eChapters

Why Water Budget?

The reliability of water supply in desert regions is at risk due to a multitude of issues including low rainfall, low snow runoff, court-ordered water transfer restrictions and hence higher price of wholesale water. Agencies in desert regions understand the importance of improving water supply reliability, facilitating better water storage, adapting to changing climate patterns and reduced precipitation, improving Environment and Water Quality.

The Desert regions have always fought back the perpetual water scarcity with infrastructure designed around saving water and utilizing alternative water resources. Off late, not only new construction but also new policies and programs have added to their water conservation activities.

One such program attends to the fair distribution of water by tending to consumers who are price sensitive and hence use water without wasting it and by extra-charging those who do not know where to put a stop to their wasteful water use.

Water Scarcity Issues
The world is running out of clean water. The subsurface water table decreases and surface runoff rises as a result of deforestation. The amount of water stored underground is decreasing as wells are being dug deeper and deeper. As a result of desertification and deforestation, perennial rivers are turning seasonal. There is not enough potable drinking water because of abuse and overuse.
Conserving Water
• In certain situations, manipulating plants, harvesting water, and other techniques might increase the availability of water supplies.
• Water use reduction achieved by the application of water efficiency or conservation techniques; alternatively,
• Better techniques for managing water can either decrease or increase the useful use of water.
• Any activity, behavioral modification, tool, technology, or better design or procedure used to lower water loss, waste, or use is referred to as a water conservation method.
• One method of conserving water is water efficiency.
Among the Objectives of Water Conservation Initiatives
• The goal of sustainability is to guarantee that water extracted from an ecosystem will not be lost faster than it naturally replaces itself for future generations.
• The pumping, delivering, and treating of water results in energy conservation.
• Habitat conservation includes limiting the amount of water used by humans, which lessens the need to construct new dams and other water diversion infrastructure while also preserving freshwater habitats for nearby species and migratory waterflow.

Abstract

In the emerging era of wide spread use of IT tools, up-to-date information on water resources is the key to support economic development, conserve the nature as well as to improve the quality of life. Due to rapid rise in population  and food demand, growing economy and improving living standards; the pressure on our water resources is increasing and it will become scarce in the coming decades if not managed at this stage in a integrated way. Water resources management requires a multi-disciplinary approach that combines a collection of technical tools and expertise along with stakeholders of diverse interests and priorities in planning and management and an operational water resources information system at national level is the first requirement.

1.0 Introduction

Population in dry lands of the world is increasing; more fresh water is required in order to meet the growing demands. To meet this challenging situation developing new technologies for identification of potential sites for rainwater harvesting (RWH) is an important step towards maximizing water availability in semi-arid areas.

Introduction
Water management is a critical aspect of agricultural science and environmental sustainability, influencing not only the efficiency of food production but also the health of ecosystems and the balance of global water resources. This chapter delves into the principles, techniques, and modern advancements in water management, emphasizing its significance in ensuring food security, conserving vital resources, and combating global warming. The chapter begins by exploring the foundational principles of irrigation, a key component of water management in agriculture. Various irrigation techniques, such as surface, sprinkler, and drip irrigation, are discussed in detail, along with the factors that influence irrigation efficiency, such as soil type, crop needs, and climatic conditions. The importance of optimizing irrigation practices to enhance water use efficiency and minimize waste is underscored. Water use efficiency and conservation strategies form the next major focus of the chapter. As global water resources face increasing pressure from population growth, industrialization, and climate change, the need for efficient water use in agriculture becomes ever more critical. The chapter discusses various methods to improve water use efficiency, including advanced irrigation technologies, crop selection, and soil management practices. Conservation strategies, such as rainwater harvesting, groundwater recharge, and the use of drought-resistant crops, are also explored. Effective drainage systems and waterlogging control are essential for maintaining soil health and agricultural productivity. The chapter provides an overview of drainage system principles, techniques for assessing soil drainage, and strategies for controlling waterlogging, a condition that can severely impact crop yields. The benefits of well-managed drainage systems, including improved soil structure, reduced salinity, and enhanced crop performance, are highlighted. Water quality and salinity management are crucial for sustaining agricultural productivity and preventing soil degradation. The chapter discusses methods for assessing water quality, the impact of salinity on soils and crops, and techniques for managing salinity, such as the use of salt-tolerant crops and soil amendments. Effective water quality management ensures that crops receive the nutrients they need while preventing harmful buildup of salts and other contaminants

