To demonstrate the effectiveness of stormwater improvement options in urban areas using proven decision making tools

PROJECT DESCRIPTION

BACKGROUND

Private wastewater discharges, which include losses from urban wastewater misconnections have a significant impact on water quality. Misconnections are when toilets, sinks, washing machines or dishwashers are incorrectly linked to drains and channels designed to receive rainwater. The result is that household wastewater ends up in the surface drainage system rather than sewers. The European Environment Agency (EEA) estimates an average misconnection rate of 3-4% in the EU and says that “there is a clear need to develop a more systematic procedure and appropriate protocols for identifying polluted surface water outfalls and in source-tracking misconnections”.

Drainage misconnections have been identified as contributing to poor bathing water quality at Merrion Strand beach in County Dublin and to Ireland's failure to achieve good ecological status for its surface waters, in contravention of the Water Framework Directive.

OBJECTIVES

The Dublin Urban Rivers LIFE project seeks to improve water quality in County Dublin and beyond by making it quicker and cheaper to carry out domestic misconnection inspections using a novel GIS-based approach. This will involve carrying out inspections at 12 000 households and using the data to help develop a decision-support tool for water managers, project developers and policy-makers to use when deciding options to improve river water quality in urban areas. Dublin Urban Rivers LIFE will also construct artificial wetlands at five strategic locations. These natural water retention measures will improve the quality of the receiving river water, provide flood alleviation, bioretention of particulates and nutrients, improve habitat conditions and biodiversity, and promote the relationship between green infrastructure and public wellbeing. The project will also develop tools that planners can use to identify suitable locations for artificial wetlands in existing and future housing development zones and development plans for the Dublin area.

Through its actions, the project intends to bring about a culture shift in the attitude of stakeholders, local authorities and policy-makers in relation to the importance of misconnections and artificial wetlands to urban water quality.

Dublin Urban Rivers LIFE is expected to have a positive impact on the implementation of the Water Framework Directive and a raft of supporting policy on water quality, including the Bathing Water Directive, Floods Directive, Urban Waste Water Treatment Directive, Groundwater Directive and Marine Strategy Framework Directive. The project will also support the implementation of the Nitrates Directive and the EU Biodiversity Strategy to 2020.

Expected results:

Some 12 000 door-to-door inspections carried out and 1 390-point sources of pollution fixed. This will result in a 45 000 litres/day reduction in domestic misconnection effluent discharged to rivers;

Installation of two artificial wetlands in the River Griffeen catchment, and three artificial wetlands in the River Camac catchment, resulting in treatment of 33 000 litres/day of storm water;

More than 90% of storm water flows to the Griffeen River and more than 80% of storm water flows to the Carrickmines Stream treated/improved. This will lead to a change of ecological status from Moderate to Good for these two waterbodies;

An online decision-support tool for use by local authorities and environmental agencies to assist in deciding options for treating contaminated storm water from domestic urban areas;

The decision-support tool used to assess one urban waterbody in each of the functional areas of the project partners of Dublin, Cork, Galway, Waterford, Limerick Cities and Sligo Town to choose the most appropriate option to return them to good ecological status;

An information campaign leading to a five-fold increase in public awareness of domestic misconnections in the project area, measured by way of surveys;

and

Assessment of future development land for its suitability for artificial wetlands.