Water Supply Design For Bambui

This report is written for the purpose of implementing a new design for the people of Bambui and to bring about a sustainable future. The engineers without borders or also known as EWB is a non-profit organization which helps in developing new and innovative ideas in different communities to make life easier. For the EWB Challenge of 2015-2016, the rural community of bambui is chosen which is located in Cameroon. This report will include the background of bambui, the design was chosen by the group and also the cost and construction. Ethics will also be discussed.  We looked at a number of different problems that bambui is facing at the moment and we chose to deal with the water problem for households.


Bambui is a rural community in the north western region of Cameroon. The map above shows where bambui is located. They have a population of 17,000 people. It is approximately 1350 meters above sea level. As years have passed, Cameroon is urbanizing their place by building more universities and more facilities. This has caused a pressure in designing new and innovative ideas for their township. The EWB challenge sends more students and professionals from many different universities to go and help out implementing their designs in the township of Cameroon. The problems faced there at the moment are to deal with water supply, housing, waste and other such issues. Water supply being the main one, the group has thought of certain ways to implement new ideas for the benefit of bambui. More on bambui will be explained in the next paragraphs namely on lifestyle, housing, water supply and waste management.

cameroon, map           World Travels

2.1 Lifestyle

Bambui is a quiet town where the people like to grow their own food. They plant their crops and do everything on their own. They like being independent. Some of the crops include corn, wheat etc. Men and woman share their work equally in bambui, but household work limited to a woman. They make money for their daily needs. Crops need water, and in turn, this was an issue for them sometimes. Water supply is key for them as, without water, nothing can be done. Below is a picture of typical housing. Few crops in the backyard as well.

2.2 Climate

The community of bambui experience a tropical climate where there is more rainfall in summer than winter. Being a tropical region, there is plenty of rain compared to the dry regions of the country. The average rainfall of bambui is close to 180 mm or so. Data changes every year in bambui. There is more rainfall in the months from June to October. As rainfall plays an important part in the climate of bambui, the water supply design was made based on the source from rainfall. The lowest temperature experiences are as low as 6 degrees. The high temperatures vary from 21 degrees to more. These values are all average temperatures. So, the importance in climate for designing is very important in this design’s case. Collecting clean rain water would be more in the summer as it is a tropical region. Winter would be slower but the water is collected in the tank for future use. The Charts below show precise information on the climate and temperatures of bambui.

2.3 Housing

Houses in bambui are small in size and made from materials that are available in plenty. Most of the housing is comprised of Brick and clay. Their roofs are made from straw in some cases and bamboo for the stronger roofs. Bamboo is found in plenty over there so it is used as roofs to prevent leaks during the rainy days. The roofs are all conical in shape to help with collection of rain water and so on. This makes it easier for the design. Typical housing in bambui. Assuming there are 60,000 people. There might be 6 people in a house. So there should be around 10,000 houses.

2.4 Water Supply

Now to the important part, water is the most important resource on the planet. It is found everywhere but how pure and hygienic is it. In bambui, water is a basic need for everyday lives. Survival will be hard if there was no water. They face issues of no clean water to use, not enough water for cooking and cleaning. Clearly this water cannot be used, yet there is very poor sanitation. Polluted water causes too many problems for the children who play in unclean water who are not aware of such things. Bad water in turn used in cooking which causes contamination in the food. Most common places to collect water are from streams, wells and tanks. But these places are often not near the households. This forces woman to travel long distance just to get a little water, which is still not clean. This is a very big crisis in bambui. That’s why, this topic was chosen for the group design.  Due to the population per household, it’s going to be difficult to go to different places to collect water. With the help of building wells, and certain streams still be contaminated, a well-developed sanitation system should also be constructed.


2.5 waste management

Waste is another issue in bambui that is not managed well. Toilet systems are bad and some people don’t even do their business in toilets but in fields and behind houses. There are advantages and disadvantages with waste in bambui. Small waste systems are built to help with the cleanliness. Some waste is collected for further agricultural uses.


