This category includs all contour surveys required by the Irrigation, Mahaweli Authority or other Government Departments and Statutory Bodies for the purpose of designing engineering projects of varies kinds. The majority of these contour surveys are for irrigation, designs and construction of roads, railways and water supply & drainage.
After a preliminary study of topographical maps a more intimate knowledge of the land form and topography is gained through an Engineering Survey. The distinguishing feature in this survey is that relative heights of points are given and the accuracy depends on the project under consideration.
These are the surveys undertaken by the department for the purpose of designing engineering projects of various kinds. The majority of these contour surveys are for irrigation, flood protection and water supply and drainage etc. The survey requirements in these schemes vary from type to type and standard departmental specifications are available for each type of survey.