L’expertise solidaire pour construire un habitat digne et durable pour tous




Report on visit of Leonardo Sibona - Civil Engineer (water supply specialist) who visited the village of Nayakarkuppam on June 27th/July 2nd - 2006

Introduction: site investigation

The village presented a gravity fed system which depends on two water tanks (already identified in previous report- bottom of tank at a height of 6m). The tanks are supplied by a pipework connected to a main water main distribution system located at about 8 km.
The habitants of the village have a supply of water which is limited to ten litres a week from the village tanks. The rest of their “needed water” is fetched on a water fountain located at approximately 1.5-2 km from the village. (Note: WHO standards suggest 25 litres per day per person as minimum standards. Other analysis prove that 15litres per day per person are sufficient)

The reservoir:

· The reservoir is located at approximately 3.5- 4 km from the village.

· It is of approximately 300 acres and having been rained over the past months it had more water than on the previous investigation.

· It is at the same altitude/level of the village.

o Consequently it is not possible, from design point of view, to consider any gravity fed system to supply water to the village.


Water Supply solution:

Below is a summary of the possible solution available to provide the village with a new water supply system. The solution below takes into account four main factors:

· Design/technical aspects
· Financial feasibility (capital investment)
· Future maintenance and repairs
· Added benefits to village and surroundings.

Summary:

1. a new connection can be made from about 1.5 km from the village. The location has been identified near the place where the habitants of the village are, to date, fetching the additional water required (1.5km from village).

2. the connection should be made into an existing water distribution system serving two water tanks. The water source for this system has been identified as the reservoir located at about an other 2.5- 3km from the connection.

3. the water for this water distribution is pumped from the reservoir through a suction pump located into pump motor room adjacent to the reservoir. (to be more precise there is a break tank/sedimentation tank inside the reservoir from which is pumped).

4. the pump is a single pump therefore it will require an additional pump to work in a duty and standby system. (The local president had suggested that they can provide the pump since they have spare one that they normally use when they need to do maintenance).

5. the pipework in which we should be connecting is a 4’ PVC pipe (these type of pvc pipe are used specifically for potable water and they are conform to the Indian standards requirements).

6. I am suggesting to use PVC pipes underground and metal GI pipes above ground:

a. The reason why we should be using the PVC are both technical and financial:
i. The soil in the area appears to be very rich in salts. This is most likely due to the fact that the area is very near the sea and it gets flooded by sea water several times during the year. This soil conditions are not suitable for GI pipes: they will have a high risk of corrosion.

ii. In addition the cost of PVC pipes (i.e. type FinOlex 4’dia 6kg/m -5-8mm thickness: the most renown company in India) it is half or even less than half of the GI pipe. The cost estimates are given in the attached Tables (Table A, Table B and Table C for detail design use).

b. The PVC pipework will be laid along the main road. Taking the pipe across the fields is not a suitable solution.

c. The GI pipe should be used where crossing water course, and should be supported on the underside of the bridge. The length of this section of work is approximately 100-150 meters. (Detailed information on the road will be sent soon from India). GI pipes should be used also where connection into the water-tanks are made.

7. IMPORTANT CHANGE IN TO THE DESIGN/PROJECT: Since the nearest village is located at only 600 meters from the selected village it was considered a feasible solution to extend the pipework and provide water to the habitants of this village too, since they have been found to be in the same condition of “shortage of water”.

a. The village is located along the main road and the pipework required is not greater than 500-600 meter of PVC pipes to connect into their closest water tank.

b. The benefits of connecting two villages to the new water supply system are considerably high: as well improving the living standards to more people, we have a greater number of people that in the future can contribute to the MAINTENACE and REPAIR of the system. With 600 meters more pipework we have shared the cost of 2100 meter of a water supply pipework system between 3000 people and not 1500.

8. WORKMANSHIP (manpower).
After a meeting with the president of the village, the president has guaranteed that manpower for the excavation works and laying of the pipework will be their contribution into the project.
i. Therefore the cost of the water supply system will be reduced, leaving more funds to improve other part of the water management. of the village such as:
1. looking into a solution for the aquifers which have become saline: reducing the saline level by injecting clean water:
2. try to use the small desalinization system donated to the village by a local company, to produce water for the irrigation or to inject it into the aquifers so that their water quality can be improved and the existing pumps reused.