ASCII Data File Format for Monthly Inflows (Obsolete)

Note: The file format described here, used in conjunction with the Read from File Method, is primarily of use for datasets created in older versions of WEAP. If you are creating a new text file for import into WEAP, use the ReadFromFile function instead.

If you have monthly data on inflows to some or all of your rivers and other supplies, the Read From File Method allows you to model the system using this sequence of inflows. You can export gaged inflow data from many conventional hydrologic databases (USGS has extensive streamflow data for the United States available for download from the Web at into ASCII files, and then edit these files into the required format described below. The following discussion is provided as a courtesy to those users that are using the older versions of WEAP that support data input by ASCII files.

These data may come from a historical record, or they may be outputs from some other model, such as a physically-based hydrologic model. A single ASCII file is meant to be a consistent set of data, both spatially and temporally. You may have many different ASCII import files, but each WEAP scenario can reference only one. For example, if you were investigating the sensitivity to climate change, you could have a different file for each of your climate scenarios.

You may include in these files data for years and supplies not included in a particular WEAP area. Thus, you could use one set of data files for several different WEAP areas, which might include different sets of rivers and supplies. Or you can easily run the WEAP calculations using different historical time periods to test a scenario’s sensitivity to a particular hydrological sequence. WEAP will ignore any data extraneous to its current analysis. In this way, the file can comprise a master database of historic flow data that you will use for all your analyses.

The files should be named with the extension .FLO, and placed in the subdirectory corresponding to the WEAP area (e.g., WEAP\Weaping River Basin\ ). Then, in the Hydrology \ Read from File branch, select this file in the drop-down box.


The ASCII file is divided into six sections.

Section Name



Set water flow unit and first year


River headflows


Surface water runoff to reaches


Local Reservoir inflows


Groundwater inflows


Other Supply inflows

In the options section you specify the first year of data to use and the units.

First Year

When using historical datasets, you need to specify which historical year to use. If your analysis is longer than the entered dataset, WEAP will loop through the historical sequence up to the number of years specified in the model time horizon. For example, if the historical dataset spanned 1950-1959, and your WEAP time horizon was 1998-2017, you would specify 1950 as the first year. In this case, the ten years of data from the file would be used twice--for 1998-2007 and for 2008-2017. You can choose different time intervals to simulate the system over various historical time periods. For instance, if your study period is twenty years and you have sixty years of historical data, WEAP allows you to easily select any of the forty-one different twenty-year periods from the historical data, to explore the effects of various sequences of hydrologic conditions.

The first year is specified in the [OPTIONS] section, in the following format:

FIRST YEAR = <year>

If you do not specify the first year, WEAP will assume the Current Accounts year is the first year to use.


You may use any unit for your data and WEAP will automatically convert it. To set the unit to be used in reading the file, include the optional first section [OPTIONS] in your data file. If you do not specify the unit, WEAP will assume cubic meters per second. However, to avoid any potential confusion, we recommend that you always include the specification of unit in the file.

The unit is specified in the [OPTIONS] section, in the following format:

UNIT = [optional scale] <volume unit> per <time unit>

The scale is optional and can be either a word (thousand, million, etc.) or a number. For volume unit and time unit, select from the tables below. You may use either the word 'per' or a slash (/) to separate them. You may also use the following flow unit abbreviations: CFS, CMS, CFM and MGD. If you use month as the time unit, WEAP will take into account the variable number of seconds in each of the twelve months when converting into its per second flow rate. You may use a mixture of upper or lower case.

The following are examples of valid units:

1000 M^3/min
million acre-inch per day

Time Unit













Volume Unit


cubic meters


cubic feet











Flow Unit


cubic feet per second


cubic feet per minute


cubic meters per second


million gallons per day


Data Sections

The other five sections contain monthly flow data for river headflow, river reach inflow, local reservoir inflow, groundwater and other supply inflow. Enter the section name in square brackets to define a section, i.e., [HEADFLOW], [REACH], [RESERVOIR], [GROUNDWATER] AND [OTHER]. To specify the flows for a particular element, first give its name on a line by itself. The name must match exactly the name given in the WEAP schematic (except for differences in upper or lower case). Because the name is used to match the Schematic element to its data, all supply elements in the Schematic must have unique names. Note: the name of an element is not its Schematic label, but its "name", as specified on General Info for the node.

