Abstract
Connorton & Reed's paper on the use of a radial flow model is an interesting addition to the knowledge of chalk aquifers and their hydraulic response. There are, however, a number of points that arise and need comment.
The first of these is concerned with the use of a radial flow concept in aquifers that are recognised to have a marked anisotropy. The authors have dismissed this by stating that within a short distance of the well (up to 100 m) radial symmetry can be assumed. During studies of a number of pumping tests in the Middle Chalk in east Kent, which had the good fortune of having observation wells located at right angles to the pumped well, I noticed that radial symmetry of aquifer parameters almost never occurs, even at distances sis near as 50 m.
The second comment relates to the use of ‘saturated thickness’ and the associated corrections for its decrease. Assigning a value related to the frequency of fissuring implies complete absence of pore water, which plays an important role in the aquifer's hydraulic response. Owen & Robinson (1978) in the same study area suggest that these thicknesses range from 45 to 60 m, while the authors have implied it to be 100 m as shown by their use of adjusted T values for their modelling.
The complexities involved indicate that the best way to understand the interactions between various parameters is to use a simple model, such as the radial model. One of the greatest
