Changes in Shallow Hydrology of the Tauhara Geothermal FieldReynolds Number)

Abstract

The shallow hydrology at Tauhara has been affected, in the north, by rainfall recharge (with about a 6-month response lag), a steady 1 to 2 m per decade drawdown, and temperature changes from a steam heating thermal pulse caused by deep pressure drawdown. Southern Tauhara springs and bores have responded only to rainfall trends and lake level variations, respectively. Although the major impacts from Wairakei drawdown have already occurred, future Tauhara developments could result in further shallow hydrological and thermal effects, particularly if pressures in the underlying steam zone are modified by steam extraction or water injection.