ABSTRACT

Remote Sensing and Geographical Information System play major role in the water planning of river basins. Varahanadhi is one of the 17 major river basins of Tamilnadu, bounded in North by Palar basin, East by Bay of Bengal and West & South by Ponnaiyar basin. It drains through Thiruvannamalai and Villupuram districts. There are three sub basins viz., Ongur, Nallavur and Varahanadhi sub basins. From Survey of India top sheets, Basin boundary, sub basin boundary maps were generated. Administrative map with district, block boundaries was prepared. GIS software - Arc view, was utilized for this purpose. By using ERDAS IMAGINE, Digital Image processing software, satellite image mosaic of Varahanadhi Basin, Geomorphology, Land use, Wasteland, Structural-Lineament maps were generated. IRS P 6 RESOURCESAT, LISS III and PAN data were used for the thematic map preparation. From the collateral data collected, the thematic maps on Geology, Soil, and annual north east, south west. summer, winter rainfall, irrigation system, pre monsoon and post monsoon groundwater levels, ground water quality were prepared using ARC GIS Software. Relief and Drainage map were also generated in GIS environment. The surface water potential was assessed by rainfall run off method for which geomorphology map interpreted by remote sensing and GIS was utilized. Based on geomorphology and land use maps, draft for irrigation was estimated. Geology, geomorphology, depth to bedrock, rainfall pattern, water level maps were used

to asses groundwater potential and draft. Sectoral demand on power, industry and domestic were made based on collected collateral data. Environmental Impact Assessment was assessed using land use maps and ground water quality maps interpreted from remote sensing data for years 1998 and 2004 were prepared and compared. Wasteland map was prepared to know the extent of wastelands and their types as per National Waste Land Board norms. Remedial measures to convert waste lands into productive lands were also suggested. By superimposing geomorphology and lineament maps upon the wastelands, sites suitable for groundwater development in the waste lands were identified. In the same way by using GIS overlay analysis developmental and action plan maps were also prepared with technical recommendations. By applying remote sensing and GIS techniques the basin water resources assessment, draft to meet out sectoral demands and balance of water available for future use can be decided. Varaganadhi basin is a surplus basin as per the study.

Ours is a Living Planet because ours is a Water Planet. The health of the Living Planet depends on the health of its water resources. Ironically, the health of its water resources is at stake. And so of its life! The waters of the Earth are in the grips of pollution. Much of the water is already polluted and the rest is increasingly becoming polluted. Water pollution, indeed, is one of the worst problems life on Earth is faced with. Water pollution is halting human progress and is phenomenally affecting all walks of human civilization. Water pollution is even putting a question mark on our sustainable future. This chapter presents the causes, magnitude, and consequences of water pollution and also suggests ways and means to prevent and control water pollution and also attempts to manage water resources.

Introduction
In the global perspective, water contamination is a significant issue. Every day, it is the cause of almost 14,000 deaths. The most valuable natural resource on Earth is water, which makes up more than 70% of its surface.
Definitions
• The term “water pollution” refers to the contamination of water bodies by human activity, which can be detrimental to the plants and organisms that call thesem bodies of water home. It can be characterized as any alteration in the quality of water brought about by human activity that makes it less suitable for any of its positive uses, actual or potential. Excess of any substance or heat that could endanger people, animals, or aquatic lifeMan’s actions alter the quality or composition of water, either directly or indirectly, making it unfit for any purpose.
Sources of Water Pollution
• Point source pollution, which is defined as pollution having a distinct source and point of entry into the water, making it easy to identify. It describes impurities that find their way into a waterway by a covert channel, like a ditch or pipe. For instance, contaminants include metals and organics in municipal and industrial discharge pipelines.

Water is indispensable for our life. About 2/3 of earth is covered with water. No organism can survive without water. So keeping water free from any pollutant is very important. Water is said to be  “polluted” when it is hanged in its quality and composition directly or indirectly by man’s activity so that it becomes less suitable for drinking, domestic, agricultural or any other purpose. Polluted water transmits a large number of diseases in man. They are cholera, typhoid, dysentery, jaundice and other bacterial or viral diseases.  Water becomes polluted by the presence or addition on inorganic or organic substances or biological agents. Soil erosion, leaching of minerals from rocks, decaying of organic matter are natural sources of water pollution. There has been an alarming increase in the degradation of water quality in the recent past in the large cities and industrial areas.

Water pollution can be studied under the following heads—  (i) medium in which it occurs (surface water, ground water); (ii) habitat (lakes, estuaries and open seas); and (iii) type of pollutants (bacterial, metallic, thermal and radioactive).

