Water shortage rained off!

Collecting water from the borewell
Gangibhai collecting water from the borewell which now yields water again thanks to the soakpits that re-charge the wells.
Credit: WaterAid / Somesh

In areas where water tables are falling, wells are drying up and groundwater is becoming a less reliable water source.

Libby Clarke explains how a drought-affected village in south India has overcome its water shortage by introducing rainwater harvesting and wastewater recycling.

There is a proverb, originating from Cameroon that says "rain does not fall on one roof alone."

For the villagers of Thanda in the Mahabubnagar District of Andhra Pradesh, southern India, this fact is very fortunate.

On the roof of every house in the village is a 'rainwater harvesting' system, waiting to collect as much precious rainwater as possible on the few days a year that it rains.

The system is very simple: water drains from the corrugated roof into a drainpipe, which feeds into a storage tank fitted with a tap. The water is then safely stored right next to the house ready for use whenever needed.

A REEDS sand filter
Sand filters, like these built by REEDS, clean the water as it flows from the roof.
Credit: WaterAid / Somesh

The villagers constructed the systems with help from WaterAid's partner organisation REEDS, after one of the two boreholes that REEDS had previously helped them construct dried up due to a fall in the water table.

The fall is attributed to increased water use by farmers in the area, who use electric pumps to extract excessive amounts of water from the ground, and by the altered weather patterns following widespread deforestation.

In much of south India there are now only 15-20  days per year of rain compared to 60 days previously. The total amount of rainfall has not fallen, but the fact it is now concentrated on fewer days makes it harder for the ground to absorb water, particularly where there are fewer tree roots.

REEDS have also helped the villagers of Thanda to construct simple drainage systems that collect the village's wastewater and channel it into a soakpit with a sand filter that feeds into an abandoned open well.

This has recharged the groundwater level and now both the borewells are yielding water again. The wells also have less chance of drying up as households also use water from their rainwater tanks and so don't need to take as much water from the wells as before.

The women of the village are delighted with the results. Prior to the installation of the borewells they had to walk for hours each day to traditional water sources to fetch water for their families, and when the borewell dried up they worried that they would have to revert to their old way of life.

Forty year-old Gangibhai is relieved that the rainwater harvesting and water recycling project saved them from this: "I used to spend hours walking in every direction from the village to collect water, and could only get four or five pots, which was the minimum my family needed for drinking. Now we are able to use four times as much water as before."

As well as rainwater harvesting and wastewater recycling schemes such as this, with WaterAid's support, REEDS is promoting recharge pits and watershed recharge programmes to help raise the water table in this area.

Both of these involve aiding the ground's absorption of rainwater: recharge pits are pits of loose, absorbent sand and soil, while watershed recharge programmes involve large pits being dug which stop the surface flow of rainwater and collect it in one place where it can slowly seep back into the ground.

REEDS is also separately promoting reforestation programmes, which should help both stimulate rain and help the ground retain water better.

Rainwater harvesting is not only a useful technology choice in areas where water tables are falling. It is also a good choice where groundwater is too deep or inaccessible due to hard ground conditions, or where it is too silty, acidic, contaminated with arsenic or fluoride or otherwise unpleasant or unfit to drink.

WaterAid promotes rainwater harvesting in a number of other countries, including Uganda and Ethiopia.

Read more about WaterAid's work in India

 

Rainwater harvesting: how it works
Falling rain can provide some of the cleanest naturally occurring water that is available anywhere.
There is considerable scope to collect rainwater when it falls, before it evaporates or becomes contaminated.
As WaterAid is concerned primarily with the provision of clean drinking water; the rainwater harvesting projects which it supports are mainly those where rain water is collected from roofs. Tiled roofs, or roofs sheeted with materials like corrugated mild steel are preferable, since they are the easiest to use and give the cleanest water.
The rainwater is collected in guttering placed around the eaves of the building and then runs down in to the storage tanks below. This pipe from the guttering needs to be able to swivel so that the first rains can be used to clean the roof without this wastewater flowing into the storage tank. Sometimes a filter is fitted as well.
The storage tanks used vary from small containers for domestic storage to large tanks for schools, clinics or other institutions with large areas of roof.
Tanks for domestic use can be made cheaply using local materials like plastered bamboo baskets or clay pots. For example in Thanda, the tanks were made from a stack of concrete rings which were cemented together to form a round tank.