{"id":502,"date":"2019-03-09T10:01:39","date_gmt":"2019-03-09T10:01:39","guid":{"rendered":"http:\/\/esp05.epgpbooks.inflibnet.ac.in\/?post_type=chapter&p=502"},"modified":"2019-04-16T10:28:12","modified_gmt":"2019-04-16T10:28:12","slug":"integrated-water-resources-management-i","status":"publish","type":"chapter","link":"https:\/\/ebooks.inflibnet.ac.in\/esp05\/chapter\/integrated-water-resources-management-i\/","title":{"rendered":"Integrated Water Resources Management-I"},"content":{"raw":"
\"epgp<\/a>\r\n<\/span><\/div>\r\n
\r\n\r\n \r\n\r\n \r\n\r\n \r\n\r\nObjectives<\/strong>\r\n\r\n \r\n\r\n1.\u00a0\u00a0\u00a0\u00a0\u00a0 Why we need better water management?\r\n\r\n2.\u00a0\u00a0\u00a0\u00a0\u00a0 Water cycle and water resources\r\n\r\n3.\u00a0\u00a0\u00a0\u00a0\u00a0 Water use and its impacts\r\n\r\n4.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 to explain integrated water resources management (IWRM)\r\n\r\n5.\u00a0\u00a0\u00a0\u00a0\u00a0 Water policy and\u00a0 IWRM in India\r\n\r\n6.\u00a0\u00a0\u00a0\u00a0\u00a0 IWRM and the role in sustainable development\r\n\r\n \r\n\r\nIntroduction<\/strong>\r\n\r\n \r\n

Water is key driver of economic and social activity as well as maintaining the integrity of the natural environment. Freshwater resources are under increased pressure to satisfy the needs of water users globally. Since 1800, the world\u2019s population has increased from 1 to 7.2 billion, but freshwater is finite upon which we all depend for our survival. The amount of freshwater on Earth does not change, yet the use of freshwater has increased nine-fold in the 20th century. Water maintains resource base of surface water and groundwater, sustains aquatic biodiversity, and the ecological integrity of the natural environment (www.gwp.org<\/a>). Freshwater water is used for food production in agriculture and meeting the needs of people for water supply and sanitation. There is delicate balance between water for livelihood and water as a resource. Water is a powerful indicator of ecological sustainability, economic prosperity, and human well being. However, the knowledge about water systems and change is still insufficient. Population growth, economic growth, and other competing demands on water resources have more demands on water resources.<\/p>\r\n \r\n

Population growth has increased demands for water, and produces more waste water and pollution. Migration from rural to urban areas increases the current level of difficulty in water delivery and waste water treatment. Economic growth, mainly in developing countries with large populations, contributes to increased demand of water for economic activities. Inter linkages among sustainable water management components as shown in Figure 34.1. Freshwater is a scarce resource and humans are changing the water system without adequate knowledge of the system.<\/p>\r\n\r\n<\/div>\r\n

\r\n\r\n\"\"\r\n\r\n \r\n\r\n35.2 Water Cycle and Global Water Resources<\/strong>\r\n\r\n \r\n

Only a few studies have provided a synthesized, quantitative view of the global water cycle (Trenberth et al., 2007; Oki and Kanae, 2006). The major pathway of water cycle involves an exchange between earth surface and atmosphere via precipitation and evaporation, and is in\u00a0study steady-state (Figure 34.2). It is evident that more water evaporates than returns through precipitation in oceans (precipitationevaporation ratio, P\/E ratio about 0.9), while in the case of land the reverse is true (P\/E = 1.5). Thus, some of the rainfall that occurs on the land is due to the evaporation of water from oceans. Changes in the hydrological cycle are an expected because of\r\nanthropogenic climate change. Under changed climatic scenarios, the major impacts include melting of glaciers, sea level rise, submergence of islands\/coastal areas and erratic rainfall patterns, a greater annual variability in the monsoon\u2019s precipitation levels ( IPCC, 2007). Climate change will have implications on river flows and water availability throughout the world (Palmer et al., 2008).<\/p>\r\n\"\"\r\n\r\n<\/div>\r\n

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Water is a key resource for humanity and sustainability of natural ecosystems. The Earth has nearly 1386 million km3 of water, out of > 96.5% is stored in the oceans and another 1% is saline or brackish groundwater (Shiklomanov, 2000). Out of the only 2.5% of global freshwater, about 69.5% is frozen in glaciers, polar ice caps, snow and permafrost, and more than 30% occurs constitutes the groundwater. Less than 0.3% of all freshwater on the Earth occurs in the lakes, rivers and wetlands and is utilizable by humans for their diverse needs (Shiklomanov, 2000).<\/p>\r\n \r\n

