Parallel Pipe Merging is the process of combining pipes that share the same two end nodes into a single hydraulically equivalent pipe. This skeletonization strategy relies on the hydraulic equivalency feature.

To merge parallel pipes, you specify which of the two pipes is the "dominant" one. The length of the dominant pipe becomes the length of the merged pipe, as does either the diameter or the roughness value of the dominant pipe. You specify which of the two attributes to retain (diameter or roughness) and the program determines what the value of the other attribute should be in order to maintain hydraulic equivalence.

For example, the dominant pipe has a diameter of 10 inches and a C factor of 120; one of these values is retained. The pipe that will be removed has a diameter of 6 inches and a C factor of 120. If the 10-inch diameter value is retained, the program performs hydraulic equivalence calculations to determine what the roughness of the new pipe should be in order to account for the additional carrying capacity of the parallel pipe that is being removed.

Because this skeletonization method removes only pipes and accounts for the effect of the pipes that are removed, the network hydraulics remain intact while increasing the overall potential for a higher level of skeletonization.