Capacity measures the total amount of flow that can be supplied to or taken from a centre to meet
demands along links and nodes. The resource capacity of the center is the maximum amount of resources
that can be supplied to or from the center. The center's capacity can determine the extent of the links
allocated to that center. As the links are allocated to the center, their resource demand is accumulated, and
if the total demand exceeds the center's capacity, the link will not be allocated to that center. In a stream
network, all stream-flow towards the catchments outlet therefore should be allocated to a given outlet. If
the total flow supplied to the centre at a given time exceeds the center’s capacity, an exceptional event will
occur (e.g. overflow or flood gate opening).