ABSTRACT
The necessary field surveys and related investigations required for the planning and design of a drainage system are described in this chapter. Most of the investigations and the indicated levels of detail are for the detailed design phase, and would generally also be undertaken during the feasibility stage at a somewhat lower level of detail. The investigations and/or evaluations are comparable to those needed for the performance and benchmarking activities described in Chapter 23. The difference is that for performance assessment and benchmarking long-term records are needed but at a lower density than for detailed design.
