The Canadian engineering company SNC-Lavalin used InfoWorks WS to model the water supply network in Banju, Gambia, in order to better manage the system.
Wallingford Software’s InfoWorks WS helped engineers devise the most effective ways to improve the water supply for the area around Gambia´s capital city, Banjul. The Canadian engineering and construction company SNC-Lavalin used InfoWorks to model the network, help determine better ways to manage the system, and identify priorities for capital investment.
The state utility NAWEC, which is responsible for water supply, sewerage, drainage, solid waste and electricity, contracted SNL-Lavalin to help improve its services given major demographic changes in the past decade.
The West African country of Gambia experienced significant migration of its population from rural to urban areas that led to a sevenfold population growth in its capital city of Banjul. The city grew by 300,000 during this period of time.
For a country only 400-km long and 70-km-wide and with a population of 1.5 million, this migration created serious water supply, sanitation, and drainage problems. The government decided to invest in expanding the water supply system to meet increased demand, improve living standards, and boost the economy. This investment will also improve maintenance and training, and introduce new technologies.
The project will improve water supply, sanitation, drainage and solid waste through a 25-year masterplan, a feasibility study looking 10 years ahead, and detailed design to meet immediate needs.
The feasibility study and InfoWorks WS modeling of the water supply focused on the Greater Banjul area, but the project also included provision for training in how to extend the models to the rest of the country.
The project started in May 2004 so work on creating the InfoWorks WS model begun in November 2005 following development of a three-phase plan. The first phase included a ring main around the area´s well fields and the construction of a new treatment facility with an ultimate capacity of 400 liters per second (l/sec). The smaller second phase includes a new well field to meet growing demand, while the third phase involves the coastal area, which is perfectly located for tourism development.
The existing distribution network includes wells, treatment facilities, water tanks and towers. Nineteen elevated tanks in the Greater Banjul area were sized from 250m3 to 500m3. Treatment includes aeration, chlorination, and use of contact tanks.
Production of the master plan, feasibility study, and detailed design highlighted local factors that influenced the choice of solutions. Gambia does not lack water, but several issues hinder its effective distribution, including a parts shortage and staff training. Maintenance was virtually non-existent.
The InfoWorks WS model provided a reliable mechanism for evaluating earlier studies and preparing the subsequent stages of work for implementation.