The stocks of fresh water are not uniformly distributed over the Earth\u2019s surface and show marked spatial and temporal variability (Gopal, 2012). For example, Lake Baikal in Russia alone contains more than 20% of all the freshwater on the Earth. The rivers such as Amazon, Ganga, Brahmaputra, Yangtse, Mississippi, Congo, and Nile account for more water than all other rivers occurring in different regions of the world (Gopal, 2012). The Amazon River alone carries far more water than all major rivers together all over the world.<\/p>\r\n \r\n

It is also important to make a distinction between <\/span>\u201cGreen water\u201d<\/strong> and <\/span>\u201cblue water\u201d<\/strong>. Water that is used directly for biomass production by plants and \u201clost\u201d in evapotranspiration is referred to as <\/span>\u201cgreen water<\/strong>\u201d. The portion of rainfall water that flows in rivers and recharges ground water is called <\/span>\u201cblue water\u201d<\/strong>. The Blue, or renewable freshwater that is used\u00a0<\/span>amounts to 3800 km3\/year (Oki and Kanae, 2006), out of which 2,660 km3 constitutes withdrawal of water for irrigation, 770 km3\/year withdrawal for industry , and 380 km3\/year withdrawal for domestic use. This accounts for less than 10% of the maximum available renewable freshwater resource in the world. The withdrawal of water that is consumed is 55%, whereas 45% constitutes the drainage and wastewater, most of which is polluted. Terrestrial ecosystems are \u201cgreen water\u201d dependent, whereas aquatic ecosystems are \u201cblue water\u201d dependent. Most of the studies on IWRM tend to focus on the \u201cblue water\u201d. Management of Green water use has a key role in global food security.<\/span><\/p>\r\n\r\n<\/div>\r\n

\r\n\r\n \r\n\r\n35.2.1 Global Water Crisis \u2013 Some Facts<\/strong>\r\n\r\n \r\n

Water quantity and water quality are important issues in water management. Some facts about the way we use our water globally are given in Box 34.1. An estimated 1.8 billion people live in areas affected by water scarcity. Recently, it has been reported that two-thirds of the global population (4.0 billion people) live under conditions of severe water scarcity for at least one month of the year; nearly 50 percent of those people live in India and China (Mekonnen and Hoekstra, 2016). Half a billion people in the world face severe water scarcity all year round (Mekonnen and Hoekstra, 2016). Women in developing countries have to walk long distances collecting and carrying water.<\/p>\r\n \r\n\r\nBox 35.1. Water Crisis \u2013 Some Facts (UNDP,\u00a0\u00a0\u00a0 2005 and various other sources).\r\n\r\n \r\n\r\nOnly 0.3% of total of global water in the world is available for humans. 2 billion people are affected by water shortages in over 40 countries.\r\n\r\n286 river basins are shared by two or more nations.\r\n\r\n \r\n\r\n2 million tonnes per day of human waste are deposited in water courses.\r\n\r\n \r\n\r\nHalf the population of the developing world are exposed to polluted sources of water that increase disease incidence. 1.4 million children die every year because of water borne diseases.\r\n\r\n \r\n\r\n90% of natural disasters in the 1990s were water related.\r\n\r\n \r\n\r\nThe increase in numbers of people from 6 billion to 9 billion will be the main\r\n\r\n \r\n\r\ndriver of water resources management in the next 50 years.\r\n\r\n \r\n\r\n1.663 million people<\/strong> <\/a>don\u2019t<\/strong> have access to safe drinking water.<\/strong>\r\n\r\n<\/div>\r\n

\r\n\r\n \r\n\r\n35.2.2 India\u2019s Water Resources<\/strong>\r\n\r\n \r\n

India has an average annual rainfall of 120 cm, receiving 392 million ha-m (Mha-m = 10 km3) of water besides 8 Mha-m snow melt from the Himalaya and 20 Mha-m surface runoff from neighbouring countries (see Chaturvedi, 2011; Gopal, 2012). The total average annual flow in all rivers is estimated at 1953 km3 (Jain et al. 2007). The utilizable surface waters are estimated to be 690 km3 of which only 399 km3is being utilized (Kumar et al., 2005). The annual renewable groundwater resources are estimated at 431.89 km3. Some of the water concerns in India are presented in Box 35.2.<\/p>\r\n\r\n\r\n

\r\n\r\nBox 35. 2. Some of the water concerns in India (Kumar and Bharat, 2014)\r\n\r\n \r\n