It is estimated that the world requires nearly 70 per cent increase in agriculture production to meet the demand for food by the year 2050 based on current trends in population growth it can be achieved either by increasing land under cultivation (which is not possible), increasing the availability of more water for agriculture and efficient utilisation of available land and water resources. The best available option is to increase in productivity of unit of land for unit water. However, the availability of water for agriculture production cannot be presumed to be same year after year as the major source of water is precipitation more known for its uncertainty due to change in weather patterns from season to season and year to year all over the world. The element of uncertainty is increasing since the beginning of the present century due to climate change under the present circumstance, the crop production is practiced -
• In Irrigated Areas
• In Rainfed Areas
• Under Conserved Moisture Condition Without Any Source Of Irrigation
For increasing crop production under irrigated condition, it is necessary to identify crops and varieties that can produce more yield per unit of water even when there is some decrease in availability of water through irrigation. Therefore, the concept of water production function is used for evaluation of water use efficiency of the crops.

1.1 Introduction

Climate change is evident from the observation of increase in global average air and ocean temperatures, precipitation and extreme rainfall, widespread melting of ice, storms / storm surges flooding and rising global mean sea level, as recorded in the Fourth Assessment Report of IPCC. Eleven of the last twelve years (1995-2006) rank among the twelve warmest years in the instrumental record of global surface temperature (since 1850). 

The presence of water in its various phases (gas, liquid, and solid) within the atmosphere plays a pivotal role in shaping our weather and climate. This chapter, “Moisture in the Atmosphere,” will delve into the crucial concept of atmospheric humidity – the amount of water vapor in the air. Water, unique in its ability to exist in all three states at Earth’s temperatures, undergoes phase changes that are fundamental to the formation of clouds, precipitation, and atmospheric stability. Understanding the sources of atmospheric moisture, the ways it is measured and expressed, and its influence on atmospheric processes is essential for comprehending a wide range of meteorological phenomena (Fig. 4.1). We will explore concepts such as evaporation, condensation, humidity indices, and the role of moisture in energy transfer within the Earthatmosphere system. Join us as we unravel the dynamics of this vital component of our atmospheric environment

The presence of water in its various phases (gas, liquid, and solid) within the atmosphere plays a pivotal role in shaping our weather and climate.This chapter, „Water Vapor in the Atmosphere,“ will delve into the crucial concept of atmospheric humidity – the amount of water vapor in the air. Water, unique in its ability to exist in all three states at Earth‘s temperatures, undergoes phase changes that are fundamental to the formation of clouds, precipitation, and atmospheric stability. Understanding the sources of atmospheric moisture, the ways it is measured and expressed, and its influence on atmospheric processes is essential for comprehending a wide range of meteorological phenomena. We will explore concepts such as evaporation, condensation, humidity indices, and the role of moisture in energy transfer within the Earth-atmosphere system. Join us as we unravel the dynamics of this vital component of our atmospheric environment.
8.1. Expressions Used for Water Vapor in the Atmosphere
The concepts of vapor pressure, saturated vapor pressure, vapor pressure deficit, and dew point has been discussed with detailed explanations:
8.1.1. Vapor Pressure (e)
Vapor pressure is the partial pressure exerted by water vapor molecules in the air. It represents the contribution of water vapor to the total atmospheric pressure. Imagine air as a mixture of gases; the vapor pressure is the „pressure“ exerted solely by the water vapor component of that mixture.

The presence of water in its various phases (gas, liquid, and solid) within the atmosphere plays a pivotal role in shaping our weather and climate.This chapter, „Water Vapor in the Atmosphere,“ will delve into the crucial concept of atmospheric humidity – the amount of water vapor in the air. Water, unique in its ability to exist in all three states at Earth‘s temperatures, undergoes phase changes that are fundamental to the formation of clouds, precipitation, and atmospheric stability. Understanding the sources of atmospheric moisture, the ways it is measured and expressed, and its influence on atmospheric processes is essential for comprehending a wide range of meteorological phenomena. We will explore concepts such as evaporation, condensation, humidity indices, and the role of moisture in energy transfer within the Earth-atmosphere system. Join us as we unravel the dynamics of this vital component of our atmospheric environment.
8.1. Expressions Used for Water Vapor in the Atmosphere
The concepts of vapor pressure, saturated vapor pressure, vapor pressure deficit, and dew point has been discussed with detailed explanations:
8.1.1. Vapor Pressure (e)
Vapor pressure is the partial pressure exerted by water vapor molecules in ,the air. It represents the contribution of water vapor to the total atmospheric pressure. Imagine air as a mixture of gases; the vapor pressure is the „pressure“ exerted solely by the water vapor component of that mixture.

