Welcome to the HEC-FDA Version 2.0 Quick Start Guide. This document is written for users who have previous experience using the HEC-FDA software or have experience working with hydrologic, hydraulic, and economic data. Please first review Differences between Version 1.4.3 and Version 2.0 and How-to Setup a Successful Compute. The example study data used throughout this Quick Start Guide can be reviewed and downloaded here: Example Study Data.  Review the HEC-FDA User Manual for more information.

2.0 Data Requirements for a New HEC-FDA Study

Study data requirements vary widely. The requirements depend on the purpose of the study, the size of the study area, the hydrologic and hydraulic conditions of the study area, and the types of alternative plans considered, just to name a few. In general, the data required to build a new study must contain:

1. Impact areas in the form of a polygon shapefile. The file must have a string or integer field that identifies a unique name. Only one set of impact areas can be imported.  
2. Analysis year(s).

Further, for a given alternative, analysis year, and impact area, a study must contain at a minimum the following data:

1. Frequency functions - either (a) or (b) below: 
   1. Analytical flow-frequency: equivalent record length, mean, standard deviation, and skew. 
   2. Graphical frequency relationship: at least 8 (preferably 9) flow-frequency coordinates and equivalent record length. Stage-frequency is an option of the hydraulic conditions warrant.
2. Stage-discharge functions consisting of flows and distributions of stages, if frequency function reflects discharge. If frequency function reflects stage, a stage-discharge function is not required.
3. Aggregated stage-damage functions consisting of stages and distributions of damage, which can be manually entered or internally computed. 

If you're using HEC-FDA 2.0 to compute the aggregated stage-damage functions, you will also need:

1. Terrain, for one or both of the following: (1) using HDF results for hydraulics, in which case the terrain should be in HDF format, or (2) using terrain data for ground elevation at structure, in which case the terrain can be imported as a raster data set or HDF. Only one terrain file can be imported.  
2. Hydraulics data set should reflect water surface elevations (not depth) with three data format options: (1) steady or unsteady: 8 subdirectories with raster datasets (2) steady: 1 HDF; or (3) unsteady: 8 HDFs.
3. Discharge-frequency function and stage-discharge function, or stage-frequency function only (same functions mentioned above). 
4. Occupancy types with damage categories, depth-percent damage functions with uncertainty, first floor elevation uncertainty, and either: (1) structure/content/other value uncertainty, or (2) content-to-structure value ratios with uncertainty and other-to-structure value ratios with uncertainty. Content, vehicle, and other configuration is optional. 
5. Structure inventory in the form of a point shapefile with at least a structure ID, structure value, first floor elevation (or ground elevation and foundation height) and occupancy type. Optionally: content value, other value, beginning damage depth, among others. 

Stage-Damage H&H Data

• There are three types of engineering data required for a stage-damage compute: a frequency function, a stage-discharge function if frequency reflects flows, and a hydraulics data set. Double-check that the project conditions are the same across the three items. The computed stage-damage function will not make sense if: (1) with-project conditions are unique from without-project conditions, and (2) with-project data is used along with without-project data for the without-project set of stage damage functions. 
• Ensure that the coordinate reference system is either set to be the same across all geospatial data sets, or that the study coordinate reference system is set by selecting the study projection from the study properties editor under the File menu. 

Optional items include:

1. Index points in the form of a point shapefile, if retrieving graphical stage-frequency from water surface elevations in hydraulics. Index points are not explicitly used for anything else within HEC-FDA, but remain an important concept. 
2. Regulated-unregulated transform function with unregulated flows and distribution of regulated flows.
3. Exterior-interior function with exterior stages and distributions of interior stages. 
4. Levee (top of levee elevation) and optionally system response curve involving stages and distributions of breach probabilities.

Here's what you'll need from engineering

For each alternative-analysis year-impact area combination, you will need from engineering:

• Frequency functions - either (a) or (b) below: 
  1. Analytical flow-frequency: (1) equivalent record length, mean, standard deviation, and skew, or (2) series of peak flows. 
  2. Graphical frequency relationship: at least 8 (preferably 9) flow-frequency coordinates and equivalent record length. Stage-frequency is an option of the hydraulic conditions warrant.
• Stage-discharge functions consisting of flows and distributions of stages, if frequency function reflects discharge. If frequency function reflects stage, a stage-discharge function is not required. 

