Paper No: 5 Water Resources and Management Module: 2 Water Resources of India Development Team Principal Investigator Prof. R.K. Kohli & Prof. V. K. Garg & Prof. Ashok Dhawan Co- Principal Investigator Central University of Punjab, Bathinda Dr Hardeep Rai Sharma, IES Paper Coordinator Kurukshetra University, Kurukshetra Dr Hardeep Rai Sharma, IES Content Writer Kurukshetra University, Kurukshetra Content Reviewer Prof. (Retd.) V. Subramanian, SES , Jawaharlal Nehru University, New Delhi Anchor Institute Central University of Punjab 1 Water Resources and Management Environmental Sciences Water Resources of India Description of Module Subject Name Environmental Sciences Paper Name Water Resources and Management Module Water Resources of India Name/Title Module Id EVS/WRM-V/2 Pre-requisites General introduction of water Objectives To know and understand different types of water resources in India Keywords Water resources, Glaciers, Oceans, Rivers, Lakes, Groundwater, Wetlands 2 Water Resources and Management Environmental Sciences Water Resources of India 1. Objectives: 1. To explain different resources of water 2. To understand different types of water resources 3. To describe importance of water resources 4. To understand different threats to water resources 2. Concept Map Water Resources Surface Ground Precipitation Water Water Glaciers Oceans Estuaries Rivers Lakes Wetlands Reservoirs 3. Introduction Liquid water is essential for the kind of delicate chemistry that makes life possible (Philip Ball) Natural resources are materials provided by the Earth that humans can use to make more complex products from them. These are useful raw materials that we get from the Earth, which means that human beings cannot create natural resources e.g. land, air, water, minerals etc. Water, an important natural resource, is essential for living being survival, food production, and economic development. There is no substitute of this natural resource and it is considered as a unique gift of nature to the mankind. It is the basis for the renewal, purge, and recovery of life on the planet. Different seasons 3 Water Resources and Management Environmental Sciences Water Resources of India are the result of global circulation of water. Three quarters of the planet’s surface is covered with water. All this water is in continuous motion between different environmental components. Being an universal solvent, different substances get dissolved and suspended in it during runoff and percolation. A proper assessment of water resources potential is important for its sustainable development and management point of view. This will be helpful in their proper planning, design, construction, operation and maintenance to provide competing demands during irrigation, drought and flood management, domestic and industrial water supply, of electricity generation, fisheries and navigation. The first Irrigation Commission in 1901‒03 has carried out the first ever attempt of water resources potential assessment of India. The main characteristic of the world’s freshwater resources is their uneven distribution in time and space. Freshwater can be considered green or blue. Green water – the rainfall that is stored in the soil and then evaporates or is incorporated in plants and organisms – is the main source of water for natural ecosystems and for rain-fed agriculture, which produces 60% of the world’s food. Blue water – renewable surface water runoff and groundwater recharge – is the main source for human withdrawals and the traditional focus of water resource management. The blue water total availability is about 40,000 cubic kilometres a year. Of this, an estimated 3,800 cubic kilometres, roughly 10% were withdrawn (diverted or pumped) for human uses in 1995. Of the water withdrawn, about 2,100 cubic kilometres were consumed. The remainder was returned to streams and aquifers, usually with significant reductions in quality (Cosgrove, 2006). Of the estimated 1.4 × 1018 cubic meters (m3) of water on Earth, more than 97% is present in the oceans. About 35 × 1015 m3 of Earth’s water is fresh water, of which about 0.3% is held in lakes, reservoirs and rivers (Shiklomanov and Rodda 2003). Remaining fresh water is stored in glaciers, permanent snow, and groundwater aquifers. Earth’s atmosphere contains approximately 13 × 1012 m3 of water and is the source of all the precipitation that occurs on Earth (Shiklomanov and Rodda, 2003). Yearly, about 151,000 quads (159,300 exajoules) of solar energy cause 577 × 1012 m3 of water evaporation that moves about from Earth’s surface into the atmosphere. Of this evaporation, 86% is from the oceans (Shiklomanov, 1993) and remaining 14% of the water evaporation is from land. About 20% (115× 1012 m3 per year) of the world’s precipitation falls on land, with the surplus water returning to the oceans through rivers (Shiklomanov, 1993). Thus, each year solar energy transfers a 4 Water Resources and Management Environmental Sciences Water Resources of India significant portion of