  • The waste can be used as fertilizers.
  • Urine can be collected separately and used in sanitation process to provide clean water.
  • It cost as little as no money to build a small waste system to get rid of the bad waste.


  • Citizens of bambui complain about smell and uncleanliness.
  • Waste thrown in streams causing unclean water.
  • Unclean surroundings.
  • The negative vibe in the community.

waste management    EWB Challenge


The initial move towards building up an answer is to characterize an arrangement of outline criteria to work with. The top level of the undertaking will concentrate on giving adequate clean water to individuals in Bambui territory. Furthermore, the outline is made for a long haul supportability and simple to keep up as it in includes straightforward, powerful plan.


The normal yearly precipitation in Bambui is 177.1mm. The lodging must have the capacity to withstand a lot of precipitation. Tough materials must be chosen so that the rooftop is solid and won’t crumble amid solid rainstorm downpours. The canals must be joined safely and securely, remembering that any blockage may bring about an extensive weight of water being contained in the canal. Notwithstanding being solid, the material should likewise be sufficiently light to be bolstered by existing dividers. In spite of the fact that some houses in Bambui are of cement and bond, there are mud houses too and these must have the capacity to bolster the structure. In the event that spillage happens through the current dividers, remaking might be essential.

According to the research, it shows that each house requires 30 liters of water per day. As we have a total of 10,000 houses in Bambui, therefore, the amount of water usage per day is;

Water Usage per day = Number of houses × amount of water per day

= 10,000 × 30

= 300,000 litres

BabbuiFernando Matoso

3.1 Proposed Design 1

We will gather water in two ways. The one and two storied houses will have their own particular water gathering framework, which is less expensive and simple to introduce. Alternate workplaces, schools and cultivating water will be gathered from the slopes.

Water from hills

For gathering the water from slopes a track will be uncovered encompassing the slopes. Every one of them will meet at one spot making a state of the channel. In each slope we will make four of them. Two of them will be utilized for family unit utilizes and other two will be utilized for cultivating and different employments. There will be four tanks for gathering the water from four passages. At the point when the water will enter the tanks, it will get a fundamental filtration. We will utilize shakes, rock, and charcoals for the family unit water. Just shakes and grass will be utilized for the cultivating water as that water doesn’t need to be so clear. The tanks will be made of timber and coverings. We will make the body with timber. At that point, we will put 2 handles of canvases inside that. We will put some stones inside the canvases for keeping that relentless. We will utilize straws for concealing that. We will likewise put some branches on the highest point of straws for not giving it a chance to take off. For minimizing the cost, we won’t make whatever other water supply framework. We will utilize the principle water supply which they are utilizing now. We will associate the family unit tanks to the primary water framework. The water will be supplied to the houses from that point. The water for cultivating will be coordinated to the cultivating lands. A long track will be uncovered for the water channel. The entire line will be secured with plastics. It will shield the water from dust and other refuse.

BambuiFernando Matoso

3.2 Proposed Design 2 – Final Design

For gathering water from the rooftops we need to make a trench which will be connected to the side of the rooftops. The trench will have a tiny bit slant on one side for the better stream of water. The trench will be associated with tanks with a UPVC channel.

The tank will be made of timber and coverings. The most productive thing is the tank will have two sections inside. One section is for family unit utilization water and the other half will be utilized for drinking water. For the family unit water, there is no compelling reason to decontaminate it as downpour water is normally sanitized. Be that as it may, for the drinking water we will do a tad bit of cleansing for expelling the waste or different things which can stir up from the rooftop. On the drinking water tank part, we will make a channel utilizing rock, charcoals, stones, and sand. Every one of them will be in a layer on the upper side of the tank. The water will turn out from the channel which is associated with the trench. At that point, it will experience the channel and get decontaminated.

The drinking water tank will have a tap. House individuals will get drinking water from that point specifically. The other part of the tank which will be utilized for family unit work will be associated with the principal water tank of that house. As the tank is as of now made up at home, it will minimize the expense on the off chance that we associate the new tank to the old one.

