The Water Storage Tank, one of the water supply source components available for the Water Distribution network in a DEW model, attaches to one or more fluid circuits providing water supply for downstream circuit components. All other types of components in the DEW model (except for other sources) must have a trace path back to at least one water supply source.
See General Dialog Details for information on common dialog fields and commands, as only the highlighted fields and commands unique to the Tank dialog (shown below) are addressed in this topic.
DEW models tanks as simple volumetric cylinders, regardless of actual shape. To model the tank's interaction with the distribution system, some basic characteristics on construction and installation, which are stored in the database, must also be defined in order to correctly input values on the tank dialog.
Tank Capacity - The working (i.e. usable) volume of water that the tank contains between the High Water Level (HWL) and the Low Water Level (LWL).
High Water Level - the HWL is the maximum height (in feet) above ground level that the water may fill in the tank. This typically equates to the height of the installed overflow line or may be defined by the height of an installed (high water) limit switch.
Low Water Level - the LWL is the minimum height (in feet) above ground level that the water is allowed to empty from the tank before shut off. This may be determined by the height of an installed (low water) limit switch or by the terminating height of the inlet/outlet riser on elevated tanks.
Ground Level (Z) - this is defined to be the topographic elevation (feet above sea level) for the installed tank's geographic location. This is indicated by the "Z" value on the tank dialog.
Current Level - The current level is specified as the height (in feet) above ground level of water presently in the tank. The current level should always occur between the LWL and the HWL defined for the tank installation.
Current Volume - the current volume is a read-only display of the estimated volume of (usable) water in the tank for the defined current level. This value is calculated based on the equivalent cylindrical tank diameter and height differential between the current level and the LWL.
Equivalent Cylindrical Diameter - this is a calculated value based on the tank's usable water head range (i.e. HWL-LWL) and the tank capacity, as installed.