Summary Arising from the discharge at the surface of minewater drainage pumped from a mine in the Kent Coalfield, which underlies the Chalk of East Kent, U.K., an area of some 27 km 2 of the Chalk aquifer has become contaminated with saline water having concentrations of chloride between 200 and 5000 mg/l. Between 1907, when the first shaft was sunk, until 1974, when the discharge onto the Chalk ceased, it is estimated that 318 000 tonnes of chloride were discharged, and only about 15% has so far been dissipated by stream flows. An investigation has been carried out to determine the size and shape of the plume of contamination, and to examine possibilities for rehabilitation of the aquifer. The work has shown that the top 40-50 m of Chalk has become saturated with highly saline water, but at greater depths the contaminant is localized around well-developed fissures. The results of fifteen months pumping of a production borehole located near the centre of the pollution plume suggests that a long period would be required for the contamination to be cleared, and this has been supported by the results of a mathematical model.

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Summary The characteristics of over fifty shallow overflowing artesian boreholes in the Chalk at twelve watercress farms in Hampshire have been studied as part of the monitoring programme for a river augmentation scheme. The boreholes are mainly 150 and 200 mm in diameter and are relatively shallow, with 90 percent of them less than 40 m in depth. Artesian flows of all the boreholes in the period 1972–75 averaged 12 litres per second and in one case exceeded 40 litres per second. Flow and caliper logging show their flows are concentrated in discrete fissures, and a number of distinct fissure levels can be identified over a wide area. Analysis of piezometric heads and artesian flows show that ground-water flow is concenrated in a narrow width of aquifer of high permeability.

There is wide concern in developed countries that groundwater resources are deteriorating in the long‐term, both in quantity and quality. Some causes of pollution have a largely agricultural origin of which nitrates and pesticides are thought to pose serious risks to human health. This paper briefly reviews the sources of agricultural pollution of groundwater and the extent of the problem. It summarizes the various processes which take place in aquifers to remove, alter or attenuate contaminants.

This paper describes many of the ways by which the Arabs in southern Spain, during their eight hundred years occupation. raised, stored and distributed water without pumps, reservoirs or pipelines. The technology which they used in their water mills was simple but ingenious and differed from that evolving in Britain at that time. Using contourhugging open channels, the Arabs transferred snowmelt from the sierra over long distances, to recharge the ground above the mountainside villages and sustain the spring flows to their fountains through the year.