Also, the first phase will consist of the planning, surveying and later the engineering of the infrastructure plans.
Haiti's surveying need to be brought up to 21st century standards and this won't happen in house. This will come from abroad and I expect with so many surveyors out of work in Florida they will gladly come and make it happen. Once the City has been gridded properly a GIS system can be created and the real planning and engineering can be done.
The engineering can be done in phases but the most important things will be to get the water and sewer lines in. Of course water and wastewater plants will be needed to be built, but these can started on almost immediately after the City is broken up into municipal districts as a quick census/demographic study can be done.
A waste water plant will be the easiest but potable water plants may be a challenge for a number of reasons. First, one needs a relatively clean water source. Salt water isn't a problem as desalinization plants are common now, especially in the Caribbean. The issue is how far does one have to go away from the port to find a relatively non human contaminated source. However, I expect that there may be a good source of well water basing this on the proximity to a project I have in the Western DR and conversations with a couple geotechical engineers. At any rate, these plant can be built concurrently while the gridding of the city is being wrapped up and the installation of the new sewer and water mains.
Haiti could very well in 10 years have the most modern infrastructure, surveying and gis of any country in the Caribbean, less the US protectorates.