Archive for April, 2014

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Towards a water sensitive city

April 23, 2014

 

The imagination of water in a city should not be limited to its delivery and withdrawal in pipes alone. A good water management plan would mean and include the many roles of water such as the spiritual, the cultural, the ecological and the recreational in addition to the functional..

In the hierarchy of the development of water infrastructure in a city there is first the arrival of piped water supply. Drainage and sewerage follow after some time.  The city then starts to understand and manage its surface water like lakes, rivers and canals. Attention then usually shifts to groundwater management. If all this is done  and fountains dot the landscape , where rivers and lakes become clean and spots of recreation and where all waste-water streams are managed the city starts educating its citizens especially its young ones on water and spreading water literacy. This city can be said to have become water sensitive. Singapore comes to mind as one such city. Stockholm and Oslo also manage their waters accordingly and celebrate it. Seoul is getting there or nearly there. We in India are on the painful ladder and it will take time but the vision has to stay firm. Of course in a water sensitive city all citizens will have equal access to the resource and there will be no deprivation and appropriation of the commons.

In Coimbatore through a citizen government partnership the Big Tank the Ukkadam was de-silted and made ready to receive rainwater which it has collected in plenty. In Dindigul de-silting has begun of the old tank. In Karnataka State ,  Tiptur has refurbished and improved a large tank so have the towns of Sira and Tumkur.

In Bangalore the Bangalore Development Authority has invested over Rs 110 crores in improving over 14 tanks. Of these tanks Jakkur in the Northern part of the city seems to offer a potential comprehensive role of creating a water ecosystem which fits the role of what a water body can do in a city – as they say to function as its kidney.

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The vast water spread of Jakkur Tank

The tank itself was a beautiful irrigation tank with a command area which grew paddy. As the city has caught up the role of the tank has now changed. There is a wetland on the upstream end which receives water from a waste-water treatment plant. The wetland further purifies the waste-water . The tank itself with a water spread of 53 Hectares is full and harbours lots of fish. Birds nest and a virtual array of them can be seen during the year.

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Treated Waste-water comes in to a wetland

The tank has recharged groundwater in the surrounding areas and the some of the remaining water heritage of the city – the traditional wells- are full to the brim. Boys learn to swim in one of them. Another well is used for large scale irrigation of coconut and banana plants. The tank has a place for immersion of Ganesha idols in one place. Storm-water inlets to bring in rain when it occurs have well designed silt traps to allow only water to come in and not debris and solid waste.

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Full wells – thanks to a recharged aquifer

The tank ecosystem fulfills many a function, from the ecological, to the cultural and spiritual, from the educational to that of recharge and many more.

This is truly a microcosm of what is called Integrated Urban water management in practice. Here we see the transformation of waste-water through a physical process of treatment followed by a biological process to drinking water.

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Fish feeds the city with proteins and provides livelihood to fishermen

Water in a city is much beyond what flows in pipes. If designed and managed well it can enhance and provide for the needs of nature and man in myriad forms. The Jakkur Lake should be managed well so that it becomes a living lab for our citizens to see and learn how urban waters can be managed. This experiment can then be repeated in most other tanks of the city and also in other cities. Bangalore has been a pioneer in many ways to urban water management. Can it take a lead in this one too? In that would lie water wisdom.

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Dealing with defunct borewells

April 20, 2014

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It mostly takes a tragedy for us to act as a society. It is possible that India has about 30 million bore-wells, the worlds largest number. The drilling of bore-wells is a flourishing industry where greater and greater depths are recorded but more significantly from a safety and security point of you the diameter of drilling is increasing. From once what was an innocuous 4 inches of diameter, boreholes now are typically 4 ½, 6 ½ and even 10 inches in diameter.

With a complex hard rock structure in the Deccan Plateau and a depleting water table many bore-wells fail to strike water. Some go defunct when the water is extracted and the level falls below the bore-wells. These bore-wells have to be treated with great care else they can become the spots for accidents. Young children falling in, is a serious cause for concern and action.

Recharge: No defunct bore-well should be left unmarked. A bore-well which yielded water and is now dry can become a great source for recharging the aquifer. A clean and sufficient catchment for run-off is a must. The water is then lead to the Borewell around which 3 feet to 5 feet diameter recharge well is dug. The well is lined with concrete rings and can be filled with filter materials or even left without it. Holes are then drilled in the casing of the bore-well and wrapped with a mesh to prevent grit from falling inside. Rainwater and storm-water is directed to the recharge well, filtered and allowed to flow into the casing to recharge the groundwater.

Making a recharge well around a defunct bore-well. Safety should be a concern.

 

Rooftop rainwater can also be led into these defunct borewells again after making sure that the rooftop is clean and ensuring filtration before the water is led in to the Borewell.

Care should be ensured that no polluted water gets in. Care should also be taken to ensure that the electric connections are dis-connected and also that the cover on the recharge well is solid, heavy and not likely to cave in.

Failed borewells: Similarly, in the case of a failed Borewell the tendency is to recover and salvage the casing pipe inserted into the drilled hole. At this instance it should be mandatory to fill up the hole with earth so that there is no chance of an accident. Responsibility is jointly that of the owner of the land where the Borewell is being drilled and that of the drilling operator. A code of procedure should be followed to ensure safety at all times.

Borewells are the lifeline of India , providing water for irrigation, industries and domestic use. Making safety a top priority in the drilling and managing of live and dead borewells is a prime necessity of the times. Developing safety protocols and ensuring that they are applied is a step towards water wisdom.