1. TR55 - Urban Hydrology for Small Watersheds Tutorial
This tutorial demonstrates the new TR55 model. You will learn how to:
Create an Input File
Run TR55
View Output

2. TR-55 Capabilities & Limitations
Maximum Area
Number of Sub-areas
Tc for any sub-area
Number of reaches
Types of reaches
Channel Routing
Structure Routing
Structure Types
Structure Trial Sizes
Rainfall Depth
25 square miles
1-10
0.1 hour < Tc < 10 hours
0-10
Channel or Structure
Muskingum-Cunge
Storage-Indication
Pipe or Weir
1-3
Default or user-defined
0-50 inches (0-1,270mm)

3. Cont. Capabilities & Limitations
Rainfall Distributions
Rainfall Duration
Dimensionless Unit Hydrograph
Antecedent Runoff Condition
NRCS Type I, IA, II, III, NM60, NM65, NM70, NM75, or user-defined
24-hour
Standard peak rate factor 484 or user-defined
2 (average)

4. Minimum Data Requirements
Data required for a single sub-area run can be entered on the TR-55 Main Window. These data include:
Identification Data - User, State, and County
Dimensionless Unit Hydrograph
Rainfall Location Identifier
Sub-area Data (Name, flows to reach/outlet, area, runoff curve number, & time of concentration)

5. TR-55 Sub-area/Reach Concepts
TR-55 represents the watershed as a system of sub-areas and reaches.
“Sub-areas” are the watersheds that generate hydrographs that feed into the upstream end of a reach.

6. Cont. TR-55 Sub-area/Reach Concepts
“Reaches” represent the configuration of flow paths within the watershed.
Storage routing (Lakes, Structures, Wetlands, etc.) and Channel Routing take place within a Reach.
All TR-55 modeled watersheds end with the final stream reach terminating at an “Outlet”

7. Schematic Example Sub-area 2 Reach 2 Outlet Reach 1 Sub-area 3 Legend
(Channel Routing)
Sub-area 3
Reach 1
(Storage Routing)
Legend
Sub-area 1
Storage Area
Sub-Area Inflow Points

8. Sub-area Data Sources
The sub-area data compiled prior to input into TR-55 include:
Drainage Area
Runoff Curve Number (RCN) Data
Time of Concentration (Tc) Data
Channel Reach Data
Structure Reach Data
Design Storm Amounts and Distribution
NOTE: RCN and Tc may be directly entered on TR-55 Main Window

9. Getting Started- Welcome to TR-55 Window
From Windows Explorer click on “WinTR55.exe”
To begin, select “Start”
To see help for a new user, select “New User”

10. TR-55 Main Window
The Main Window allows input of basic project data. Other data and settings are accessible through the menus, buttons, and boxes on the window.

11. TR-55 Main Window-Help
The “Help” pull-down shows the introduction, help for the Main Window, system information, and the display program version number and date.

12. TR-55 Main Window
To begin a new project, click “file”, then “new”
To set the units (English or Metric), click “Options”, then “Units”

13. TR-55 Main Window
It is important to remember that before exiting the TR-55 program, or before the“Run TR-55” option is selected, the input file should be saved.
To save, click”File”, then “Save” (for current file name), or “Save As” to save input file with a different file name.

14. TR-55 Main Window-Data Entry
Input Project Identification Data (User, Project, etc.)
Select Data units for sub-areas (square miles or acres)
Select which Dimensionless Unit Hydrograph to use for the project
Input known project data in the “Sub-area Entry and Summary” portion of the window (remember Tc & RCN can be direct inputs)

15. TR-55 Main Window-Project Data
RCN/Tc can be computed by clicking “Project Data”, then “Land Use Details/Time of Concentration”, or by clicking the land use/Tc icon on the tool bar, or by double clicking the RCN/Tc column in the sub-area entry and summary grid.
Note Reach and Structure Data are accessible here too.

16. Land Use Details Window
Here the user enters, edits, and/or views the sub-area’s detailed land use data.
Cover descriptions can be found in two ways-the vertical scrollbar or select the Land Use category.
Once the desired cover description is found, enter the area in the appropriate HSG box.

17. Land Use Details Window
The accumulated sub-area area and weighted CN are displayed in the three boxes at the bottom of the window.
Clicking “Accept” retains all entered data, then redisplays the TR-55 Main Window.

18. Custom Curve Number
Occasionally, it is necessary to develop a custom urban curve number when the standard Cover Descriptions do not apply.
The user can enter appropriate numbers into the Custom Curve Number window to create a Custom CN to fit a specific land cover.

