| Abstract: | In advanced countries, the survey of gravel deposits and soil for road construction is being increasingly conducted through aerial photographs as the process is expeditious and economical. However, no Air photo Interpretation technique had been developed to locate hiddenKankar deposits and other low grade aggregates met with in India. In view of this, research was undertaken at the Central Road Research Institute for the establishment of new Air Photo Patterns which enable the location of sources of these construction materials in the country. Since shortage of road aggregates both in the alluvial plains as well as desert areas is very acute andkankar is known to occur under an overburden of 2 to 4 ft. of soil, attempt were made for the formulation of Air Photo Patterns for the identification of such deposite. The investigation covered an area of about 4,500 sq. miles. (12,000 sq. kms.) in U.P. and 5,000 sq miles (13,000 sq kms.) in western Rajasthan and comprised a study of aerial photographs of the area in conjunction with ground survey. As a result of this study, well defined and distinct Air Photo Patterns for the location ofKankar deposits in both the above mentioned regions have been established. The accuracy of interpretation has been experienced to be of the order of about 75 to 80 per cent. Recently Air Photo Patterns for the indentification of hidden gravel deposits have also been confirmed by carrying out interpretation and survey in an area of about 300 sq miles (800 sq kms.) around Chandigarh. Since the country is embarking on big projects of road construction in the Five Year Plans, the utilisation of this technique for rapid survey of highway materials and the timely information about the location of such deposits, will go a long way in economising the cost of road construction. The Paper discusses the techniques of Air Photo Interpretation developed for hidden aggregate deposits and soils which would enable the indentification and location of potential natural resources, for future programme of the road construction. |
