An electrical resistivity survey in the Darfield and Templeton areas (Canterbury)

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Risk, G.F. 1967 An electrical resistivity survey in the Darfield and Templeton areas (Canterbury). [s.l.]: [s.n.]. Report / Geophysics Division 44 5 p.

Abstract: The purpose of this survey is to determine the depth of the water table in the Darfield area and investigate the nature of the aquifer and overburden. Several unsuccessful attempts have been made i the past to improve the water supply to the township of Darfield which is at present dependent on a water race. This work has been summarised by L.J. Brown in a New Zealand geological Survey report entitled "Ground water in the vicinity of Darfield". In most of the wells in the area the water level is more than 200 ft below ground level and varies considerably throughout the year. Between 13 June and 6 July 1966 20 electrical resistivity soundings were made in the vicinity of Darfield. In addition, four soundings were made near Templeton in order to test the apparatus and method under known conditions. The positions of the soundings are listed in Table 1. The Schlumberger configuration of electrodes was used, in which the distance between the current electrodes was increased in steps from 20 ft to 2500 ft. An e,m,f, of 45, 90 or 135 volts was applied to the current electrodes. The potential difference between the potential electrodes (which were 4, 16 or 100 ft apart) was fed into a "Philips" VTM (Model GM6020) and monitored on one channel of a twin channel "Esterline Angus" chart recorder (Model 602). The current was monitored on the other channel (auth)