Tanks are node elements in InfoWater Pro that represent true storage nodes within InfoWater and generally have a fixed volume of storage.  Tanks are distinguished from Reservoirs as having a known finite volume and water surface levels that can change with time (EPS only) as water flows into or out of the Tank. 

How do I...

Create a Tank?

To create a Tank node, do the following:

Click on the InfoWater Pro Ribbon in the Edit Group using the  Insert Command dropbox  .  

Select the Insert Tank icon  from the  Insert Command dropbox  

When the Insert Tank command is the active command it will be highlighted in Blue as shown:

Once the command is initiated, select the location of the new node by left mouse clicking anywhere on the map display. Suggest a new ID and/or a description on the Tank Identification dialog box and click on the OK button to accept the ID and create the new Tank. The Tank should visually appear at the specified location. If the insert location is near an existing model pipe the software will ask if you wish to insert the Tank into that pipe. If you wish to split the pipe, the Tank Identification dialog box for the new Tank and the new pipe will appear in a pop up window.

You can also use the Digitize Network icon  from the  Insert Command dropbox  to create a pipe and node network "on the fly".  Once digitized, the user is able to add relevant modeling data in the Model Explorer - Attribute Tab window or via the DB Editor.

Types of Tanks?

There are 2 different types of Tanks  the user is able to input in InfoWater.

Cylindrical Tank

A cylindrical tank represents any tank that has a constant diameter in relation to its high and low water levels.  

Specify the Tank Type as Cylindrical in the Type field of the  Model Explorer - Attribute Tab window.

A tank needs the following fields to be populated:

  • Elevation -The elevation (above sea level) of the bottom of the tank, ft (m).
  • Minimum Level - The lowest allowable water level above the bottom of the tank (ex. 3 ft.), ft (m)
  • Maximum Level - The highest allowable water level above the bottom of the tank (ex. 22 ft.), ft (m).
  • Initial Level - The height of water above the bottom of the tank (ex. 12 ft.) when the simulation is to begin, ft (m). NOTE: do not set the Initial Level equal to the Maximum Level or Minimum level of the Tank because the hydraulic solver will temporarily close all pipes connected to the Tank when the Maximum or Minimum Tank level is reached. 
  • Diameter - The diameter of the tank, ft (m). NOTE: If the tank is not circular but has a constant cross sectional area, use an equivalent diameter that has a similar cross sectional area to the square or rectangular tank cross sectional area.
  • Minimum Volume - Only required when minimum level is not known, ft3 (m3).


Minimum Volume is an optional field and needs to be entered only in cases when the Minimum Level is not known but the Minimum Volume is known. Also for Cylindrical tanks the curve field needs to be left blank.

The Hydraulic solver will assume percent full calculations for the tank based on the Minimum Level (zero percent full) and Maximum Level (100% percent full) of the tank, so set the Minimum Level accordingly to account for the entire storage height volume desired in the output results for Percent Full. Many users will set this value to zero so that the percent full is based on the entire tank height even if part of the storage is not technically useable.

Variable Area Tank

A variable area tank refers to a tank type where the volume of the tank does not vary linearly with the height. Examples of such tanks would be conical tanks, spherical tanks etc.

The only way to model such a type of tank would be to create a curve that represents the relationship between height and volume.  Specify the Tank Type as Variable Area in the Type field of the Model Explorer - Attribute Tab window. 

  • Curve - The curve assigned to the tank for an EPS.  The curve may contain any number of data points, but the more points the better the curve will be represented.  When a Tank selected is the active element in the Model Explorer - Attribute Tab window to quickly open the Curve Editor, the user can double click on the word "Curve"  in the Modeling section to quickly open the Curve Editor. Then select the Curve option drop down box and choose the representative multi-point curve.  Refer to the Curve section of the help file to learn more about a Volume Vs Depth curve. 

Volume vs. Depth (Tanks - Variable-Area) Curves

The curve for variable-area tanks is now defined as the volume of the tank versus its corresponding depth.  It is very important to note that the volume must be defined in cubic feet (ft3) or cubic meters (m3) and not in any other unit (such as gallons or MG).  This curve now relates to having the volume of the tank on the (Y-axis) with the corresponding depth on the (X-axis).  A sample table and curve are provided below:


Edit a Tank?

