A Study of the Hydrological Sustainability of the Roads Programme in Ireland – Orla Sweeney, Paul Johnston

From the Sustainable Development Evaluation of Road Infrastructure Programmes and Projects


This work is a study of the Hydrological Sustainability of Road Development in Ireland and was undertaken in association with FEASTA (Foundation for Economic Sustainability), as part of a larger project on the overall sustainability of road development in this country.

The focus of this work is an analysis of the effectiveness of the environmental impact assessment process and its under-lying legislation in protecting the aquatic environment and its dependent ecosystems. In addition to this the overall requirements of the national road development programme in ensuring environmental sustainability, was considered.

The main finding and recommendations of this thesis are:

Flooding issues have historically not been given sufficient, documented consideration in EISs. Flooding risk analysis should be carried out on all major proposed roads, especially if sub-surface drainage is a significant factor.

Commonly used pollution control BMPs are insufficient in retaining soluble pollutants. Soluble fraction of major runoff pollutants, such as heavy metals can be significant. As well as this the problem of sustainable methods for disposing of sediment and soil that has been contaminated by insoluble pollutants, remains largely unsolved.

From the EISs studied it would appear that groundwater disturbance investigations are usually inadequate and mitigation measures proposed to deal with the effects of the disturbances are largely unsubstantiated. In areas of ecological importance mitigation by avoidance would appear to be the only sustainable approach to groundwater disturbance issues.

Monitoring requirements and associated standards and conditions need to be formalised. Results should be published to ensure openness and transparency.

To significantly improve the environmental impact of road development, policy needs to be focussed on issues that contribute to transport growth, with the specific aim of reducing transport demand. These issues include land-use planning and modes of operation of industrial and commercial businesses.

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