The Ballinglen River is a tributary of the Derry Water River, located in County Wicklow, Ireland. The Derry Water flows between the villages of Tinahely and Aughrim where it is joined by the Ow River and becomes the Aughrim River. The Ballinglen is located within the Aughrim Sub-Catchment in the larger Avoca Avonmore Catchment in the Eastern River Basin District (Figure 1).
The Ballinglen River catchment is predominantly rural and includes various aquifer types, such as locally important karstified and bedrock aquifers. Pressures on water quality in the catchment include agriculture, forestry, peat harvesting, and domestic wastewater treatment systems. Monitoring indicates that while some nutrient levels occasionally exceed environmental quality standards, overall water chemistry remains within acceptable limits.
The Ballinglen River has been designated as a Priority Area for Action under Ireland’s River Basin Management Plan and supports several fish species, such as Atlantic salmon (Salmo salar), Sea lamprey (Petromyzon marinus), River lamprey (Lampetra fluviatilis) and Brook lamprey (Lamperta planeri), species that are included in the Annex II of the EU Habitats Directive, as well as European eel (Anguilla anguilla). However, man-made barriers have historically impeded fish migration. Ongoing conservation efforts focus on improving fish habitats, mitigating barriers to migration, and monitoring water quality to ensure the ecological health of the river system.
In 2012, Inland Fisheries Ireland (IFI) conducted a survey to identify obstacles to fish migration in County Wicklow’s rivers. The findings revealed significant challenges in the Avoca Catchment, where nearly half of the area may be affected by artificial barriers that partially or completely obstruct fish movement (Figure 2). One such obstruction creating a hydraulic drop of 1.2 m was the apron of the Ballinglen Bridge on the Ballinglen River, situated between the villages of Aughrim and Tinahely (Figure 3). The Ballinglen Bridge is a three-arched stone bridge built circa 1790. It is constructed of local shale with lime mortar and cut stone granite voussoirs. The floor bed underneath each archway of the bridge is laid with cut granite stones.
Since 2020, the Wicklow Fish Barrier Mitigation Programme has been implemented by a group of organizations, including the East Wicklow Rivers Trust (EWRT) a conservation NGO and registered charity, Wicklow County Council (WCC), IFI, and the Local Authority Waters Programme (LAWPRO), aiming at improving habitat and biodiversity for migratory fish in rivers and streams in Wicklow County. Local riparian landowners and National Parks and Wildlife Service are also supportive to the project.
The project at Ballinglen Bridge began in 2021 with the financial support of IFI Salmon & Sea Trout Rehabilitation, Conservation & Protection Fund 2021. The bridge apron at Ballinglen Bridge was prioritised due to it being a large-scale high-risk barrier to migratory fish species with pristine habitat upstream of the barrier. The grant funded a series of surveys to inform the design of the rock ramp and the modification of the apron of the Ballinglen Bridge (Figure 4) to restore fish passage. These included topographical studies, flow duration curve assessments, an ecological impact assessment and screening for appropriate assessment, as well as heritage and archaeology studies which were completed to inform planning consent.
In 2024, IFI conducted an ichthyological survey (Figure 5) and WCC a water quality assessment prior to the works commencing. Once complete, RIVUS Ecological Engineering begun the construction works. This phase of the project was funded by the IFI Salmon & Sea Trout Rehabilitation, Conservation & Protection Fund 2023 and costed 130000 euro.
The works involved constructing a full-width (8 m), 45-m-long cascaded rock ramp with eight weir stone cross sections spaced approximately 5 meters apart (Figure 6), designed to facilitate fish migration. The construction was complete in September 2024 (Figure 7, Video 1).
“We are really looking forward to the results of the fisheries studies and post-construction monitoring which will be completed by Inland Fisheries Ireland in 2025 and to working with our project partners on completing the relevant surveys and studies and designing a solution to the next barrier on the Aughrim River system”
Faith WilsonEast Wicklow Rivers Trust
The co-operation of so many parties made this project a success – a conservation NGO, the various statutory agencies and the local authority all worked together alongside local landowners and the community to make this project come to fruition. The main challenge for the project lead East Wicklow Rivers Trust was in securing the additional funds to meet the cost of the bridge funding for the works and EWRT were supported by Wicklow County Council in same. Funding from the LAWPRO Catchment Support Fund enabled the trust to manage the project on the ground and respond to media interest on it. Maintaining enthusiasm and energy for a project of this nature over a number of years is also required – studies and planning for the project took 2-3 years whereas the works themselves were actually completed within two weeks.
The construction of the rock ramp at Ballinglen Bridge reopened ~41 km and ~10 km upstream and downstream of the bridge, respectfully. This initiative represents a meaningful contribution toward restoring river habitats for a range of protected species, helping Ireland fulfil its obligations under the EU Water Framework and Habitats Directives. It also highlights effective cooperation among non-governmental organizations, private sector partners, and government bodies in implementing the kind of river-focused projects outlined in the EU Nature Restoration Regulation.
More information is available on the following sites:
https://www.wicklowrivers.ie/news/restoration-of-fisheries-habitat-on-the-ballinglen-river
Before & After photo pair
With many thanks to Faith Wilson from East Wicklow Rivers Trust for providing the information and the visuals presented herein.
Prepared by Foivos A. Mouchlianitis