Rising tides and the Sands of Time.

A case study of archaeological mitigation of the Clonakilty Flood Relief Scheme
​by Jonathan Millar

Seymour Street to Clarke St Bridge, during works. The artificial 'reefs' built in the river improve flow and assist wildlife habitats.

​Flood Relief Schemes are becoming an increasingly necessary and urgent intervention world-wide, as the effects of man-made climate change alter patterns of environmental behaviour and threaten coastal and riverine settlements. Ireland is not exempt with the OPW taking continuous steps to mitigate for the most threatened towns across the country. These Civil Flood Relief Schemes are huge projects which require a process of balance, compromise and collaboration across multiple agencies and disciplines. They represent a colossal investment of time, resources, ingenuity, engineering, planning and manpower. 

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Kent St car park, during works. The River Fealge runs across shot, temporarily canalized to facilitate works.

​Archaeology is a finite resource and, of necessity, Flood Relief Schemes have the potential to interact with and impact upon that resource. So, understanding and characterising the archaeological environment of any proposed Flood Relief Scheme in order to identify, mitigate and manage these impacts is essential. This process must begin at the earliest conception and planning for any scheme and continue right the way through the planning and construction process.

The flow-control structure and fluvial storage embankment at Miles townland, to the west of Clonakilty mid-construction. A fulacht fiadh was excavated within the proposed flood plain during mitigation prior to construction commencing.

​Rubicon’s involvement with the Clonakilty Flood Relief Scheme began in 2013 when it was at the planning and design stage and continues during the present construction phase (expected to be completed in 2021).

​Our initial phase of work involved the preparation of Constraints Studies and an Options Appraisal. These provide, respectively, an initial characterisation of the archaeological landscape of the wider scheme area and a comparative assessment of the different design solutions under consideration (and how they might interact with that landscape and resource). Once a preferred design had emerged we then prepared the Cultural Heritage chapter for the Environmental Impact Assessment (EIA) of the scheme. This set out the mitigation measures to be employed to avoid or minimise negative impacts to the archaeological resource. Following on from this we were commissioned to provide archaeological services at construction stage to ensure the successful delivery of this mitigation strategy.

Setting up for archaeological building survey of the river walls at the Fire Station near Rossa Street.

​During preparation work, surveys are undertaken across the landscape to assess known archaeological sites and to look for evidence of previously unrecorded ones. We also record the nature and characteristics of the built environment which may be threatened by the project, such as historic river walls and buildings near sensitive flood-risk zones. Archaeological assessment is made of the riverbed itself, using maritime archaeologists and underwater survey techniques.

​Known or discovered sites may be evaluated archaeologically, with initial trial trenches and then excavations to assess the extent of their survival and their value as Cultural Heritage Assets. Some sites within threatened landscapes may be excavated fully to mitigate impact and preserve the archaeology ‘by record’ – in the form of photographs, measured drawings and survey data and objective scientific descriptions. This forms part of mitigation where an impact cannot be avoided by any other means. These results are interpreted by experts and added to the corpus of knowledge for the study area.

Rubicon Project Manager Bruce Sutton preparing a cobbled surface for recording in a trench outside Kent St Fire Station. The surface likely related to the towns Fish Market which was on the site by the early 19th Century.

​During the construction phase of a Flood Relief Scheme, archaeological monitoring is undertaken in partnership with the construction company. In Clonakilty, our client is Ward & Burke Construction, an international civil engineering firm with unique experience and expertise in large scale water and waste management projects. Our archaeologists have monitored all aspects of ground-breaking and excavation associated with the project and undertaken ongoing survey work as the project has progressed through the town.

We excavated four disturbed burnt mounds in Miles townland to the west of Clonakilty, within the impact of the Fluvial Storage Area, including a stone-lined trough. We found remains of the earlier quay wall at Deasy's Quay, but no trace of the shipyard visible on the historic maps. At Kent Street we found a cobbled surface outside the Fire Station which likely related to the old Fish Market - present on the site until the 19th century and we assisted with survey and recording during the process to number, deconstruct, store and rebuild a portion of the old market wall which is incorporated into the fire station structure.

Graphic representing the process of recording, dismantling and rebuilding a surviving portion of the Fish Market structure, incorporated into the Fire Station building.

​Finding the balance between quickly and effectively protecting and recording Cultural Heritage landscape features whilst facilitating the necessary essential works of major infrastructural projects is a skill in which Rubicon Heritage Services Ltd have proven our expertise over the last 20 years, we’re looking forward to using these skills to help protect the future of Ireland’s threatened coastal towns.