Factors had to be normalized in order to be comparable, since they all had different associated units of measurement. The following summarizes the range and meaning of normalization for the constraint and factors, where 0 is bad and 1 is good:
Constraint:
As noted, infrastructure being considered “Fish-Friendly” may not actually be acting as such. However, for the purpose of this analysis, if the infrastructure was deemed Fish-Friendly, it was excluded from being considered for the priority upgrade list, since there was a possibility that it already was sufficiently connecting waterways.
Factors:
This factor was determined based on estimates from Watershed Watch staff of the cost to upgrade the two kinds of flood infrastructure – floodgates or pump stations. Floodgates are considerably less expensive ($75 000 – $150 000) than pump stations ($1.5 million). The lower cost (and thus the floodgates) is preferred for priority infrastructure, since it will be easier to convince municipalities to make the Fish-Friendly upgrades.
The rankings of “very high”, “high”, “medium”, or “low” with the associated distances was calculated using an algorithm for the upstream gradient, provided by Watershed Watch. The more upstream habitat, the better.
The presence of water quality data is good for prioritizing upgrades, since it provides a baseline and demonstrates interest in the waterway. It can thus indicate whether opening up the waterway to more flow would drastically improve potential salmon habitat.