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We consistently deliver the technical and organisational expertise to engineer innovative and economic solutions to the management of flood risk -  and to protect people, infrastructure and property from the effects of coastal, river and urban flooding.  

This is managed in adherence to the strictest environmental regulatory requirements, the Office of Public Works Flood Risk Policy and the EU Floods Directive.  

We provide a full suite of engineering services for planning, design and implementation, establishing best practices in the areas of:

Catchment Management Hydrological Assessments

The Water Framework Directive (2000) is a combined high level focus on river basin catchment management and use from catchment drainage, groundwater, riparian uses, effluent discharges from agricultural, commercial and industrial sectors to urban run-off and water abstraction.  

Our services include: catchment area determination, low-flow analysis, receiving waters assimilation capacity assessment for discharge licences, water quality monitoring, hydrometric analysis, determination of run-off from ungauged catchments.

Flood Risk Assessment and Management

The Planning System and Flood Risk Management- Guidelines for Planning Authorities published in 2009 were established to ensure that, where applicable, flood risk is a key consideration in preparing development and planning applications to avoid increasing flood risk to new and existing developments.  

River Engineering and Hydraulic Modelling

A key technical input for detailed flood risk assessment is the development of a computer model of surface water and river channel within the catchment.  

Hydraulic Modelling of a river system involves the input of physical properties of the river channel and bankside area, tributaries, inline structures such as weirs and bridges, combined with established hydrological flow data to determine the hydraulic performance of the river system.  

Flood Defence Design

Nicholas O’Dwyer have designed flood defence systems for a large number of projects.  When it is established that the risk of flooding cannot be contained within the channel system and modifications to the river system are not sufficient or not possible, it is necessary to construct a barrier to the flood waters to protect the areas at risk.  The level of flood defence solutions ranges from earth embankments, retaining walls, bypass culverts to demountable barriers and storm water pumping cells.  

Climate Change

The predictions associated with Climate Change indicate a reduction in flows for river systems, with impacts on water abstraction availability and an increase in the frequency and intensity of rainfall events - leading to an increase in flash flooding as well as river and coastal flooding due to rising sea levels.

Factoring in the impact of Climate Change is critical in flood defence design to determine the level of protection required - both now and in the future.

Our range of engineering and technical services includes:

  • master planning
  • technical and economic feasibility studies
  • environmental impact assessments
  • project development planning
  • design
  • risk management assessment
  • optioneering of alternative designs
  • conceptual and detailed designs and documents
  • quality management
  • training and capacity building

Featured Project(s)

Duleek (Nanny River) Certified Drainage Scheme, Ireland

Following a detailed hydrological assessment that included the use of a HEC-RAS computer simulation model, a flood protection scheme of up to 200 year return period was developed.



Barry Dunphy

+353 1 296 9001

Key facts


Major Clients:  Dublin Flood Unit, OPW, Meath County Council 
Key Expert Staff  
Individual Project Value   €5 million