ZoneBudget is a program developed by the U.S. Geological Survey to calculate water budgets for user-defined zones in the model. The user-defined ZoneBudget zones are created during the Define Zone Budget Zones workflow step. The Zone Budget program calculates the flow mass balance for each user-defined zone.
The Flow Zone Budget Graphs plot the flow rates of water entering and leaving the user-defined zones through the flow boundary conditions, from aquifer storage, and through other user-defined zones.
To plot the Zone Budget Graphs, select the View Charts workflow step, click the Zone Budget Button on the upper left corner of the Chart view, and a Zone Budget: MODFLOW window will appear as shown below:
There are four different Flow Zone Budget Graphs:
•Percent Discrepancy plots the temporal changes in the Flow Mass Balance for the selected zone (total flow IN minus total flow OUT) expressed as a percentage of the total flow in the zone.
•IN - OUT plots the temporal change in the Flow Mass Balance for the selected zone (total flow IN minus the total flow OUT).
•Time Series plots the temporal flows IN and OUT of the selected zone through the individual sources and sinks (flow boundary conditions and storage).
•Time Steps plots a bar chart of the flow IN to the system and the flow OUT of the selected zone through the individual sources and sinks (flow boundary conditions and storage) for selected Output Times.
Note: With both the Time Steps and the Time Series graphs, it is important to remember that these graphs present the rate(s) at a point (or points) in time, and not the cumulative volume at a point in time.
On the left-hand side of the Zone Budget: MODFLOW window is a list of the Zone Budget zones available for the current model. The Zone Budget graphs described above will display the Zone Budget data for the selected Zone Budget zone.
The Zone List Box Control
The Zone Control indicates the current Zone for the active charts and the list box below shows all available ZoneBudget zones in the model. Clicking directly on a Zone in the list will switch to that Zone.
The IN/OUT List Box Controls
The IN list contains each of the possible source terms which may contribute flow to the selected Zone Budget zone, while the OUT list contains each of the possible sink terms which may divert flow out of the selected Zone Budget zone.
The checkboxes beside each term can be used to add or remove the individual source and sink terms from either the Time Series graph or the Time step graph.
The group checkboxes will add or remove the entire IN/OUT group.
The Percent Discrepancy graph and the IN-OUT graph consider only the total flow into and out-of the entire system as a whole. As a result, the settings for the individual IN and OUT terms do not influence the results and appearance of these graphs.
Note: By convention, Zone Budget considers mass balance from the perspective of the groundwater system. For example, the IN term for River Leakage represents the river leakage INTO the groundwater system.
Each of the graphs can be maximized to occupy the entire Zone Budget window by clicking the maximize button in the top right-hand corner of each graph window. Alternately, the graphs can be tiled in the Zone Budget window by selecting Window/Tile from the top menu bar.