65. Engineering Geophysics Utility in Small Hydropower Development

Small hydropower (SHP) is a clean source of renewable energy. In the present scenario of environmental and economic constraints, growing need for SHP is being felt due to its short gestation period and limited environmental impact as well as the aspect of socio-economic benefits. Establishing a sound high/medium head SHP scheme, involving diversion and appurtenant civil structures, call for a well-considered approach in view of the restricted timeframe and finance. In planning and development of SHP adequate knowledge of the geotechnical conditions at site is important besides the other factors that are involved. Application of tools and techniques that are helpful in enhancing efficiency of the geotechnical evaluation study is therefore preferable: Engineering geophysics is an efficient means of subsurface investigation. The merit of application of this low cost aid lies in its ease of deployment and rapidity in providing a reliable knowledge of the underground over a large area, substantiating the requisite geotechnical evaluation studies thereby. The paper discusses the gainful utilization of the indirect techniques of engineering geophysics in SHP project development. Geophysical methods rely in measuring the physical properties of soil/rock. It is the contrast in physical properties between different materials and their relationship with engineering and other parameters that make these indirect techniques a powerful aid in subsurface exploration. Technological advancements and development of portable digital data acquisition instrument systems have increased the versatility in evaluating underground conditions and site characterization. The state-of-the-art subsurface geophysical investigation techniques of refraction seismics and resistivity imaging are described herein that are helpful towards minimizing involvement of the conventional direct exploration methods, aiding in accelerated and economical development of the SHP scheme.