DRAINMOD Input Weather Utility Format

 

DRAINMOD 6.0 includes a utility program to create DRAINMOD formatted weather files.   The utility converts columnar weather data to DRAINMOD format.   From the main menu, select UTILITY and then Create Weather File to use the utility program. The input file is read 'format free' which means that the location of the data on a line does not matter.

 

 

1.  Converting columnar daily max/min temp to DRAINMOD format

 

The program reads a four column daily maximum and minimum temperature file and writes a daily maximum and minimum temperature file in DRAINMOD format (.TEM file).  The first and second columns of the input file are the year and the day of the year. The third and fourth columns are the maximum and minimum temperatures, respectively, (in oF or oC) for that day.

 

Sample input lines (temperature in oF)

 

1960           1       64       49

1960           2       53       29

1960           3       49       27

1960           4       49       28

1960           5       36       16

1960           6       65       15

1960           7       67       46

1960           8       49       31

 

 

2.  Converting  columnar daily potential ET to DRAINMOD format

 

The program reads a three column daily potential evapotranspiration file and writes the daily potential evapotranspiration file in DRAINMOD format (.PET file).  The first and second columns of the input file are the year and the day of the year.  The third column is the daily PET amount (in inches, centimeters or millimeters) for that day.

 

Sample input lines  (PET in cm.)

 

1960     1    .076

1960     2    .076

1960     3    .076

1960     4    .051

1960     5    .025

1960     6    .000

1960     7    .102

1960     8    .178

1960     9    .102

1960    10    .051

1960    11    .025

 

 

3. Converting columnar hourly rainfall to DRAINMOD format

 

The program reads a three column hourly rainfall file and writes an hourly rainfall file in DRAINMOD format (.RAI file).  The first and second columns of the input file are the year and the day of the year.  The day values include decimals that represent hours (ie. the sixth hour of Jan 5 is expressed as 5.250 which is

equal to 5 + 6/24).  The third column is the rainfall amount ( in centimeters, millimeters or inches)  for  that hour.

 

Sample input lines (in cm)

 

1960    4.8750      .0508

1960    4.9167      .0762

1960    4.9583      .2032

1960    5.0000      .1524

1960    5.0417      .0508

1960    5.0833      .1270

1960    5.1250      .1016

1960    5.1667      .0762

1960    5.2083      .0508

1960    5.2500      .0508

 

 

4.  Converting columnar daily rainfall to DRAINMOD format

 

The program  reads a three column daily rainfall file and writes an hourly rainfall file in DRAINMOD format (.RAI file).  The first and second column of the input file are the year and the day of year.  The third column is the rainfall amount ( in inches, centimeter or millimeter) for that day.

 

Sample input (inches)

 

1990       1    0.58

1990       2       0

1990       3    0.02

1990       4       0

1990       5       0

1990       6    0.29

1990       7    0.05

1990       8    0.87

1990       9       0

1990      10      0

1990      11      0

1990      12      0

1990      13      0

1990      14      0

 

 

 

 

 

Example 1

 

Number of hours to distribute the rainfall     4  

Hour to begin distribution of the rainfall    17

Daily rainfall amount (inches)                 1.20

 

Hour        Rainfall amount(100ths of an inch)

  17                30

  18                30

  19                30

  20                30

 

 

Example 2

 

 Number of hours to distribute the rainfall     6  

 Hour to begin distribution of the rainfall    16

 Daily rainfall amount (inches)                 1.20

 

 Hour        Rainfall amount(100ths of an inch)

  16                20

  17                20

  18                20

  19                20

  20                20

  21                20

 

Example 3

 

 Number of hours to distribute the rainfall     2  

 Hour to begin distribution of the rainfall    18

 Daily rainfall amount (inches)                 1.20

 Hour        Rainfall amount(100ths of an inch)

  18                60

  19                60

 

Example 4

 

 Number of hours to distribute the rainfall     4  

 Hour to begin distribution of the rainfall    17

 Daily rainfall amount (inches)                 0.34

 

 Hour        Rainfall amount(100ths of an inch)

  17                 8

  18                 8

  19                 8

  20                10

 

Example 5

 

 Number of hours to distribute the rainfall     4  

 Hour to begin distribution of the rainfall    17

 Daily rainfall amount (inches)                 0.62

 

 Hour        Rainfall amount(100ths of an inch)

  17                16

  18                16

  19                16

  20                14

 

 

 

The program estimates the hourly distribution of daily rainfall using a very simplistic method.  The user has some control over how this distribution takes place, and should consider typical rainfall patterns for your region.  DRAINMOD will not be very sensitive to hourly distribution of rainfall for cases where surface storage is high and infiltration rates are high (such as wetland and forestry situations).  DRAINMOD will be sensitive to hourly distribution of rainfall for cases with good surface drainage (low surface storage) and low infiltration rates.  The user is advised to check the sensitivity of DRAINMOD to the hourly distribution of rainfall for the situations they are considering.