially. Since 1950, the renewable supply per person has fallen 58 percent as world population has swelled from 2.5 billion to 6 billion. Moreover, unlike oil and most other strategic resources, fresh water has no substitute in most of its uses. It is essential for growing food, manufacturing goods, and safeguarding human health.

According to a World Policy Forum report, the largest and most combustible imbalance between population and available water supplies will be in Asia, where crop production depends heavily on irrigation. Asia today has roughly 60 percent of the world’s people but only 36 percent of the world’s renewable fresh water. China, India, Iran, and Pakistan are among the countries where a significant share of the irrigated land is now jeopardized by groundwater depletion, scarce river water, a fertility-sapping buildup of salts in the soil, or some combination of these factors. Groundwater depletion alone places 10 to 20 percent of grain production in both China and India at risk.

Introduction

All models are but approximations of reality. When we approximate there is always room for uncertainty. The preference of a particular model over the other is the relative degree of uncertainty acceptable to the objective and budget of the study. With the advent of computers, hosts of modeling software promising a lot to the researcher have arrived on the horizon. It is not in the scope of the book to enumerate all the techniques of hydrogeological modeling. Physical modeling using sand tanks was the earliest attempted modeling technique, about 107 years ago. Most recent and significant modeling technique practiced by many in groundwater potential identification is Geographic Information System (GIS) based modeling. After a brief treatment of physical models, concepts of mathematical models and GIS modeling are elaborated. The modeling techniques have involved mathematics and or software specific instructions. Hence it is recommended that relevant text books for individual techniques be referred. This chapter deals more on modeling concepts.

INTRODUCTION

The debate on climate change is going on. From the report of the Inter Governmental Panel on climate change (IPCC), a premier organization set up in 1998 by the World Meteorological Organisation and United Nations Environment Programme, it is known that the average surface temperature has increased over the 20th century by about 0. 6ºC. The number may seem insignificant but it is an unprecedented rise. In the past 150 years, the 11 hottest years were witnessed. It says that 1990s was the warmest decade and 1998 the warmest year since 1861. Worse, the Artic is warming twice as rapidly as the rest of the world and there is a distinct possibility of the Greenland Ice Sheet collapsing altogether and pushing up sea levels by several metres. It is predicted that 2035 is the year when Himalayan glaciers may totally disappear causing catastrophic disruptions. Unfortunately, India is among the countries that will suffer the most serious consequences as a result of global warming. Following is the probable effect of global warming.

INTRODUCTION

Research in agriculture and allied activities and the subsequent technological innovations are important requisites for enhanced productivity and generating income for the farmers. In India, farming is a way of livelihood to 65 per cent of nearly 1. 1 billion population. Our farm population is increasing annually by 1. 84 per cent. The average farm size is becoming smaller each year and the cost-riskreturn structure of farming is becoming adverse with the result that farmers are getting increasingly indebted. There is no option except to produce more food and other commodities under conditions of diminishing per capita arable land and irrigation water resource. Hence, we must harness the best in frontier technologies, thus integrate them with traditional wisdom and thereby launch an eco-technology movement.

The productivity in agricultural sectors is dependent on several bio physical and socio-economic factors. The significant biophysical factors are weather parameters, soil health, water resources, crops/ varieties and pest environments. In order to monitor the impact of weather parameters, we need to have weather forecasts and the accuracy of which to harvest the economic benefits should be given top priority. Only fifty years ago, weather forecasting was an art which was derived after interpretation of data received from land based observing stations, balloons and aircraft etc. Now, modern technology particularly computers / weather satellites / radars has resulted in enormous improvements in the accuracy of weather forecasting with the help of various coordinated meteorological observing networks.

INTRODUCTION

Inspite of recent technological developments which have helped to increase agricultural production in many countries, growth of plants and animals continue to depend to a large extent on the weather conditions. Each plant has its own climatic requirements for growth and development and any large scale deviation from it exert negative influence.

Growth of plants is most sensitive to temperature just above a threshold value and near the maximum value, where growth normally stops. Therefore, periods of extreme temperature i. e. low temperatures below the threshold value and high temperatures above the maxima are hazardous to plant development and growth. Extreme temperature conditions during cold spells cause stress and frost; high temperatures lead to heat stress, and both affect agricultural production. Snow and ice storms in late spring or early autumn are very hazardous to many temperate crops.

Similarly extremes of moisture conditions namely dry desiccating winds, drought episodes and low moisture conditions as well as very humid atmospheric conditions including wet spells tend to affect agriculture. High soil moisture situations of water logging and flooding associated with heavy rainfall and tropical storms have adverse effect on plant growth and development since they influence the rate of transpiration, leaf area expansion and ultimately plant productivity. Drastic changes in rainfall variability can have very significant impact, particularly in climatically marginal zones such as arid, semi-arid and sub-humid areas where incidence of widespread drought is frequent. Dry desiccating and strong winds reduce agricultural production as a result of very high evapotranspiration rates. It also causes mechanical damage to plant with weak stems by lodging such as the sugarcane and the banana.