By Bob Cairns
One of the major problems in providing clean water in Africa is keeping boreholes operative. In East Pokot, Kenya, 90% of the boreholes are not operative because of a lack of maintenance.
The Port Orchard Rotary Club in Aug and Dec 2016, enacted two major clean water projects, a rainwater harvesting system and a sand dam, that are theoretically sustainable forever. Both systems work on gravity alone and thus minimal maintenance is required. Additionally, these water projects avoid the problem of chemical contamination from boreholes drilled into the volcanic rocks of the Great Rift Valley. The water from boreholes has a high fluoride content and in some locations has 7 to 12 times the amount of fluoride recommended by the World Health Organization.
Borehole water is consumed by the East Pokot people because they are no other alternatives. Its consumption is readily evident by the heavily stained teeth. Borehole water is so contaminated that it can be classified as a poison.
A sand dam functions by constructing a concrete wall 2 meters high in a seasonal stream that gradually traps sand grains behind the dam. When it rains, then water is trapped within the sand grains creating an artificial aquifer. Sand dams have been known to last hundreds of years. Over time, the sand dam will function as a diversionary device creating a giant “sponge” of water in a perched aquifer. Shallow wells with hand pumps will be used to supply water to the people, animals and to a drip irrigation system. A 10,000 liter plastic tank will be used to gravity feed water into the drip irrigation system.
What adds some uniqueness to the project is that the pastoral Pokot tribe had no rules on how agriculture would be pursued on tribal lands. This is because almost all efforts of growing food in the past have failed due to the extreme dryness of the area and the ever-increasing drought conditions caused by Global Warming. Consequently, with water now available for irrigation, rules had to be established. For example, where do families grow their crops? Who gets the benefit of being closed to the sand dam? How big are the plots for each family? What crops are grown? How is the food distributed to those that are too old or frail to grow their own food? Without rules governing an area so water poor, serious conflicts are an ever-present risk where water is a life or death commodity.
Construction of the 18 meter long sand dam was labor intensive involving the mixing of 38 tons of rocks and 30 tons of sand with 310 bags of cement weighing 110 pounds each. Construction took 13 days involved primarily a 25 person team of young boys and girls. Over 100 people were involved if you include all aspects of the construction process. The dam was finished on Dec 22, 2016 and it was not expected to retain water till the seasonal rains start next May. It has not rained in East Pokot since Jun 16, 2016. As if a miracle occurred, 2 kilometers of water backed up behind the sand dam around Feb 11. The water came from a rainfall in Samburu, over 120 kilometers away. This water is sustaining a huge population of people and animals. People are coming from over 70 kilometers to obtain water at the sand dam.
The rainwater harvesting system was also selected because of its sustainability. Although the rainwater harvesting system will not harvest enough water to sustain the needs of the Pokot people, one of its components provides stability not present in other water sources. It has a 225,000 gallon concrete tank that can hold enough water to sustain the local people over long dry spells. The tank can be filled by either a Baringo County Water Truck or a water truck operated by a commercial entity. Because of the extreme demand on these water trucks during severe drought conditions, it is often not possible to get these trucks to supply the water when it is most needed. But if the tank is filled during low demand periods, it can sustain the local populace even though rain has not been used to replenish the water tank. Rain has not occurred in East Pokot since Jun 16, 2016 and having the tank with trucked water has proven to be a literal life saver.
Several unanticipated benefits of the rainwater harvesting system is that the canopy provides a basis for infrastructure improvements. East Pokot has virtually no infrastructure, i.e., buildings, roads, etc. The community now wants to build a Community Center under the canopy and also to use it to conduct meetings, religious services, etc.