Whakarewarewa Natural Features - Update of Chemical and Isotopic Compositions and Comparison with Historical Data

Abstract

A geochemical survey of 17 selected Whakarewarewa natural features was undertaken for comparison with historical data. The purpose was to provide an overall assessment of the recovery of the springs following the 1986 bore closure programme and implementation of resource management plan polices for the Rotorua field. The features show a range of chemical and isotopic changes ranging from continuing decline to recovery with aquifer re-heating. The most outstanding recovery is at Parekohoru which is now discharging less-dilute fluids and at Pohutu where re-heating of the shallow aquifer is indicated by a significant increase in dissolved silica. Pohutu fluid composition is now comparable to that discharged in 1937. Possible increases in the temperature of the deeper water component are indicted by THC Blowout fluid compositions and by the Okianga Geyser.