Source of Water

For now, the main source of drinking water in the territory is the USUMA DAM water works. The dam is located within the higher altitude areas of the territory and is sited on a virgin location where human activity is minimal thereby ensuring non pollution of the environment and free from industrial impurity. The dam is a homogeneous earth fill dam with an upstream face of rock fill a grassed downstream face with grout cut-of wall with vertical and horizontal filters.

The Usman Dam reservoir has a maximum capacity of 100 million cubic metres. The main Dam is 1,300 meters long. The maximum height of the main dam and saddle dam is 45 meters and 10 meters. The tower is equipped with eight intake point at four different levels. Screens are provided at each intake. The whole gallery has 2 levels, the upper level supports the two 1,500mm steel pipes while the lower level is used to draw down the level of the reservoir and for the passage of the permanent draft. The overflow spillway structure provided on the right bank of the main dam for the safe discharge of excess water during extreme flood. The discharged water flows throw a rock tunnel 240 meters long and 10 meters high into a concrete stilling basin before finally discharging into the Usman River. The dam is located at about the highest oint of the territory and feeds the water treatment plants by gravity. The dam is also provided with a pumping station in order to pump raw water from the main dam reservoir to the water works in the event of extreme drought situation when the reservoir water level is serverely depleted.