Frequency of flooding within Bandon town increased due to changes in land management practises in the upper catchment over a long period of time. The Office of Public Works proposed a scheme which comprised of dredging 3.5km of the Bandon River between Bandon Weir and O’Driscoll’s Bridge, constructing embankments and walls, replacement of an existing footbridge within the town environs, underpinning of Bandon Bridge, constructing three fish passes, a new pump station and works to the existing drainage system. Wills Bros Ltd. were employed as the civil engineering contractors whilst Rivus performed the role of environmental specialists from commencement through to completion.
The Rivus Solution
Rivus fulfilled their role using a multi-disciplinary approach to cater for all requirements on this scheme. Such a large, complex project conducted over a long period of time demanded focused attention to all aspects of works within the river and on land. After devising a Construction Environmental Management Plan (CEMP), Rivus carried out continuous daily monitoring and supervision to ensure all works met environmental requirements set out for this scheme. Intense instream works of this nature throughout challenging summer conditions called for innovation to ensure works could be conducted. Rivus developed a Risk Matrix for instream works which considered all vital parameters pertinent to the task at hand. This relied upon sustained in-situ monitoring using handheld and static meters and provided the primary source of mitigation throughout the instream works period. Fish passage for all fish species was paramount at all times during the construction phase within the Bandon River. Rivus adapted to constant changes within the river’s morphology by setting out clear, instream dredging methodologies which facilitated continuous movement of fish past the works area. The demands of the job required co-ordination and flexibility of all Rivus team members so daily tasks such as electro fishing fish rescue operations, monitoring instream concrete works and supervising works within Japanese Knotweed areas could be undertaken in a sensitive and efficient manner.
Continuous monitoring, supervision and managing of works by Rivus throughout the project resulted in Wills Bros Ltd and the Office of Public Works completing the Bandon Flood Relief Scheme. A dredging operation of this magnitude, taking into consideration stipulated environmental protocols, had never been undertaken in Ireland, in a river of this size, with such rich aquatic biodiversity.