Topographic Considerations

For proper site selection/planning, in addition to climatic data, the following information 

is also important : 

1. Topographic data 
2. Geological information 
3. Hydrology of the area 
4. Soil types of the site 

A site is not simply a collection of buildings and streets, but it is a system of structures,surfaces, spaces, living things and climatic parameters. It is a good practice to prepare a site plan whenever substantial groups of buildings are erected,such as housing colonies,factories, shopping centres, institutions, cultural centres etc., inorder to help future planning. 

Past experience indicates the categories of data that is most likely to be useful. For example, foundation conditions and the water table are the key sub-surface conditions to be considered. The rock or the earth below the ground level has importance primarily with regard to the way in which they can be excavated, their drainage characteristics, and the manner in which they will support the structures and plants. The engineering characteristics of the soil depend on its type and moisture content. While critical problems must be studied by laboratory methods, a surprisingly good picture can be gained from field reconnaissance also. Other sources of information include small test pits, geological maps, existing cuttings and foundations, the types of vegetation at site and the experience of previous builders and engineers. 

Money spent on these preliminary investigations will help in avoiding : 

1. expensive site-preparation, (cut and fill, drainage of the sub-soil etc), 
2. rectification of damage caused to buildings (due to settling, sliding and tilting), and  
3. discomfort due to dampness, insanitation, flooding etc. 

Plants and trees are particularly good indicators; they speak not only of the climate, but of the soil, the water and the history of the place. 

We shall study in the following Sections, the methods of collecting data, and reaching broad conclusions. In the case of large-scale projects the services of experts will have to be utilised.