Construction Time!

Weeks 11 - 13 in INTAG

After 3 weeks of finalising designs and getting hold of materials we are ready to begin on the construction works in Limones and Villadora. A new elevated water tank will be built at the school to provide a guarantee supply of water where a lack of pressure and intermittent supply has been a continued problem. Up at the sources, improvements to one of the spring captures will be made to provide a cleaner and safer supply of water for the two villages.

holhola
Site Office

Construction begins at the school. Eva and Tom set up their site office next to the school buildings as materials arrive: the 2,500 L Rotoplas tank along with formwork, rebar and pipework. Meanwhile a "minga" (community work day) is arranged to deliver the bulk materials down to the remote spring capture site. Young and extremely fit community members make impressive work of carrying down the laden bags of sand, aggregates and cement to the spring site. Materials that will form the new spring capture boxes.

Material Delivery

holh

Elevated Tank Construction

At the school the "maestro" (construction foreman) and his team quickly get to work on preparing the structure's columns. The structure will be 4.2m high to ensure that a sufficient flow rate can be provided to the furthest most taps across the school.

holahola

Rebar columns are created at an impressive speed, and formwork is put in place, ready for the concrete pour. Demonstrating their ingenuity the maestro's use only a small array of simple tools to carry out the tasks required.
holahola

A carefully fastened scaffolding frame of bamboo will serve as a working platform for finishing the pour to the coluimns and forming the base slab that will support the water tank.

After only 5 days working on site formwork and reinforcement is being completed for the tank's base slab.

The Tank Structure Takes Shape

From (left) finishing the pour for the concrete colums to (right) installing perimeter fencing to the tank's slab, with the rotoplas water tank in place on top of the finished tructure. Supporting formwork will be kept in place for a good 3 weeks after the pour to ensure the concrete has reached its fullest strength before taking the full load of the tank. With mostly sunny and hot days during the construction period we were very thankful for the evening of rain on the day the tank's base slab was finished, so that the slab could be kept cool and watered: perfect weather for curing concrete.

holhola

Pipe-laying: Community Work Force

The parents of the children attending the school were on hand to provide the labour required to connect the new tank into the network. Working as an efficient unit it wasn't long until trenches and pipes had been laid to both connect in the new tank and remove a damaged and leaking length of pipe across the playground area. The completed tank can be seen in the background (right).

holholahol

At the same time a soakway is dug and backfilled with rocks brought up from excavation work at a mining area only a few minutes from the school.

All Hands on Deck! Tank's Pipe Connections
holahola

On the last day of construction at the school it was non-stop working to get the new connections made to the tank before night fell. The aerial shot below shows finishing touches being made to the valve chamber that will allow the school to the option of using just the tank, or taking water directly from the network when pressure in the system is sufficient.

h

The maestro heats the end of rubber hose pipe (mangera) to make the final connection from the network into the entry pipe up to the tank (top right and below left) whilst the operator of the system uses his "roscable" kit to make screw end fittings for the pipework (below right).

holahola

With the final connections made and the tank "on-line" by the end of the day, it was only left for a nervous wait through the night until we could see if the tank had filled and would do its job.

Early the following morning the walk up to the school was made in silence, a mixture of nerves and excitment at what we would find. Eva scaled the steps up to the tank and removed the cover and greeted with me with exclamations of "It's full! It's full!". The pressure within the network during the night was sufficient to fill the tank. Despite our calculations showing that this would be the case we still needed to see this with our own eyes to be rest assured it had worked.

Flow measurements around the school showed desirable flow from taps at the furthest point away from the tank demonstrating that the tank is fit for purpose. After months of planning and preparation it was with great relief and satisfaction that we could see the tank working as planned. The operator of the system summed up our experience by saying that "at times the works have been stressful, at times a lot of fun and in the end we have reached success".

Spring Protection

In the last week of the construction programme, works moved up to the remote spring - nearly 3 hours walk from the operators house and still a 30 minute hike down from the nearest road. Getting materials to the site has been one of the trickiest part of the construction programme. With the corrobation of the community members and finding a mule and a horse the remaining materials could be brought down to the site to complete the works.

In the photos above, (first) the spring eye is being diverted so that work can be carried out around the eye. In the same picture a diversion channel can be seen on the right hand side. This is more clearly shown in the photo (second). A retaining wall above the eye will divert any surface water from entering the eye, with run-off being by-passed through the channel. One of the key aims of our work was to provide a spring capture that only took water directly from the eye, and made the separation between spring water and surface water. As we'd seen at the existing spring capture that took water that had already ran over ground, any surface water is more likely to be laden with sediment and have a greater risk of carrying contaminants into the captured water.

In the photo above (second) the finished spring box is being covered with a layer of plastic sheeting, which will provide another barrier against surface water entry.

Sedimentation

Below, Eva explains to the "maestros" the dimensions required for a sedimentation tank that the pipe from the new spring box will feed. On first observations it appears that the direct capture from the spring eye is sediment free, and that by having protected the spring there will be little need for sedimentation. However, the tank will provide a inspection chamber and the ability to remove sediment should this become a problem.

Below the maestros make the finishing touches to the sedimentation chamber, with an internal waterproof finish. Working up at the spring has been a challenge due to it's remote location within a narrow valley surrounded by thick vegetation and an ever quickening muddy ground. However only 2 and a half days are required to compelte the works at the spring.

Meanwhile the operator begins to investigate a potential third source of water to the system, amid concern that the supply of water for the future needs to be gauranteed. From our observations we learn that in the minds of the people here it seems to be that "clean water" is one free of sediment, with little consideration given to further treatment. Before our time working in Limones and Villadora comes to an end we intend to obtain water samples of the sources currently in use and envisaged, with the hope of opening up the debate of what is "clean water".

holahola

As we reach the end of the construction period we relfect that the past few weeks have been the most demanding period of our time here. Eva describes the time on site as a "rollercoaster", moving from excitment at seeing our designs take shape to frustration over missing materials, delays to the work and at times a struggle to get the finished result that we want if this method seems more work than the team of maestros had envisaged.

holahola

The early morning hikes up through the mist in the fresh country air will be missed, as too the chance to learn firsthand on a busy construction site.