Monrovia, Liberia
Monrovia’s climate offers abundant rainfall, with nearly 500 cm (200 inches (in)) of rain per year. This, coupled with estimated long-term costs of water delivery, led the design team to investigate the feasibility of rainwater harvesting. The project site had no access to a water well or municipal supply and therefore would require water to be trucked to the facility from a local stream at a cost of approximately $0.06/L ($0.02/gal), with some security risk.
By optimizing roof collection area and tank size, and by installing low-flow fixtures (37% savings from Energy Policy Act (EPAct) requirements), rainwater collected from building roof was designed to supply nearly 100% of all plumbing fixtures, allowing Post to virtually eliminate the need for purchased water delivery. The system collects and treats almost three million L (792,000 gal) of collected rainwater per year.
Collected rainwater is piped to storage tanks, with overflow routed to the stormwater pond located nearby during periods of excessive rainfall. The system includes in-line vortex filters to keep sedimentation generated during the dry season from entering the treatment system.
Figure 8: U.S. Embassy Monrovia uses rainwater collection to achieve greater water autonomy
