Holes in the pipeline!
The Centre for Science and Environment (CSE)'s Excreta Matters brought together, for the first time, a wealth of data providing a comprehensive overview of the current situation of water supply and its distribution, generation, and disposal of sewage, problems of finance and management, and strategies to meet the growing demand in 71 cities and towns across India. It highlights critical deficiencies in all these aspects, the need for a major reorientation of strategy and policies to address them, and, the key issues that need to be addressed in the process.
While issues have been brought into focus, the data that have been collated and analysed, mostly relate to public water supply and sewage disposal systems. Information on their operational efficiency, the contribution of private sources, actual water availability at the users' end and the purposes for which it is used, are of variable coverage and quality. In many cases, it is not available at all.
Conditions, problems, and potential solutions vary widely across cities and towns. It is important to have a fuller and more detailed, location-specific assessment, of sources and uses of water; the relative roles of public systems and the private sector in organising and managing water supply for different uses; technical aspects of design and functioning of water treatment and distribution; volume of sewage generated, modes of its treatment and disposition; and, financing of investment and operational costs of water supply. We need to examine strategies which different cities and towns have adopted to meet growing water demands, their actual contribution to augmenting supply relative to assumptions/expectations underlying their design, the technical, organisational and managerial factors that affect the efficiency of their performance. All this requires considerable further work both for filling in significant gaps in available data, and for systematic analytical research.
Sources and uses of water
Water supply in urban areas is met partly by public systems and partly, by the private sector. Both draw their supplies by drawing water from streams, natural and human-made surface storages and groundwater located within the boundaries of their respective municipalities.
Increasingly, from one or more of these sources located outside, often at considerable distances. In many cases, supplies for urban use draw upon sources meant for agricultural purposes. The relative importance of these different sources varies across towns and also changes over time.
Water supply from public systems
Currently, all we have is an estimate of the total volume of water supplied through public systems, with some approximate break up between surface and groundwater and, in a few cases, between local and external sources. When water is brought from outside sources, there are losses in the course of conveying it, so the volume that reaches the town is less than the volume drawn at the source. This loss, which increases with distance, needs to be taken into account.
Though estimates about the capacity for supply and of volumes supplied are available for public systems of cities and towns, several aspects of the basis of this estimate need to be clarified. For instance, it important to know not only the total volume of supply available to each system, but also of the contribution of different internal and external sources, and the extent to which these are measured, the basis on which these are estimated and how these can be improved.
It is important to document the methodology of these estimates, measuring devices used, the frequency of measurements and maintenance of records. We must also note the availability of measurements/estimates for the last decade or two. We need to take into account where water from all sources pass through water treatment plants before feeding into the distribution network, and whether metered measurements at the main distribution points provide a reliable estimate of the total volume of water supplied by the system. When a system gets supplies from multiple sources, we must account the basis and procedures to estimate the actual contributions of each regarding quantity and period.
Systems may draw and distribute water from wells/tube wells or waterbodies within their boundaries to particular localities without passing through water treatment plants. How they are estimated and whether these are included in estimates of total system supply needs to be clarified.
The volume of water actually received by public systems from different sources and volumes they feed into the distribution network varies between and within seasons. Both receipts and distribution must, therefore, be based on the sum of daily/weekly measurements of their respective actual volumes. These can be worked out from records that need to be maintained by system authorities.
In most cases, estimates available relate to the current or a recent year. To better understand the magnitude and sources of expansion in supplies over time, we need estimates of source-wise supply over, say, the last decade or two.
(The writer is one of India's leading scholars on water. Views are personal.)