The frequency function and stage-discharge function should reflect the same place in the channel, i.e. the same index point. You will also need a data set of hydraulic modeling for each alternative-analysis year combination. The modeling should reflect water surface elevations (not depth) with three data format options: (1) steady or unsteady: 8 subdirectories with raster datasets (2) steady: 1 HDF; or (3) unsteady: 8 HDFs

Create New Study and Compute Workflow

This section walks you through creating a new study and computing all results. This section assumes that you will use HEC-FDA Version 2.0 to compute aggregated stage-damage functions. Steps on optional functionality that will not be used for all studies, i.e. steps that are not required, will be indicated as optional. Right-click on each item in the study tree to import or create new study data. 

Duplicates Not Needed

1. If a given study data item is the same for multiple project conditions, then that study data item need not be duplicated. For example, assume that you have a flow-frequency function for the existing condition of a given impact area, but the flow-frequency function is also representative of the hydrologic conditions of the future-without project condition, and all with-project conditions. In that case, create one frequency function, and select the same frequency function for each of the Scenarios. 
2. Except for terrain and the set of impact areas, many items can be created for a given study data element. For example, multiple structure inventories can be imported. 

Part A: Create Study then Import or Specify Study Data

Step A-1. Create New Study and Set Study Properties

Be sure to review and update the discounting and price information every fiscal year.

Please review the short instructional video for more information on creating a new study from scratch and setting the study properties for the new study in HEC-FDA Version 2.0.

Step A-2 (Optional). Import Terrain

If you wish to use a terrain file to calculate the ground elevations at structures (i.e., in the case that ground elevations are not recorded in the structure inventory), you should import a terrain file. A name and path to the terrain file are required for import.

Step A-3. Import Impact Area Set

A dataset name, description, shapefile path, and selection for unique impact area name(s) (a field of the attribute table) are required for import.

Take a look at the following video to learn about including a set of impact areas in your HEC-FDA study.

Import Index Points (Optional)

For this HEC-FDA guide, index points are not included in the quick start example study. However, the information in the expandable section below is included for users planning to retrieve graphical stage-frequency functions from imported water surface elevations.

Step A-4. Import Hydraulics Data Sets

For a given hydraulics data set, one HDF is required for steady hydraulics modeling, eight HDFs are required for unsteady hydraulics modeling. Gridded water surface elevation data is accommodated, see the HEC-FDA User's Manual, Hydraulics page for more information. Specify a name, description, source file (or folder for unsteady), and be sure to identify either the correct annual exceedance probabilities or correct return intervals.

Step A-5. Specify Frequency Relationships

 The frequency relationships may be one of the three below. Please see EM 1110-2-1619, HEC-FDA on Discourse, or speak with HEC about choosing one of the three. Recall that uncertainty in EAD is most sensitive to uncertainty in flow so we want to include flow in our models if the hydrologic and hydraulic conditions permit. 

1. Analytical flow-frequency function. Select Analytical. Provide the mean, standard deviation, skew, and equivalent record length. 
2. Graphical flow-frequency function. Select Graphical. Select Flow. Provide at least eight coordinates of exceedance probability and flow, and an equivalent record length. 
3. Graphical stage-frequency function. Select Graphical. Select Stage. Provide at least eight coordinates of exceedance probability and stage, and an equivalent record length.
4. Right-click on Compute Confidence Limits to view the .025 and .975 confidence limits. 

Step A-6 (Optional). Specify Regulated-Unregulated Transform Flow Relationships

Specify with a series of coordinates of unregulated flow and distribution of regulated flow.

Step A-7 (Highly Recommended). Specify Stage-Discharge Relationships

If your frequency function reflects flows (discharge), you'll need to specify a stage-discharge function to accompany each flow-frequency function. Specify with a series of coordinates of flow and distribution of stage. 

The stage-discharge function should be provided as paired data with uncertainty: a column of flows and a column of the corresponding stage distributions. Take a look at the following video to learn about configuring a rating curve in HEC-FDA.

Step A-8 (Optional). Specify Levees

Specify minimally with a top elevation using the "default" system response curve with the implicit assumption of a "perfect" levee. Ideally, select user-defined and enter a system response curve in stages and failure probabilities. 

Step A-9. Import Occupancy Types

The recommended workflow is to import occupancy types using the same flat-file format as that which was used for HEC-FDA Version 1.4.3. See Appendix D of the Version 1.4.1 User's Manual for more information (References). Optionally, occupancy types may be entered manually. The occupancy types editor is the most complicated editor. See the page on the HEC-FDA User Interface for more information. 

