Why is this project needed?
The reservoirs at Stillorgan store treated drinking water from water treatment plants at Vartry in County Wicklow and Ballymore Eustace in County Kildare. These reservoirs were open to the environment which is not in accordance with current best practice as it presented quality risks to the water supply.
The new Stillorgan Covered Reservoir is now complete, eliminating these risk and ensuring a safer, more secure and sustainable water supply for over 200,000 in south Dublin.
What stage is the project at?
The new Stillorgan Covered Reservoir is now complete, eliminating these risk and ensuring a safer, more secure and sustainable water supply for over 200,000 in south Dublin.
Uisce Éireann awarded the contract for the design, construction and commissioning of a new covered storage reservoir at Stillorgan to J. Murphy & Sons Limited. Construction commenced in November 2018.
Now that the new covered storage is fully commissioned, the existing Upper and Lower Reservoirs will be decommissioned and the site will be landscaped. It is expected that this will take approximately twelve months.
The site will remain an active water supply site and contains high pressure pipes and valves. As a consequence the use of the site for publicly accessible open space is not feasible.
Uisce Éireann's absolute priority is to protect human health by ensuring the safety and security of the drinking water supply for the 200,000 people served from Stillorgan, while being able to plan for future growth and development.
What is involved in the Stillorgan Reservoir Upgrade project?
The Stillorgan Reservoir Site was constructed as part of the Vartry Water Supply Scheme over 150 years ago and consisted of three open reservoirs of treated drinking water named the Gray, Upper and Lower Reservoirs.
The Stillorgan Reservoir Upgrade Project involved the drain down of the Gray Reservoir and the construction of a new covered reservoir within the existing reservoir.
The Upper and Lower Reservoirs were retained as active reservoirs throughout the construction period.
Now that the new covered reservoir is operational, the Upper and Lower Reservoirs will be drained, decommissioned and their areas reserved for future use. The base of the reservoirs will be landscaped for visual amenity.
Why does the reservoir have to be covered?
Best international practice insists that treated drinking water supplies should not be stored in open reservoirs where they are susceptible to contamination. The new covered reservoir will ensure the safety and quality of the water supply.
What Environmental Assessments were completed and how will the environment be protected?
Following consultation with stakeholders, Uisce Éireann prepared an Environmental Impact Statement (EIS) which was submitted in support of the planning application. This document set out the impacts (both positive and negative) which the proposed development would have on the environment.
Following preparation of outline designs for the upgrade works, a screening assessment of the potential for environmental effects was completed. This included assessment of whether the construction or operation of the elements are likely to have significant effects on any surrounding environmentally sensitive sites or species protected under European Directives (Habitats or Birds Directives), known as Appropriate Assessment. The screening assessment concluded that the project would not result in significant adverse effects on protected sites and species.
How long will the construction of the project take?
The new covered reservoir is now operational, ensuring a safer, more secure and sustainable water supply for over 200,000 in south Dublin.
The existing Upper and Lower Reservoirs will be decommissioned and the site will be landscaped. It is expected that this will take approximately twelve months.
How will construction traffic be managed?
Works for the Stillorgan reservoir are confined to the existing Stillorgan site. The most noticeable impact during the works is likely to be on traffic. Uisce Éireann, and its Contractor, have agreed a traffic management plan with Dún Laoghaire County Council in consultation with the local Garda station.
A wheel wash will be installed on the site to minimise construction dirt on the public road and road sweepers will be on standby and used when required. Parking of construction vehicles will be on the site.
Will there be noise and vibration from the works?
Some noise and vibration will result from the construction works. The project requires excavation of some rock to level the site for the construction of the buildings. The Contractor is required to meet the noise and vibration limits set out in the Environmental Impact Statement at the boundary of the Stillorgan Reservoir site.
Noise and vibration monitors will be installed by a specialist contractor at nominated locations throughout the site. The vibration data will be recorded and alerts will be distributed to the site project team should the vibration data approach the prescribed limits for the site.
Individual work activities will be re-evaluated should the levels approach the limits set for the site. Records will be compiled and issued to Uisce Éireann during the course of the works.
How will rodents and other pests be managed?
A specialist contractor has been contracted for proactive pest management throughout the works. Pest management control is in compliance with best practice from the Campaign for Responsible Rodenticide Use (CRRU).
Will the site be secure?
A security fence with dust and noise reduction netting will be installed along the embankment and maintained for the duration of the construction works. Monitored site security will be in place throughout the Contract.
The site perimeter will be strengthened where required. Once the works are complete, the site will remain an active treated water storage area and consequently public access will not be permitted.
Security of the Stillorgan Reservoir site and the water supply from the reservoirs is our priority throughout the project.
Will there be impacts on air quality from dust?
The works are not expected to result in adverse impacts to air quality. A dust management plan has been prepared to ensure that the creation of dust from site activities is limited. Dust monitors will be put in place by a specialist contractor at agreed locations around the perimeter of the site to confirm that the dust levels do not exceed the industry standards of 350mg/m2/day. This will be monitored and recorded.
Individual work activities will be re-evaluated should the levels come near to the limits set for the site. Records will be compiled and issued to Uisce Éireann during the course of the works.
What will happen to the remainder of the site?
The new covered reservoir will have the capacity to support future growth to 2031. The remainder of the site needs to be reserved for future water services infrastructure to secure drinking water for the community. The site will remain a live drinking water storage, treatment, and distribution centre for over 200,000 customers.
The Stillorgan reservoir site will remain a strategically important part of Dublin's water services infrastructure for the long term.