This old river keeps rolling: characterising natural solutions to baseflow maintenance and flood mitigation in a catchment in the Burren, Co Clare, Ireland.

Climate change will impact on water resources, as rainfall patterns, intensities, durations and depths shift. Nature-based solutions and natural flood management measures may provide a means of protecting water resources and may provide approaches that can work with existing morphologies of catchments. However, this requires that there is a clear understanding of how existing systems operate, and in certain complex locations this may not be the case. This study focuses on a catchment in the Burren, County Clare and considers aspects that must be considered when characterising the operation of river systems. The small catchment described here is underlain by pure-bedded limestone where groundwater flows dominate, and the upper portions of the system are underlain by siliciclastic sediments where surface water flows dominate. A blanket bog caps the siliciclastic rocks; during dry spells or extended periods of low or absent rainfall, water released from the bog sustains baseflow to the system and sustains a series of springs across a wider area. During storms and extended wet periods, the bog provides no additional storage (it remains largely saturated), and surface water rapidly moves downhill. A karst conduit network backs up creating a turlough which acts as a temporary storm water sump, mitigating impacts downstream. The resilience of the river system is mediated by the continuous input of baseflow from the blanket bog, and by flood mitigation provided by the turlough. Understanding these natural systems is critical in considering responses to climate change impacts.