Technical data

Using the TR-55 Tabular Hydrograph Method to Calculate Runoff
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To calculate the peak discharge using the TR-55 Tabular Hydrograph Method
Steps
Use
to look up
1 Determine the rainfall distribution type for the
specific watershed.
2 For each subarea, determine the subarea’s
hydrologic parameters, including the area, time
of concentration, travel time, 24-hour rainfall, and
runoff curve number.
To do this, use hydrologic data from soil maps,
rainfall frequency distribution charts and other
relevant publications acquired for your county or
region from your local SCS office or county Soil &
Water Conservation District office.
Overview of Calculating
the Runoff from the
Watershed Areas
3 From the Hydrology menu, choose Settings to
access the Hydrology Tools Settings dialog box.
Click Units to specify the TR-55 Tabular
Hydrograph Method measurement units. Click
Precision to specify the required precision settings
for your units.
Change the Hydrology
Unit Settings
4 From the Hydrology menu, choose
Runoff ➤ Tabular to display the TR-55 Tabular
Hydrograph Method dialog box.
Calculate the Peak Runoff
by Using the TR-55
Tabular Method