This project was a joint venture between PUNCH, JB Barry and WYG Consulting Engineers.  The Limerick Main Drainage Scheme was a major environmental and infrastructural project to enable Limerick City and its environs to provide for the domestic, industrial and commercial development of the area well into the new millennium.

The City of Limerick has over 70,000 people living within a 4km radius of the city centre.  There are over 15,000 households within the city limits and up to a further 6,000 households in counties Clare and Limerick which use the city sewer system.  Each household generates on average 150-250 gallons of wastewater per day.  The city drainage infrastructure covers some 30km².

A preliminary report was initially compiled as a joint venture of which PUNCH Consulting Engineers were a part of.  The report highlighted the shortfalls within the existing network in terms of hydraulic, structural, operational and water quality problems and put forward effective solutions to overcome the problems.  PUNCH then completed design works as part of the joint venture which included a 19km of Interceptor Sewer varying in diameter from 300mm to 2.7m diameter.

Two major tunnel crossings of the River Shannon were required in addition to pumping stations, outfalls, outfall headwall structures and other ancillary works.

Structural and hydraulic rehabilitation of the existing network was undertaken using on-line replacement and lining techniques when them completed.

One of the largest structural design projects in Ireland at the time was the Waste Water Treatment Plant (137,000 P.E.) and Corcanree Main Lifting Pumping Station.

Finally the Storm Water Interceptor Sewer was constructed, including a 700l/s pumping station.  In addition to the water and wastewater treatment works, a potable watermain was upgraded, extending some 940m in length and constructed with associated valve chambers, water meters and branch connections.

The project has significantly upgraded the existing sewer network and pumping facilities in Limerick and its surrounding areas with a new system linked to a state of the art waste water treatment plant, thereby eliminating untreated discharges to the Shannon and Abbey Rivers from Limerick.

PUNCH Consulting Engineers was responsible for all aspects of design, procurement and contract administration for the following contracts procured for the scheme:

Northern Interceptor Sewer (Lower), comprising approximately 3.5km of DN 300mm to 900mm diameter interceptor sewers, 582m of DN 1800mm interceptor sewer in tunnel, 257m of DN 1200mm interceptor sewer in tunnel and associated shafts, manholes and ancillary works.  Twin DN400 watermains were also installed in the DN1800 tunnel sewer.

Loggers Stormwater Sewer, which is designed to reduce the risk of storm water flooding in Clare Street, Limerick City (which is exacerbated by tidal influence from the Abbey River), and to intercept storm flows previously discharging to the Park Canal.  The scheme also included for some separation of flows from existing developments and to provide for storm flows from future developments within the catchment area.  It included 2 No. interceptor sewer crossings of the Park Canal and an interceptor sewer crossing of a railway line, all by trenchless construction methods.

Strategic Watermain Construction; as part of the Limerick Main Drainage Scheme a Contract was procured to construct a 600mm diameter ring watermain, extending approximately 1500m, from the Dock Road to the Ennis Road, with associated valve chambers, water meters and branch connections.  The detailed design, tendering and construction administration of the watermain was undertaken by PUNCH Consulting Engineers as part of the Limerick Main Drainage joint venture team.

The success of the project was highlighted by achieving first place in the Association of Consulting Engineers of Ireland (ACEI) Annual Award 2006.