Graphic Selection - To select a Tank node for data edit do one of the following:

Choose the Select icon  from the Model Explorer - Attribute Tab window and click on the specific Tank or select the InfoWater Pro Ribbon in the Edit Group using the  Select icon 

If a Tank has been prior selected and is a part of the Browse history, it can be re-selected by choosing it from the Browse-History section of the Model Explorer - Attribute Tab window.

Data Edit - To edit the data related to a Tank, first select the Tank using the tools above. Once selected, edit Junction related data by adding/modifying the fields in the Model Explorer - Attribute Tab window.  Additionally modifications may be done by editing the DB Tables that may be accessed from the InfoWater Pro Ribbon in the Edit Group using the  DB Editor icon  .

Graphic Edit  - To edit the node graphically do one of the following: From the  InfoWater Pro Ribbon in the Edit Group using the  Edit Command dropbox icon  select the Move Node command  from the dropdown . Left click on the mouse and hold the left click down on the junction to select it. With the junction highlighted move the node to the desired position while keeping the left click mouse button depressed. Once in the desired location, release the left mouse button and the node location will be updated to the new location.

When the Move Node command in the InfoWater Pro Ribbon in the Edit Group  Edit Command dropbox is the active command it will be highlighted in Blue as shown: 

If the user has not enabled "Auto Length Calculation" checkbox  under the InfoWater Pro Ribbon in the Project Group using the Preferences icon  and the Operations tab, all pipes connected to a node moved will not have their lengths automatically changed.

Edit Data for a Group of Tanks?

Group edits can be made by either creating a domain or by creating a selection.

Using the Domain Manager - Create a domain selecting the specific Tanks that you want to edit. Refer to the section on Domain Manager for details on the domain creation process. Once the domain has been created, choose the InfoWater Pro Ribbon in the Edit Group using the  DB Editor icon . Depending on the data you want to edit choose the appropriate table type from among the different database tables. Choose as the Data Scope and click on OK.

Using the User Selection - Select choose the InfoWater Pro Ribbon in the Edit Group using the  DB Editor icon .  Depending on the data you want to edit choose the appropriate table type from among the different database tables. Choose  as the Data Scope and choose the User Selection  command. This places the software in User Selection Mode.  In InfoWater Pro, the Selected elements will be in a cyan color.  Once all of the desired Tanks are selected, right click and choose Enter to access the DB Tables for the selected Tanks.

Once the specific tables have been opened with the desired scope, enter data one cell at a time or Block Edit data to make changes in bulk to multiple cells.

Group Editing for certain specific features may also be done by choosing the Group Editing icon  or the Edit Domain icon  under the InfoWater Pro Ribbon in the Edit Group . Refer to the sections on Group Editing and Edit Domain to learn more.


Delete a Tank?


To delete a Tank, select the Delete Node option  in the InfoWater Pro Ribbon in the Edit Group  Edit Command dropbox. Select the node to be deleted and InfoWater Pro prompts the user to confirm deletion (if the Delete Confirmation checkbox  is checked in the Operation Settings tab in the Preferences settings .

The active selected Tank in the Model Explorer - Attribute Tab window may also be deleted by selecting the Delete icon  with the InfoWater Pro prompt to confirm element deletion.

All pipes attached to the Node being deleted will also be deleted if the Auto Pipe Delete checkbox  is checked in the Operation Settings tab in the Preferences settings .  The Node and associated pipes are deleted and saved in the InfoWater Pro recycle bin and can be recalled from the database using the Model Explorer - Command Center Tab under Utilities -> Recall (Node or Pipe) command. However, if Auto Database Packing  is checked (Operation Settings tab in the Preferences settings ), then any element deleted is permanently deleted from the database and cannot be recalled. Deleted elements can be recalled until the Pack and then Clean commands (found in the Model Explorer - Command Center Tab under Utilities  Database menu list) are completed which removes deleted element ID's from the database.


Recall a Deleted Tank?


To recall a deleted Tank, go to Model Explorer - Command Center Tab under Utilities -> Recall and select the Node command. In order to perform the recall, the user must know the ID of the Tank that was deleted. You may choose the Show Deleted Node command to obtain a list of  nodes deleted from the InfoWater project but saved in the InfoWater recycle bin. Deleted elements can be recalled until the Pack and then Clean commands (found in the Model Explorer - Command Center Tab under Utilities  Database menu list) are completed which removes deleted element ID's from the database permanently.