eChapters

Rivers are the most important system for water, for irrigation and human settlement. Historically, civilizations always nucleated near rivers, and latter also had social and religious significance. Rivers in India are considered holy and play the most important part in the lives of people, fauna & flora and the future environmental system.

The Ganga Basin is the largest river basin in India which includes the Ganga, the Yamuna, the Ghagra, the Gandak, the Kaveri basin etc. Compared to these, the Vishwamitri River, situated between Mahi River in North and Narmada River in South in Central Gujarat is a small seasonal river but it is very important for the city of Vadodara and Central Gujarat region. This seasonal river originates from Pavagadh hills and flows east to west. It is a typical small river with the kind of problems in most rivers in India and other countries – liquid and solid wastes, enouncements, blocking of water ways, floods in monsoon months and dry dumping basin during most other months etc.

Abstract

Prediction of the occurrences of Landslides requires a set of complex analyses, involving multitude of factors which are to be studied systematically in order to evaluate the landslide vulnerability. The increasing availability of computer-based tools and data storage capabilities are found to be useful in landslide vulnerability mapping. One such significant tool in landslide studies is Geographic Information System (GIS). In this article some approaches were made to model the land slide hazard for Sirumalai Hills, Dindigul District, Tamil Nadu, India using Geographical Information Systems and the same is presented in this paper.

4.1 Introduction

The developed or commercially available models can be applied for any water bodies such as fresh water lakes, ponds, rivers, estuaries and marine ecosystems. The predicted results can be compared with proved with field data and existing approved models and applies to the other such ecosystems. In this chapter, we can discuss about modeling of water bodies, water quality model, spatial discretizafion, modeling pollutants and toxicants, concentration modeling, hydrodynamic mixing zone analysis.

4.2 Modeling of Water bodies

The need for predictive water quality modeling has arisen largely as a result of increased eutrophication of lakes throughout the world (Forsberg, 1987; Canfield and Hoyer, 1988). The most common modelling approach is exemplified by the development and application of steady state, input-output models. Generally, nutrient concentrations are calculated from net inputs and chlorophyll a concentration is predicted by correlation with the limiting nutrient, most often phosphorus (Dillon and Rigler, 1975; Canfield and Bachmann, 1981; OECD, 1982).

Factors that can also influence phytoplankton biomass, such as light, climate, biological interactions and internal loading of nutrients, are not considered. Further more, the assumption that a lake is a continuously mixed system is very restrictive and only applicable at discrete times of the year. As a result, the shortcomings of such approaches include an inability to make predictions in the face of varying physical and biological conditions, and a failure to offer insights into the determinants of changing water quality.

7.1 Introduction

The coast is one of the most important boundaries in the world. It separates the marine part of the world from the continents. It separates the salt-water communities from fresh water communities; it separates land life from water borne life but amphibians living both environments (Fig. 7.1).

Some of the marine organisms move towards estuary for reproduction with less water salinity. The coastline as such is not a stable. It fluctuates in place over considerable distances due to erosion and sedimentation, but also due to the relative change of sea level with respect to land. The coastal zone is thus a very mobile part of the earth from a geographical point of view. Due to its specific geophysical properties, the coast is also a very important area for the development of flora and fauna. There is hardly any other part of the world that houses such a variety of species, both in flora and fauna.

The abundance of opportunities along the coast has also attracted a lot of human activities. The coastal zone has become an indispensable resource for mankind. It provides excellent opportunities for fisheries, housing, recreation, transport, defense purpose, industrial activities and many others. The influx of man with their social and economic activities, their needs for safe housing, food, drinking water, and with the tremendous quantities of waste they are producing poses at the same time a serious threat to the unique features of the coastal zone. It is therefore necessary to study this valuable region so as to prevent that competing activities are gradually causing depletion of the resources in the coastline. The following figures (Fig. 7.1and 7.2) show the typical coastal area of rocky coast and sandy coast.

8.1 Introduction

A lake is a body of water or other liquid of considerable size surrounded entirely by land (Fig. 8.1). A vast majority of lakes on Earth are fresh water, and most lie in the Northern Hemisphere at higher latitudes. In ecology, the environment of a lake is referred to as lacustrine.

