Questions and Answers about STEPL and the Region 5 Model
Got Even More Questions?
Question 1: Is the Region 5 Model only for EPA Region 5 states?
Question 2: What are the differences between STEPL and Region 5 Model?
Question 3: My ‘Total Load’ worksheet has ‘#VALUE!’ in result cells. What went wrong?
Question 4: The septic system failure rate seems low, are there other alternative data?
Question 5: How can I add my own BMPs to STEPL’s BMP list?
Question 6: Where can I find the definitions of BMPs used in the STEPL and Region 5 Model?
Question 7: Can you help me use the BMP Calculator?
Question 8: What are other models that can be used for load reduction calculations?
Question 14: Can STEPL be used to model bacteria?
Question 15: How to enable macros in MS Excel spreadsheet?
Question 16: How to set Excel default file location to C:\STEPL or D:\STEPL?
Question 18: Can STEPL be used with Macintosh Operating System (Mac OS)?
No, the Region 5 Model can be used for other states. The model got its name because it was originally developed by Indiana Department of Environmental Management based on Michigan Department of Environmental Quality’s 319 watershed training manual. Both Indiana and Michigan are EPA Region 5 states.
Below are the major differences between the two models:
- Calculates load at the source level
- Sources are independent (no relationship between worksheets)
- Users can not specify and update BMPs used in the model
- Calculates load for different sources at source and watershed level
- Sources are related in watershed
- Users can specify and update BMP list
- Users can use BMP calculator to estimate combined BMP efficiencies for complex BMP arrangements
- On-line input data server for initial model setup (Caution: Do not substitute the on-line data for real local data!)
First, make sure that you have selected the appropriate State, County, and Weather Station from the lists in the Input Sheet.
Another possibility is that you probably entered some non-numerical characters in the input tables on the ‘Input’ sheet. For example, when you copy and paste ‘Agricultural animals’ data from the tables generated by the ‘STEPL Input Data Server’, you may paste non-numerical characters to the STEPL input sheet if the animal number is indicated with ‘D’ for data withheld to avoid disclosing by US Department of Agriculture.
Yes. The failure rate data have very high uncertainty. Users are encouraged to obtain the septic failure rate from their local health departments.
Besides the data from the ‘STEPL Input Data Server’ (National Environmental Service Center formally National Small Flow Clearinghouse, 1992 and 1998), Electric Power Research Institute conducted a state-by-state survey on septic failure rate. Below is the summary:
State |
Estimated system |
Failure definition |
---|---|---|
Alabama |
20 |
Not given |
Arizona |
0.5 |
Surfacing, backup, surface or ground water contamination |
California |
1-4 |
Surfacing, backup, surface or ground water contamination |
Florida |
1-2 |
Surfacing, backup, surface or ground water contamination |
Georgia |
1.7 |
Public hazard |
Hawaii |
15-35 |
Improper construction, overflow |
Idaho |
20 |
Backup, surface or ground water contamination |
Kansas |
10-15 |
Surfacing, nuisance conditions (for installations after 1980) |
Louisiana |
50 |
Not given |
Maryland |
1 |
Surfacing, backup, surface or ground water contamination |
Massachusetts |
25 |
Public health |
Minnesota |
50-70 |
Cesspool, surfacing, inadequate soil layer, leaking |
Missouri |
30-50 |
Backup, surface or ground water contamination |
Nebraska |
40 |
Nonconforming system, water quality |
New Hampshire |
<5 |
Surfacing, backup |
New Mexico |
20 |
Surfacing |
New York |
4 |
Backup, surface or ground water contamination |
North Carolina |
15-20 |
Not given |
North Dakota |
28 |
Backup, surfacing |
Ohio |
25-30 |
Backup, surfacing |
Oklahoma |
5-10 |
Backup, surfacing, discharge off property |
Rhode Island |
25 |
Not given |
South Carolina |
6-7 |
Not given |
Texas |
10-15 |
Surfacing, surface or ground water contamination |
Utah |
0.5 |
Surfacing, backup, exceeding discharge standards |
Washington |
33 |
Public health hazard |
West Virginia |
60 |
Backup, surface or ground water contamination |
Wyoming |
0.4 |
Backup, surfacing, ground water contamination |
You can add, delete, or edit BMPs in the “BMPList” worksheet, which can be shown (unhidden) by clicking the STEPL > View/Edit BMP List menu. On the ‘BMPlist’ worksheet, follow the steps outlined on the top-right corner. See more information in section 4.6 of the STEPL user’s guide.
