Waikato peat lakes sediment nutrient removal scoping exercise

Abstract

This report was commissioned by Environment Waikato to examine the available methods for internal (bottom sediment) nutrient removal and their suitability for application in the Waikato peat lakes. Lakes Ngaroto, Kainui, Rotomanuka and Cameron were chosen as focus lakes for the study, based on existing restoration objectives and recreational and conservation values. A range of methods designed to reduce internal nutrient loading was reviewed, including hypolimnetic aeration, hypolimnetic withdrawal and fish removal, with sediment removal, and additions of alum, Phoslock, zeolite, iron making slag and carbon examined in detail.