Designing a HydroElectric Dam in Kalehe, DRC
The Tuungane project has been in operation for the past 5 years and is entering its 2nd phase. Phase 1 saw certain strategies in financing, construction and community involvement that have been adjusted and improved. Almost all of the large Tuungane 1 projects have been completed – but the most complicated one has yet to break ground: construction of a hydroelectric plant in Kalehe Centre.
Spanning the entire length of Lake Kivu’s west coast, Kalehe is among the most beautiful regions in all of South Kivu. The beauty of the mountain views are surpassed only by the picturesque islands and peninsulas that define the water’s edge.
After meetings and elections, the community of Kalehe Centre indicated that its biggest need was for consistent electricity. Kalehe is the least electrified region in South Kivu, which is surprising, since it rests between the two largest cities in the Eastern Congo, Bukavu and Goma. The community leaders decided to use their $80,000 grant for construction of a hydroelectric plant, and pointed the IRC team to an ideal site: a waterfall located 2km outside of the town center. Upon inspection of the site, it was clear that construction of such a system had once been attempted. The crumbling foundation of a turbine house along with some overgrown canals exist adjacent to the 10m high waterfall. It is unclear if the project had ever been completed, or if construction had halted at the start of the wars, fifteen years ago.
This project marked a large jump in complexity for the Tuungane team. Some of the other Tuungane communities had chosen to use their funds for electricity, but those projects had required only a connection to existing electrical lines. This project would require expensive machinery, substantial planning, and a technical expertise that was not currently available. The IRC team explained the difficulty of the project, and proposed to the community that they build a school or market instead; but the community of Kalehe Centre was unwavering.
These meetings occurred two years ago. Since then, the project has moved forward in stops, starts and tangents. Feasibility studies have been done, quotes for turbines have been sought and nearby existing hydroelectric dams have been studied. The estimated budget for the turbine and 2km of electrical wires alone have topped $100,000; putting more and more pressure on the community to finance the difference.
Upon arriving at my office for my first day in Bukavu, I was told that this project that would become my “mal de tête”, and was handed a folder that contained a pile full of papers:
a narrative listing the power needs (the demand),
a photograph of a hand drawn site plan,
a quote for a turbine with technical specs,
some sketches of a reservoir and dam,
a budget with little correlation to anything,
a feasibility study warning that “this project is not viable”.
I began by reviewing the energy demand of the community. The people’s primary concern was servicing the local hospital. They also wanted current for market areas and for a few mills to process cassava into FuFu, a staple dish of the Congolese diet. It was estimated that their electrical demand was approximately 130Kw. The cheapest turbine option would provide a maximum current of 32kw, so the math was obvious: we would be able to
provide current only to the hospital. I asked for a complete survey to be done of the hospital’s power needs: number of light bulbs, incubators and anticipated additions of equipment. Our estimates came to 27kw, putting the hospital’s power needs within reach.
The proposed development of the waterfall site showed substantial construction. A 20m wide water dam would not only require enormous quantities of raw material, but it would not take advantage of any of the existing canals and terrain. I began with this simple sketch to show how this large construction can be consolidated into a few components. This sketch illustrates my basic strategy for the project, and within a few weeks, we began moving towards a complete design.
Upon choosing the appropriate turbine, we began to size each of the components: the dam itself (technically a “wier”), canals, settling pond, final conduit, and the turbine house. Each of these components were sized in relation to the flow rates of the river. This ensures that the flow to the turbine will remain perfectly at the turbine’s maximum capacity during both the rainy and dry seasons.
As I began to develop the construction documents, amid numerous miscommunications with the community’s contractor, I opted to place site photos directly into the construction set. By drawing on top of these images to create colored diagrams, the plans are clarified and references are made to each construction detail.
In creation of the final budget for the project, the total has risen to $170,000. Amazingly, the community has not only committed to contributing $10,000 worth of manual labor, but they also reached out to a local leader who has committed to donating $30,000 towards the project. Further, two of the sub communities in Kalehe offered to forgo their plans for construction of schools, and allocate their grants towards the balance of the budget.
Currently, we are waiting on the community to write a formal proposal. Soon after, funds will be released, orders will be placed, and ground will be broken.
This project will provide a fascinating construction process. A waterfall will have to be diverted and controlled, and each component must be constructed with extreme precision. I look forward to guiding the construction of this project – and of course, to providing consistent updates on our progress.