You can find BMP descriptions in a Microsoft Word document, BMPDefinition.doc, under your [Local Drive C or D]:\STEPL folder after you install STEPL on your PC.
Yes. The STEPL user’s guide has a detailed section (Appendix A) that describes the procedures and examples of using the BMP Calculator.
STEPL and the Region 5 Model are two of the simplest models for calculating pollutant load reductions. There are many other models that can be used to calculate the load reductions, and these models are described in a document in the STEPL website. You can find out more about these models in the document "Nutrient and Sediment Estimation Tools for Watershed Protection (PDF)".
Most non-structural BMPs should be used in parallel configuration (with the BMP Calculator) if you do not know their locations and spatial relationship. Some downstream structural BMPs or on stream BMPs may be in serial connection with the upstream BMPs; for example, a sediment settling pond may be in serial to upstream BMPs such as no-till practices. If you do not know the BMP locations in a watershed, assuming parallel BMP configurations will be better than assuming serial configurations if most of the BMPs are non-structural (except filter strips) or not in-stream.
The sediment output from a watershed is different from on-site erosion. For cropland in your calculation, erosion rate may be larger than 1 t/ac/yr; however, the sediment output from your watershed is much lower. The STEPL model calculates sediment output using "erosion x sediment delivery ratio". Your watershed area is pretty large, so it results a low sediment delivery ratio. To see the sediment delivery ratio in STEPL model, click on STEPL menu > unhide/hide other STEPL sheets, and navigate to the ‘Sediment’ worksheet, and then check cell "W9". Your can modify the sediment delivery ratio based on your local data.
- the area of the filter strip is usually significant smaller than the affected area, and
- the filter strip is not a source of nonpoint source pollution (in STEPL, you may exclude it from the load calculation or treat it as a type of forest).
For assessment and planning purposes, you can use STEPL to compare effects of land use changes on pollutant loads (N, P, and sediment). However, STEPL was created to only give rough estimates on load and load reduction, and it is not intend for making very precise predictions. For urban land uses, STEPL does not use USLE. STEPL uses annual runoff volume x pollutant concentration to estimate pollutant loads, including sediment load.
This is due to a peculiar Excel behavior. Change the Input worksheet zoom level to 100% percent and try. If this is not working, make the hidden sheet visible (using the Hide/Unhide menu under STEPL) and then change the zoom level.
STEPL can not be used to model bacteria. There are other models available to model bacteria. These include models like HSPF, SWATExit, and PLOAD, which is now part of BASINS.
Question 15: How to enable macros in MS Excel spreadsheet?
Excel 2003 version: Click on Tools menu > Macro > Security > Security Level > Medium.
Excel 2007 version: Click on Office icon > Excel Options > Trust Center > Trust Center Settings > Macro Settings.
Excel 2010 version: Click on File menu > Excel Options > Trust Center > Trust Center Settings > Macro Settings.
Question 16: How to set Excel default file location to C:\STEPL or D:\STEPL?
Excel 2003 version: Click on Tools menu > Options > General tab.
Excel 2007 version: Click on Office icon > Excel Options > Save.
Excel 2010 version: Click on File menu > Excel Options > Save.
This error occurs only on machines with a combination of Windows 7 and Microsoft Office Excel 2007 installed. STEPL program is not compatible for this combination. You need to upgrade your Excel program (e.g., Excel 2010).
No, STEPL is only compatible with the Windows Operating System.
- Go to Start\All Programs\Accessories.
- Right-click Command Prompt and then click on Run As Administrator.
- Type the following and then press Enter: cd c:\windows\systemWOW64.
- Type the following and then press Enter: regsvr32 MSCOMCTL.OCX.
- You should get a message saying this succeeded.