Powerstown stream diversion and enhancement
This first-of-its-kind project saw our teams produce an Ecological Impact Assessment (EcIA) to support a planning application, which would involve the diversion and enhancement of Powerstown stream.
With Powerstown stream being of high ecological and aquatic value, we were appointed by Channor Limited to support their planning application for a 12.9ha development site which would require the watercourse to be diverted.
- Client Channor Limited
- Location Tyrellstown, Co. Dublin
- Partners TOT Architects and Doherty Finegan Kelly
Sustainable landscape design and environmental enhancement to support the success of a one-of-a-kind planning application
With multidisciplinary expertise in flood risk, ecology and landscape design, we were appointed to conduct an EcIA concerning the diversion and enhancement of Powerstown stream, which ran through the centre of a proposed 12.9ha development site.
To support the development's planning application we were required to demonstrate that the stream could be successfully diverted, whilst also improving water quality, enhancing the aquatic habitat and recreating a riparian zone. This required close collaboration across our flood, ecology, environment and landscape design teams to ensure the flood and ecology requirements were taken into consideration.
Through the EcIA we were able to establish the baseline conditions, assess ecological impacts, identify mitigation measures and determine opportunities for enhancement. This included conducting a range of site surveys such as habitat mapping and species-specific surveys.
Having established the proposed diversion and enhancement project would have a short-term impact, we used the EcIA and Construction Environmental Management Plan (CEMP) to demonstrate how this could be mitigated. This involved the development of an eight-step process, which detailed how habitats and species could be translocated in accordance with seasonal constraints.
Powerstown stream diversion is the first example of a successful planning application to divert a stream of high ecological and aquatic value within Ireland.
Multidisciplinary expertise to incorporate flood and ecology requirements
Through close collaboration between our flood, ecology, environment and landscape design teams we were able to ensure flood and ecology requirements were considered in the final landscape design. This included incorporating the provision of a riparian zone and a series of swales and ponds as part of the diverted watercourse. We also ensured planting species included ecological mitigation and that flood attenuation was accommodated.
Providing evidence of environmental enhancement
Through the EcIA we were able to provide evidence that the stream diversion and riparian enhancement works would help to enhance the overall aquatic and riparian floral and faunal biodiversity of the site. Despite the negligible short-term impact on biodiversity, we were also able to successfully demonstrate that the works would support a long-term minor to moderate positive impact once all the newly created habitats (such as bat roosting and bird nesting boxes) had matured.