Fig 8.1 A Typical Lakes

Large lakes are occasionally referred to as “inland seas” and small seas are occasionally referred to as lakes. Smaller lakes tend to put the word “lake” after the name, as in Green Lake, while larger lakes often invert the word order, as in Lake Ontario, at least in North America. The term lake is also used to describe a feature such as Lake Dal, which is a wet basin most of the time but may become filled under seasonal conditions of heavy rainfall and snowfall. Many lakes are artificial and are constructed for hydro electric power supply, recreational purposes, industrial use, agricultural use, or domestic water supply.

10.1 Introduction

Biochemical Oxygen Demand (BOD) is a chemical procedure for determining how fast biological organisms use up oxygen in a body of water. It is usually performed over a 5 day period at 20 C. It is used in water quality management and assessment, ecology and environmental science. BOD is not an accurate quantitative test, although it could be considered as an indication of the quality of a water source.

10.2 Typical BOD values

Most pristine rivers will have a 5-day BOD of less than 1 mg/l. Moderately polluted rivers may have a BOD value in the range of 2 to 8 mg/l. Municipal sewage that is efficiently treated by a three stage process would have a value of about 20 mg/l. Untreated sewage varies, but averages around 600 mg/l in India and as low as 200 mg/l in the U.S., or where there is severe groundwater or surface water infiltration. Slurry from dairy farms is around 8000 mg/l and silage liquor around 60000 mg/l.

5.1 Introduction

The water quality modeling methodologies are started from conceptual models such as defining the problem in a particular region of interest like fresh water ecosystem, coastal ecosystems, ocean ecosystems, the following methodology can be studied carefully for water quality modeling.

Identification of problems in the region of interest

Monitoring of field data using standard methods like APHA, USGS, BIS etc.

Evaluation of primary data for the toxins, higher amount of concentration from the ambient conditions

Processing of primary data to secondary data

Based on the primary data and secondary data, suitable modeling software can be used. If the temperature of the region is higher than the ambient, it should be used Qual2E, MIKE21 etc.

Modeling results can be compared with field data for calibration and validation.

9.1. Introduction

Oceans (from Okeanos in Greek) are saline waters that cover almost three quarters (71%) of the surface of the Earth. The area of the oceans is 361 million sq. km., and nearly half of the world’s marine waters are over 3,000 meters deep.

Though somewhat arbitrarily divided into several “separate” oceans, these oceans are in fact one global, interconnected body of salt water, often called the World Ocean. The major divisions are defined in part by the continents and a variety of archipelagos, and are labeled the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean, and the Arctic Ocean. Smaller regions of the oceans are called seas, gulfs and straits.

There are a some smaller bodies of salt water that are not interconnected with the World Ocean. These are not considered to be oceans or parts of oceans, though some of them have been given the name, sea.

Geologically, an ocean is an area of oceanic crust covered by water. Oceanic crust is the thin layer of solidified volcanic basalt that covers the Earth’s mantle where there are no continents. From this point of view, there are three “oceans” today: the World Ocean, and the Black and Caspian Seas that were formed by the collision of Cimmeria with Laurasia. The Mediterranean Sea is very nearly its own “ocean”, being connected to the World Ocean through the Strait of Gibraltar, and indeed several times over the last few million years movement of the African Continent has closed the strait off entirely, making the Mediterranean a fourth “ocean”.

3.1 Introduction

By the end of the twentieth century one of our most important scientific accomplishments has been the explicit realization that the human population is changing the earth system. Some of these changes are occurring at a remarkable rate. We know, with certainty, that human activities are changing land use, habitats, the chemistry of the Earth’s atmosphere and water, rates and balance of biogeochemical processes, and diversity of life on the planet (Vitousek et al. 1997). One prominent mode of human disturbance has resulted from activities that mobilize the nutrient elements nitrogen and phosphorus through land clearing, production and applications of fertilizer, discharge of human waste, animal production, and combustion of fossil fuels (Nixon 1995).

