Water Resources and Sanitation
Total Page：16
File Type：pdf, Size：1020Kb
Chapter 2: Water Resources and Sanitation Introduction More than 97 per cent of the world’s water resources occurs in the form of oceans and only about 2.7 per cent as fresh water bodies including both surface and ground water resources. Thus, fresh water occupies a very small portion of the total water on the Earth in which rivers and lakes do not even get counted as they contribute to a negligible amount (0.014 percent) of all fresh water. Chemically, water is H2O and since it is regarded as a universal solvent it never exists individually in nature. Nor it is desirable in its purest form as some components like minerals, salts, etc. are required from the health point of view. If any one or more components of water exceed the prescribed limits, it causes water contamination. Acute shortage of drinking water is probably the most important issue in India. Millions of villages in the country have become water-scarce or no-source villages. The National Water Policy (NWP) gives highest priority to drinking water but despite more than five decades of planning, much lesser than the expected has been achieved. More than three-fourth of the rural population still does not have proper water supply systems. In the urban areas, quantities delivered are inadequate and the service is unreliable, mostly intermittent, resulting in wastage of water. Although, on an average, the country gets enough rainfall each year, it is unequally distributed. As a result, same region could be affected by drought in one year and by flood in another. Continuous droughts affect many parts of the country due to both natural and man-made reasons. Natural reasons of droughts are wide variations in rainfall and inequitable distribution of perennial rivers in various parts of the country. Man-made reasons are improper water management like excessive groundwater extraction, inefficient use and wastage of water, absence of rainwater harvesting, etc. This has resulted in a sharp decline in the ground water table, which in turn, has increased salinity in coastal areas. On the other hand, several regions in the country remain flood affected every year and measures for flood plan zoning and disaster preparedness are inadequate. Broadly, there are two kinds of uses of water- abstractive use and in-stream use. The former includes domestic, industrial and agricultural uses while the latter refers to hydropower, fisheries, navigation, community bathing and washing and cattle bathing and watering. Ground water exploitation is divided into three categories. Category I consists of lesser than 65 per cent, Category II lies between 65 to 85 per cent and Category III consists of more than 85 per cent of exploitation of the annual utilisable groundwater resources. In respect of quantity, India has a precipitation of about 4000 km3 but most of it is lost through evaporation, transpiration and surface flow and only 700 km3 can be put to any beneficial use. Taking into consideration all inland resources (rivers, canals, reservoirs, tanks, lakes and ponds, derelict water and brackish water), Orissa has the largest area of water bodies followed by Andhra Pradesh. According to the Ministry of Water Resources (MoWR) in 2001-02, nearly 25 billion cubic meters (BCM) was used for domestic, 460 BCM for irrigation and 40 BCM for industry purposes, in the country. Inefficient use and misuse of water in all sectors are the major problems in the country. State of Environment Report Maharashtra (Final Draft) Due to lack of education, awareness and civic sense and use of inefficient methods and technology, more than 50 per cent of water is wasted in domestic, agriculture and industrial sectors. Widespread water pollution and contamination is making much of the available water unsafe for consumption. Both negligence of authorities and lack of willingness of people are responsible for deteriorating quality of water resources. Due to inefficient work on operation and maintenance (O&M), inadequate quality and substantial leakage and unaccounted for water (UFW) levels are observed. While data on actual leakage levels do not exist in most cases, it is estimated to be in the range of 40 to 55 per cent. For example, as per studies by NEERI, the physical leakages in areas of Pune were found to be 43 per cent, while 6.2 km transmission lines in Kolhapur was found to be leaking at 17 locations, and Nagpur experiences 55 per cent of such leakage. In addition to water scarcity, quality of water is also to be considered relative to the proposed use of water. The release of domestic wastewater, agricultural run-offs and industrial effluents promote excessive growth of algae in water bodies, which result in their eutrophication. Further, these wastewaters containing high organic matter use up the dissolved oxygen (DO) in water resulting in oxygen depletion