The hydrogeological investigation of fissure-flow by borehole logging techniques

Abstract

Summary The instrumentation and techniques developed for the investigation of fissure-flow in consolidated aquifers are described and illustrated by three case histories. The use of closed-circuit underwater television inspection of boreholes is outlined and consideration is given to the implications of flow rates by analyses of the tritium contents of some water samples.

Tracer tests and the structure of permeability in the Corallian limestone aquifer of northern England, UK

“…Thus, the fraction of the Irton discharge that was derived directly from the River Derwent via the conduit in the first 24 hrs was 0.16/0.17 or 94%. This estimate is close to the 83% river water contribution to total abstraction at Irton suggested by Tate et al (1970) on the basis of tritium measurements, and the 77-83% by Foley (2006) on the basis of major ion chemistry. Similar calculations based upon test 3 (SF 6 ) indicate that, with 30% recovery within 24 hrs, a leakage rate of 0.34 m 3 s -1 and an abstraction rate of 0.22 m 3 s -1 , a discharge of 0.10 m 3 s -1 occurred through the conduit system (0.34 m 3 s -1 × 30%) and that the fraction of Irton discharge thus derived was ∼45% (0.10/0.22).…”

“…The karstic system in the vicinity of Irton and the River Derwent swallow-holes As noted, Tate et al (1970) conducted flow and geophysical logging tests at Irton old well under various pumping regimes. They observed major, flowing fissures at 51 m bgl (metres below ground level) and 30 m bgl.…”

“…Comparing the recovery of the two most conservative tracers (Photine C and fluorescein), the higher recovery rate (49% in test 2, as opposed to 40% in test 1) also occurred at a higher rate of abstraction (17.1 ML day -1 in test 2 but only 13.7 ML day -1 during test 1). On the basis of tritium (Tate et al 1970) and major ion hydrochemistry at Irton under different pumping conditions, Foley (2006) demonstrated that a decreasing proportion of river-derived groundwater is abstracted with increasing pumping rate. However, this decrease is insufficient to offset the amount of tracer recovered, so that optimal management of the aquifer during a pollution incident would be to maximise the pumping rate in order to extract the maximum amount of contaminant from the aquifer before double-porosity diffusion and/or sorption processes could become effective.…”

“…4. However, the sparsity of boreholes and the inhomogeneity and anisotropy of the aquifer, implied by observation at outcrop (Foley 2006) and geophysical logging studies by Tate et al (1970) and Foley (2006), make it extremely difficult to produce such a map. The solution offered in Fig.…”

Characterising the vertical variations in hydraulic conductivity within the Chalk aquifer

“…A number of field investigations in the 1970s and 1980s used a combination of TV logs, flow logs, and packer test to investigate vertical variations in Chalk permeability (Tate et al, 1970;Headworth, 1972;Foster and Milton, 1974;Foster and Robertson, 1977;Price et al, 1977Price et al, , 1992Owen and Robinson, 1978;Connorton and Reed, 1978). Allen et al (1997) summarized the main observations of these studies as follows:…”