Summary As part of a hydrogeological investigation in a Permo-Triassic Sandstone aquifer in northwest England, various methods of field permeability testing have been developed and evaluated. These techniques involve the use of borehole packers to isolate specific test sections and permeability measurements made by either injection or pumping tests. Field results have been compared with both laboratory permeability measurements and conventional pumping tests. The test procedures were found to have a significant effect on the results obtained. Packers have also been employed to examine the vertical distribution of piezometric heads within an aquifer, both in pumping and non-pumping conditions, and to obtain groundwater samples from selected horizons. Some of the test results are presented to illustrate the value of packer techniques in hydrogeological investigations.

In order to investigate the aquifer parameters of a fissured layered sandstone aquifer, it was found necessary to construct and test an abstraction borehole using laboratory, double packer, geophysical and pumping test techniques. Good correlation was found between the techniques when the aquifer was represented by a fissured layered aquifer with low permeability bands separating layers of higher permeability. The use of multiple piezometers proved to be the only way of obtaining sensible results for field pumping tests and has given storage coefficients for both the confined and unconfined sections of the aquifer.

A current trend is the requirement for complex civil engineering projects to be carried out to very short time-scales. These projects often involve difficult and protracted planning consultations. This leads to increased pressure on all the professionals involved to work at a very fast, though erratic, pace that is dictated by others. This is particularly the case with the collection and utilization of information about the ground that is required for the design and construction phases of projects. Large changes in scope and detail often occur due to a wide range of environmental, technical, financial and other external factors.The engineering geologist plays a crucial part in the management of projects that are to be completed successfully to time and within budget. This paper discusses key areas in which engineering geologists can significantly affect the outcome of a project and also factors that may influence the professional development of engineering geologists in future years.

The measurement of permeability, or more correctly, hydraulic conductivity of an aquifer is of fundamental importance in the understanding of water movement within it and to the prediction of the behaviour of engineering works. A wide range of techniques is available to the hydrogeologist and engineering geologist, and includes: laboratory measurement, using both gas and water permeameters; pumping test, with and without observation boreholes; inflow and outflow packer tests; and numerical and analogue aquifer models. Each technique is described, and its practical problems and relative merits discussed. It is important to realise that some of the techniques measure the hydraulic properties of the borehole while others measure the properties of the surrounding aquifer. Care is needed to choose the appropriate methods for different problems. A brief case history is presented explaining the use of these techniques for the dewatering of a large civil engineering structure.

The measurement of water levels in the ground is a routine part of groundwater resource assessments and most site investigations. However the techniques used are often inadequate to reveal the true behaviour of aquifers, often resulting in inadequate data or a large number of expensive but useless readings. Continuous recording of groundwater levels using both float-operated chart recording and electric pressure transducers have been made on a wide range of observation wells to determine the most economical frequency of measurement for different aquifers and different purposes. The results of the investigation revealed a number of factors which are relevant in the observation of groundwater levels and these are discussed. Of these the construction of the observation point in the form of an open observation well, tube well, standpipe or one of a variety of piezometers is of fundamental importance. The behaviour of the aquifer as confined, or unconfined, with or without perched water tables, has considerable bearing on the results obtained. Barometric, tidal, fluvial, seasonal and abstraction effects on groundwater levels are discussed with reference to the amplitude of groundwater fluctuation and its rate of change. Finally suggestions are made for the design of observation points and the frequency of readings for different applications.