Regional frequency analysis of hydrological extremes - Poster only session & Open Forum (Sessione HS26 nell'ambito della EGU General Assembly 2005)

For more than four decades regional frequency analysis (RFA) of hydrological extremes (i.e., flood flows, droughts and rainstorms) has represented one of the most viable approaches for estimating design events at ungauged sites and defining regional-scale policies on water resource allocation or hydrological risk mitigation. The scientific literature reports a plethora of RFA procedures, ranging from simplistic and empirically-based methodologies to sophisticated and physically-based approaches. This session aims at presenting and discussing the latest developments and future perspectives on RFA of hydrological extremes. In particular, contributions are solicited that address one or more of the following points: (i) identification of key physical indicators describing the frequency regime of hydrological extremes and controlling causative mechanisms of floods, droughts and rainstorms; (ii) assessment of the impact of intersite correlation on the information content of regional samples; (iii) quantification of the uncertainty associated with regional estimates of the design event for ungauged sites. The session format consists of a poster session and an open forum discussion in a splinter meeting room afterwards. During the open forum discussion we will examine the feasibility of establishing a European Working Group on RFA of hydrological extremes

Assessing climate change impacts on river flows and environmental flow requirements at catchment scale

The fourth assessment report of Intergovernmental Panel on Climate Change (IPCC) suggests studies that increase the spatial resolution to solve the scale mismatch between large-scale climatic models and the catchment scale while addressing climate change impacts on aquatic ecosystems. Impacts occur mostly at the local scale. though potential changes in the hydrological cycle and eco-hydrological processes are more difficult to model and analyse at this level. The difficulty is even greater for studies on lowland river systems, which require the modelling of hydrological processes in greater detail. In this Study, the regional impacts of climate change on river flow and environmental flow requirement. which is a negotiated trade-off between water uses, are analysed for a lowland catchment in Denmark through MIKE SHE/MIKE 11 coupling. The Coupled model possesses an important capacity for simulating stream flows and groundwater head levels in a dynamic system. Although the simulation results from different global circulation models (GCMs) indicate different responses in flows to the climate change, there are obvious deviations of the river flows and environmental flow potentials computed for all the scenario cases from the averages of the base period with current conditions. Copyright (C) 2010 John Wile), & Sons. Ltd