Tanks are nodes with storage capacity, where the volume of stored water can vary with
time during a simulation.
Below is the list of Tank properties:
- bottom elevation
- diameter (or shape if non-cylindrical)
- initial, minimum and maximum water levels
- initial water quality.
- total head (water surface elevation)
- water quality.
Tanks are required to operate within their minimum and maximum levels. EPANET stops outflow if a tank is at its minimum level. It stops any inflow if the tank is at its maximum level unless its Can Overflow property is set to YES. In that case any inflow becomes overflow (i.e., spillage).
Tanks can also serve as water quality source points.
| Field | Description |
| ID | A unique label used to identify the tank. |
| X-Coordinate | Horizontal location of the junction on the Study Area Map. If left blank then the junction will not appear on the map. |
| Y-Coordinate | Vertical location of the junction on the Study Area Map. If left blank then the junction will not appear on the map. |
| Elevation | The elevation above a common datum in feet (meters) of the bottom shell of the tank. This is a required property. |
| Initial Level | The height in feet (meters) of the water surface above the bottom elevation of the tank at the start of the simulation. This is a required property. |
| Minimum Level | The minimum height in feet (meters) of the water surface above the bottom elevation that will be maintained. The tank will not be allowed to drop below this level. This is a required property. |
| Maximum Level | The maximum height in feet (meters) of the water surface above the bottom elevation that will be maintained. The tank will not be allowed to rise above this level. This is a required property. |
| Diameter | The diameter of the tank in feet (meters). For cylindrical tanks this is the actual diameter. For square or rectangular tanks it can be an equivalent diameter equal to 1.128 times the square root of the cross-sectional area. For tanks whose geometry will be described by a curve (see below) it can be set to any value. This is a required property. |
| Minimum Volume | The volume of water in the tank when it is at its minimum level, in cubic feet (cubic meters). This is an optional property, useful mainly for describing the bottom geometry of non-cylindrical tanks where a full volume versus depth curve will not be supplied (see below). |
| Volume Curve | The ID label of a curve used to describe the relation between tank volume and water level. This property is useful for characterizing irregular-shaped tanks. If left blank then the tank is assumed to be cylindrical. |
| Can Overflow | If set to YES then any inflow to a full tank becomes overflow (i.e. spillage). Otherwise any links that would normally send flow to the tank are temporarily closed when the tank becomes full. |
| Mixing Model |
The type of water quality mixing that occurs within the tank. The choices include:
|
| Mixing Fraction | The fraction of the tank's total volume that comprises the inlet-outlet compartment of the two-compartment (2COMP) mixing model. Can be left blank if another type of mixing model is employed. |
| Reaction Coefficient | The bulk reaction coefficient for chemical reactions in the tank. Use a positive value for growth reactions and a negative value for decay. Time units are 1/days. Leave blank if the Global Bulk reaction coefficient will apply. See Water Quality Reactions for more information. |
| Initial Quality | Water quality level in the tank at the start of the simulation. Can be left blank if no water quality analysis is being made or if the level is zero. |
| Source Quality | Quality of water entering the network from the tank(regardless of what the actual quality in the tank is). |