A dam is a national property which is constructed for the national economy with a huge national investment and other resources. The safety of a dam is of prime importance for safeguarding national investment and benefits derived by the nation from this project. An unsafe dam causes hazard to human life and property in downstream. Improper investigation and incorrect feasibility reports may lead to national disaster.

This chapter narrates to readers the different types of exploration, such as geological, geotechnical, hydrological, and seismic to be conducted in the prefeasibility, feasibility, detailed investigation and construction stages.

This chapter explains to readers how geologists make the geological logging of foundation and advises consolidation grouting and other foundation treatment to fill interstices, fissures, fractures and seams to ensure the stability of the dam foundation.