Evapotranspiration Gage Data Command

Evapotranspiration is the combination of evaporation from the ground surface and transpiration by vegetation. It includes both evaporation of free water from the surface of vegetation and the land surface. It also includes transpiration, which is the process of vegetation extracting moisture from the soil through the plant root system. Both processes return water from the land or subsurface to the atmosphere. Even though evaporation and transpiration are considered together, transpiration is responsible for a larger portion of water movement than evaporation. Combined evapotranspiration is often responsible for up to 60% of precipitation returning to the atmosphere. The theoretical evapotranspiration, also called the potential evapotranspiration, serves as the upper limit for what can happen on the land surface based on atmospheric conditions.

Evapotranspiration gages are utilized to define evapotranspiration point data. In GeoHECRAS software, users can define evapotranspiration gage point locations and corresponding precipitation data using the Evapotranspiration Gage Data command. This data can later be used in the meteorological model to define one or more gages. Refer to this article in our knowledge base to learn how to define a meteorological model.

This article describes how to use the Evapotranspiration Gage Data command in the GeoHECRAS software.

Follow the steps below to use the Evapotranspiration Gage Data command:

1. From the Input ribbon menu, click the Meteorology Data dropdown menu and select the Evapotranspiration Gage Data command.
   
2. The Evapotranspiration Gage Data dialog box will be displayed, as shown below.
   

The following sections describe how to use the Evapotranspiration Gage Data command and interact with the above dialog box.

Selecting Evapotranspiration Gage

The Select Evapotranspiration Gage section allows the user to select the evapotranspiration gage for which evapotranspiration gage data will be defined. In this section, the user can create, delete, or copy existing evapotranspiration gage data to a new evapotranspiration gage. In addition, the user can navigate between evapotranspiration gages and enter a description for each evapotranspiration gage.

The following parameters are provided in this section:

• Evapotranspiration gage ID
  This dropdown combo box lists all the evapotranspiration gages that are defined in the current scenario. Click on the edit option (i.e., pencil icon) to edit the evapotranspiration gage ID. The user can navigate between the previous and next evapotranspiration gage using the Up and Down arrow buttons. Note that the Up and Down arrow buttons will be disabled (i.e., grayed out) if the current scenario contains a single evapotranspiration gage.

• Description
  This optional text field allows the user to enter additional information that describes the selected evapotranspiration gage.

• New
  The [New] button allows the user to create a new evapotranspiration gage. The ID of every newly created evapotranspiration gage must be unique.

• Copy
  The [Copy] button allows the user to copy an existing evapotranspiration gage along with its associated data to a new evapotranspiration gage. When this command is executed, the software automatically provides a unique default name for the duplicated evapotranspiration gage. The cursor is then placed into the Evapotranspiration gage ID entry field. The user can go with the default name or enter a different valid and unique ID before moving on to add any other data.

• Delete
  The [Delete] button allows the user to delete the selected evapotranspiration gage from the current scenario. Clicking the [Delete] button displays the following confirmational dialog box:
  
  Click the [Yes] button to delete the selected evapotranspiration gage. To abort the deletion process, click the [No] button.

Evapotranspiration Gage Location

This section allows the user to provide a precise description of the evapotranspiration gage’s location. The location is specified for each gage in terms of latitude and longitude. The latitude and longitude can be entered in decimal degrees in the Latitude and Longitude fields, respectively. Upon entering the latitude and longitude, the software will provide the physical address in the Location read-only field. Alternatively, the user can click the [Pick] button to pick the location interactively from the Map View. The software will then display the physical address, longitude, and latitude values for the selected location in the respective fields.

Constant Evapotranspiration Data

This section allows the user to define a constant evapotranspiration rate. By default, the radio button on the Constant Evapotranspiration Data section is selected. This section is disabled (i.e., grayed out) if either the DSS Data or Time Series Data radio button is selected.

DSS Data

This section allows the user to select a DSS data file to define the evapotranspiration gage time series data. By default, the content of this section is disabled (i.e., grayed out). Select the radio button on the DSS Data section to enable the content of this section.

The following parameters are provided in this section:

• DSS file
  This entry denotes the file directory path to the DSS data file. Clicking on the [Select] button allows the user to select the directory path and data path using the DSS Data File & Path dialog box. To know more about the DSS Data File & Path dialog box, refer to this article in our knowledge base.

• DSS path
  This entry denotes the data path within the DSS data file, which contains the evapotranspiration gage data.

Time Series Data

This section allows the user to manually enter time series data for the selected element. By default, the content of this section is disabled (i.e., grayed out). Select the radio button on the Time Series Data section to enable the content of this section.

The following parameters are provided in this section:

• Select control
  This dropdown combo box is used to define the control data set to use. The following options are available:
  

• 1. Manual date and time – This option is used to define evapotranspiration time series data for irregular time intervals.
  2. Manual simulation time – This option is used to define evapotranspiration time series data for irregular time intervals.
  3. Regular interval (default) – This option is used to define evapotranspiration time series data for regular, fixed-time intervals.
• Data type
  This dropdown combo box is used to define the type of data that are to be entered. The following options are available:
  

• 1. PER-AVER (default)
  2. PER-CUM
  3. INST-VAL
• Evapotranspiration data starting date time
  This subsection is used to select the simulation date and the start time to define the time series data. This subsection is enabled only when the Regular interval is selected in the Select control dropdown combo box. Otherwise, this subsection is disabled (i.e., grayed out). The following radio button options are available in this subsection:

• 1. Use simulation time – Selecting this radio button option allows the software to use the simulation date and time as the starting time.
  2. Fixed start time – Selecting this radio button option allows the user to enter a specific date and time that defines the simulation period as the starting time.

• Date time interval
  This dropdown combo box is used to select the time interval that defines the time series data. The following options are available:
  

  Seconds	Minutes	Hours	Days	Weeks	Months	Years
  1 second	1 minute	1 hour	1 day	1 week	1 month	1 year
  2 seconds	2 minutes	2 hours
  3 seconds	3 minutes	3 hours
  4 seconds	4 minutes	4 hours
  5 seconds	5 minutes	6 hours
  6 seconds	6 minutes	8 hours
  10 seconds	10 minutes	12 hours
  12 seconds	12 minutes
  15 seconds	15 minutes
  20 seconds	20 minutes
  30 seconds	30 minutes

• Time Series Table
  The Date & Time and Simulation data grid columns automatically get filled in based on the option selected in the Evapotranspiration data starting date time subsection. The user can manually enter data into the Evapotranspiration data grid column field.

Evapotranspiration Time Series Plot

This section displays the Evapotranspiration (in/hr) vs Date time plot of the selected evapotranspiration gage data. If no time series data are available, the graph will not show any data.