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Engineers Without Borders – USA Water Infrastructure Expansion Project for the Community of Muramba, Rwanda
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In July 2005, civil, geological, and chemical engineering students, an economics student, two journalists from the Milwaukee Journal Sentinel, and faculty advisor and civil engineer, Peter Bosscher, collaborated with students from the University of Surrey in the United Kingdom, the University of Butare in Rwanda, and the community of Muramba on several initiatives including solar cooking and water pasteurization, fuel briquetting, and expansion of the community’s water supply.
Invited to Muramba by Father Musinguzi John Bosco, the town’s Ugandan-born priest, Peter Bosscher and EWB students helped develop a water system that will bring desperately-needed water to this rugged mountain town of more than 30,000.
The existing water infrastructure in Muramba is in such poor condition that it does not meet international World Health Organization standards for quality and quantity. A few taps exist, but are not dependable. A new water source was identified by Bosscher and a different team of students the summer before. The objective of this project was to expand the water system and get the water flowing – laying down three miles of pipe – to increase quantity available to the community. It is estimated that the new water sources will double the quantity of water entering the village system.
EWB-UW supported the project by financing the material cost, provided technical support to Muramba project managers and assisted in designing and constructing key hydrologic structures that added two water sources and increased total flows from 37 liters per minute (L/m) to 83.8 L/m. The EWB-UW team helped construct system additions and imparted knowledge regarding sustainable water system maintenance and operations. The EWB team also helped community leaders form a Water Board to establish and govern system water usage, oversee maintenance and acquire funds for maintenance and future system expansions. The community provided skilled laborers, knowledge of local natural systems, and “sweat-equity.”
The Muramba Community
The Muramba community regularly volunteered during construction and committed daily volunteers to help dig, flag the pipeline route and transport pipe – most of these volunteers were women. Skilled laborers provided invaluable help mixing concrete, building masonry junction boxes, and connecting hydraulic elements. These people, mostly men, were paid for their efforts.
Rwanda President Paul Kagame recently institutionalized a community work day throughout Rwanda. Able-bodied community members commit a half-day’s work, one day per month, to collectively improve local infrastructure throughout the country. In Muramba, the community work day focused on the water project. Over 1,000 people volunteered to dig the pipeline trench. The community turned out in full force to support he water project, as shown below.
Nearly 1000 community members turned out to help dig pipeline trench
Approximately 10,000 individuals will ultimately benefit from this project, including students, widows, orphans and villagers. The community has deteriorating water infrastructure and few commercial or industrial activities. There is evidence of textile manufacturing and carpentry, and a few private establishments service the community with grocery shops and bars. Subsistence farmers comprise the majority of the community.
The project consisted of developing two new water collection sources and constructing a pipeline (5 km in length) connecting two main water source collection areas.
A pipeline was designed and constructed to connect two new water sources to the uppermost village collection box. The pipeline paralleled the main road leading to Muramba for much of its length. Roughly 5 km of PVC pipe transports water from the two sources to the village. Pipe was laid in 6 m lengths in a trench 1 m deep; lengths were connected using pipe epoxy. In several instances the pipeline crossed small ravines and gorges, precariously exposing the pipe to the effects of weathering. To bridge these gaps, technicians constructed steel-trussed encasings to protect the line.
New Water Source Development.
Two new water sources were developed. Source 1 is comprised of two subsidiary sources, referred to as Source 1A and 1B, which issue as natural seeps from the high water table within the area. Source 1A yields nearly double the flow of Source 1B. Both sources were found to be contaminated with Coliform, though there was no indication of either being contaminated with E.Coli.
The local community relies on Source 1 as their primary water source. To accommodate the needs of the community, a tap was constructed at this source to allow the community to continue to collect water.
Three seepages flow into the Source 2 collection box. Each site was excavated with volunteers doing much of the physical labor and technicians conducting most of the skilled labor. As with Source 1, water seeps to the surface at a number of places in the hillside; the three sources issuing the most water were subsequently tapped. Water collected from each source contained Coliform; source 2D also registered E.Coli in a presence/absence test. However, a later Colilert test for a fecal Coliform count yielded no presence. Further investigation of this source may be necessary if a treatment system is to be considered. The new water source locations are shown in the figure, below.
Schematic of New Water Source for Village Spring Box Design.