As a result of these activities, surface waters and ground waters throughout the world now have elevated concentrations of N and P compared to concentrations even in the middle of the 20th century. Our mobilization of N and P has accelerated the fluxes of these elements to coastal waters, and fertilization of coastal ecosystems is now a serious environmental problem because it stimulates plant growth and disrupts the balance between the production and metabolism of organic matter in the coastal zone. Coastal eutrophication is a recently recognized phenomenon (Nixon 1995), and scientific investigation of this human disturbance has progressed for only a few decades, so our conceptual model of the problem is evolving rapidly. Here, I describe 2 phases in the evolution of our conceptual model of how nutrient enrichment disrupts coastal ecosystems, and then finish with a view to the future, suggesting critical questions that must be answered as we work to advance and broaden our understanding of this complex environmental problem. This examination of conceptual models is designed as a complement to the excellent general reviews of coastal eutrophication (Vollenweider 1992, Heip 1995, Nixon 1995, Jørgensen & Richardson 1996, National Research Council 2000).

6.1. Introduction

A river is a large natural waterway. The source of a river may be a lake, a spring, or a collection of small streams, known as headwaters. From their source, all rivers flow downhill, typically terminating in the ocean. The mouth, or lower end, of a river is known as its base level.

A river water is confined to a channel, made up of a stream bed between banks. Most rainfall on land passes through a river on its way to the ocean. Smaller side streams that join a river are tributaries. The scientific term for any flowing natural waterway is a stream; so in technical language, the term river is just a shorthand way to refer to a large stream. Rivers throughout history have been the source and support for civilization, and many major cities today are near a river of some sort (Fig. 6.1).

6.1.1 Topography

A river conducts water by constantly flowing from a higher to a lower elevation, thereby converting the potential energy of the water into kinetic energy. It starts to form loops and snakes through the plain by eroding the river banks. Sometimes the river will cut off a loop, shortening the channel and forming an oxbow lake from the cut off section. Rivers that carry large amounts of sediment may develop conspicuous deltas at their mouths, if conditions permit. Rivers, whose mouths are in saline tidal waters, may form estuaries. River mouths may also be rias.

7.1 Introduction

Energy has become a critical input for the economic development of the India because of the wide spread scarcity of oil and electricity and other commercial form of energy.

The rural areas are often the worst affected because of these shortages and the rural population continues to depend on the inefficient non-commercial energy from like fire wood, cow dung, human and animal for meeting their energy requirement for subsistence, production and devolvement needs.

The rural energy crises or “The energy crisis” has been getting increased attention from the policy makers to tackle the problem in a planned and integrated manner.

The rural energy sector is concerned with two major planning issues.

1. Provision of energy for meeting substance needs for cooking, heating and lighting of the rural areas of the country. This problem is also directly linked to the problem of deforestation and environmental destruction being caused in the rural area because of indiscriminate and wide spread use of non conventional energy sources.
2. Meeting energy requirements for production activities which would create employment and productivity in rural areas.

Abiotic Stress Tolerance: The ability of plants to withstand and adapt to nonliving environmental stressors, such as drought, salinity, or extreme temperatures. Afforestation and Reforestation: Afforestation involves planting new forests in previously non-forested areas, while reforestation involves restoring degraded or deforested lands with trees to sequester carbon. Agrarian Society: A society characterized by agriculture as the primary means of subsistence and economic activity. Agrarian: Pertaining to the cultivation of land, agriculture, or rural life. Agribusiness: The commercial activities, including production, processing, and distribution, related to agriculture and farming. Agricultural Chemistry: A branch of chemistry that focuses on chemical processes and substances related to agriculture, including soil chemistry, fertilizer composition, and pesticide development. Agricultural Diversification: The strategy of expanding the range of crops, livestock, or other agricultural activities in a rural area to increase income and food security. Agricultural Economics: A branch of economics that focuses on the production, distribution, and consumption of agricultural goods and services, as well as the economic factors and policies that influence agricultural markets. Agricultural Extension: The application of scientific research and new technologies to agricultural practices through education and advisory services. Agricultural Innovation: The process of developing and adopting new ideas, practices, and technologies in agriculture. Agricultural Machinery: Various mechanical devices and equipment designed for use in farming, such as tractors, plows, and harvesters. Agricultural Subsidies: Financial incentives provided by governments to farmers or agricultural producers to support their production, stabilize prices, or achieve other economic or social objectives. Agriculture: The science and practice of cultivating crops, raising livestock, and managing resources for food production and other agricultural products. Agroecology: The scientific discipline that applies ecological principles to the design and management of sustainable agricultural systems, focusing on biodiversity, nutrient cycling, and reduced environmental impact.

