             1 HURST EXPONENT ANALYSES OF TURLOUGHS IN IRELAND V. Pakrashi 1 , L. Gill 2 , Paul Johnston 3 and Owen Naughton 4 Abstract: Turloughs are intermittently and annually flooded topographic depressions in lowland karst areas of Ireland. The flooding in turlough basins could occur as a result of several different hydrological settings and hydraulic configurations but for many it is due to insufficient capacity of the underground karst system to take increased flows following excessive precipitation events, causing the conduit-type network to surcharge. This paper considers five such linked turloughs for which continuous water level was available over a period of three years with a time resolution of fifteen minutes. The paper investigates the processes governing the turloughs from an output only point of view and investigates the Hurst exponents of the fluctuating water levels. The scaling of the Hurst exponents is obtained and the five linked turloughs are assessed based on their Hurst exponent footprints. Scale properties of the fluctuations are highlighted by assessing the presence and absence of possible multifractality in the system. A time shuffled assessment also investigates the possibility of the existence of a fat tail. Keywords: Turlough; Hurst; scaling; pipe network; fluctuation analysis. 1 Lecturer, Dynamical Systems and Risk Laboratory, Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland. Email: V.Pakrashi@ucc.ie 2 Associate Professor, Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin, Ireland. Email: gilll@tcd.ie 3 Assistant Professor, Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin, Ireland. Email: pjhnston@tcd.ie 4 Postdoctoral Research Fellow, Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin, Ireland. Email: naughto@tcd.ie INTRODUCTION Turloughs are temporary water bodies which are significantly influenced by groundwater levels and rainfall. In winter this leads to the formation of lakes and these lakes disappear in summer. These intermittently and annually flooded topographic depressions in karst (EPA, 2004) are ecologically extremely sensitive. Turloughs provide a habitat for many protected flora and fauna species and are designated a Priority Habitat in Annex 1 of the EU Habitats Directive (92/43/EEC) (EEC, 1992) as well as Groundwater Dependent Terrestrial Ecosystems (GWDTE) under the Water Framework Directive (EC, 2000). Different hydrological settings and configurations can be related to the flooding of turlough basins. However, there remains significant uncertainty in the exact nature of these configurations and the relative influences of different parameters require careful and in-depth study.           