Hidrología y Cambio Climático/
Hydrology and Climate Change
NEWS AND PUBLICATIONS
Extreme Floods in Small Mediterranean Catchments: Long-Term Response to Climate Variability and Change
-The influence of climate variability on flooding was evaluated by an analysis of a 500-year palaeoflood and documentary records at Montlleó River, eastern Spain.
- Five paleofloods exceeded 740–950 m3 s−1; vs. 129 m3s-1highest gauged flood s.1971.
- Flood occurred in cluster episodes (30-year duration) either during cooler than usual climate (about 0.3 °C and 0.2 °C), or during high climate variability (floods and droughts).
- Flood quantiles from palaeoflood data showed 30%–40% higher peak discharges than those using only instrumental records.
- These extended flood records can assist on low-regret actions for flood-risk adaptation.
Large ice-age megafloods have significantly altered Patagonian landscapes, acting as triggers of climate change.
We provide the first detailed reconstruction of catastrophic glacial lake outburst flooding (>110,000 m3s-1) from the Southern Hemisphere, focusing on the Río Baker catchment in central Patagonia.
Morphological changes and sediment connectivity evaluation during flooding using high resolution photogrametry
- We evaluate morphological changes, sediment tranfers and functional sediment connectivity caused by flood events.
- Quantification of morphological change and sediment budgets was provided by Photogrammetric flights.
- A sediment connectivity index is proposed.
Frequency of boulders transport during large floods in hyperarid areas using paleoflood analysis – An example from the Negev Desert, Israel
- The 2004 flood (470 m3 s−1) in the hyperarid, ungauged Nahal Hatzera ephemeral stream (45 km2), transported and deposited 0.85–2.1 m concrete boulders.
- A 600 years paleoflood record of 23 floods with peak discharges of 200–760 m3 s−1, indicates an average return period of 120 years for this event.
-The shear stress and stream power indicate that the moderate-large floods are the most geomorphically effective floods rather than the largest floods in Nahal Hatzera.
Flood hydro-geomorphology and vegetation dynamics along the hyperarid Kuiseb River, Namibia and detecting large floods in remote deserts
- The Kuiseb River flash floods travel ~280 km downstream, before recharging the aquifers that sustain a 130-km long green belt across the hyperarid Namib desert.
- This study reveals the importance of flood properties on the oasis life cycle and emphasizes the impact of drought and wet years.
- The downstream aquifers are fed only by the largest flood discharge that allows the infrequent germination of vegetation.
-Variations in NDVI index was revelead as an effective tool in determining occurrences of large floods in these headwater-fed hyperarid regions.
Impacts of sediment connectivity on Holocene alluvial records across a Mediterranean basin (Guadalentín River, SE-Spain)
- Alluvial chronologies in two contiguous valleys show out-of-phase sedimentation periods under low connectivity conditions (9-3 ka), and in-phase cut-and-fill cycles after valley re-connection (post-3.0 ka).
- Vertically stacked alluvial sequences were dominant during periods of low connectivity.
whereas stair-case fill terraces due to cut-and-fill cycles occurred on connected reaches
- During the late Holocene alluvial activity periods coincide with morpho-stratigraphic data from the lower Guadalentín, indicating that fluvial connectivity throughout the catchment was only completed in the late Holocene.
