PHOTO - ANALYSIS FOR WATER RESOURCES DEVELOPMENT PROJECTS

Abstract

Photo-analysis has been applied for study and development, to many varied fields. Soil, geology, urban planning, engineering and water-resources are only a few in a long list. The water-resources engineer needs to have an ample knowledge of hydrology for any water-resources development planning. The study of hydrology demands know-ledge of the hydrologic cycle that occurs in the area under investigation. Each of the parameters of the hydrologic cycle - starting from precipitation down to surface run-off, can be studied effectively with the help of aerial photo-analysis which includes both measurement and interpretation. Precipitation apart, run-off is the most important factor in the hydrologic cycle and, as such hydrologists have done much work on it and are still in the search for techniques for bet er estimation of ruz-off. The rur-off factor, which helps in the evaluation of run-off by the formula Q = C.I.A., thus assumes paramount importance in engineering hydrology. The knowledge of the run-off factor leads to the evaluation and prediction, of discharges which the hydro-logist or engineer needs to design control on regulatory structures in a stream system. In this dissertation, an attempt has been made through photo-analysis, to determine quantitatively the value of the run-off factor of the Tons (v) catchment that falls, partly in Uttar Pradesh and partly in Himachal .Pradesh. Such an analysis needs photo-interpretation study on soil, geology, vegetative cover, land-use, stream and areal geometries of the catchment, since the value of the run-off factor is a function of all these and more (antecedent moisture condition, climatic factors etc.). if a topographic map is available, work is made easier, since overlays can be prepared directly from these by filling in the deficiencies from the photographs. For an unmapped area, any photogrammet-ric method, of the many available, depending ,on the accuracy desired, can be adopted. Chapter 1 has been devoted to emphasise the importance of Water Resources development projects and intro-duce the subject matter and scope of the problem. Chapter 2 deals with the hydrologic cycle and its parameter . How photo-analysis techniques can be employed to estimate the parameters are also discussed in detail. Photo-inte --pretation- of geology, soil, vegetation and land-use pertaining to the subject of study and use of the technique in dam-site selection have been discussed in chapter 3. Chapter 4 embodies the work done through photo-analysis of the Tons Valley. Tables have been inserted to show the various data collected from the photographs and the results arrived at. Chapter 5 deals with the outcome of the photo-analysis work carried out on the Tons Valley with certain recommendations and the author's ideas on future research and extension of the present work.