Cherrywood Regional Attenuation Pond 2A

Acting as consultant engineer to Dun Laoghaire Rathdown County Council (DLRCC), ROD undertook the preliminary design and Part VIII planning of the Cherrywood Regional Attenuation Pond 2A, a piece of surface water infrastructure critical to facilitating the development of the Cherrywood strategic development zone (SDZ) in south County Dublin. We are currently progressing the detailed design stage of the project.

In addition to the regional attenuation pond, the project includes associated inlet / outlet surface water infrastructure, access tracks and approximately 370km of greenway (preliminary design only).

ROD is providing engineering and environmental services on the scheme, supported by specialist archaeological, arboricultural and landscape specialists.

The scheme is being funded by the Urban Regeneration and Development Fund (URDF), established by the Department of Heritage, Local Government and Housing (DHLGH) to support more compact and sustainable development through the regeneration and rejuvenation of Ireland’s five cities and other large towns, in line with the objectives of the National Planning Framework and National Development Plan.

The project is being developed as part of the Cherrywood Parks, Greenways and Attenuation Project, the total cost of which is estimated at €17.8M. This will see the development of four distinct sub-projects, including Cherrywood Regional Attenuation Pond 2A.

DHLGH formally approved 75% URDF funding for the project in June 2020, with DLRCC financing the remaining 25% through other revenue streams.

Following our appointment, ROD undertook a rigorous review of feasibility studies previously undertaken by the council to explore the design options for the proposed regional attenuation pond. These included several configurations of ponds in combination with underground attenuation tanks.

Our design team determined that a tiered cascading pond, with inlet and outlet vegetated swales, was the most appropriate solution given the steep, difficult topography of the site. This ensured that excavation would be kept to a minimum, reducing the impact on the existing landscape and ecology, and negating the need for underground attenuation tanks.

The regional attenuation pond and associated inlet / outlet surface water infrastructure was designed to convey, attenuate and treat surface water run-off from the public roads in the upstream catchment. The pond was designed to attenuate to 1l/sec/ha in accordance with the Cherrywood SDZ planning scheme. The infrastructure will convey attenuated flows from the upstream private development plots within the catchment to the Cabinteely River and will enhance biodiversity in the Cherrywood area. Allowance for climate change was made in accordance with the Greater Dublin Strategic Drainage Strategy.

Planning permission was granted in 2021.

The scheme is currently progressing through detailed design stage, with the procurement of a contractor expected to follow shortly thereafter.

• Engineering consultancy
• Environmental engineering
• Hydrological assessment