Department of Civil Engineering Faculty of Engineering Mahidol University Lecture Notes EGEN 612 Applied Hydrology Areeya Rittima D Eng

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Department of Civil Engineering Faculty of Engineering Mahidol University Lecture Notes EGEN 612 Applied Hydrology Areeya Rittima D Eng Powered By Docstoc
					Department of Civil Engineering
Faculty of Engineering, Mahidol University




      Lecture Notes
EGEN 612 Applied Hydrology


                   Areeya Rittima, D.Eng.
                   E-mail: egart@mahidol.ac.th
Department of Civil Engineering
Faculty of Engineering, Mahidol University



         Chapter 1
        Introduction
     Hydrologic Cycle
     Systems Concept
     Hydrologic System Model
               Hydrology


Hydrology is the science of water.

It is the study of the occurrence, character,
and movement of water within and between
the physical and biological components of
the environment.

The practical application of hydrology is
called Applied Hydrology.
           Applied Hydrology


Applied Hydrology are found in such tasks as

     Design and operation of hydraulic
     structures.
     Water supply
     Wastewater treatment and disposal
     Irrigation
     Drainage
     Hydropower generation
     Flood control
     Applied Hydrology


Navigation
Erosion and sediment control
Salinity control
Pollution abatement
Recreation use of water
Fish and wildlife protection
    Role of Applied Hydrology


The role of applied hydrology is

  to help these tasks
  to provide guidance for planning and
  management of water resource
                Hydrologic Cycle

 15 km   Hydrosphere
                       Water on earth exists :
  1 km   Lithosphere    in a space called Hydrosphere
                        (15 km up into the atmosphere)
     Earth              in the crust of the earth (1 km
                        down into the Lithosphere)




Water circulates in the hydrosphere through the
maze of paths constituting the Hydrologic Cycle
        Hydrologic Cycle


The hydrologic cycle is the central focus
of hydrology.
The cycle has no beginning or end.
Its processes occur continuously.
                 Hydrologic Cycle
  Hydrologic Cycle
Hydrologic cycle



                                    Atmospheric Subsystem




                                         Surface Subsystem




                                    Groundwater Subsystem
       Hydrologic Cycle


                                      96.5% of all the earth’s water is in the oceans.

                                                1.7% of all the earth’s water is in
                                                the groundwater.

                                                1.7% of all the earth’s water is in
                                                the polar ices.



0.1% of all the earth’s water is in the surface and
atmospheric water system.




                                                           Estimated world
                                                           water quantities
                   Hydrologic Cycle
Hydrologic cycle with global annual average water balance.




                                           Average Water Balance in 1978
                     Hydrologic Cycle




Average Water Balance in 2005
                Hydrologic Cycle



                     100%



                     61%
Global annual
water balance
                      39%
                     Example 1

Estimate the residence time of global
atmospheric moisture.
         Tr = Residence time (the average duration for a water
     S         molecule to pass through a subsystem of the
Tr 
     Q         hydrologic cycle).
         S = Volume of water
         Q = Flow rate

 S  12,900 km3 Table                          km3
                           Q  458,800  119,000     Table 
                                                  yr
                                     km3
                            577,000
                                      yr
                 S  12,900    (km3 )
             Tr                     0.033 yr  8.2 days
                 Q 577,000 (km / yr)
                                3
Systems Concept


             Global hydrologic cycle is
             represented in a simplified
             way by means of “The System
             Concept”

             Most hydrologic system is
             inherently random, because
             their major input is
             precipitation, a highly variable
             and unpredictable
             phenomena.

             The statistical analysis plays a
             large role in hydrologic
             analysis.

                 Block diagram
              representation of the
            global hydrologic system.
                         Example 2

   Represent the storm rainfall-runoff process on
   a watershed as a hydrologic system.

                      Input            A watershed is the area of
                                       land draining into a stream
                                       at a given location.

                                       The watershed divide is a
                                       line dividing land whose
                                       drainage flows toward the
                              Output   given stream from land
                                       whose drainage flows away
                                       from that stream.

A Watershed as a Hydrologic System
  Basic Equation of Hydrologic Cycle


   Input        Process      Output
  (Rainfall)    (Basin)      (Runoff)

Simple Hydrologic System Model

Unsteady Flow Equation ; I-Q=dS/dt
     I = Input (volume/time)
    O= Output (volume/time)
    dS/dt = Time rate of change of storage
          Basic Equation of Hydrologic Cycle

                  P
                                        Region A                     P=Precipitation
                                                   Earth’s surface   E=Evaporation
R1                                                                   T=Transpiration
                        Rg   Eg         Tg
                                                        R2
                                                                     R=Surface Runoff
                                                                     G=Groundwater Flow
     Es    Ts


                                                                     Rg=Subsurface Flow
                                                                     I=Infiltration
G1
                  I
                                                                     S=Storage
                  Sg                                     G2

                                                                     s=Land Surface
                                                                     g=Groundwater


                Level of plastic rock
     Basic Equation of Hydrologic Cycle

 Water Budget in Land Surface
   (P+R1+Rg)-(R2+Es+Ts+I)=Ss                (1)

 Water Budget in Groundwater
   (I+G1)-(G2+Rg+Eg+Tg)=Sg                  (2)

     P-(R2-R1)-(Es+Eg)-(Ts+Tg)-(G2-G1)= Ss+Sg *

R (Net Surface Flow)=R2-R1
E (Net Evaporation) =E2+E1
T (Net Transpiration)=Ts+Tg      P-R-E-T-G=S
G (Net Groundwater Flow)=G2-G1
S= Ss+Sg

				
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posted:12/9/2011
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