LAND DRAINAGE POLICY IN IRELAND. DUBLIN, 1982

Bruton, Richard and Convery, Frank J. (1982) LAND DRAINAGE POLICY IN IRELAND. DUBLIN, 1982. [Policy Paper]

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Abstract

Ireland suffers from an extensive drainage problem. The source of the difficulty is not exception rainfall. It is the saucer shape of the countryside with its high maritime rim and flat interior. As a result, the rivers flow slowly through poor channels. Much of the land suffers from periodic or prolonged flood damage. Even at low-flow, the rivers provide poor outfalls that prevent adjoining lands being properly drained. If left unattended, these slow-flowing rivers tend to silt up and the drainage conditions degenerate. So, the need for remedial drainage work is recurrent. State involvement in arterial drainage has a long history, dating back to famine times. At that time, the work was all done manually, and it employed about forty thousand people at peak. The process has now become highly mechanised with the use of dragline excavators and floating dredgers for excavation, and specialised equipment for drilling and blasting rock. It is all carried out under the central direction of the Office of Public Works (OPW). Fewer than one thousand people are now employed on the programme. Almost all of the arterial work has consisted of deepening and widening river channels to accommodate existing river flows. The alternative - moderating river flows by diverting rivers or storing in reservoirs - is uncommon. Schemes are designed after the study of long records of water flows and a detailed survey of the catchment. Typically, the channel enlargement aims to give immunity from the three-year flood and to reduce the low-flow water table sufficiently so that satisfactory drainage is achieved of the land areas to be improved. This level of flood immunity means that flooding in the Spring-Autumn growing season will be very rare. The low water table provides sufficient outfall to enable farmers to fully rehabilitate their land by field drainage. State involvement in field drainage is of quite recent origin. It takes the form of grant aid. The one experiment in direct work by tile state proved unwieldy and was short-lived. The grant is administered by the Department of Agriculture.

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