Physical and chemical limnology of six hydroelectric lakes on the Waikato River, 1970–72

Abstract

The Waikato River flows from oligotrophic Lake Taupo through eight impoundments to the sea. As it does so, physicochemical changes occur; conductivity and dissolved oxygen levels decrease, patterns in the seasonal variation in pH and alkalinity change, and the nitrogen and phosphorus concentrations increase. Except for the changes in conductivity, changes in the other parameters are characteristic of eutrophication. This eutrophication is associated with an increase in the intensity of pastoral farming in the catchment of the Waikato River downstream of Lake Taupo.