Hydrologic and Hydraulic Uncertainties Workshop

Last Modified: 2024-08-01 19:21:11.062

Objective

Using the HEC-FDA Version 2.0 software for Workshop (in-person 75 min) – In this hands-on workshop participants get introduced to HEC-FDA Version 2.0 to familiarize students with entering data for defining exceedance-probability and stage-discharge functions, and associated uncertainties.  This workshop pertains to the Hydraulic data and frequency functions.

Downloadable Workshop Materials

Software Version

HEC-FDA pre-release Version 2.0 will be used during the 2024 PROSPECT #209 course.  (Note: the HEC-FDA Version 2.0 software is available here: FY24 Download HEC-FDA Version 2.0 Portable Package).

Note: To follow along with the instructions provided in this workshop

Unless you've already downloaded the HEC-FDA software, the Example Study Data (zipped folder contains all data needed for all HEC-FDA workshops) and the workshop datafiles then please follow the following instructions.

1. Download the HEC-FDA Version 2.0 software by following the instructions provided here: FY24 Download HEC-FDA Version 2.0 Portable Package.
2. Download and save the Workshop Datafiles to the specified path. (Note: the Example Study Data is the same data used for all HEC-FDA workshops, so you only need to download it once).

Workshop Overview

The goal of this workshop is to familiarize students with using HEC-FDA Version 2.0, including navigating the user interface for importing hydrologic data and for defining exceedance-probability and stage-discharge functions, and their associated uncertainties.

• Steps already completed for the students include:
  • Creating the study
  • Importing the terrain and impact area set.
• Students will complete the following steps in this workshop:
  • Import the hydraulic data
  • Enter the exceedance probability functions
  • Enter the stage-discharge functions with uncertainty

Introduction

The hydrologic and hydraulic data you're working with are from a section of the White River in Muncie, Indiana. The example data set draws on an example data set used in HEC-RAS Training. The 0.02 annual chance exceedance (50-year) floodplain is illustrated in the image below. 

Instructions

Task 1 – Open Study for Workshop 2

1. If you haven't already, download the software and workshop datafiles listed in the Downloadable Workshop Materials section of this page.
2. Open the HEC-FDA Version 2.0 software. 
3. From the File menu, click Open. The Open Study dialog opens as a tab.
4. Click the ellipse button in the Study Path box to open the Select File browser window.
5. Navigate to the Workshop 2 starting project (e.g., C:\Workshops\FDA\startingWS\Muncie_WS2_Start), select the *.sqlite HEC-FDA file and click Open.
6. From the Open Study tab, click OK.

Note which project elements have been entered for you in the starting workshop file.

Task 2 – Import Hydraulic Data

Considerations

Hydraulic modeling is used in HEC-FDA to identify the water surface elevation at each structure for at least 8 unique events. This information is used in calculating the stage-damage functions for each structure. The structure-level stage-damage functions are then aggregated to stages at the index point, which are defined by the combination of the input summary relationships. The hydraulics data can also be used to develop graphical stage-exceedance probability functions. Hydraulic engineers will use HEC-RAS or other hydraulic modeling software to develop the spatial data sets like the ones used in this workshop.

Steps

1. From the Study Tree under Hydraulics right-click on the appropriate spatial data sets type, and click Import Hydraulics. The Import Hydraulics dialog opens as a tab.
   

   Test Your Knowledge - Question 1

   Which import option should be selected to import the hydraulic data?

   1. Unsteady HDF
   2. Steady HDF
   3. Gridded Data

   

   Review the FY24 HEC-FDA Example Study Data to determine the correct spatial data set type for the Muncie, Indiana Hydraulic study data.

    

2. From the importer enter a name for the hydraulics profile (e.g., Existing Conditions) and enter a description for the profile.
3. From the Source File box select the ellipse button to open the Select File browser window.
4. Navigate to the folder containing the existing conditions hydraulic data (e.g., C:\Workshops\FDA\data\MuncieFinal\Hydraulics\Native Output), select the file "Muncie.p10.hdf" and click Open.

5. The importer tab updates with a table displaying the name of the profiles, the annual exceedance probability and the return interval. The return interval will need to be corrected. Manually enter the appropriate interval value for each profile name based on Table 1.
   
   

   Table 1
   Name	Return Interval
   2	2.00
   5	5.00
   10	10.00
   25	25.00
   50	50.00
   100	100.00
   200	200.00
   500	500.00

   

   Copy and paste is not an option in the import table. Select each cell to type in the appropriate return interval.

6. Note that the Annual Exceedance Probability column updates based on the Return Interval. Check that your return interval entered values are correct and click Save. The hydraulic data is added to the Study Tree.
7. Click Close to close the Import Hydraulics tab.

Task 3 – Enter the Flow-Frequency Function

Steps

1. From the Study Tree, right-click on Frequency Functions and select Create New Frequency Function. The Create Frequency Function opens as a tab.
2. Enter a name for the function in the Name box (e.g., Existing Condition LP3s), and enter a description for the frequency function (e.g., Flow-Frequency LPIII distribution for a period of record (Record Length) of 48 years).

3. Select the Analytical and Parameter Entry radio buttons and enter the LP3 Parameters listed below. 

   Mean	Standard Deviation	Skew
   3.707	0.24	-0.475

   Test Your Knowledge - Question 2

   What is the correct Record Length (period of record) value for the flow-frequency LPIII distribution?

   

   Review the FY24 HEC-FDA Example Study Data to determine the correct Record Length for the Flow Frequency Function.

4. Enter the correct period of record in the Record Length box.
5. Click Save. The flow-frequency function is added to the Study Tree.
6. Click Close to close the Create Frequency Function tab.

Task 4 – Enter the Without-project Condition Stage-Discharge Function

Steps

1. From the Study Tree, right-click on Stage-Discharge Functions and select Create New Stage-Discharge Relationship. The Create New Stage-Discharge Relationship opens as a tab.

2. Enter a name for the relationship in the Name box (e.g., Existing Condition Relationship), and enter a description for the relationship (e.g., This stage-discharge function represents the relationship between stage and discharge for the without-project condition.).

   Test Your Knowledge - Question 3

   What is the correct Distribution Type for the without-project stage-discharge relationship?

   

   Review the FY24 HEC-FDA Example Study Data to determine the correct without-project condition stage-discharge function.

3. Use the information in Table 3 to create the new stage-discharge relationships for the without-project condition. 
   Table 3

   {"name":"Stage-Discharge_Function_Without-Project.xlsx","page":"FY24 All HEC-FDA 2.0 Workshop Files","type":"xlsx","pageID":"173934355"}

   Loading

4. Click Save.

Conclusion

That's it! Download the project (provided at the top of this page) and review the best answers to test your FDA knowledge questions and compare with yours to see how you did! You can close the HEC-FDA software when you are finished reviewing the project (click the red X at the top right to close the software).

Return to top of page.

Best Answers to Test Your FDA Knowledge Questions