Soil fertility evaluation is conducted for providing an adequate supply of essential plant nutriens to ensure optimum plant productivity, while maximising economic benefits and minimising environmental degradation.
 
Mathematical modelling of nutrient application

The significance of an essential plant nutrient was contained in the Liebig’s law of minimum.

During most of the years, there will be loss of agricultural production by at least 15 to 20 per cent per annum due to unfavourable weather situations. The farmers practicing agriculture expect uniform returns every year as the investment costs are much higher and cannot afford loss in production. Of late, the inter-seasonal and intra seasonal variations in weather are very frequent. The weather conditions observed were found to exceed even beyond known limits. Exceptional deviation from any one single weather parameter like air temperature, rainfall and wind can trigger considerable loss in production or sometimes even crop failure (Fig.12.1). Fig. 12.1: Components of a microclimate and its interlinkages Large scale weather modification is not practicable to a greater extent as uniform results cannot be expected under these conditions. There is need to explore cost effective management options that may significantly alter some weather parameter that is detrimental to crop production at field level by the farmers themselves. Therefore, microclimatic modification is an emerging technology to alter or change the unfavourable weather conditions detrimental to crop growth using cost effective and easily manageable techniques for minimizing the loss in crop production. The options for microclimatic modification have to be decided based on whether and the nature of weather aberrations. For example, dry spells are most common during rainy season in most of the arid and semi-arid regions. The farmers growing crops under rainfed conditions suffer considerable loss in production due to occurrence of dry spells as the crop experiences moisture stress. These dry spells may occur any time during the growing season. In such situations, the farmer needs to adopt a management option even before sowing a crop. Sometimes, the occurrence of weather aberration cannot be anticipated and the farmer has to prepare for adopting a management option based on weather forecast. Such measures are temporary and needs to be adopted to ward off the unfavourable weather conditions to a certain extent. Microclimatic modification can be a permanent, seasonal or temporary option depending upon the climate of the region. The crop microclimate refers to the climate just above and within the crop canopy and in the soil root zone that can be influenced by the day-today management practices. Microclimate modification is a measure to change or regulate the weather parameter at farm level. The microclimate management option also depends upon the nature and type of the soil as well.

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.

Moisture plays by far the most important role in soils as regards vegetation. It is through the medium of water that the plants obtain their quota of mineral food vital for their growth. If water is gradually withheld from the soil, at a certain stage, the plant will begin to wilt and soon dry up. The soil may still contain some moisture but the plant is unable to make use of it. The minimum moisture in the soil below which wilting will take place is called the Wilting Coefficient and at one time great importance was attached to it. The determination of this Coefficient, however, is tedius. One must grow a number of plants and slowly watch them wilt and determine the moisture content at that point. Moisture content of the soil is determined by heating a weighed quantity of the sample in an oven kept at 100-110 ^oC. The moisture is expressed as percentage on the oven-dry soil.

Clouds play very important role on weather and climate. The formation of clouds takes place when water condenses in the sky. Clouds are visible accumulation of tiny water droplets and ice crystals in the Earth’s atmosphere. The moisture is always present in the atmosphere though it may not be visible. Clouds form when air becomes cooler until the water vapour present in it condenses to liquid form. The condensation over oceans occurs around solid particles like salt, dust, smoke etc. suspended in the atmosphere. The type of clouds depends upon temperature and wind. The clouds are classified based on physical appearance and the height at which clouds are formed (Fig. 7.1).

