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(The Gist of Kurukshetra) WATER SECURITY AND SUSTAINED DRINKING WATER SUPPLY [JUNE-2019]

(The Gist of Kurukshetra) WATER SECURITY AND SUSTAINED DRINKING WATER SUPPLY

[JUNE-2019]

WATER SECURITY AND SUSTAINED DRINKING WATER SUPPLY

Introduction

As India is a vast country the challenges related to drinking water in rural regions would be unique for different regions. India receives an average annual rainfall of around 1100 mm but there is a huge regional and temporal variation in the distribution of rainfall.
The country receives more than 80 per cent of the rainfall from June to September. The unequal spatial distribution could be easily observed by the fact that the Brahmaputra and Barak basin, with only 7.3 per cent of the geographical area and 4.2 per cent of the country's population, have 31 per cent of the annual water resources (CPCB (2014) States of Water Quality in India). Across the year, it could be found that one region is facing floods while some other region is having drought at the same time.
This shows the diversity in rainfall pattern across the country. Also, the same region might experience floods followed by droughts during different months in a year. Over-reliance on centralised systems and insufficient attention towards traditional water harvesting systems and disconnect of the community from water management is one of the major cause of such situation.
Groundwater (GW) which is currently the lifeline of Rural India, as it supports more than 85 per cent drinking water requirements in rural areas, is depleting at an unprecedented rate. Overall, India in real sense is mining groundwater and is way ahead, in terms of total groundwater withdrawal, of various countries.

Drinking Water Situation in Rural India

Rural regions in India, which primarily have agricultural and domestic water requirements, suffer from many challenges such as water pollution and decreasing groundwater availability, etc. Arsenic and Fluoride contamination is very high in some of the regions of the country. National Rural Drinking Water Programme (NRDWP):
It is a Centrally Sponsored Scheme launched in April, 2009 aimed at providing every person in rural India with adequate safe water for drinking, cooking and other domestic basic needs on a sustainable basis.
Historically, communities in India managed water and had their unique mechanism of fighting climate extremes. Due to different topography and agro-climatic conditions, various regions in India had different structures to utilize and conserve water. Broadly these practices could be classified into the following three categories:

Obstructing/diverting the flow of stream/river: In this practice, the natural flow of the stream/river Is obstructed and water is stored by using gully bunds/check dams/gabion structures etc. Prominently built in hilly regions, these structures in addition to water conservation and groundwater recharge, also act as soil trap.
Storage in wells/step wells/below ground level storage structure: Mainly used to meet domestic water requirements, such structures could be found in western arid regions of India. The step-wells traps rainwater and because of no direct exposure to sunlight and surface temperatures it reduces evaporation losses. These were treated as auspicious as temples in Gujarat and Rajasthan.
Collection and use of rainwater on surface: Commonly found across India, these structures are constructed in the flow of a seasonal stream or the excess runoff is diverted into this. Some examples of such structures include nodis, kundis, talabs, jaldhar, farm ponds etc. The bottom of the surface is generally pervious but it could be made impervious using plastic sheets to prevent GW recharge.

Drinking Water Treatment

While the quantity of water is generally considered as the parameter to define access to water, however, understanding the quality of water would be necessary to provide clean and safe water to rural households. The choice of treatment technologies would be largely determined by the quality of raw water and the nature of demand. Few of the basic water treatment technologies/methods are discussed below:
Slow sand filters (SSF) - SSF is one of the most recommended methods of water treatment for rural areas. If designed properly, it purifies the water efficiently by reducing turbidity and bacterial contamination and it does not require highly skilled labour for operation and maintenance.
Chlorination - Disinfection using chlorine has been a common practice in various water supply systems. Being a strong oxidant, chlorine is used to remove taste and odour, as well as biological contamination. It can be used for community water supply system as well as at the individual household level.
Solar Disinfection (SODIS) - The SODIS method utilizes solar energy for water disinfection at the household level. A clean and transparent PET plastic bottle (preferably below 2 litres) is filled with water and kept in direct sunlight for 6 hours during noon on sunny days and two days if the sky is more than 50 per cent clouded. It has no chemical and external energy requirements thus making it an affordable choice. As reported, it removes 99.9 per cent of micro-organisms. The major limitations are that the raw water should not have turbidity more than 30 NTU and there is sufficient sunlight available.