Chapter 1: Introduction

CHAPTER 1: INTRODUCTION Water Cycle "The world has enough for everyone's need, but not enough TrJ" *^* for everyone's greed." -Mahatma Gandhi CHAPTER 1: INTRODUCTION 1.1 INTRODUCTION The earth consists of 71% water, out of which 97% is found in sea, oceans, out The remaining is the fresh water which includes around 1.75-2.0 % in frozen glaciers, ice and snow, 0.5-0.75 % contributing to fresh ground water and soil moisture, and less than 0.01 % is available in surface water bodies like lakes, dams and rivers. Globally, only 0.003% of available fresh water is unpolluted and safe for drinking. Our body is made up of 70% water and it constitutes one of the most important fundamental needs for our survival. This clearly indicates that the most important natural resource is the scarcest and thus proper management of this resource is the need of the hour. The tremendous increase in population in the last few decades is exerting excessive demand on available scarce water resources. This situation is further aggravated by climate change. India, a country dominated by agriculture and one of the fastest urbanizing countries, is even more vulnerable to the problems of water scarcity, droughts and flooding. Land degradation in rain fed areas due to soil erosion from runoff, acute shortage of water including water for domestic, livestock and fodder needs and for drinking especially in summer, degradation of natural resources due to their over-exploitation, etc., are some of the major problems faced by India. To harness the full potential of the available natural resources and prevent its further degradation, watershed management is vital. These problems can be effectively addressed by adopting watershed as a basic unit of development. Watershed management basically involves harmonizing the use of soil and water resources between upstream and downstream areas within a watershed to fulfill the objectives of natural resource conservation, increased agricultural productivity and a better standard of living for its inhabitants. Watershed being natural hydrological entity, responds most effectively to various engineering, biological and cultural treatments. Watershed is not simply the hydrological unit but also socio-political-ecological entity which plays crucial role in determining food, social and economic security and provides life support services to rural people (Wani et al. 2008). Thus, effective management of water resources in a watershed is critical for social, economic, and political stability, as well as for sustainable development. The major component of managing the 21 watershed is managing the processes occurring during the hydrological cycle and within its component. Thus, watershed plays a major component of hydrologic cycle and suitable geographical unit for planning and anahsis of water resources. A watershed is an area of land that drains all the streams and rainfall to a common outlet such as the outflow of a reservoir, mouth of a bay. or any point along a stream channel. The word watershed is sometimes used interchangeably with drainage basin or catchment. Hydrological cycle occurring in any particular watershed forms the fundamental concept in hydrology. According to the National Research Council (NRC. 1982). hydrologic cycle is defined as "the pathway of water as it moves in its various phases to the atmosphere, to the earth. o\ er and through the land, to the ocean and back to the atmosphere". This c>'cle also plays an important role in controlling the climate of a place. Precipitation varies in amount, intensity, and form by season and geographic location. Hydrological cycle can be studied from a global perspective or on a catchment scale. Human-induced and natural changes in a watershed influence the quantity and quality of water. Watershed management is aimed at the sustainable distribution of its resources by studying the relevant characteristics of a watershed. Watershed is composed of its natural, hydrological and demographic resources. The major factors influencing the watershed functions are size, shape, topography, slope, geology and soils, climate, amount and intensity of precipitation, and land-use/land-cover (.laiswal et al. 1978). Watershed management has important aspect of creating and implementing plans, programs, and projects to sustain and enhance watershed functions that affect the plant, animal, and human communities within a watershed boundary. It also aims to balanced consumption of resources of land and water with minimum impact on environment. Detailed study and rigorous understanding of the occurrence and movement of water in the surface and sub-surface systems along with soil and nutrient losses in a watershed is required for a proper watershed management. Certain physical properties of watersheds significantly affect the characteristics of runoff and are thus of great interest in hydrologic analyses. The broader objectives which are covered during the national level watershed management programs mostly includes Generation of data regarding the hydrology, meteorology, soil, and watershed process. Perform watershed modeling studies and calibration on watershed hydrology process. Development of decision support system on the basis oi' obser\ations of hydrological modeling carried out. Deri\ e a watershed management plan and preparation of standard operating procedures for implementation on site. According to the World Bank report titled 'Watershed dexelopment in India - An approach evolving through experience', about half the demand for water in the country by 2030 cannot be fulfilled as a result of increase in population and economic growth. Besides water scarcity, poor quality of the available water resources ma\ exacerbate the situation. Thus, to better manage and augment its water resources. India needs to implement good watershed management practices and approaches. 1.2 WATERSHED MANAGEMENT CURRENT STATUS Managing the water resources in India is not a new concept. The first ever watershed integrated watershed management plan was implemented by Damoder Vally corporation (DVC) in early 1949 and set up a department for the watershed planning with a scientific team. Later on the series of integrated watershed management projects started in late seventies and early eighties in India. The watershed management programs adopted by Government of India (GOI) were generally based on the traditional practices of management. These programs aim to manage the micro watersheds with the planning and economic involvement since 1980s. These programs started to implement in 1995 with having an effect on the watershed performances at small level. These programs have a plan for improving the rain water harvesting systems, building check dams, rehabilitation of project affected places, and enhancement of ground water recharge techniques. There was lot of emphasis given to the programs as it was thought that the water sustainable rural areas would have their economic growth too. So these programs were aimed towards the rural development instead of watershed developments. Studying of these watershed management programs and considering the limited success got to these projects these National Watershed Development Projects for rain fed Areas (NWDPRA) which are continued during seventh plan they need to be modified and evaluated for their cost effectiveness and replicability in real time implementations. (GOI. Eight five year plan 1992-1997). However it was soon realized that the earlier programs were primarily aimed towards the rural development 23 instead of watershed developments. Hence, the prams focusing on watershed development were plan in late 1990s and started implementing thereafter. There are various recent watershed management projects initiated by state and central government like Hariyali .Neeru-Meeru. ArvaryPani Sansad etc. however these watershed management projects are still in the experimental stage and needed to be modified a lot with the use of modern technologies and methods of watershed developments. The modern technologies of watershed management are more complex than the original concept. The new concept not only aimed towards the conservation of runoff, soil and vegetation but it also aims towards the remarkably increase the productivity of natural resources with the help of economic and sustainable practices. 1.3 WATERSHED MODELING USING ADVANCED TECHNOLOGIES The watershed modeling plays an important role in initiation of watershed management programs. Many process of environment and the socioeconomic activities occurring within watershed are too dynamic, complex and spatially and temporally variable to be monitored and maintain precisely. The degraded perfonnance of the watershed is needed to be modeled first to understand the issues occurring within watershed. Watershed modeling is a set of various software tools which can help to simulate the underlying watershed processes and improve the watershed component performance. More precisely, they have holistic approach and propose a directorial system to decision makes during the management of water resources and related hazards. Watershed modeling studies requires the simultaneous consideration of various hydrological. meteorological, biological, instrucfional. soil, landuse, and other resources, involved in the watershed. Watershed usually covers a ver>' large area and to handle the complexities in the studies the advance like Global Information System (GIS) and Remote Sensing (RS) are used. These technologies use satellite imagery and

Load more