3.2 Judgment matrix and weight coefficient
The establishment of a connectivity judgment matrix is the key to the
AHP model. In this paper, drawing on previous research results, we
obtain the judgment matrix by comparing the connectivity indicators at
different levels based on the river’s basic functions. The specific
analysis is as follows.
The continuity and mobility of water flow are the basis of river health.
On the one hand, water conveyance and sediment transport are the most
important functions of rivers; on the other hand, sediment transport and
channel evolution also require power or energy generated by the water
flow. Therefore, water flow connectivity is more important than boundary
connectivity and sediment connectivity. In addition, the balance of
erosion and deposition will be disturbed if the sediment is not
connected, which will change the boundary characteristics of the
channel. In addition, there is no channel for water conveyance and
sediment transport if the boundary is damaged, which would cause serious
floods. Therefore, boundary connectivity is more important than sediment
connectivity. According to the relative importance of each connectivity
index, the constructed judgment matrix is shown in Table 2. The weights
of boundary, flow and sediment connectivity indexes are 0.143, 0.571 and
0.286, respectively.