To develop efficient and effective flood water control measures, a good knowledge of the topography of the study area is important for the design.
As much as practicable, the engineering survey here followed the existing street layouts.
The delineation of the study areas into catchments and sub-catchment using road networks was made for ease of collation and analysis of ground data.
Survey control points were established within the project areas for ease of referencing during the study and construction periods.
The spot heights (ground surface data) obtained during the Engineering Survey work were used to produce the terrain modelling showing the surface flow directions, generate a contour map of the entire project area, as well as perform the hydrological analysis.
With the modelling of these rainfall-runoff flow patterns, an idea of the natural surface flow pattern was obtained for all the catchments.