The boundary connectivity index includes the comprehensive stability
coefficient C1 and the stream gradient C2, which are the basis to ensure
the function of water conveyance and sediment transport, respectively.
The stability of the boundary is slightly more important than the
continuity of the boundary. Therefore, the weight of the stability
coefficient is 0.55, and the stream gradient is 0.45.
The judgment matrix of the flow connectivity index is shown in Table 3.
Runoff C3 has the greatest impact on channel connectivity, with a weight
of 0.39. The discharge capacity C4 reflects the maximum discharge that
the river can transport safely, which is also important for flow
connectivity, with a weight of 0.24. The matching index of minimum flow
C5 is the ratio of the minimum discharge and ecological discharge; this
ratio reflects the ecological function of rivers, and its weight is
0.23. The matching index of maximum flow C6 is calculated by the maximum
discharge and discharge capacity. It can reflect not only the
longitudinal connectivity but also the lateral connectivity between the
floodplain and main channel, with a weight of 0.13.