On the lines following the name, enter the monthly inflows to this element, one year per line. Each line of data must contain thirteen pieces of data: the year, followed by data for each of the twelve months.

The years must be listed in increasing order, although there may be gaps in the years. During calculations, the flows for the Current Accounts Year will be taken from the data year specified with the First Year option (or the Current Account year if not specified). Inflows for each subsequent year will be taken from the next sequential year in the data file. If there is no data for the next year, WEAP will cycle back to the first year of the contiguous block of yearly data, which might be before the First Year. In this way, you can use a subset of historical data as a cycle. For example, if the time horizon is 2000 to 2020, the First Year is 1930, and there is historical data for years 1925 through 1934, the sequence of historical data used will be: 1930, 1931, 1932, 1933, 1934, 1925, 1926, 1927, 1928, 1929, 1930, 1931, 1932, 1933, 1934, 1925, 1926, 1927, 1928, 1929, 1930.

Numeric Format

Numbers can be entered in either floating point or fixed point notation or a mixture of the two. Floating point format is as follows: <mantissa>E<exponent>, with no spaces before or after the E. The following numbers are all equivalent:


Data Delimiters

Numbers can be separated by commas, tabs or spaces. Names of rivers and nodes can be enclosed in quotes or not, although you must use quotes if a name itself includes a comma.

Tip: It may be convenient to collect and format your data in Excel, then export them as tab-delimited or comma separated value (CSV) files. WEAP will be able to read these exported files without any further reformatting.


Any line that begins with a semicolon (;) will be treated as a comment line and ignored. Comments can be very useful for documenting your historical data. Blank lines are also ignored and can be used to enhance readability.


The following example comes from the file HIST.FLO in Weaping River Basin. (To save space, ellipses are shown in place of data for months 4-11.)

; Sample historical data file for 1950-59
; All flows are in cubic meters per second
Unit = CMS
FirstYear = 1950


"West Aquifer"
  1950, 8.606448, 7.03752, 21.57701, ..., 3.302112
  1951, 2.659248, 7.360368, 4.820064, ..., 4.77192
  1952, 11.20906, 14.1515, 8.38272,..., 11.22038
  1953, 7.921104, 11.92838, 10.63699, ..., 13.91928
  1954, 9.116208, 11.15242, 10.50389, ..., 5.22504
  1955, 4.684128, 9.413568, 5.468592, ..., 5.32416
  1956, 3.981792, 3.86568, 4.664304, ..., 8.546976
  1957, 8.173152, 9.484368, 11.54606, ..., 4.004448
  1958, 7.402848, 5.151408, 4.075248, ..., 2.832
  1959, 5.669664, 5.641344, 8.532816, ..., 7.836144


"Blue River"
  1950, 17.22706, 10.33397, 41.10081, ..., 3.22848
  1951, 2.982096, 17.88408, 8.844336, ..., 6.125616
  1952, 16.66632, 38.58034, 11.5489, ..., 22.04995
  1953, 13.7437, 20.48669, 19.41619, ..., 33.88488
  1954, 15.88469, 15.91584, 17.83027, ..., 7.252752
  1955, 6.68352, 21.81206, 7.921104, ..., 9.031248
  1956, 5.06928, 6.105792, 8.207136, ..., 8.051376
  1957, 20.75856, 10.43592, 16.96085, ..., 4.505712
  1958, 10.50955, 9.184176, 4.910688, ..., 2.560128
  1959, 5.740464, 6.842112, 11.5489, ..., 12.37584


"Blue River","Below Industry East With."
  1950, 3.205824, 1.948416, 7.765344, ..., .620208
  1951, .555072, 3.188832, 1.523616, ..., 1.229088
  1952, 2.928288, 6.366336, 1.945584, ..., 3.664608
  1953, 2.319408, 3.460704, 3.726912, ..., 6.493776
  1954, 2.829168, 3.007584, 3.29928, ..., 1.57176
  1955, 1.365024, 3.234144, 1.416, ..., 1.67088
  1956, 1.050672, 1.084656, 1.6992, ..., 2.248608
  1957, 3.404064, 2.741376, 3.474864, ..., .674016
  1958, 1.951248, 2.118336, .982704, ..., .75048
  1959, 1.07616, 1.333872, 1.710528, ..., 2.509152


; No local reservoirs exist


; No other supplies exist