Water scarcity hotspots travel downstream due to human interventions in the 20th and 21st century

Water scarcity is rapidly increasing in many regions. In a novel, multi-model assessment, we examine how human interventions (HI: land use and land cover change, man-made reservoirs and human water use) affected monthly river water availability and water scarcity over the period 1971–2010. Here we show that HI drastically change the critical dimensions of water scarcity, aggravating water scarcity for 8.8% (7.4–16.5%) of the global population but alleviating it for another 8.3% (6.4–15.8%). Positive impacts of HI mostly occur upstream, whereas HI aggravate water scarcity downstream; HI cause water scarcity to travel downstream. Attribution of water scarcity changes to HI components is complex and varies among the hydrological models. Seasonal variation in impacts and dominant HI components is also substantial. A thorough consideration of the spatially and temporally varying interactions among HI components and of uncertainties is therefore crucial for the success of water scarcity adaptation by HI

The effectiveness of hillshade maps and expert knowledge in mapping old deep-seated landslides

Large deep-seated landslides with a shear surface deeper than 3 m and a mean affected area of 4.2 ha are common features in the Flemish Ardennes. None of these deep-seated landslides are dated, but they are assumed to be rather old (> 100 years). Because most of these landslides are located under forest, aerial photo interpretation commonly used for the creation of landslide inventories is not a suitable tool to map the landslides in the Flemish Ardennes. Therefore, an intensive 100-day field survey was carried out by two geomorphologists in a 430-km(2) study area. This resulted in a landslide inventory map, indicating the location of 135 large deep-seated landslides.status: publishe

Use of LIDAR-derived images for mapping old landslides under forest

Large, deep-seated landslides are common features in the Flemish Ardennes (Belgium). As most of these old (> 100 years) landslides are located under forest in this hilly region, aerial photograph interpretation is not an appropriate landslide mapping method. This study tested the potential of LIDAR (Light Detection and Ranging) images for mapping old landslides under forest. Landslide inventory maps were created for a 125 km(2) area by applying the expert knowledge of seven geomorphologists to LIDAR-derived hilishade, slope and contour line maps in a GIS environment. Each of the seven LIDAR-based landslide inventories was compared (i) with the other six, (ii) with a detailed field survey-based inventory, and (iii) with a comparable study in which topographic data were extracted from a topographical map. The combination of the percentage of field landslides indicated by an expert and the percentage of positional discrepancies (expressed in terms of positional mismatch) were used to evaluate the quality of the LIDAR-based inventory maps. High-quality LIDAR-derived landslide inventory maps contain more than 70 per cent of the landslides mapped during the field survey, and have positional discrepancies smaller than 70 per cent when compared with the field survey-based inventory map. Four experts and the combination map of all experts satisfied these criteria. Together the seven experts indicated all landslides mapped in the field. Importantly, LIDAR enabled the experts to find ten new landslides and to correct the boundaries of eleven (of the 77) landslides mapped during the field survey. Hence, this study showed that large-scale LIDAR-derived maps analysed by experienced geomorphologists can significantly improve field survey-based inventories of landslides with a subdued morphology in hilly regions. Copyright (c) 2006 John Wiley & Sons, Ltd.status: publishe

Microstructural analysis of multi-phase ultra-thin oxide Overgrowth on Al–Mg Alloy by high resolution transmission electron microscopy

High-resolution transmission electron microscopy analyses are carried out to understand the microstructure of the ultra-thin oxide-film grown on a (native) amorphous Al2O3-coated Al-0.8 at.% Mg alloy substrate at T = 600 K for t = 2 h and at pO2 of 1 × 10−2 Pa. This oxide-film is found to be non-uniformly thick with thicknesses varying from 1.50 to 4.60 nm. Occasionally, this oxide is found to diffuse into the Al–Mg alloy substrate, forming oxide thicknesses up to 10.5 nm. Overall, this oxide-film is found to consist of a mixed amorphous, (poly) crystalline and an intermediate amorphous-to-crystalline transition regions, with crystalline regions consisting mostly of MgO and the diffused oxide regions into the Al–Mg alloy substrate coated with γ-Al2O3. These observations are then compared with the experimental results obtained using angle-resolved X-ray Photoelectron Spectroscopy analysis and thermodynamic predictions for the growth of an ultra-thin oxide-film due to dry, thermal oxidation of Al–Mg alloy substrates.by Narendra Bandaru, Darshan Ajmera, Krishna Manwani, Sasmita Majhi and Emila Pand