Hydrologic modeling of Waller Creek

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Hydrologic modeling of Waller
Creek

• Prepared by Mustafa AKCAY

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TABLE OF CONTENTS

• ? BACKGROUND
• ? WORKING WITH HEC-Prepro
• ? RUNNING HMS
• ? CALIBRATION OF HMS PARAMETERS
• ? RESULTS
• ? CONCLUTION

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BACKGROUND ?HYDROLOGIC
SYSTEM MODEL

• HSM is an approximation of the actual system
  in which inputs and outputs are measurable
  hydrologic variables and system operator is
  described by a set of equations linking the
  inputs and outputs.
• Input
  Output
• I(t)
  Q(t)
• Q(t)? I(t)

Operator,?
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Hydrologic Model Classification

• Hydrologic Models
• Physical Models
  ? Abstract Models
• 
  Input
  Output
• HMS (Hydrologic Modeling System)
  Deterministic ? Stochastic
• 
  
  Output is not a fixed
• Input F(infiltration,transform,routing)
  Output value
  but instead
• 
  
  described as a
• Precipitation, i Stream
  flow,Q
  probability distr.
  

System f(ran.,space,time)
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RUNNING HEC-Prepro

• Dem ? Digital Elevation
• RF3 ? Stream Network

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?BURNING IN ? ?FILLING STREAM
GRIDS?FLOW DIRECTION ? ?FLOW ACCUMULATION

• Rising the land surface cells that are of stream
  to delinate streams from DEM.
• Filling the pits that are probably to cause wrong
  flow directions
• Defing threshold or minimum drainage area
• Darker the color of individual grid,the more grid
  cells drain into that cell.

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?GAGES--OUTLETS--LINKS?SUB-WATER DELINEATION
?VECTORIZATION

• Shape file with points representing gages that
  will be imported into ArcView.
• Adding outlets to change the places of gages that
  are off the river and pointing the joints
• Delineation of watershed according to
  gages,outlets,links
• Vectorization for easyness of using and storing
  data compared with grid base analysis.

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RUNNING HMS
RUNNING HMS
?Transfer of Hydrologic Attributes to
Schematic ? Creating the HMS Components

• HMS schematic is conceptual model that captures
  the connectivity between the different elements
  of the hydrologic system
• Opening a new HMS project and importing the basin
  file , and then adding a background map .

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?Location of USGS Stations ,38th street and 23rd
street, and their annual peak values for
corresponding rainfall.
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?Stream flow vs Precipitation
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?Best-lines for runoff-rainfall data
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? Application of Rational Method

• Assumptions
• Computed peak rate of runoff at the outlet point
  is a function of the average rainfall rate during
  the time of concentration.
• Time of concentration Time from most remote part
  of the drainage area to the out flow point.
• Constant rainfall intensity.

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?Most critical flow between 1959-64
Q1(HMS)173cfs Q1(Measured)289cfs 40
accuracy Q2(HMS)295cfs
Q2(Measured)717cfs 143 accuracy
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?Most Critical Flow Between 1965-1972
Q1(HMS)366.9cfs Q1(Measured)589 60
accuracy Q2(HMS)633cfs Q2(Measured)857
35 accuracy
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?Most Critical Flow Between 1973-1979
Q1(HMS)614cfs Q1(Measured)521cfs 15
accuracy Q2(HMS)1059cfs Q2(Measured)1386cfs
30 accuracy
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RESULTS

• According to data I obtained, by the definition
  of stochastic model
• the runoff will fall in ?140, ?60, ?30
  neighborhood of runoff you obtained from HMS
  between 1959-64, 1965-72, 1973-1979 respectively.
• For runoff from 1997-... ?

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CONCLUSION

• Using SCS Method for Infiltration may increase
  the precision of the model.
• Lots of uncertainty affecting the output so it is
  difficult to make modeling with high accuracy
• Dont even think of a modeling of a basin by just
  one rainfall gage station!

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Appreciations

• Esteban AZAGRA
• Jona F.JONSDOTTIR