Water harvesting pans for dry areas
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CTA. 2007. Water harvesting pans for dry areas. Rural Radio Resource Pack 07/1. Wageningen, The Netherlands: CTA.
Permanent link to this item: http://hdl.handle.net/10568/57395
Pans are a simple method of storing water, particularly relevant for livestock farmers in arid areas.
Cue: In the dry parts of northern Kenya, water is very scarce, and harvesting rainfall is essential for communities to survive. Tribes in this area are livestock keepers, and harvest water for themselves and their animals. One of the most common water harvesting structures is called a pan. Pans are ponds dug in the ground, usually 2 to 4 metres deep. They can vary in size, with large ones being as much as 200 metres long, and smaller ones being only 10 metres square. Pans are dug in low-lying land, normally in flat areas. They collect water from small streams and rivulets which flow over the surrounding land during rainfall. The NGO Action Aid is currently working in 20 districts in Kenya, helping people there to access clean, safe water, and to reduce the amount of time that villagers must spend collecting water. Part of that work involves helping communities to dig new pans, and to restore pans that have been lost to siltation. Siltation occurs when a pan fills with sand and mud, perhaps because of flooding or poor maintenance, reducing the amount of water that the pan can hold. Yusuf Artan, an engineer with Action Aid, spoke to Winnie Onyimbo about their work, and began by explaining how the pans are actually excavated, or dug. IN: ?The pans are either excavated by machine?? OUT: ??thing could happen in that area.? DUR?N: 5?48? BACK ANNOUNCEMENT: Yusuf Artan, an engineer with Action Aid, describing work in northern Kenya which has used rainwater harvesting to bring clean, safe water to livestock keeping communities. The interview comes from a radio resource pack produced by CTA. Transcript Artan The pans are either excavated by machine, or they can actually be excavated hand dug. Some of them are big, some of them are small. You can have a pan of 10 metres by 10 metres square; that is actually about 200,000 litres of water stored in that pan. The design is simple. It has to have an inlet, and after the pan has filled we try to make sure that the water does not come out. And in case there is excess, we have a spillway where the excess water can flow without actually affecting the pan itself. Onyimbo What are the benefits of the system? Artan The benefits of the system, first of all, is that they are simple to construct. The communities themselves can actually come together, do the excavations communally. It does not require a lot of technical expertise. It is just by observation that actually you can see that we can have this. The community themselves have been doing that for quite some time. Onyimbo And what kind of crops does this system support? Artan In the drier parts of the country the cushitic people actually don?t grow any crops. They use it for livestock purposes, because livestock rearing is their main means of livelihood, and it is very important to them. So the livestock themselves get water from that area and the human beings also, they get their domestic water from those pans. Onyimbo What challenges have you faced in building and maintaining the physical structures? Artan Some of the challenges we have faced with pans is they are actually open to the air, and due to the high temperatures, the rate of evaporation is quite high. So as much as possible we try to dig pans which are deeper, so long as the bottom of the pan is actually not pervious, and we don?t have seepage of water to the ground. And in areas where we find the seepage is quite high we try to use clay; either we import or we get clay from the neighbourhood, simply to make an impervious layer. Another challenge that we face also is mobilising the community to understand that we need to control that source of water. Because in most of the pans that you visit, the animals, the human beings all take water from that pan, where they actually just go into the pan. So the issue of hygiene is quite a problem. Onyimbo What kind of challenges do you face in terms of the environment? Artan First of all is the invasion of the water catchment areas by human beings. That is quite a challenge, that we see a lot of depletion of forests within the country, simply because of the explosion in human numbers. The other challenge we are also facing is that ground cover is actually being depleted in most of the areas, either through over-grazing, especially in the northern part of the country. And we find that the water structures, the pans that were there, one of the biggest challenges is actually siltation, and siltation is simply because the surface waters carry a lot of silt, that is sand and mud, to the pans. So with time you find these pans are actually slowly filled up by sand, thereby reducing their capacities. And that is actually one of the biggest challenges we have been facing in that area. And hopefully if we can involve the communities more in terms understanding what are the causes of siltation, building silt traps and ensuring that the catchment areas, the bushes and the grass and everything are not depleted, they will actually be able to link siltation to actually conserving the environment. Onyimbo What is the role of the community in managing the system? Artan One of the projects we have been doing is Takaba community water supply project. This is a project to supply water to the people of Takaba and their environs. The project was started in 2004. The project entails construction of about 3 pans, and joining them together, and the water is pumped to the top of a hill where it is filtered and distributed to the communities. The role of the community in terms of this project is that actually it has been from the beginning, where we actually have been doing the consultations with them. They were actually involved in the design itself. It was taken back to them, they validated the design. And they have also been doing the supervision of the works by the contractor. Because we believe that the inclusion of the communities is very important in management of water resources. Because a water project which the communities have not been involved with will not be sustainable in the long run. Onyimbo So how is the response from the community? Artan The response from the community initially is that they could not, first of all, believe it. The design itself was a little bit quite foreign, because we were trying to link up three dams and people were to get water from communal water points, or kiosks. And the communities there are used to getting water from the pans themselves, where actually the animals and the human beings, all of them go to the pans to get water. But what we are trying to do is we are trying to improve on the hygiene and to have water which is not actually contaminated. So we are distributing this water at communal points. And initially there was sort of some sense of disbelief that actually this system might not work. It has never been seen within that area. But eventually when they saw water coming out of the taps, there was actually a sense of happiness, there was joy and there was a lot of thanksgiving to the almighty, that actually such a thing could happen in that area. End of track.