Interbasin Water Transfers and the Régimes of Three Northwestern Ontario Rivers

Runoff régimes of three northwestern Ontario river systems undergoing interbasin transfer of water were compared to the natural flow patterns of neighbouring rivers. Long-term diversion effects can be identified by analysing the probability distributions of annual runoff, annual floods, and annual low flows, representing mean, maximum, and minimum flow conditions of each year, respectively. Rivers exporting water have reduced annual flow and highly variable peak runoff, accompanied by high probability of zero low flow. Rivers importing water exhibit smaller variations of annual flow and peak flow but more variable low flow than the unregulated streams. The Albany River-English River systems are particularly interesting because they offer stream flow records for the periods before and after interbasin water transfer, making it possible to analyse the changes in their flow characteristics through time.