FAQs

Why is this project necessary?

The Vartry Water Treatment Plant provides over 200,000 people with drinking water. It is currently on the Environmental Protection Agency’s (EPA) Remedial Action List (RAL) which identifies supplies that are in urgent need of improvement. There are two items that need to be addressed at Vartry, one is security of supply and the other is drinking water quality.

The security of supply from Vartry is at risk due to the algal (diatom) blooms which can occur from March to May each year which can reduce the amount of drinking water that the plant can output by over 50%. In addition to this,  the existing tunnel which supplies the drinking water to communities in north Wicklow and south Dublin is over 150 years old and is at risk of collapse.  Upgrades are also required to improve the final quality of the drinking water and ensure it fully complies with the drinking water regulations.

More information on the history of the scheme is provided on the homepage.

What is involved in the Project?

The Vartry Water Supply Scheme project will involve:

  • Constructing a new Water Treatment Plant on the site of the existing plant at Vartry. This will ensure that water currently being abstracted will be treated to meet Drinking Water Regulations and will resolve supply issues associated with algal blooms. There will be no increase in the amount of water abstracted from the existing Reservoir.
  • Constructing a 4km pipeline to secure the transfer of treated water from Vartry to Callowhill pumping station. The element commenced in January 2018 and was commissioned in December 2018.
  • Decommissioning the existing Water Treatment Plant. A number of existing slow sand filter beds will be decommissioned and landscaped. The original filter beds close to the dam will be retained as heritage features.
  • Decommissioning the Vartry to Callowhill tunnel to allow for remediation works to be carried out.
  • Replacing ageing pipes and fittings within the dam of the Vartry Reservoir.
  • Upgrading control measures to ensure efficient supply of water from the Vartry reservoir to the water treatment plant.
  • Making improvements to the Vartry dam spillway to improve dam safety.
  • This project is closely linked to the Stillorgan Reservoir Upgrade Project which will provide covered water storage in Stillorgan and associated pipeline modifications that will improve the protection of the water supply to the network.

What’s happening now?

Works are progressing on the Vartry Water Supply Scheme Upgrade project to ensure that water provided complies with water quality standards set out in the European Union Drinking Water Directive and the current, national Drinking Water Regulations. There are three main contracts as part of this project:

  • Vartry Water Treatment Plant Upgrade - constructing a new water treatment plant on the site of the existing plant at Vartry.

Construction on the new Vartry Water Treatment Plant commenced in July 2018 and are at an advanced stage. The plant is now structurally complete, with mechanical and electrical fit-out ongoing and testing and commissioning to follow. The treatment plant will be operational in the third quarter (Q3) of 2021.

  • Vartry to Callowhill Pipeline - constructing a 4km pipeline to secure the transfer of treated water from Vartry to Callowhill pumping station.

Irish Water has completed this new pipeline from Vartry to Callowhill. This pipeline secures and safeguards the water supply for more than 200,000 people in north Wicklow and south Dublin, one of the most densely populated areas in the country.

  • Stillorgan Reservoir Upgrade - constructing a new covered storage reservoir as part of the Stillorgan Reservoir Upgrade

Construction on the new covered reservoir commenced in November 2018 and is now structurally complete. Testing and landscaping is ongoing and the reservoir will be operational in the third quarter (Q3) of 2021.

What are the benefits of the Project?

The Water Treatment Plant Upgrade will bring a number of benefits to the Wicklow and Dublin areas, including:

  • Improved Water Quality – the treatment plant upgrade will provide over 200,000 people with safe and sustainable drinking water.
  • Improved Security of Supply – the treatment plant upgrade works will provide improved  security of supply.
  • Improved Operation and Maintenance – the critical water supply infrastructure at Vartry will benefit from improved operation and maintenance as a result of the treatment plant upgrade works.
  • Improved Local Supplies – other local supplies within the mid-Wicklow area, which are also on the EPA (Remedial Action List), will be supplied from Vartry once the works are complete. This will be possible through improved efficiencies within the Greater Dublin Water Supply area.

Will any additional water be abstracted?

The volume of water abstracted will be same in the future as it has been over the last 150 years.  Irish Water will not increase the amount of abstracted water from this man-made reservoir. 

Will the flow regime in the River Vartry change?

The normal flow regime that has been in place in the River Vartry since its impoundment in the 1860s will be maintained. The project also proposed an improved benefit of guaranteed flows of 5 million litres per day at all times including drought periods. These freshwater flows will come directly from the existing Vartry reservoir. The natural flows from groundwater and downstream tributaries will not be affected.

Will the new Water Treatment Plant discharge any pollutants to the River Vartry?

All process water (washwater and cleaning water within the water treatment plant) will be pumped back into the water treatment plant and recycled.  No process water will discharge directly to the river or back to the reservoir.

The proposed  flow of five million litres per day will flow directly from the Vartry reservoir through pipework into the River Vartry.

What environmental assessments have been undertaken by Irish Water?

Following the preparation of outline designs for the proposed development, an initial screening assessment of the potential for environmental effects was completed. This included an assessment of whether the construction or operation of the upgrade works are likely to have significant effects on any surrounding environmentally sensitive sites or species protected under European Directives (Habitats or Birds Directives). Detailed environmental studies on the full range of potential human and ecological interactions with the proposed works were completed and these reports were submitted with the planning application in April 2016. Following a request for further information from Wicklow County Council, additional reports detailing hydrology and bats were prepared and the Appropriate Assessment Screening Report was updated.

Links to the key environmental reports are available below:

Is an Environmental Impact Statement required?

The requirements for an Environmental Impact Statement (EIS) are set by European Directive which is transposed into Irish Regulations. An EIS can be required if it is determined that a development is likely to have significant effects on the environment based on the Characteristics, Location and Potential Effects of the development.

The current proposal is an upgrade to an existing water treatment plant site to replace structures which are failing. The existing water treatment plant site has been in place for 150 years.  There is no additional abstraction proposed and there will be no discharge of pollutants from the site. The Screening Report has therefore determined that an EIS is  not required for this project.

Environmental assessments have been prepared for all environmental and human interactions with the development including ecology, landscape and visual, noise and dust, traffic and transport and others. These environmental assessments were all submitted with the planning application.