 Climate Chwiki


User Requirements
Clean and Efficient Rainwater Capture
Rain water filtration
Design Criteria Performance


Effectively Filtering Good
Maintenance Good
Cost < 60 AUD


Rainwater Storage
Design Criteria Performance




< 60 AUD
Durability >20 years
Accessibility Good


           Rainwater Capture
Design Criteria Performance


Source Ability Good
Durability >20 years
Chemical Safety Good
Sustainability Good
Cost-effectiveness < 50 AUD

bambuiFernando Matoso

Roofing Solution
Design Criteria Performance


Unit Cost < 60 AUD
Water Resistance Good
Anti-mildew Good
Local availability Good
Insulation Good
Installation Good
Water Resistance Good


Clearly the drinking water must be 100% clean and decontaminated. As we are gathering precipitation water for houses, we don’t need to do a considerable measure for cleaning the water. We will simply channel the water with grass, rock and charcoals. We will place them in a layer at the passageway of the drinking tank. At that point the water will be prepared to drink specifically from the tap.


The water which will be gathered from the slopes and utilized for drinking will confront a legitimate and full filtration framework. We will utilize sand, stones, charcoals, rock and little shakes. We will place them in a container and the water will go through that. After a specific time, the filtration jug will be supplanted.

Household use

Water gathered from the rooftops won’t require refinement as that will be downpour water and rain water is normally filtered. Thus, there will be no issue of utilizing that for family unit works.

Water from the slopes will get through a filtration procedure. It contains shakes, grass, and charcoal.

Farming use

For farming the water doesn’t need any kind of filtration. It will be stored in the tank and will be supplied when needed.


Distribution system (Water from hills)

Water from the slopes will have two destinations. One is to the cultivating lands and another is to the ebb and flow water framework. The tanks for the cultivating will be opened when required. Alternate tanks will be associated with the primary water supply framework. There will be a valve between these two. I the emergency time that will be opened and the putaway water will be exchanged to the principal water framework. From that point, the water will be circulated.

Water from roofs

The water from rooftops will be coordinated to the principle tasks of the house which they are right now utilizing. As said sometime recently, the drinking water tank will have no association with anything. They will need to gather the water from the tanks as there will be a tap introduced there.

Water recycling

The water utilized as a part of toilets for washing and cleaning can be utilized as a part of the greenhouses. In the event that the houses have gardens, we will guide the bowl and shower lines to the patio nursery sprinkles. That is the manner by which they can spare water as plants couldn’t care less about the root of water. That is truly exceptionally effective and the houses won’t need to rely on upon different wellsprings of water for cultivating.

Needed human power

For finishing the entire venture, we require an awesome measure of human force. There will be a considerable measure of work to do. Every one of them is anything but difficult to set up. For that, we will utilize the nearby work as the work expense will be less expensive there contrasting with others. Also, as it is not that troublesome, the nearby work will have the capacity. Then again, clearly there will be a group of experienced architects for controlling them. They will check and give them directions consistently.

 bambui peopleFernando Matoso


The following is a detailed explanation of the final design of harvesting water from the roof. This will include;

  • Prototype
  • Water filtration and storage Solution
  • Concept Equations and models
  • Construction techniques
  • Maintenance Cost
  • Running and Maintenance Cost


The accompanying models are pictures where by figure 1 clarifies the entire graphical model of the entire outline arrangement portraying new material arrangement, figure 2 clarifies graphical model of downpour water gathering framework in subtle element and figure 3 clarifies model created.

Full Design




Developed Design

3.5 Concept Equations and Models

This segment covers all the scientific conditions worked out behind the utilization of the ideas. They give a model to the execution premise of the undertaking and there are a couple of presumptions required also. The initial segment is to build up a model for the measurements of a normal family expected in the town of Bambui.

