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Training

Flow Calibration Tutorial

Calibration Scenarios

Progress through the following four categories from top to bottom.  For each category, click on the scenario which best describes your situation.  The links provide advise on which parameter(s) to adjust, and in what direction, in order to address the scenario.  Subsequent links provide recommendations on how to estimate parameter values (in BASINS Technical Note 6) as well as links to figures demonstrating how parameters impact modeled stream flow over their range of acceptable values.  Parameters to which modeled stream flow is unsensitive have no associated figure; input values for these parameters should instead be based on the literature or field estimates given in BASINS Technical Note 6.  The example diagnostic plots linked from this page, are sample graphs you can produce to help determine if your simulation output matches the scenario conditions. You will likely need to iterate through the four categories, but ensuring the annual water balance and high/low distributions are reasonable first will help reduce the number of iterations.

The structure of this page and the advise on linked pages are based on the algorithms used in the Expert System for Calibration of HSPF (HSPEXP) and detailed in the HSPEXP User Manual (Lumb, et al, 1994).

    Annual Trends and Water Balance
    (see example diagnostic plots in PDF format: simulated/observed flow , evapotranspiration, ET components)
     
  1. Observed Flow Less Than Simulated

  2.  
  3. Observed Flow Greater Than Simulated

  4.  
  5. Simulated Peaks Characteristically Lag Behind, Or Are Ahead Of, Observed Peaks
  6. High Flow/Low Flow Distribution
    (see example diagnostic plot in PDF format: baseflow v. total flow, ET components)
     

  7. Simulated Daily Or Storm Flows Are High, Subsequent Simulated Base Flows Are Low

  8.  
  9. Simulated Daily Or Storm Flows Are Low, Subsequent Simulated Base Flows Are High

  10.  
  11. Simulated Base Flow Recedes Faster Than Observed Base Flow

  12.  
  13. Simulated Base Flow Recedes Slower Than Observed Base Flow
  14. Storm Flow
    (see example diagnostic plot in PDF format: simulated/observed flow, surface/inter-/stream flow)
     

  15. High Simulated Peak Storm Flows, With Poor Simulation Of Storm Runoff Volumes

  16.  
  17. High Simulated Peak Storm Flows, Good Simulation Of Runoff Volumes For Major Storm

  18.  
  19. Low Simulated Peak Storm Flows, With Poor Simulation Of Storm Runoff Volumes

  20.  
  21. Low Simulated Peak Storm Flows, Good Simulation of Runoff Volumes For Major Storms

  22.  
  23. High Simulated Peak Flows and Storm Volume

  24.  
  25. Low Simulated Peak Flows and Storm Volume
  26. Seasonal Discrepancies
    (see example diagnostic plots in PDF format: baseflow and sim/obs flow, ET components, baseflow and rainfall [flow])
     

  27. The Summer Flow Error Is Greater Than The Winter Flow Error

  28.  
  29. Storms In Dry Periods Simulated Low, Storms With More Antecedent Rain Simulated High

  30.  
  31. Storms In Dry Periods Simulated High, Storms With More Antecedent Rain Simulated Low

  32.  
  33. Simulated Base Flow During Wet Periods Or Winter Recede More Slowly Than Observed,While Simulated Base Flow During Dry Periods Or Summer Recede Faster Than Observed

  34.  
  35. Simulated Base Flow During Wet Periods Or Winter Recede Faster Than Observed, While Simulated Base Flow During Dry Periods Or Summer Recede More Slowly Than Observed

  36.  
  37. Observed, But Not Simulated, Base Flow Increases In Fall Without Substantial Rainfall

  38.  
  39. Observed, But Not Simulated, Base Flow Decreases In Fall Without Substantial Rainfall

  40.  
  41. Simulated High Flows During The Summer Are Greater Than Observed

  42.  
  43. Simulated High Flows During The Summer Are Less Than Observed
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