Based just outside Longford this site was in essence largely bog and effectively waste ground. The site of 54 acres was purchased by our client with the intent of developing some 174 residential homes together with an industrial development of some 450.000 sq ft.
The ground stabilisation works necessary were considerable and because of the high water table level the site water was always an issue however on further investigation it became evident that the presence of running sand would require greater consideration.
We began excavating out the bog and in some places went down to a depth of 3 metres. The area was then first filled with numerous layers of black stone, then layers of reduced size clean stone in order to increase the level of the site by a metre to bring it up to the level of the adjoining main road.
As the site also ran adjacent to the local river it had leant itself to being a flood plain and although we had raised the level quite significantly widening works to the river embankment were also carried out to help minimise the risk of any future flooding.
The drainage systems also had to be renewed and upgraded and this particular element offered us new and fresh challenges, the first being that a new pumping station had to be constructed not only a large diameter, but some 6.5 metres deep in running sand and adjacent to the main Athlone Road. The road had to be temporarily supported with a piled retaining wall consisting of piles being driven in excess of 10 metres in depth, a specialist designed de-watering system to help minimise the ingress of water during our works was used even with this system and additional pumps, the project was still difficult but successfully completed.
The project then required the installation of a new rising main and this involved excavating in and around a listed railway bridge structure, which at the time was being closely inspected by both Local Authority and Rail officials. The new rising main and pumping station serviced not only our project but also a large part of South Longford.