water from oceans to land areas. There is uneven distribution of water resources among different regions of India. The water availability differs considerably from the desert areas of the Western India to the hilly regions of the North-East. The national per capita annual availability of water as per the distribution of water resources potential in India is 1545 cu m (as on 1st March 2011 estimation) which is more than scarcity condition of 1000 cu m per capita as considered by international agencies (CWC, 2016). India is blessed with different types of natural water resources which include glaciers, oceans, rivers, lakes, and ground water. However human beings made dams and reservoirs to store and water. Among different types of water resources, glaciers are solid form of water and oceans has saline water therefore making both unfit for direct utilization. Rainfall the important constituent of hydrological cycle is the main driving force for the water supply in these resources. In the present module we will discuss about the main water resources starting from the rainfall. 4. Precipitation: The environment of India is characteristically monsoonal: half the precipitation takes place within a 15-day period, and more than 90 % of annual river run-off occurs during four monsoon months (June‒September). India receives annual precipitation of about 4000 km3, including snowfall. Out of this, monsoon rainfall is of the order of 3000 km3. Rainfall in India is dependent on the south- west and north-east monsoons, on shallow cyclonic depressions and disturbances and on local storms. Most of it occurs between June and September under the influence of south-west monsoon except in Tamil Nadu, where it is under the influence of north-east monsoon during October and November. There is a high spatial and temporal variability in the rainfall pattern in our country resulting into floods and droughts. The Northern, Central and Eastern parts of India receives annual normal rainfall between 75 and 150 cm. Highest rainfall of about 11,690 mm is recorded from Mousinram near Cherrapunji in the North Eastern State of Meghalaya whereas Jaisalmer in Rajasthan receives about 150 mm of rainfall in a year (Kumar et al. 2005). 5. Surface water resources: It includes water present on the surface of the earth in different aquatic bodies like oceans, seas, estuaries, rivers, lakes, reservoirs, tanks, ponds etc. In glaciers water is found in it solid state. Oceans, seas, estuaries and salt water lakes water is not fit for drinking due to high salt content but they have significant contribution in water cycle. According to National Institute of 5 Water Resources and Management Environmental Sciences Water Resources of India Hydrology, India’s average annual surface run-off generated by rainfall and snowmelt is estimated to be about 1869 billion cubic meter (BCM). Out of this only 690 BCM (37%) of it can actually be mobilized. 5.1 Glaciers: A glacier is a mass of ice consisting of compacted and recrystallized ice on land that flows down under its own weight due to gravity. These are the main source of water for perennial Himalayan Indian Rivers. There are 9575 glaciers in the Indian Himalayas, covering a total area of about 18054 km2 and a volume of about 1291 km3 as per the glacier inventory by the Geological Survey of India (CWC, 2008). The principal glaciers in Himalayas can be divided in four groups i.e. Punjab, Garhwal, Nepal and Assam group of glaciers. Gangotri Glacier is an example of Garhwal group of glaciers while glaciers adjoining Kanchenjunga peak are part of Assam group of glaciers (NIH, 2017). The principal glaciers of the Indian Himalaya, are: Gangotri, 30 km (length); Zemu (Sikkim Himalaya), 28 km; Milam (Nanda Devi area), 19 km; and Kedarnath (Gangotri-Chaukhamba area), 14.5 km. Gangotri Glacier is one of the largest glaciers in the Himalayas is located in the Uttarkashi District of Uttarakhand State in the Garhwal Himalayan Region. The snout of the Gangotri Glacier is known as ‘Gomukh’ and a proglacial melt water stream, known as Bhagirathi River, emerges out from Gomukh at an elevation of 4,000m. Data on glacial retreat for 1868 glaciers in 11 basins distributed across the Indian Himalaya for the period 1962-2001/2004 (Kulkarni, 2010) show that the overall glacial area has decreased from 6332 km2 to 5329 km2 which amounts to an average loss of ~16%. Figure 1. shows the in Baralacha La glacier in Himachal Pradesh. 6 Water Resources and Management Environmental Sciences Water Resources of India Figure 1: Baralacha glacier in Himachal Pradesh (Photo by Prof. Rajesh Lohchab, August 2017) 5.2 Oceans: About 71% of the Earth’s surface is covered by oceans. The average depth of the oceans is 3700 m, and they contain 97% of the Earth’s water. India is surrounded by oceans in three directions by Bay of Bengal (East), Arabian Sea (West) and Indian Ocean (South). The Bay of Bengal, the Arabian Sea, the Mozambique Strait, and the Great Australian Bight are the sub-regions of the Indian Ocean.