3.3 Connectivity index dimensionless
Because of the different dimensions of each connectivity index, the index value needs to be dimensionless. The larger the index value is, the better the channel connectivity will be, and we call this a positive index. The smaller the index value is, the better the channel connectivity will be, and we call this a negative index. In addition, the closer the index value is to the intermediate critical value, the better the channel connectivity, and we call this an intermediate index. In this paper, the positive index includes the comprehensive stability coefficient, stream gradient, runoff, discharge capacity, matching index of maximum flow and matching index of minimum flow; the intermediate index is the sediment matching index; and the negative index is the sediment load. The dimensionless methods of each index are different, and the specific methods are as follows:
For the positive index, the ratio of the index value to the mean value of the sequence is taken as a quantitative index,