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Project Proposal: Rain Water Harvesting

Full description of problem/need

Pabal and its surrounding area experience a lack of water typically between the months of February and May, though recently drought conditions have arrived as early as October (creating an 8 month dry period) if a poor monsoon season occurs. There is a scheme under construction to provide a year-round supply of drinking water to Pabal and its surrounding area which is due for completion at the end of 2005. However, the success of the scheme is yet to be seen and any additional moves to help gain a more reliable and plentiful water supply would be beneficial.

A method of rainwater collection and storage for home or community use could help to alleviate the water shortage problem. Ideally the water would be best saved for the dry session. The solution must be low-cost, sustainable and utilise locally available materials and skills.

How will the local community use the proposed solution?
The solution would compliment the drinking water scheme and ensure the reliability of the water supply. The harvested water could be used for a vast array of purposes, from domestic to small-scale business use. Perhaps it could also be used for drinking if it is of a suitable standard. The system would operate on a home or community level.

Estimate of the economic benefit anticipated and plans for training of the local community? What are the major impacts on such a project?
A more reliable water supply is likely to promote sustained growth of Pabal.

During the rainy session the consumption of water per person increases twofold compared to that in the dry session. Any solution should take into account that water use increases with availability.

Any proposed solutions would be trialled at Vigyan Ashram and should be easily maintainable.

Full description of the local situation (e.g. social, economic, geographical, political)

Water consumption in the rainy session is approximately 100-120 litres per person per day for domestic use, and between 30-800 litres per day for business use. The business figure is solely from local businesses from the central area of Pabal (e.g. café, laundry, mechanic).

Collection of water in the Pabal area is predominantly from wells. Rainfall is absorbed into the soil and groundwater flows travel and fill the wells at lower elevations. No filtering of the rainwater occurs other than through the percolation of the water through the soil. Wells are abundant and are the primarily source of water. A significant proportion of houses in Pabal have their own well and more remote settlements have wells nearby. There are town wells for communal use.

Drought occurs in the dry session, which last approximately 8 months (October - May). In this period the wells in the region run dry and water is trucked in by the government. Large tankers deposit 12,000 litres of water daily into Pabal's town well. This supply is frenziedly emptied from 6:45am and is gone in 20 minutes in a first-come-first-served basis, water then goes on resale in the village for 2 Rs. per 15 litres.

There is a storage tank in Pabal that is used on a regular basis. When there is water in the well naturally it is pumped into the storage tank and from there pipes take the water into people's homes (or at least to the homes of those with running water). The running water is available for 20 minutes in the morning, so most people fill up barrels during those 20 minutes and use stored water for the rest of the day.

There are no efficient home rainwater harvesting schemes at present; collection in pots and pans is the only benefit derived at the home level, though it does show the attitude of rainwater harvesting is present. Some examples of small-scale dams for agricultural use exist; these are constructed to promote absorption of the rainwater into the soil. All the methods documented involve the same concept; rainfall is captured with the intention of allowing it to absorb into the soil.

Agricultural damming

Full description of relevant infrastructure available locally and/or internationally

There is a drinking water scheme due for completion at the end of 2005. This project is a large-scale dam with the intention of providing a year-round supply of drinking water. The completed dam captures rainwater and allows it to absorb into the soil, increasing the water table in the area and preventing wells from running dry.

There is a large well nearby that is filled via groundwater flow; this dam-site water will be pumped to a 170,000 litre tank which is under construction (as of 21-July 2005) close to Vigyan Ashram. The tank is elevated in relation to Pabal and most of its surrounding area, allowing water to be piped to Pabal by utilising the height difference.

170,000 litre water tank at Vigyan Ashram

Dam near Pabal

Individual connections to the water tank will have a one-off connection cost of 3000 Rupees then a 700 Rupee per year charge. Combined connections will be available at 1200 Rupees one-off cost.
If people do not wish to connect to the tank, the increase in groundwater is intended to better guarantee the water supply from their nearby well. Finance for the drinking water scheme was 90% German and 10% local input.

Space is limited in the centre of Pabal. Houses and other buildings are tightly packed next to each other, but small external spaces are commonly found within the house layout. Traditionally constructed housing has wooden frame roofs with ceramic tiles on top. Modern constructions are reinforced concrete with perhaps a corrugated metal roof or a concrete one. In both cases guttering on the building is not standard, and was observed on few occasions in and around the local area. Town-scale guttering was evident in some areas in the form of dug trenches on the edges of the roads.

© engINdia 2005