 Technical
Support
Installing DFLOW
Obtaining and Processing Flow Data
Using DFLOW
EPA References and Contacts
Installing DFLOW
What should I do if I receive the error message
"The paging file is too small for this operation to complete"?
The paging file is a hidden file on the hard disk that Windows uses
to hold parts of programs and data files that do not fit in memory. If
you receive this message, you need to increase the size of your paging
file. The steps to change the size of the paging file vary by operating
system, but should be outlined in the Windows help file. For Windows 2000,
go to Control Panel, Systems, and then select the Advanced tab. Click
"Performance Options" and then "Change." Increase
the number of the initial size and maximum size of your paging file.
Obtaining and Processing Flow Data
Where do I obtain flow data?
In what format should the input flow data be?
The DFLOW 3.0 Download
(zip file, 851kb) contains several sample flow data files. The flow
data should be in a text file (.txt). As the files illustrate, initial
comment lines in a flowdata.txt file should be denoted with the "#"
symbol. The data should be listed in row and column format, where the
four columns are: Agency Code, station number, Date of daily mean streamflow,
and Daily mean streamflow value.
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Using DFLOW
What is meant by "Common dates" and "Longest period"
in the "Calculation Period" box?
Although a flow record may be for a long period of time (e.g., 1900-present),
there may be no data for some dates. When DFLOW is calculating design
flow statistics for multiple stations and "Common dates," is selected,
only flow measurements from days in which all stations have recorded
data will be used in the calculations. This could be important to insure
consistency of results between stations. The "Longest period" specification
directs DFLOW to only use data from the longest period of consecutive
daily measurements within a flow record.
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Can DFLOW be used to calculate seasonal design
flows?
Yes. In the "Season" box, specify the first and last day of the Julian
day of the season, where in this context the Julian day is the number
of days that have elapsed in the particular calendar year (e.g., January
1 = 1, February 28 = 59).
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EPA References and Contacts
What references does EPA have on design flows?
Who should I contact at EPA if I have additional
DFLOW questions?
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