Note for Water Resources Engineering - WRE by Vssut Rulers

Topics ( 7 )

Text from page-1

5th Semester B.TECH. [ CIVIL ENGINEERING ] WATER RESOURCES ENGINEERING The Need… water is curative in indigestion, water is nourishing after digestion; water is appetizing during food, and ill-affects immediately after food. ajIrNe bheShajam vAri, jIrNe vAri balapradam | bhojane chAmRitam vAri, bhojanAnte viShapradam || Water - the least appreciated thing, right before air. We just take it for granted. There was a time, not too long ago, when you could drink water from pretty much any tap in india, or a well, river. There would be water sheds called 'pyaaoo' on road sides, sponsored by local businessman or charitable person, manned by local hands. You would get some of sweetest natural water, along with some jaggery and roasted grams (at least in hot and dry Rajasthan), easing your travelrelated travails. Thanks to recent decades of industrial progress, even in india it is difficult to find drinkable water from free natural resources. And the rivers, the life line of any civilization, are terribly polluted as well like the Brahmani, GangA (ग ग ) and YamunA (य ). WATER WATER WATER …WATER EVERY WHERE…NOT A DROP OF WATER TO DRINK!!! … BEFORE THIS HAPPENS, LET US GET UP AND GIVE DUE PRESTIGE TO WATER. HENCE IS THE COURSE IMPORTANT FOR THE ENGINEERS, WHO ARE RESPONSIBLE FOR THE WELBEING OF THE SOCIETY. MODULE 1:

Text from page-2

Instructional Objectives After completion of this Module, the student shall know about 1. Hydrologic cycle and its components 2. Distribution of earth’s water resources 3. Distribution of fresh water on earth 4. Rainfall distribution in India 5. Land and water resources of India; water development potential 6. Need for development of water resources 7. Forms and Types of precipitation 8. Methods of Measurement of Precipitation 9. Presentation and interpretation of rainfall data 10. Abstractions from Precipitation INTRODUCTION Water on the surface of earth is available in the atmosphere, the oceans, on land and within the soil and fractured rock of the earth’s crust. Water molecules from one location to another are driven due to the solar energy transmitted to the surface of the earth from Sun. Moisture circulates from the earth into the atmosphere through evaporation and then back into the earth as precipitation. Hydrology: It is the study of physical geographic which deals with the origin, distribution and properties of water present in earth surface. Hydrological Cycle:Precipitation ↑ Condensation ↑ Formation of Clouds ↑ Evaporation ↑ Ocean

Text from page-3

Water Budget Equation:Mass inflow – Mass outflow = Change in storage P – R – G – E – T = ∆S Where, P = Precipitation T = Transpiration G = Ground water Resources R = Runoff E = Evaporation ∆S = Chang in Storage Catchment Area:River Streams

Text from page-4

World Water Balance:Total quantity of water in the world is estimated to be about 1386 million cubic kilometer (M Km3). About 96.5% of this water is contained in the oceans as saline water. Some of the water on the land amounting to about 1% of the total water is also saline. Thus, only about 35.0 M Km 3 of fresh water is available. Out of this about 10.6 M Km3 is both liquid and fresh and the remaining 24.4 M Km 3 is contained in frozen state as ice in the polar regions and on mountain tops and glaciers. PRECIPITATION INTRODUCTION: The term “precipitation” denotes all forms of water that reach the earth from the atmosphere. The usual forms are rainfall, snowfall, hail, frost and dew. The magnitude of precipitation varies with time and space. For precipitation to form: (i) the atmosphere must have moisture, (ii) there must be sufficient nuclei present to aid condensation , (iii) weather conditions must be good for condensation of water vapour to take place, and (iv) the products of condensation must reach the earth. FORMS OF PRECIPITATION: Some of the common forms of precipitation are rain, snow, drizzle, glaze, sleet and hail. 1. Rain