Ideally, only a few pipes will need to be closed or metered to create the DMA. Closing a large number of isolation valves reduces the capacity of the distribution system (especially during fires) and installing a large number of flow meters is expensive. In cases where you feel there are too many boundary elements between adjacent DMAs, you can merge them into a single DMA. Select the row of one of the DMAs in the table and choose "Assign DMA Status" > "Merge Adjacent DMAs". The following dialog appears. The two adjacent DMAs will be graphically displayed in the drawing (click the "Zoom To" tool if the DMA is not visible on screen).

And the adjacent DMAs look like this:

If the user selects Merge, the DMAs will be combined into a single DMA (by assigning the DMA Status). This usually results in a reduction of the number of boundary pipes (i.e. valves to be closed).