Addressing issues of water scarcity and contamination of surface and ground water, AB Pandya, Chairman, Central Water Commission, paints a holistic picture and suggests remedies.
What are the challenges facing India´s water resources?
The pressure on our water resources is continuously increasing with the rise in population, urbanisation, industrialisation and due to threat of adverse impacts of climate change. India is facing many challenges in water that call for timely and effective redressal.
Although from a national viewpoint, average annual per capita water availability as in 2011 was about 1545 cum, which is above the internationally accepted standards of water scarcity (1000 cum per capita per year), yet many areas face scarcity. The situation is only going to worsen. The quality of water in rivers, other water bodies and underground aquifers is deteriorating day by day.
The condition with respect to management of supply of water resources is also not promising. Although India has made impressive progress in creation of storage since Independence, the ground situation is that India still lags several other countries in respect of per capita storage capacity. There is an urgent need to accelerate building additional storage capacity. There are about 4,900 large and several thousand small dams. Providing proper surveillance, inspection, operation and maintenance to ensure their safe functioning is a major challenge. Rapid pace of ground water development has resulted in over exploitation of ground water in many areas, affecting water quality.
Water use efficiency in almost all sectors, namely, irrigation, domestic water supply and industries is very low as compared to international standard. Efficiency in irrigation sector, which is highest consumer of water, is of the order of about 40 per cent in most of the surface irrigation systems.
In addition, issues related to management of water resources, namely, inter-basin and international coordination, water governance, financing of water resources projects, O&M of existing projects also pose challenges.
A recent NASA report shows a worrisome situation of ground water depletion for some states. What is the approach needed for these regions?
The Central Ground Water Board is assessing the stage of ground water development in the country at block level. Based on their assessment made in the year 2011, they have indicated that out of 6,607 assessed administrative units (blocks, Taluks, Mandals, or districts), ground water resources are over exploited in about 1,071 units (about 16 per cent). The over-exploited units are such where the stage of ground water development is more than 100 per cent and where significant long term decline of ground water level has been observed in both monsoon and non-monsoon period. 18 tehsils out of 27 in Delhi; 110 blocks out of 138 in Punjab and 172 blocks out of 243 in Rajasthan have been categorised as æover-exploited´ units.
It is mentioned that the ground water extraction in the states of Rajasthan and Punjab is mainly for the purpose of irrigation, whereas in Delhi it is mainly for the purpose of domestic and industrial water supply. Obviously, to improve the situation, a two pronged strategy involving both demand and supply side management is necessary. Demand side management is mainly effected by improving water use efficiency, crop as well as cropping pattern modification, etc. Supply side management is mainly effected by augmenting the water resources through water conservation measures, recycling and reuse, increasing surface water irrigation by creating more storage and inter-basin transfer of surplus water. The Central Government has adopted the National Water Mission, aiming to improve efficiency by about 20 per cent. The Ministry of Water Resources has also launched Jal Kranti Abhiyan, to be observed in 2015-16 to consolidate conservation and management through a holistic and integrated approach, involving all stakeholders, making it a mass movement.
What are some recent successful projects of CWC?
As per existing arrangements, responsibility of planning, development, operation and maintenance of projects has been entrusted to state governments. CWC has to play the role of advisor, coordinator, technology provider and to some extent, a supervisor in the sector.
CWC has made an excellent contribution in design consultancy to projects in India and in neighbouring countries. Right now, we are consultants to about 30 ongoing projects and 20 projects at DPR stage in India. International projects are Salma Dam in Afghanistan; Punatsangchhu Hydro Electric Project St-I and St-II in Bhutan and Pancheswar Multipurpose Project, Sapt Kosi & Sun Kosi Multi Purpose Project in Nepal. We are also conducting hydrological studies for water resources development projects in India and Nepal.
CWC operates a vast network of about 875 hydrological observation sites to collect hydro-meteorological data such as rainfall, runoff and temperature, etc., relating to major rivers. We have upgraded about 100 sites and added about 150 stations in the past two years. This is a step forward in providing a reliable data support for planning water resources projects and taking informed decisions of management of water resources. CWC in association with NRSC has developed and is maintaining a web-based GIS enabled system ´India-WRIS´ which provides comprehensive, authoritative and consistent data and information of India´s water resources. The system contains 12 major info systems, 35 sub info systems, having 95 spatial layers along with large attribute data of the water resources assets and temporal data of 5-100 years. Various studies, including ¨ILR Projects Planning for Mahanadi-Godavari and Ganga-Damodar-Subernrekhaö have been done in CWC using data from the platform.
CWC provides flood forecasting services at about 175 stations in all major flood prone inter-state river basins. CWC has launched a flood forecasting website for timely dissemination of flood forecasts. Hourly hydrographs of the last 72 hours are also provided on the site. The information is being used by various stakeholders like state governments, NDMA, SDMA, NDRF, etc., in advance planning for combating water related disasters. We are in the process of extending flood forecasting services to 100 more stations.
CWC is also playing a key role in ensuring dam safety. It has established a Central Project Management Unit for coordination of activities related to dam rehabilitation and is managing the Dam Rehabilitation and Improvement Project (DRIP) which envisages rehabilitation and improvement of about 223 dams within four states.
Arsenic, fluoride, iron and nitrate contamination of drinking water is a major health hazard in India. What can be done to rectify the situation?
The country is facing the problem of pollution and contamination mainly due to geogenic contamination, excessive use of fertilisers and pesticides and discharge of sewage and industrial effluents.
High concentration of fluoride in ground water beyond the permissible limit of 1.5 mg/l poses health problems. Studies conducted by CGWB have indicated that ground water in 224 districts in 19 states contains excessive fluoride content. Arsenic as a contaminant is significant in terms of its toxic nature with exceedingly diverse manifestations of poisoning. Elevated concentrations of arsenic in ground water are reported from various parts of India but particularly affecting the large parts of the Ganga-Brahmaputra plains. High concentration of arsenic beyond permissible limit of 0.05 mg/l in ground water has been reported from 86 districts of 10 states. High concentration of iron (>1.0 mg/l) in ground water has been observed in more than 1.1 lakh habitations in the country. Ground water contaminated by iron has been reported from 22 states and UT of Andaman & Nicobar. Excessive use of fertilisers and pesticides are not only contaminating the ground water but surface water as well. There is urgent need to formulate a detailed plan of action for water quality management by involving all the existing organisations and other stakeholders. The assessment of water quality situation is very important in this regard. At present, the network for water quality monitoring is being maintained by different departments and is also not adequate to provide the true picture of water quality in space and time. It sometimes leads to non-focussed approach and wasteful expenditure. There is a need to strengthen the monitoring network to acquire the data on existing water sources at micro scale. Further, a mechanism for sharing of data between various departments will have to be developed.
Various types of ex-situ removal techniques are available for adoption at household scale or community scale. Some of the options available for treatment are source substitution, coagulation, precipitation, oxidation, ion exchange, membrane filtration and adsorption. For addressing the problem of arsenic contamination, use of dug wells which are found to be arsenic free is a viable option. Further, providing drinking water supply from arsenic free deeper aquifers (hydro-geologically suitable ones) and surface water based supply can be adopted on a long term basis. The use of fertilisers and pesticides on sound scientific and agronomic principles will also help in reducing the extent of the problem. However, the success of any of the mitigation measures depends upon awareness creation and capacity building of the people residing in the affected areas.