The outline design will examine alternative sites, and alternative layouts at each site, so that a number of feasible implementation options that will provide the basic operational requirements for the PPP project could be specified. The outline design will also identify any critical areas where physical limitations on available sites could restrict the design layout.
It is also necessary to identify other facilities or components, which, although they may have no impact on the ability of the scheme to satisfy the primary operational requirements, are necessary due to safety or environmental protection considerations. These secondary facilities should be identified at this stage of the scheme development so that any necessary land and budget provisions can be incorporated in the proposal. For example a public market cum commercial center, which is expected to generate large volumes of waste water, will need an onsite wastewater treatment facility considering that sewerage connections in the Philippines are almost non-existent. To appraise such issues, site assessment will be required including geography, topography, geology, hydrology, etc.