19. Time of Concentration Details Window
The Tc window allows entry, editing, and/or viewing of sub-area flow path segment data and resulting travel times and time of concentration.
Up to five flow segments may be entered: one for sheet, two for shallow concentrated, and two for channel flow.
Again, click “Accept” to retain all entered data and redisplay TR-55 Main Window.

20. Reach Data Window
Here, entry, editing and/or viewing of the stream network, specifying if the reach is a channel reach or storage (structure) reach, and creating a channel reach rating table is possible
If the watershed exceeds 10 reaches, or the channel hydraulics require a more complex rating, use another method such as NRCS TR-20.

21. Reach Data Window
Each reach must have a unique “Reach Name” and a “Receiving Reach” (no more than 10 characters)
If the “reach” is a channel, enter specific details and dimensions for the channel.
If the “reach” is a structure, enter a structure name, then double-click the Structure Name to display the Structure Data Window.

22. Reach Data Window
A graphical representation of the channel rating or storage rating may be produced by clicking “Plot”.

23. Reach Data Window
A schematic of currently entered reaches, sub-areas, and structures can be displayed by clicking “Reach Flow Path” on the Reach Data window

24. Structure Data Window
Entry, editing and/or viewing of a pond’s surface area, structure outlet type and dimensions, and rating can be found on this window.
Up to three outlet sizes (trials) may be defined for each structure.
If the temporary structure storage or hydraulics require a complex rating, use another method like TR-20 or Sites.

25. TR-55 Main Window-GlobalData
To select NRCS-supplied rainfall data, click “GlobalData”, then “Storm Data”.
The user may also choose to enter custom rainfall depths and a different rainfall distribution from this pull-down
The user may also open the Dimensionless Unit Hydrograph Window here

26. Storm Data Window
This window allows the user to select the NRCS-supplied rainfall depths and distributions for the state and county.
The storm data set is developed in 2 ways: NRCS-supplied data may be selected, or the user may modify an NRCS data set.

27. Watersheds Outside U.S.
TR-55 can be used for watersheds outside the United States.
The “State” and “County” boxes on the TR-55 Main Window change to “Region” and “Locale”
No rainfall data is provided outside the US, so the user must modify an NRCS data set and supply the appropriate distribution

28. Custom Rainfall Distributions
Watershed areas in and outside the US may need to have custom rainfall distributions created.
To do this, go to the TR-55 Main Window, click on “GlobalData”, and click “Custom Rainfall Distribution”

29. Custom Rainfall Distributions Plot
Clicking on “Plot” produces a graphical representation of the current rainfall distribution.
Only one distribution may be displayed at a time.

30. Dimensionless Unit Hydrograph Window
This window allows the user to input and revise non-standard dimensionless unit hydrographs.
As with the standard NRCS rainfall distributions, the standard dimensionless unit hydrograph in TR-55 may not be edited or deleted.

31. Dimensionless Unit Hydrograph Plot
A graphical representation of the dimensionless unit hydrograph may be produced by clicking “Plot” on the Dimensionless Unit Hydrograph window

32. TR-55 Main Window-Run
To run the TR-55 model, click ”Run” on the TR-55 Main Window menu bar (or the run icon), select the storm(s) to evaluate, then click the “Run” button in the lower right-hand corner.

33. Viewing Output After a TR-55 run, the File Display window opens.
This window, also known as the Report View, displays various TR-55 reports.
If there are errors in the run, this window open with the title “Error File”. The error messages can be found by clicking “View”, then “Error File”

34. Output Definition Window
Once TR-55 has enough data to execute a run, the “Output Definition” button on the TR-55 Main Window will be operational.
In the Output Definition window, specify which output is to be viewed by clicking the box to the left of the desired report.
Output may be sent to a file or to the report viewer.

35. Other Reports File Display Window (report viewer) Input file
TR-20 Printed Page file (tabular hydrograph)
Debug file
Error file

36. Plotting and Viewing Hydrographs
Click “Hydrographs” on the TR-55 Main Window to open the Output Graphics window.
Select either Sub-areas or Reaches and check the box next to the name for the desired hydrographs
Select storm event hydrograph by checking the appropriate box.

37. Graphics Window
Click “Plot” on the Output Graphics window to plot selected hydrographs
The plot may be saved to a file or sent directly to a printer.

38. TR-55 Web Site For downloading the latest version of TR-55, go to:
This web page also has information on:
Update notes
TR-55 User Manual
address for the TR-55 Support Team