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Press release issued on 5 June 1997

VFM examination report on Boyle and Bonet arterial drainage schemes

The Comptroller and Auditor General, Mr John Purcell, has carried out an examination of the arterial drainage schemes carried out by the Office of Public Works (OPW) on the Boyle and Bonet rivers. A report on the examination was presented to Dáil ?reann (the Irish parliament) on 4 June 1997.


The examination focused on the planning and management of the schemes, the quality of work, the cost outturn and the effectiveness of the schemes.

The Boyle and Bonet drainage schemes started together in 1982. It was planned that the Boyle scheme would be completed in five years and the Bonet scheme in three years, at a total cost of ?17.2 million (in 1982 prices).

Arterial drainage schemes are designed to alleviate flooding problems, thereby enabling agricultural land to be put to more productive use.

Main Findings

Both schemes extended over much longer periods than originally planned. The Bonet scheme ended in 1992, six years later than originally estimated; the Boyle scheme continued until 1995 i.e. eight years after its planned completion. Progress on both schemes was delayed because the funding provided over the scheduled project period was much less than envisaged when the schemes were planned.

When the schemes were stopped, about 85% of the work originally planned had been carried out.

The schemes went ahead on the basis that 88% of the flood-damaged land would be improved, to the extent that it could support extra livestock. The improvement would be as a result of carrying out arterial drainage work and the subsequent installation of field drainage systems by landholders in the river catchments. It is estimated that less than 25% of the damaged agricultural land shows evidence of significant improvement, suggesting that very little field drainage work has been carried out.

Total expenditure on the two schemes between 1982 and 1995 was ?31.6 million. The estimated cost of the 85% of planned work which was carried out was ?14.5 million in constant 1982 prices. Inflation accounted for almost one third of the difference. The remainder of the increase was mainly due to extra spending on overheads, which arose because of the additional time required to carry out the schemes. The OPW indicated to the Department of Finance that its policy of restricting annual funding for drainage schemes would result in inefficient use of overheads and increased costs.

The schemes were not re-assessed during the course of their construction, although it was clear at an early stage that costs would be higher than planned and that there was a policy shift away from schemes designed to increase agricultural production.

Although the Boyle and Bonet schemes give a lower level of flood protection than other schemes, the cost per hectare of land to be improved by the Bonet scheme was higher than for any other arterial drainage scheme carried out by the OPW. The cost per hectare for the Boyle scheme was about the same as for other schemes carried out at the same time.

The OPW’s project management and planning procedures for the schemes were appropriate, but some shortcomings were evident in budget preparation and monitoring of efficiency levels. Excavation and construction work on both schemes was carried out to a high standard by OPW.

With some exceptions, rehabilitation of the environment was satisfactory.

Much more rigorous evaluation criteria are applied to prospective arterial drainage projects since 1986. No new schemes have been undertaken since that date and none are envisaged in the foreseeable future.

For further information about the report contents, please contact:

Seamus McCarthy

Tel: +353 1 679 3122

Fax: +353 1 679 3288


Publication Details

VFM Report No. 16: Arterial Drainage of the Boyle and Bonet Rivers

ISBN 0-7076-3829-1

Price ?5

Government Publications Sales Office

Sun Alliance House

Molesworth Street

Dublin 2

Tel: +353 1 661 3111

Fax: +353 1 475 2760

The contents of this page were last updated on 26/09/03