A watershed is an area that provides pathway to the surface or sub surface water flow to a given drainage system. The watershed is a hydrological unit. The area of watershed may vary from few hectares to thousands of square kilometres. The watershed development involves effective management of land and vegetation in order to conserve and improve the quantity of water. The watershed development is a comprehensive and sustainable solution to water conservation (Fig.13.1).
The watershed development has several advantages. It helps in
• Conservation, upgradation and utilization of natural resources particularly land, water and vegetation
• Minimise the inequalities between rainfed and irrigated areas
• Promoting cost effective adoptable simple technologies
• Supply water for domestic ,agricultural and industrial use
• Poverty alleviation and employment generation
• Reducing chemical pollution
• Adopting flood control measures by constructing water storage or impounding structures

As we conclude this comprehensive review of the complex relationships between weather, crop diseases, and disease management, it is essential to reflect on the current state of knowledge and identify areas that require further research and attention. The preceding chapters have highlighted the significant impacts of weather factors on crop diseases, emphasizing the need for a deeper understanding of these relationships to develop effective disease management strategies. Significant work particularly on effects of different weather combinations on pathogen population and disease severity needs to be addressed well in time. Despite significant advances in our understanding of the weather-crop disease nexus, there remain substantial knowledge gaps that hinder our ability to predict and manage disease outbreaks effectively. For instance, the complex interactions between weather factors, crop physiology, and disease development are not yet fully understood, making it challenging to develop accurate predictive models. Furthermore, the impacts of climate change on weather patterns and crop diseases are still being researched, and more work is needed to understand these relationships fully. To address these knowledge gaps and improve our understanding of the weather-crop disease nexus, several action plans are required. Firstly, continued research is needed to elucidate the complex relationships between weather factors, crop physiology, and disease development. This research should focus on developing a deeper understanding of the underlying mechanisms driving these relationships, as well as identifying key weather thresholds that trigger disease outbreaks. Secondly, the development of accurate predictive models that can forecast disease outbreaks based on weather data is critical. These models should be able to account for the complex interactions between weather factors, crop physiology, and disease development, as well as incorporate data from multiple sources, including weather stations, satellite imagery, and field observations. Thirdly, there is a need for more effective communication and collaboration between researchers, policymakers, and farmers to ensure that research findings are translated into practical disease management strategies. This will require the development of user-friendly decision support tools that can provide farmers with timely and accurate advice on disease management, based on weather forecasts and other relevant data. Finally, addressing the impacts of climate change on weather patterns and crop diseases will require a coordinated effort from researchers, policymakers, and

The march of weather factors during crop period is never smooth and regular. Agriculture, because of its dependance on climate is inevitably subjected to unpredictable long and short term fluctuation characteristic of atmosphere conditions. Climate introduces an element of risk in farming which makes it particularly hazardous occupation.

A Weather hazard in this context can be defined as any type of extreme weather condition that can damage the crops and animals leading to abnormal decrease in production and income. The extent to which these hazards create risk depends on the time of occurrence, intensity and duration of the hazard besides the age, stage of development and inherent resistance of the crop or livestock involved. Major abnormalities affecting the crop production are:

Agriculture, the cultivation of life that sustains human civilization, is profoundly intertwined with the rhythms of the natural world. Of all the environmental factors that influence farming, weather reigns supreme, orchestrating a complex symphony of elements that dictate the success or failure of crops. This chapter delves into the intricate relationship between weather and agriculture, exploring how temperature, precipitation, sunlight, and other atmospheric conditions shape every facet of agricultural production.
Weather’s influence begins with the very first stage of a plant’s life. Temperature governs seed germination and seedling development, while sunlight provides the energy for photosynthesis, the process by which plants convert light energy into chemical energy. The availability of water, dictated by rainfall patterns, is crucial for plant growth and nutrient absorption. Wind patterns can aid in pollination but also cause damage to crops.
Throughout the growing season, weather continues to play a critical role. Optimal temperatures are essential for each stage of plant development, from flowering to fruit production. Adequate rainfall, or irrigation to supplement it, ensures healthy growth and abundant yields.

Agriculture, the cultivation of life that sustains human civilization, is profoundly intertwined with the rhythms of the natural world. Of all the environmental factors that influence farming, weather reigns supreme, orchestrating a complex symphony of elements that dictate the success or failure of crops. This chapter delves into the intricate relationship between weather and agriculture, exploring how temperature, precipitation, sunlight, and other atmospheric conditions shape every facet of agricultural production.
Weather’s influence begins with the very first stage of a plant’s life. Temperature governs seed germination and seedling development, while sunlight provides the energy for photosynthesis, the process by which plants convert light energy into chemical energy. The availability of water, dictated by rainfall patterns, is crucial for plant growth and nutrient absorption. Wind patterns can aid in pollination but also cause damage to crops.
Throughout the growing season, weather continues to play a critical role. Optimal temperatures are essential for each stage of plant development, from flowering to fruit production. Adequate rainfall, or irrigation to supplement it, ensures healthy growth and abundant yields.
Extreme weather events, such as droughts, floods, heatwaves, and frosts, can have devastating consequences for agriculture. These events can destroy crops, reduce yields, and disrupt food production, leading to economic losses and food insecurity (Fig. 18.1).