Return to Task 4. Perform a Period of Record Simulation for Water Years 1916-2018

Last Modified: 2024-06-26 15:43:51.849

Allotted Time

This task should take approximately 10 - 15 minutes to complete.

Download the initial project files here:

Final Model Parameters

Enter initial and final model parameters (average them for all subbasins) on the attached Final_Project_Results.xlsx.

Snow ParameterInitial ValueFinal Value

PX Temperature (deg F)



Base Temperature (deg F)



ATI Coefficient



Wet Melt Method



Wet Meltrate (in / deg F - day)



Rain Rate Limit (in / day)



ATI-Meltrate Function



Cold Limit (in / day)



ATI-Coldrate Function



Water Capacity (%)



Groundmelt (in / day)



Loss ParameterInitial ValueFinal Value

Initial Deficit (in)



Maximum Deficit (in)



Constant Rate (in / hr)



Percent Impervious Area



Transform ParameterInitial ValueFinal Value
Time of Concentration (hr)

Storage Coefficient (hr)

Baseflow ParameterInitial ValueFinal Value

GW1 Initial (cfs / sq mi)



GW2 Initial (cfs / sq mi)



GW1 Fraction



GW1 Coefficient (hr)



GW1 Steps



GW2 Fraction



GW2 Steps



GW2 Coefficient (hr)



Final Flow-Frequency Results

Enter flow-frequency results for several time periods using both observed and model results in the tables on the spreadsheet:


Observed vs Model Results Comparison Using 

Annual Exceedance Probability (%)Daily Average Flow (cfs) Using:
Observed Data for WY 1973 - 2018Model Results for WY 1973 - 2018

0.2



0.5



1.0



2.0



5.0



Observed vs Model Results Comparison Using All Data

Annual Exceedance Probability (%)Daily Average Flow (cfs) Using:
Observed Data for WY 1973 - 2018Model Results for WY 1916 - 2018

0.2



0.5



1.0



2.0



5.0



Summary Questions

Question: Describe the process(es) you followed to calibrate the model to WY 1983 - 1992.

Share your thoughts with others.  We will discuss as a group. 

Question: What was the most challenging part of model development and calibration?

Share your thoughts with others.  We will discuss as a group. 

Question: How much confidence do you have in the initial parameter estimates?  How much confidence do you have in the final parameter estimates?

Share your thoughts with others.  We will discuss as a group. 

Question: How well did the model validate to WY 1993 - 2002?

Share your thoughts with others.  We will discuss as a group. 

Question: How confident are you in the estimated discharges for WY 1916 - 2018?

Share your thoughts with others.  We will discuss as a group. 

Question: Which parameters are the most impactful to Success Dam inflows?

Share your thoughts with others.  We will discuss as a group. 

This concludes the Advanced Applications of HEC-HMS Final Project workshop. Submit your spreadsheet results to June 2024 Final Submissions - Files - HEC Drive (hecdev.net) in the format LastName_FirstName.xlsx.