  • Average floor area in Bambui households = 38m2
  • Estimate for average roof dimensions = 40m2 (based on floor area)
  • Estimated average roof dimensions 6m x 7m
  • Perimeter of roof = 2 x (6m + 7m) = 26m 25m


The next section is related to the estimated collection of rainwater from the harvesting system. This is based on the average rainfall in the district as per data obtained from the Bambui Meteorological Department (IMD, 2010).

  • Annual rainfall in Bambui= 1331.48mm = 1.33m
  • Total rainfall per year on roof = 40m2 x 1.33m = 53.2m3 = 53,200L
  • Estimated rainwater run-off loss = 20%
  • Estimated wastage loss = 5%
  • Estimated rainwater captured = 0.75 x 53,200L = 39,900L 40,000L
  • Average rainfall captured per day = 40,000L / 365.25 days 110L
  • Average water consumption per household per day = 18L
  • Water storage recommended (considering dry periods) = 500L
  • Estimated gutter volume = (0.5 x π x radius2) x length of gutter
  • Estimated gutter volume = (0.5 x π x 0.12) x 25m = 0.3926m3 = 392.6L

3.6 Water Filtration Solution

The following table explain the filtration design using the selection matrix.

Criteria Gutter Mesh 3PFilter Collector FirstFlush Diverter Rain Tube Gutter Collector
Effective filtering 3 4 3 5 4
Low Maintenance 5 4 4 3 3
Cost 4 1 3 1 2
TOTAL 12 9 10 9 9

Table 3 Water Filtration Solution

This anticipate scope concentrates on essential filtration for which two arrangements have been chosen from the above choice grid. A drain cross section ought to totally cover the highest point of the canals. This keeps the greater part of flotsam and jetsam from entering the drains and downpipes. Garbage may bring about the canals or pipes to wind up blocked keeping water from going through the canal framework into the water tank or cause the drains to flood.

The canal downpipes must be associated with a first flush water diverter, keeping in mind the end goal to keep the principal stream of contaminated water running off the rooftop to be put away in the tank. The main flush diverter’s chamber ought to have the capacity to redirect 25L to 100L of water, contingent upon the span of the rooftop and its introduction to contamination.

3.7 Water Storage Solution

The following table explains the storage design using the selection matrix.

Criteria PVC Tank Steel Tank Fibre Glass Tank Concrete Tank
Source-ability 4 2 2 3
Durability 4 4 4 5
Chemical Safety (0,1) 1 1 1 1
Sustainability 2 2 2 3
Cost 5 3 2 1
TOTAL/21 16 12 11 13

Table 4 Water Filtration Solution

The first thought for the idea determination of the water stockpiling framework was the area (above or subterranean). Given the high establishment expense of an underground tank and its required parts (e.g. water pump), it was likewise chosen that an over the ground tank would be more appropriate for the Bambui people group’s methods. An underground tank likewise postures upkeep troubles if splits or holes happen. Given the normal principles for materials utilized as a part of these tanks, these were examined utilizing a lattice.

Fernando Matoso

Rainwater Harvesting System
So as to attach the drains to the dividers of the houses, circle holders and shanks will be required for each 1.2 m of guttering. A metal spring clasp is required to associate the canal to the holder; a nut and screw will be required to interface every holder to a shank and four nylon tap-ins will be required to interface every shank to the dividers.

Gutter installation method (Gutter Supply)

One end of the canal cross section is screwed to the rafters under the second last line of the roofing panels. The flip side of the canal lattice is associated with the top-external edge of the drain. The PVC funnels require a PVC section each 1 meter to be safely mounted to the mass of the house. Every section requires two nylon tap-ins to be joined to the divider. The first flush diverter requires two thick metal sections, one at the highest point of the chamber and one at the base, to be connected to the mass of the house. These sections are connected to the dividers with Nylon Tap Ins.

Running and Maintenance Costs
The arrangements and materials in this project were chosen in such a way that requires minimal maintenance as per the design criteria. However, there are still some maintenance procedures the clients will need to adhere to in order to guarantee the life span and fruitful operation of the item. The water gathering and material framework have no running expenses as the major input is only provided by the natural rainfall. In any case, a couple support techniques have been suggested as underneath.