Spring boxes were constructed at each source to make optimum use of the natural spring water. Spring boxes protect spring water from contamination by surface runoff or contact with human and animals, and provide a point of collection and place for sedimentation. Each spring box was crafted to fit the specific location. Once the seepage source was exposed, the source was dammed with local clays and filled with washed gravel, as pictured in the figure, below. An exit pipe embedded in the clay and gravel served as the outflow pipe.
The source was covered with plastic to prevent contamination and then sealed with more clay and backfilled with gravel. In the case of Source 1A, a concrete cover was placed over this second layer of gravel and sloped down to further drainage points in the wall. Gravel and soil serve as the drainage bed and effectively filter surface runoff.
Photo of spring box construction
Protecting the source from overflow is a concern as surface runoff could undermine the integrity of the spring box structure. Technicians constructed a concrete apron around the base of the retaining wall to channel the drainage water away from the foundation and limit potential erosion. The source pipe exited below the apron directly into the trench. This design was implemented on Source 1A, 2B, 2C and 2D and possibly Source 1B. Source 1A is illustrated below.
Emmanuel Tuombe inspects the spring box at Source 1A Local Supply.
The local population uses the seeps at Source 1 and 2 as a primary water source. The community will continue to access to this water after the addition of the new water sources. To provide water to both Muramba and local farmers, a tap stand was constructed on the side of the junction box that combined Source 1A and 1B. While both sources empty into the junction box, only the smaller of the two flows (from Source 1B) was to be tapped. A portion of this flow was redirected to the communal tap stand through a T-junction fitted with a restrictor valve. The remaining water flows into the junction box and feeds the new line. This design ensures minimal water loss if the tap is left open or is broken. The tap stand schematic is pictured below.
Schematic of Source 1 tap stand
A tear-drop tap was installed so that when it is not in use, the tap will automatically turn off and allow the full flow to pass to Muramba. The EWB-UW team believed the tap stand may be flooded during rainy season high flows; the local inhabitants believed the box was situated well above the river high flow. The base of the junction box is approximately 30 to 40 cm above dry flow conditions. Construction had commenced on the junction box before EWB-UW could discuss the issue with project leaders, making it difficult to question the location. If high flow conditions pose a threat to the integrity of the junction box and tap stand, the stream could be dredged along a 3 m section that runs past the tap stand.
Source 1 junction box and tap stand
The pipeline from Source 1 travels down a small valley before crossing the tea road. The pipeline then rises to a height only 15m below source 1A. EWB-UW was concerned that there was not sufficient head to pass water over the hill, even without the construction of the junction box. To examine the potential, pipes were connected temporarily and, as expected, the water did not flow over the rise. Consequently, laborers re-excavated a portion of the trench at a lower elevation, rather than adjust the junction box design.
The pipe from Source 2 travels down the valley and joins the road just prior to the junction box. The two sources combine in the junction box, pictured in the photo, below, which acts as a break-pressure tank. Upon exiting this junction box, water flows to the village in a single pipe. The new source will enter the village at the entry junction box.
Water from Sources 1 and 2 enter this junction box before flowing to the village
Project Status Upon EWB’s Departure
When Bosscher and the first group of students left on July 18, 2005, the first phase of pipes had been laid. And by the time the second team of EWB undergraduate students left on August 3, 2005, just 700 feet of piping remained to be laid. By now, a steady, strong stream of water should be flowing through the pipes to the remote hilltop town. Civil engineer and EWB volunteer, Peter Bosscher (as reported by Susanne Quick in the Milwaukee Journal Sentinel) noted “As engineers, we have the ability to make people’s lives easier. An engineer is someone who allows realty to happen faster or better” than it would without their help.
Sustainability of the New System
EWB-UW assisted the Muramba source technicians institute a maintenance schedule. The team discussed the need for establishing a regular routine before the system begins to visibly degrade to facilitate long-term system sustainability. The schedule was divided into required regularity with responsible individuals; regular maintenance may entail hiring additional laborers.
New Water Supply Usage
The community of Muramba plans to use the new water supply to enhance flow to the village and ensure the health clinic always has a constant supply of water. Community members plan to renovate the clinic reservoir and use it for storage, as needed. The community plans on installing three additional lines to the Muramba Parish, the Muramba College and the Maria Greta school. A restrictor valve will be placed on each of these lines to restrict flow, while bolstering current supplies.