Abstract

Anantapur is the driest district of Andhra Pradesh and hence, agriculture conditions are very often precarious. Groundnut grows where other crops fail and thus it is the predominant crop of Anantapur district. Groundnut is grown in about 7.5 lakh ha in Anantapur district; however the average yields are low at 500 kg ha^-1. Among various available vegetation indices, normalised difference vegetation index (NDVI) is widely used for all reasons, which is a single numerical indicator of presence and condition of green vegetation. NDVI mapping at a regional scale helps to assess the spatial changes in the vigour of green vegetation and thus occurrence of any moisture stress. Climate tools have a great role in understanding the crop performance and estimating the yields. This study was taken up by using freely available MODIS data to understand NDVI in terms of abiotic stresses over Anantapur district and linking with the actual rainfall conditions, groundnut crop acreage and production. Results indicate that low groundnut yields in general could be related to NDVI-based stress measurements and rainfall quantum and distribution in the area however, with a few exceptions. It is hoped that by combining improved practices through IWM with climate-adapted crop varieties, rainfed farmers of Anantapur district can sustain their crop production under present climate variability and become resilient to future climate change.

Keywords: Climate, MODIS, NDVI, Anantapur, Groundnut, Integrated Watershed Management

Introduction

Food supply is a major concern in the near future as the human population touches 9 billion in 2050 and therefore, more food has to be produced. This has to be achieved in the face of climate change amounting to constant pressure of biotic and abiotic stresses. However, Swaminathan (2007) opined that science and technology can play a very important role in stimulating and sustaining an evergreen revolution leading to long-term increases in productivity without associated ecological harm. Rice is considered as global grain since it is consumed by more than half of the world population. In India rice supplies calorie requirement to more than 70 per cent of its population. This is evident from the fact that rice is cultivated in all the 30 states and 5 union territories of the Indian subcontinent of diverse ecologies ranging from below sea level to mountainous regions. Though India tops in rice acreage (43.61 mha) its productivity of 3.19 t/ha (rough rice) is far below world average of 4.12 t/ha and that of Asia’s average of 4.19 t/ha (Shobharani et al., 2010). This low productivity is mainly due to unfavourable ecologies of the varied ecosystems which, rice encounters during critical stages of its growth. Salinity and submergence are major abiotic stresses, next to drought, limiting rice production in South East Asia including India.

In India nearly 8 mha are salt affected of which 2 mha are coastal saline and 3.4 mha are sodic (Singh, 1994). Rice is predominant crop in these areas especially in vast stretches of eastern and western coasts of India. The presence of salts, in excess to plant growth, in the soil solution makes the soil detrimental to crop growth. The source of the excess salt may be from soil or irrigation water. The content and composition of salts (ions) in tandem with types of soil and weather conditions prevailing during the crop period decides the severity of salt stress. Similarly, f lash floods or short-term submergence regularly affect rice growing areas in South and Southeast Asia. Even more favorable irrigated areas experience flooding problems during the monsoon season. It is also prevalent in rainfed lowlands where most of the present day rice varieties do not survive complete submergence for more than a week. In India 30% of the rice growing area is prone to such menace resulting in severe yield losses (Neeraja et al., 2007).

Key words : GPS, GIS, DSS, SDSS, RS, Digital Elevation Model (DEM), Ground Water Exploration, Conjunctive Use of Surface and Ground Water, Digital Terrain Modeling (DTM).

Introduction

Water is one of the most precious gifts of nature to living beings and particularly to the mankind. On account of erratic distribution of rainfall both in time and space, the country is subjected to cycles of floods and droughts. With the increase in demand for water for various purposes and to mitigate the twin problems of floods and droughts faced by the country, a coordinated approach for optimum utilization and proper management of this precious resource is of prime importance. In addition, proper development and management of both irrigation and drainage systems are essential. This would require integrated management of surface water as well as gorund water. All the water related problems whether mitigating droughts or floods or better irrigation management practices, dictate for adoption of state of the art water management practices. Water management deals with the control, distribution and allocation of water flows and the treatment of rivers and catchments, consequently, solutions to many of the problems in water management require the knowledge and expertise from diverse sources.