Sunday, November 23, 2008

Harvesting Rain Droplets in Bisate Village

Bisate, a rural village in Northwest Rwanda, is located in the volcanic region below Bisoke volcano. The fertile soil and abundant agriculture products in Bisate have attracted many people to live in the area. The Bisate population has greatly increased since the 1970’s, with the village currently being the most populated in the volcanic region. However, this growth has decreased the welfare of the population due to problems typically associated with growth such as lack of access to primary health care and clean water. Despite the soil fertility and abundant rainfall, Bisate has suffered from a water scarcity problem for a long time. This water scarcity has increased the usage of contaminated surface water, thus spreading waterborne disease in the village. Women and children, who are traditionally responsible for collecting water, are the most vulnerable to these diseases. They travel long distances seeking runoff water that may have been detained in impermeable rock after a rainfall event. Furthermore, the village is at the altitude of 2500 meters and does not have any spring water. After heavy rainfall, rainwater percolates through cracks and crevices, and the area remains in a continuous shortage of water.

One affordable solution to this problem is to establish a rainwater harvesting system. This system consists of collecting rainwater from the roofs of houses and storing that water in a reservoir for future usage. This system consists of four main parts: a roof for water collection, gutters and pipes to transmit water to the reservoir, a water filter, and a reservoir which has a water tap. The capacity of the reservoir varies depending on the size of the roof, rainfall and the water demand of the people supplied. As a result, the reservoir capacity may vary from one cubic meter to thousands of cubic meters. This rainwater harvesting system is cost effective and can be adapted to low-income populations.

In Bisate village, a number of people have tried this method using local materials. They collect rainwater on the roofs of houses, and drain it into a plastic water tank. However, only a small number of families in Bisate village have such a system. Most of the houses are covered by thatches, which are inadequate roofing material for rainwater collection because they do not allow water to drain effectively. In addition, this type of collection system is susceptible to contaminants like dust, dead birds and trees leaves. The dust, which is deposited on the roof by winds, may contain bacteria carried from areas of poor sanitation with open defecation. Inadequate maintenance of the system can then become another source of waterborne diseases in the community. Therefore, it is also recommended that the water tank always remain covered to reduce the possibility of contamination from these sources.

Further research is needed to develop a rainwater harvesting model that will be affordable for all different types of roofing materials. This will encourage the usage of the system in other remote areas of the world with few surface- and ground-water resources but high rainwater availability.

LifeEngine Clean Water Project

LifeEngine Clean Water Project
Testing Water Filtration Technology in Bisate Village