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HEC-SSP Examples Introduction
Welcome to the U.S. Army Corps of Engineers, Hydrologic Engineering Center's (HEC) Statistical Software Package (HEC-SSP). HEC-SSP software allows users to perform statistical analyses of hydrologic data. The purpose of this guide is to illustrate the input and output results for 35 example problems. The example problems are provided to illustrate the use of specific options in HEC-SSP and to assist in verifying the correct execution of the HEC-SSP software. The HEC-SSP Examples guide provides a brief description of each example.
Out of the 35 example problems, the first six examples are the same examples described in the HEC-FFA (Hydrologic Engineering Center's Flood Frequency Analysis) software user's manual. Furthermore, a comparison between the HEC-FFA and HEC-SSP results verifies that the HEC-SSP software produces the same results as HEC-FFA for these six data sets. The first six examples were analyzed in HEC-SSP with both Bulletin 17 and General Frequency Analysis; however, this guide displays only the results obtained using a Bulletin 17 Analysis. Full results for both analyses are included in the SSP_Examples.ssp study and show that the results are the same whether a Bulletin 17 or General Frequency Analysis was performed.
Within the first six examples, the weighted skew option was selected and a regional skew value was entered from the generalized skew map of the United States provided within Bulletin 17B (Plate 1).
Overview of Example Problems
Example Number | Example Problem Title | SSP_Examples.ssp | |
---|---|---|---|
Analysis Name | Data Record Name | ||
1 | Fitting the Log-Pearson Type III Distribution | FFA Test 1 | Fishkill Creek-Beacon, NY |
2 | Analysis with High Outliers | FFA Test 2 | Floyd River-James IA |
3 | Testing and Adjusting for a Low Outlier | FFA Test 3 | Back Creek-Jones Springs |
4 | Zero Flood Years | FFA Test 4 | Orestimba Creek-Newman, CA |
5 | Confidence Limits and Low Threshold Discharge | FFA Test 5 | Kaskaskia River-Vandalia, IL |
6 | Use of Historic Data | FFA Test 6 | Ridley Creek-Moylan, PA |
7 | Analyzing Stage Data | Stage Analysis Test 7 | Reservoir Stage |
8 | Using User-Adjusted Statistics | Local Runoff at Alb Test 8 | Rio Grande at Alb Local Runoff |
9 | General Frequency - Graphical Analysis | Reg Flow Rio Grande Test 9 | Rio Grande at Alb Reg Flow |
10 | Volume Frequency Analysis, Maximum Flows | Unreg Flow Rio Grande Test 10 | Rio Grande at Alb Unreg Daily |
11 | Volume Frequency Analysis, Minimum Flows | Low Flow Analysis Test 11 | Chattahoochee River |
12 | Duration Analysis, Bin (STATS) Method | Fishkill Creek Test 12 | Fishkill Creek-Daily Flow |
13 | Duration Analysis, Rank All Data Method | Duration Curve Test 13 | Wondering River-Franklin |
14 | Duration Analysis, Manual Entry | Manual Duration Curve Test 14 | Not Applicable |
15 | Coincident Frequency Analysis, A and B can be Assumed Independent | Coincident Freq Test 15 | Not Applicable |
16 | Coincident Frequency Analysis, A and B cannot be Assumed Independent | Coincident Freq Test 16 | Not Applicable |
17 | Balanced Hydrograph Analysis, Using an Historical Event Hydrograph | Balanced Hydrograph Test 17 | Sinnemahoning Creek-Hourly |
18 | Balanced Hydrograph Analysis, Using a Triangular-shaped Hydrograph | Balanced Hydrograph Test 178 | Sinnemahoning Creek-Triangular |
19 | Curve Combination Analysis, Combining Multiple Frequency Curves using Graphical Techniques | Curve Combination Test 19 | Not Applicable |
20 | Distribution Fitting, Analyzing Model Uncertainty Using a Time Series of Annual Maximum Streamflow | Distribution Fitting Test 20 | Potomac River-Flow-Annual Peak |
21 | Distribution Fitting, Analyzing a Time Series of Daily Average Flow Using Time Window, Seasonal, and Annual Maxima Filtering | Distribution Fitting Test 21 | Sinnemahoning Creek-Daily |
22 | Distribution Fitting, Analyzing a Time Series of Daily Average Flow Using Time Window, Seasonal, and Peaks Over Threshold Filtering | Distribution Fitting Test 22 | Sinnemahoning Creek-Daily |
23 | Distribution Fitting, Analyzing a Time Series of Daily Precipitation Accumulation Using Peaks Over Threshold Filtering | Distribution Fitting Test 23 | Hawley 1 E PA-Daily-Precip-Inc |
24 | Distribution Fitting, Analyzing a Time Series of Daily Average Snow Water Equivalent Using Annual Maxima Filtering | Distribution Fitting Test 24 | Little Meadows-SWE |
25 | Distribution Fitting, Analyzing a Time Series of Daily Average Flow to Estimate Flood Seasonality | Distribution Fitting Test 25 | South Fork Shoshone River-Daily |
26 | Distribution Fitting, Analyzing a Paired Data Record of Hydrologic Model Output | Distribution Fitting Test 26 | MCMC OUTPUT-TC |
27 | Mixed Population, Combining Two Frequency Curves using the Probability of Union Concept | Mixed Population Test 27 | Kettle Creek-Summer-Flow-Annual Peak Kettle Creek-Winter-Flow-Annual Peak |
28 | Mixed Population, Combining Three Frequency Curves using the Probability of Union Concept | Mixed Population Test 28 | Not Applicable |
29 | General Frequency, Fitting a Log Pearson Type III Distribution using the Expected Moments Algorithm | General Frequency EMA Test | South Fork Shoshone River-Flow-Annual Peak |
30 | General Frequency, Fitting an Analytical Distribution to a Precipitation Time Series | General Frequency Precip Test | Hawley 1E PA-3DAY-Precip-AMS |
31 | Volume Frequency, Fitting a Family of Log Pearson Type III Distributions to Volume-Duration Data using the Expected Moments Algorithm | Sinnemahoning_VolumeFrequency | Sinnemahoning Creek-Daily |
32 | Data Filtering, Extracting an Annual Maximum Series | Jamestown-Daily Max Temp | |
33 | Data Filtering, Extracting a Partial Duration Series | Miami Beach-Daily Precip | |
34 | Data Filtering, Using Multiple Filters | Palisades Dam-Daily Inflow | |
35 | Data Filtering, Starting Pool/Elevation Filtering | Sayers Dam-Daily Elevation |
Installing HEC-SSP Example Data
To install this study on your computer open the HEC-SSP software and select the Help | Install Example Data menu command. After the install is complete, open the SSP_Examples.ssp study and the HEC-SSP main window will appear as shown in Figure 1.
After opening the SSP_Examples.ssp study for the first time on your computer, you must compute each example before viewing tabular and graphical results.
The SSP_Examples.ssp study includes, nine Bulletin 17B analyses, eleven General Frequency analyses, three Volume Frequency analyses, three Duration analyses, two Coincidence Frequency analyses, one Curve Combination analysis, two Balanced Hydrograph analyses, seven Distribution Fitting analyses, and two Mixed Population analyses in this study. The following sections document each of the example data sets. HEC-SSP Bulletin 17C Examples details ten additional examples which make use of the Expected Moments Algorithm and Bulletin 17C procedures.