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Introduction hydrology


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Introduction hydrology

  1. 1. Presented by: Muhammad Aleem
  2. 2. It begins with a storm … They were rolls, waves that finished in a puff: known noises, village things. Everything that we have here is animated, lively, maybe because the distances are short and fixed as in a theatre. The downpours were onto the courtyards here around, the thunder up here above the roofs; I could recognize by ear, a little further up, the place of the usual God that made storms when we were children, He too a village character. Here all is as if intensified, a matter of scale probably, of inner relationships. The shape of the noises and of these thoughts (which were, after all, the same thing) seemed to me for a moment truer than true, but it cannot be recreated with words
  3. 3. Objectives “To explain what hydrology is and what it deals with..” • • • The elements of the water cycle The spatial and temporal scales involved The mass and energy balance at a global scale
  4. 4. The Water Cycle The water on Earth flows from the atmosphere to the ground. And then from the rivers to the sea, from where it returns to the atmosphere: “Hydrology is the science that studies these flows, which make up the water cycle.”
  5. 5. The flows from the atmosphere to the surface of the Earth are called Precipitations. The water that reaches the ground can infiltrate and flow within the soil or it can run off on the surface - these are referred to as “Horizontal Flows”. At the same time, there is evaporation from the soil and water surfaces, and transpiration from plants and animals (in a word, evapotranspiration) Infiltration and evaporation constitute the “Vertical Flows.”
  6. 6. During the first seconds after the Big Bang, Hydrogen and Helium were created. According to the Theories, oxygen was formed a little later. However, it is the third element more diffuse in the universe.
  7. 7. If you consider that Helium is not very much reactive, it couldn’t be a real surprise that an element built on Hydrogen and Oxygen is abundant on the Earth.
  8. 8.  For a given catchment, in an interval of time ∆t, the continuity equation for water in its various phases can be given as: Mass inflow – Mass outflow = Change In Mass Storage  If the density of the inflow, outflow and storage volumes are the same: Vi – Vo= ∆S Vi - Inflow volume in to the catchment, Vo - Outflow volume from the catchment and ∆S - change in the water volume
  9. 9. Therefore, the water budget of a catchment for a time interval ∆t is written as: P – R – G – E – T = ∆S P = Precipitation R = Surface runoff G = net ground water flow out of the catchment, E = Evaporation T = Transpiration ∆S = change in storage The above equation is called the WATER BUDGET EQUATION for a catchment.
  10. 10. Total quantity of water in the world is estimated as 1386 M km3 1337.5 M km3 of water is contained in oceans as saline water  The rest 48.5 M km3 is land water    13.8 M km3 is again saline 34.7 M km3 is fresh water  10.6 M km3 is both liquid and fresh  24.1 M km3 is a frozen ice and glaciers in the polar regions and mountain tops
  11. 11. Estimated World Water Quantitites 96% 2% 1% 1% Ocean-saline Land - saline Fresh - Liquid Fresh - Frozen
  12. 12. • The variation of water production from catchments can be calculated and described by hydrology. • It is used to find out maximum portable flood at proposed sites. e.g. dam .. • Used in prediction of flood over a spillway, at highway culvert or in urban storm drainage. • Used to assess the reservoir capacity required to assure enough water for irrigation or municipal water supply during drought.
  13. 13. • • Engineering hydrology enables us to find out the relationship between a catchments' surface water and groundwater resources. Used in connection with design and operations of hydraulic structure.
  14. 14. THANK YOU …. ANY QUERIES ?????