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BASINS
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Training

Flow Calibration Tutorial

Calibration Scenarios

High Flow/Low Flow Distribution
 

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

  2. Increase infiltration (INFILT). The major effect of increased infiltration is to shift drainage from rapid response (surface runoff and interflow) to delayed response (base flow). This decreases both simulated storm volumes and simulated storm peaks.

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

  4. Decrease infiltration (INFILT). The major effect of decreased infiltration is to shift drainage from delayed response (base flow) to rapid response (surface runoff and interflow). This increases both simulated storm volumes and simulated storm peaks.

  5. Simulated Base Flow Recedes Faster Than Observed Base Flow

  6. If this occurs in either summer or winter, increase the basic groundwater recession rate parameter, AGWRC. AGWRC is the ratio of today’s base flow to yesterday’s base flow. An increase will flatten the base flow recession.

  7.  Simulated Base Flow Recedes Slower Than Observed Base Flow
    1. If this occurs in either summer or winter, decrease the basic groundwater recession rate parameter, AGWRC . AGWRC is the ratio of today’s base flow to yesterday’s base flow. A decrease will steepen the base flow recession. HSPEXP Appendix A specifies that a value in PERLND of >= 0.88 is sufficiently high to reduce.
    2. If PERLND has a value for AGWRC < 0.88, increase BASETP. Decreasing the base flow recession constant further would make it behave more like interflow. Thus, it would be better to increase the effect of transpiration along the channels.
    3. If PERLND has a value for AGWRC < 0.88, increase DEEPFR . Decreasing the base flow recession constant further would make it behave more like interflow. It might be best to send drainage from the soil profile to deeper aquifers instead of base flow.
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