Step A-10. Import Structure Inventories 

A structure inventory is imported using a point shapefile, where the attribute table must have the following attributes: unique ID, dollar-denominated structure value, occupancy type, and either both foundation height and ground elevation or just the first floor elevation. Identify whether first floor elevation or foundation height will be used, and if foundation height, identify whether the ground elevations will come from the structure inventory or a terrain file. Select optional attributes and identify what occupancy type names in the structure inventory correspond to which occupancy types in the study database. 

Part B: Compute Aggregated Stage-Damage Functions

The following items must be selected for configuration of an aggregated stage-damage compute: 

1. Hydraulics data set
2. Structure inventory 
3. Discharge-frequency function and discharge-stage function or just a stage-frequency function 

Hit Compute. An aggregated stage-damage function is computed for each impact area, damage category, asset category combination. 

Part C: Specify and Compute Scenarios

Workflow Overview:

Specify a scenario for each project condition-analysis year combination. The following must be selected for each impact area for a given scenario:

1. Discharge-frequency function
2. Stage-discharge function 
3. Stage-frequency function if not able to use discharge-frequency function and stage-discharge function 
4. Stage-damage functions, one for each damage category - asset category combination 

The following may optionally be selected for any impact area for a given scenario:

1. Regulated-unregulated flow transform function
2. Interior-exterior stage transform function 
3. Levee elevation, system response curve optionally 
4. Additional thresholds 

After completing the configuration of the scenario for each impact area, hit save and close, right click on the scenario, and hit compute. When the compute is complete, a message will be displayed prompting on whether to display results. See Scenario Results for more information.

Example Study with Instructional Video:

All necessary study data must be defined before the scenarios can be created. For the quick start guide example study and the Scenarios instructional video, the following data listed in Pre-scenarios Study Data Overview Table was imported.

The information provided in the Aggregated Stage-Damage Functions Overview Table was used to create and compute the four aggregated stage-damage functions used in this quick start guides' Scenarios instructional video.

The information provided in the Scenarios Overview Table was used to create and compute the 8 scenarios used in this quick start guides' Scenarios instructional video.

Please review the short instructional video for more information on creating, defining and reviewing scenario results in HEC-FDA Version 2.0.

Thresholds and Project Performance Statistics:

The project performance statistics are calculated on the basis of a "threshold." HEC-FDA Version 2.0 will base the threshold on:

• For an impact area with no levee, this is the default threshold in the without-project condition. The default threshold is the stage at which 5% of the 0.01 AEP damage occurs. 
• For an impact area with a levee, the threshold is either a fixed threshold equal to the top elevation of the levee or not a fixed threshold (i.e., the levee can fail at different heights) and is calculated as a function of the system response function.

Part D: Specify Alternatives and an Alternative Comparison Report

Step D-1. Alternatives

An alternative should represent a given project condition and should include one scenario for each analysis year. Right-click on each alternative to view results. See Alternative Results for more information.

The information provided in the Alternatives Overview Table was used to create and compute the 4 alternatives used in this quick start guides' Alternatives instructional video.

Please review the short instructional video for more information on creating, defining and reviewing alternative results in HEC-FDA Version 2.0.

Note: The results reviewed in the Alternatives video is for instructional purposes only and should not be used for by users to compare HEC-FDA results. Review the HEC-FDA Training for HEC-FDA Version 2.0 workshops.

Please review the Scenarios video before viewing the Alternatives video.

Step D-2. Alternative Comparison Reports

Specify the Alternative Comparison Report by identifying the without-project condition alternative and each with-project condition alternative for comparison. Right-click on the alternative comparison report to view results. See Alternative Comparison Report Results for more information. 

Please review the short instructional video for more information on creating, computing and reviewing alternative comparison reports in HEC-FDA Version 2.0.

Note: The results reviewed in the Alternative Comparison Reports video is for instructional purposes only and should not be used for by users to compare HEC-FDA results. Review the HEC-FDA Training for HEC-FDA Version 2.0 workshops.

Please review the Scenarios and Alternatives videos before viewing the Alternative Comparison Reports video.

Related Topics

Review the HEC-FDA User Manual's Create New Study from Scratch page for additional information for creating a new study from scratch.