Irish Water is planning to build a new covered reservoir at the Stillorgan Reservoir site in Co Dún Laoghaire–Rathdown.The utility company said it will submit proposals to develop the facility as part of an €80 million upgrade scheme over the coming weeks.As one of the last remaining reservoirs of its kind in Europe, the project will help safeguard the water quality for around 200,000 customers, as treated drinking water exposed to the environment presents an “unacceptable contamination” risk.The development would include draining one of the reservoirs to build the new facility. Once it is operational, the other open reservoirs will be decommissioned, and landscaping of the site will take place. The new covered reservoir will have the capacity to support future growth up to 2031. Subject to approval, it is expected construction will begin in 2018 and take two years to complete.