Frederick Noronha on Fri, 12 Mar 1999 21:19:58 +0100 (CET)

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<nettime> Software for the poor...


In Rajasthan, voluntary agencies have worked out a new software program
which will help villagers predict their drinking water supplies, and
remind us of the receding dream of providing every human being with a
reliable and safe source of water. 

By Frederick Noronha <>

Rural India's developmental efforts could get an unexpected boost from the
software field. To kick-off such attempts the first program of its kind
has just been launched by public-spirited citizens, which offers to
simulate the performance of rainwater collection tanks. 

Called SimTanka, this free computer software is meant at simulating
performance of rainwater harvesting systems with covered water storage
tanks under the influence of a fluctuating rainfall. Such systems are
called Tanka in the western parts of Rajasthan. 

Western Rajasthan -- the region's inhospitable desert tract -- is known to
have once had prosperity, wealth and habitability in medieval times. This
is believed to have been based on the extremely sagacious use of its
natural resource base, which has got badly eroded over time. Now, the
search is on for a software fix which could help offer a solution. 

"Traditional water harvesting techniques have been severely eroded, thrown
into disuse and even eliminated in most parts of the country," warned a
citizens' report on the state of India's environment, brought out by the
Centre for Science and Environment in New Delhi recently. 

Most desert-tract villages have small ponds, which gave them enough
drinking water for upto eight months in a good season.  Villages also have
used 'tankas'. These are circular holes in the ground lined with fine
polished lime ('chunam'), in which water was collected during rainfall and
used only when other supplies failed. 

Using computer simulation, this software will predict the performance of
this rainwater harvesting system, based on a mathematical model of the
actual system. SimTanka simulates the fluctuating rainfall on which the
water harvesting system relies. 

Rainwater harvesting system are often designed using some statistical
indicator of the rainfall for a given place, like the average rainfall.
When the rainfall is meager and shows large fluctuations -- as is the case
in India's desert tracts -- then a design based on any single statistical
indicator can be misleading. 

But SimTanka takes into account the fluctuations in the rainfall, giving
each fluctuation its right importance for determining the size of the
rainwater harvesting system. 

"The result of the simulation allows you to design a rainwater harvesting
system that will meet your demands reliably. It lets you find the minimum
catchment area and the smallest possible storage tank that will meet your
demand with probability of 95% in spite of the fluctuations in the
rainfall," says Vikram Vyas of The Ajit Foundation in Jaipur, which
developed this software. 

You can even use SimTanka to find out what fraction of your total demand
can be met reliably by your system. 

SimTanka uses the rainfall record of the immediate past, say last fifteen
years, to obtain probabilities of the future rainfall. Simulation results
give a guideline based on past rainfall record, not a definite prediction
of future performance. 

SimTanka needs at least 15 years of rainfall record for the place where
it's being used. If not available, then rainfall records from the nearest
place which has the same pattern of rainfall can be used. It has an
included utility, RainRecorder, to enter and updating the rainfall data. 

"SimTanka is free and is being developed by the Ajit Foundation in the
spirit that it might be useful for meeting the water needs of small
communities in a sustainable and reliable manner,"  added Vyas of The Ajit

SimTanka runs on Windows 95. Copies are available by simply sending in
three 3-1/2 inch floppies to Vikram Vyas, The Ajit Foundation, 396
Vasundhara Colony, Tonk Road, Jaipur 302 018 India

Vyas, announcing his plans this week to members of the not-for-
development community, welcomed collaboration from those working on
similar projects. His next model will aim to simulate rainwater harvesting
systems with open storage tanks, and is tentatively named SimTalab. 

Vyas told this correspondent: "The dream of providing every human being
with a reliable and safe source of water seems to be ever receding. In
pursuit of this vision the traditional rainwater harvesting systems, as
developed in the arid and semi-arid regions of India, have an important
and unique role to play." 

Such systems, feels Vyas, can provide water in a "sustainable and energy
efficient manner". In spite of all these advantages the use of these
systems have declined. Besides other reasons, one serious technical
shortcoming is these systems are unreliable, being dependent on a meager
and fluctuating rainfall. 

To seek a solution, this computer-based approach tries to meet the
villagers' demand with as much as 95% confidence. 

Primary users of SimTalab and SimTanka are all individuals and
organizations -- governmental and non-governmental -- involved in
developing water resources for rural communities. The software SimTanka
and SimTalab will also be useful to organization funding the development
of traditional water harvesting systems. (Third World Network Features)
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