
The Usalama Water Pipeline is a gravity flow water system that connects to the main Kibwezi line and is meant to provide potable water for the village of Usalama. Mwikali's Gift contracted AMREF to design and build the project in late 2006/early 2007. As of today the project is incomplete with some water kiosks operational and intermittent water reaching the main tank.

One of EWB-NY's secondary goals during the Classroom Construction project was to perform a third party ex-poste evaluation of the Pipeline system in order to provide recommendations for remediation if necessary. There were some obvious limitations to our ability to perform a thorough evaluation. First, the project is incomplete, which makes "ex-poste" a little unrealistic. Second, we could not dedicate more than one Engineer (Matt Sisul) to the task, though he was teamed with the pipeline supervisor, James. This limited the extent in which the various system components could be evaluated and tested.

A little about the system:
The pipeline is run by the Usalama Water Board (UWB), a committee set up with the help of Mwikali's Gift and AMREF. The UWB is in charge of operation and maintenance of the system from the intake at the Kibwezi Pipeline junction, the mainline to the tank, the tank, and return lines from the tank going in two directions, north to Kiosks 1 & 2, and south to Kiosks 3, 4, & 5. The board also employs attendants to sell the water at the kiosks for 2 ksh per 20L Jerry Can. (Pretty Standard). The UWB pays the government water agency a tax for the use of the water that costs somewhere around 15 ksh per cu. meter. So the UWB makes a profit of 100 - 15 ksh per cu. meter water sold that goes toward paying attendants, maintenance and loses, the remainder of the money goes into a bank account for future capital expenditures.

Source:
The source of the water is the Umani Springs. Umani (or sometimes Umanyi) supplies water to Kibwezi town and many points north and south of Kibwezi (Makindu, Mtito Andei). The water emerges from the spring in a very clean condition, but likely picks up some bacteria in the pools before entering the pipeline. In 2006 the water at the spring tested positive for fecal coliform presence/absence.

Present State of the System:
It was not easy getting a sense of the present state of the system. But after discussions with many individuals and a first hand inspection I was able to get an idea of how the system is currently functioning in its incomplete state. The final system is meant to have a mainline that connects to the tank with two return lines, one going north to kiosk 1/2 and another south to kiosks 3/4/5. However, kiosk 1 is attached to the mainline and the return line is about 20 feet short. Kiosk 2 is attached to both the mainline and the return line, with a bypass system in place so the kiosk operator can switch between the two lines. Kiosks 3/4/5 are all attached to their return line. The tank does not receive adequate flow to fill in the 24 hour cycle, in part because kiosks 1/2 reduce the flow while operational and in part due to an overly optimistic design by the engineers at AMREF. Kiosks 3 & 4 can get adequate water when the tank is full, but this is rarely available due to issues with the flow into the tank. Kiosk 5 may be in a position to receive little to no flow, as it is in line with kiosks 3 & 4, and at a higher elevation, so perhaps when the tank is full and kiosks 3 & 4 are closed there may be potential, but that has not been verified.

Next Steps:
Our next task is to take the data collected during the pipeline inspection: alignment, elevations, pipe diameters/types, locations of intake, airvalves, kiosks, tanks, etc and try to create an "As-Built" profile of the pipeline. The profile can be used to determine the dynamic head losses in the pipe as the water travels from the intake to the tank and from the tank into the kiosks in order to determine:
1) That the profile and components are consistent with allowing water to flow via gravity.
2) What steps or changes to the system can be made increase the flow of water into the tank, thus ensuring adequate flow of water from the tank into the kiosks.
3) Key data is lacking in order to accurately determine expected flow rates, and that is the flow and pressure at the intake. We will have to set up a measuring program to measure the pressure at the airvalves closest to the intake and tank, as well as the flow into the tank (where pressure=0) at various times of the day, days of the week and months of the year to determine variation in flow at the intake and reliability of the system.
Pictures from the inspection are available here. See this older post for detailed maps of the system.
