thereby threatening the survival of aquatic life difficult. Pathogenic pollution or microbiological contamination of water due to mixing of untreated wastewater is the main cause of disease and even mortality in India. Groundwater quality is also a serious issue as about 85 per cent of India’s population depends on it for drinking and other domestic uses. Leaching of toxic chemicals into the groundwater on account of contamination and over- exploitation is visible in many parts of the country. Status of Water Resources Safe and regular water supply is a necessary aspect of development process. Just as surface water is stored in the form of tanks, reservoirs, lakes within the river or drainage channels, groundwater is stored in the aquifers. This section describes the status of various surface and gound water bodies in the State. Surface Water Resources As shown in Table 2.1, the quantity of inland water resources in Maharashtra is about 3.39 lakh ha, which accounts for only 4.93 per cent of the total inland water resources in the country. Since the state has more than 9 per cent of the country’s population, it indicates that the per capita water availability in the state is lower than the national average. Rivers and lakes are the main sources of surface water in the State. Table 2.2 gives details of some major and minor river basins in Maharashtra. The water flow of two major river basins (Krishna and Godavari) in the state is below the national average. While the average annual surface water potential for an Indian river is 1869 km3/year, it is only 110.54 km3/year for the Godavari basin and 78.12 km3/year for the Krishna basin. With respect to the basin-wise ground water potential, total replenishable water resources are 40.65 km3/year for Godavari and 26.41 km3/year for Krishna (MoWR, 2003). 54 State of Environment Report Maharashtra (Final Draft) Table 2.1: Inland Water Resources in Maharashtra Water Resource Quantity Rivers & Canals (Length in kms) 16000 Reservoir (In lakh ha) 2.79 Tanks, Lakes & Ponds (In lakh ha) 0.50 Beels, Oxbow Lakes & Derelict Water (ha) NA Brackish Water (In lakh ha) 0.10 Total Water Bodies (In lakh ha) 3.39 Source: GoI (2004) Table 2.2: Major and Minor Rivers originating in Maharashtra Major Rivers Area Length (km) Catchment Area (km2) Godavari Nashik 1465 312812 Krishna Mahabaleshwar 1401 258948 Minor Rivers Vaitarna Nashik 171 3637 Dammanganga Nashik 143 2357 Ulhas Raigad 145 3864 Savitri Pune 99 2899 Sastri Ratnagiri 64 2174 Washishthi Ratnagiri 48 2239 Source: MSDR, 2005 Ground Water Resources Ground Water is the major source of drinking water in both urban and rural Maharashtra and also an important source of water for the agricultural and the industrial sectors. Water utilisation projections for the year 2000 put the groundwater usage at about 50 per cent. Being an important and integral part of the hydrological cycle, its availability depends on the rainfall and recharge conditions. Groundwater is used as an important supplementary source of water in certain parts of the MMR, such as Vasai, Virar, Bhiwandi, Kalyan, Ulhasnagar, Thane, Alibag, Pen and Panvel areas. The coastal areas of Vasai- Virar region have a large number of wells, which supply water for domestic as well as irrigation purposes. The rapid growth of urban development in this region and inadequacy of piped water supply has led to over abstraction of water from these wells. This has resulted in the intrusion of seawater into the underground reservoir affecting the quality of the well water. Apart from this, groundwater in certain parts of the region is polluted on account of microbial contamination and excess concentration of nitrates (MMRDA, 1995). The groundwater analysis of Mira-Bhayander Municipal Corporation (MBMC) showed that the water was contaminated or harmful to health, and hence, not potable (MBMC, 2004). In Navi Mumbai, the sampling revealed 55 State of Environment Report Maharashtra (Final Draft) organic pollution in well waters at Belapur and Shirvane necessitating frequent controlled chlorination (NMMC, 2004). Analysis of groundwater in Ichalkaranji indicates that the water at most places is hard. When compared with the WHO and ISI guidelines for drinking water, most of the tube well water is contaminated, hence, unsuitable for drinking. The groundwater in most of the industrial and residential areas of Ichalkaranji is highly polluted (INP, 2005) Rainfall Distribution of rainfall is highly uneven in the State. For example, while the Konkan region receives as high as 2500 mm; Marathwada receives lesser than 800 mm of rainfall, annually. The precipitation is concentrated between the months of June and September, particularly in the Konkan and Sahyadri regions. In Central Maharashtra, though the total precipitation is much lower, it is more widely spread over the months of June to October with a noticeable maximum in September.