  • Check downpipes at least every 3 months to prevent clogging
    · Keep the water tank tidy and clean
    · Each month, clean the mesh of gutter
    · After every major storm, empty the First Flush Diverter

These exercises are genuinely straightforward and don’t request equipment or labor force. The just need is that the client has the capacity to achieve the drain and considering visual confirmation of house structures in the town, it is seen that low rooftops are utilized and this wouldn’t be a hindrance. At most extreme, just a tool or stepping stool may be required for this reason. In the situation where the residents are not ready to clean their water tanks, it might be genuinely simple to acquire the administration of a Dalit resident in the town whose list of professions include cleaning too. (National Geographic, 2003) Hence, the running and upkeep costs for the arrangement can be considered as to be negligible in terms of extensive labor and costs.

Bill of Materials

Table: Bill of Materials for Roofing And Material Production

Item No. Item Purpose Quantity Cost (AUD)
1 Transportation of Material Materials as required 200
2 Labour Production Production 20 local people 0
3 Safety Goggles Work 20 12
4 Safety Gloves Work 20 18
5 Safety Masks Work 20 13
6 NaOH Processing 1220 kg 487
7 Formalin Processing 7.5 kg 3.5
8 Mixer Machine (100L) Production 1 unit 1500
9 Hydraulic Press (15T) Production 1 unit 2500
10 Sisal Fibre Roof as required 0
11 CNSL Liquid Roof 1500 kg 900
                 Total Cost for Village        (50 houses)                                             = 5633.5
                 Total cost per Household                                                                   = 112.67
Item No. Item Purpose Quantity Cost (AUD)
1 PVC downpipe Gutter 5m 15
2 Guttering of Aluminium Gutter 25m 125
3 Materials of Plumbing Gutter as required 15
4 Plumbing labour Gutter 10 hours/day 30
5 Tank (500L) Storage 1 unit 50
6 First Flush Diverter Filtration 1 unit 10
7 Gutter Mesh Filtration 25m 15
                      Total Cost per Household                                                                      = 260

Table: Bill of Materials for Rainwater Harvesting

The above tables summarize the Bill of Materials for the proposed solution. Based on these lists, the total implementation cost for each household is AUD 372.67 incorporating aluminum guttering and AUD 258 incorporating bamboo guttering – roughly 45 to 67% of an average Bambui household’s annual income.

The procedures proposed aimed to improve the quality of life and personal satisfaction of these people in a remarkable manner. So for this purpose, our group made decisions objectively and reasonably. The sole reason for our exploration and proposals is to provide the Bambui’s community with the most effective and reliable strategies to elevate a desperate need. This innovation might not have possessed the capacity to take care of Bambui’s vitality issue and it might have cost too much for the community to maintain. In spite of this, it might have been rewarding for our group as the design was inventive and possibly exceptionally useful it could be managed or afforded. We planned to do what was better for our community, to overcome poor asylum and the deficiency of clean water, over what may have been more gainful for our group. This choice to take care of the safety and health problems of Bambui, exhibited our honesty and integrity as engineers.

Fernando Motoso

We practiced competently, as we worked in a way where we met as often as possible to review each other’s work and team up on it. Furthermore, our group was attached with one another through emails and messages. These procedures practiced by our group exhibits how the group frequently used peer review and furthered the improvement of every colleague by giving useful feedback on their work.

Teamwork was demonstrated when our group sorted out a meeting, to talk about the potential dangers of our design because of the lack of research into the material to be utilized for roofing, the sisal-CNSL composite material. Our group promoted sustainability in our design as we chose to utilize the sisal-CNSL composite material in our configuration. This material uses the privately sourced sisal plant, which was the sufficient resource in the area. It also provides employments to local people in gathering the plant. Our design likewise promotes sustainability in that it looks for the contribution of the community in deciding if they want to actualize the design after the trial period, and if so, whether they need to execute the design with half round aluminum drains or bamboo gutters.


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Featured Image Credits: Fernando Matsoso

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