Our strategy worked. Within two months we had proposals from six of the eight companies, and CEF knew others were on the way. Unfortunately, the proposals were wish lists, lacking practical ways to design water and sewerage systems in the favelas . Rio favelas climb the high hills surrounding the city. Houses appear to sit on top of one another and often do.
Population density is extremely high.
Their layout has no rhyme or reason. Virtually every bit of space is in use by someone somehow. The laying of pipes, even underground, would more than likely intrude on someone' s sense of ownership. Adjudicating disputes from the outside can be next to impossible. At the same time, the laws of hydraulics can't be changed, and engineers don't like to negotiate their designs with nonengineers.