Suchergebnisse

The Nile River Basin / Wossenu Abtew and Assefa M. Melesse -- Streamflow data needs for water resources management and monitoring challenges : a case study of Wami River Subbasin in Tanzania / Preksedis Marco Ndomba -- Satellite rainfall products and their reliability in the Blue Nile Basin / Ayele Almaw Fenta, Tom Rientjes, Alemseged Tamiru Haile and Paolo Reggiani -- Africa-wide monitoring of small surface water bodies using multisource satellite data : a monitoring system for FEWS NET / Naga M. Velpuri, Gabriel B. Senay, Henok Alemu, James Rowland and James P. Verdin -- Surface water and groundwater resources of Ethiopia : potentials and challenges of water resources development / Belete Berhanu, Yilma Seleshi and Assefa M. Melesse -- Land and water in the Nile Basin / Wossenu Abtew -- Soil erosion and discharge in the Blue Nile Basin : trends and challenges / Tammo S. Steenhuis, Seifu A. Tilahun, Zelalem K. Tesemma, Tigist Y. Tebebu, Mamaru Moges, Fasikaw A. Zimale, Abeyou W. Worqlul, Muluken L. Alemu, Essayas K. Ayana and Yasir A. Mohamed -- Spatial and temporal patterns of soil erosion in the semi-humid Ethiopian Highlands : a case study of Debre Mawi Watershed / Seifu A. Tilahun, Christian D. Guzman, Assefa D. Zegeye, Essayas K. Ayana, Amy S. Collick, Birru Yitaferu and Tammo S. Steenhuis -- Modeling sediment dynamics : effect of land use, topography, and land management in the Wami-Ruvu Basin, Tanzania / Juliana J. Msaghaa, Assefa M. Melesse and Preksedis M. Ndomba -- Assessment of soil erosion in the Blue Nile Basin / Gizaw Desta Gessesse -- Hydro-epidemiology of the Nile Basin : understanding the complex linkages between water and infections diseases / Michael C. Wimberly and Alemayehu A. Midekisa --

For thousands of years, soil resources in Greece have been a critical underpinning of local socio-economies. However, soil threats are increasing rapidly, primarily due to human activity and the impacts of climate change. Greek and other European state governments have established legal frameworks to protect soil, but there is a great need for centralization and harmonization with European Law. This chapter highlights the importance of integrated soil governance frameworks that could be applied at the regional or international level while also supporting public engagement and local focus. It also considers the urgent need to address erosion - a major threat to soil resources in Greece that affects local well-being, environmental sustainability and heritage sites.

Abstract. Compound floods are an active area of research in which the complex interaction between pluvial, fluvial, coastal and groundwater flooding are analyzed. A number of studies have simulated the compound flooding impacts of precipitation, river discharge and storm surge variables with different numerical models and linking techniques. However, groundwater flooding is often neglected in flood risk assessments due to its sporadic frequency (as most regions have water tables sufficiently low that do not
exacerbate flooding conditions), isolated impacts and considerably lower
severity with respect to other types of flooding. This paper presents a
physics-based, loosely coupled modeling framework using FLO-2D and
MODFLOW-2005 that is capable of simulating surface–subsurface water
interactions. FLO-2D, responsible for the surface hydrology and infiltration processes, transfers the infiltration volume as recharge to MODFLOW-2005 until the soil absorption capacity is exceeded, while MODFLOW-2005 returns exchange flow to the surface when the groundwater heads are higher than the surface depth. Three events characterized by short-duration intense precipitation, average tide levels and unusually high water table levels are used to assess the relevance of groundwater flooding in the Arch Creek Basin, a locality in North Miami particularly prone to flooding conditions. Due to limitations in water level observations, the model was calibrated based on properties that have experienced repetitive flooding losses and validated using image-based volunteer geographic information (VGI). Results suggest that groundwater-induced flooding is localized, and high groundwater heads influence pluvial flooding as the shallow water table undermines the soil infiltration capacity. Understanding groundwater flood risk is of particular interest to low-elevation coastal karst environments as the
sudden emergence of the water table at ground surface can result in social
disruption, adverse effects to essential services and damage to infrastructure. Further research should assess the exacerbated impacts of
high tides and sea level rise on water tables under current and future
climate projections.

Landslides are the most frequent phenomenon in the northern part of Iran, which cause considerable financial and life damages every year. One of the most widely used approaches to reduce these damages is preparing a landslide susceptibility map (LSM) using suitable methods and selecting the proper conditioning factors. The current study is aimed at comparing four bivariate models, namely the frequency ratio (FR), Shannon entropy (SE), weights of evidence (WoE), and evidential belief function (EBF), for a LSM of Klijanrestagh Watershed, Iran. Firstly, 109 locations of landslides were obtained from field surveys and interpretation of aerial photographs. Then, the locations were categorized into two groups of 70% (74 locations) and 30% (35 locations), randomly, for modeling and validation processes, respectively. Then, 10 conditioning factors of slope aspect, curvature, elevation, distance from fault, lithology, normalized difference vegetation index (NDVI), distance from the river, distance from the road, the slope angle, and land use were determined to construct the spatial database. From the results of multicollinearity, it was concluded that no collinearity existed between the 10 considered conditioning factors in the occurrence of landslides. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) were used for validation of the four achieved LSMs. The AUC results introduced the success rates of 0.8, 0.86, 0.84, and 0.85 for EBF, WoE, SE, and FR, respectively. Also, they indicated that the rates of prediction were 0.84, 0.83, 0.82, and 0.79 for WoE, FR, SE, and EBF, respectively. Therefore, the WoE model, having the highest AUC, was the most accurate method among the four implemented methods in identifying the regions at risk of future landslides in the study area. The outcomes of this research are useful and essential for the government, planners, decision makers, researchers, and general land-use planners in the study area.

Since it is not possible to determine the exact time of a natural disaster's occurrence and the amount of physical and financial damage on humans or the environment resulting from their event, decision-makers need to identify areas with potential vulnerability in order to reduce future losses. In this paper, a GIS-based open source software entitled Seismic-Related Vulnerability Calculation Software (SEVUCAS), based on the Step-wise Weight Assessment Ratio Analysis (SWARA) method and geographic information system, has been developed to assess seismic vulnerability by considering four groups of criteria (i.e., geotechnical, structural, socio-economic, and physical distance to needed facilities and away from dangerous facilities). The software was developed in C# language using ArcGIS Engine functions, which provide enhanced visualization as well as user-friendly and automatic software for the seismic vulnerability assessment of buildings. Weighting of the criteria (indicators) and alternatives (sub-indicators) was done using SWARA. Also, two interpolation methods based on a radial basis function (RBF) and teaching–learning-based optimization (TLBO) were used to optimize the weights of the criteria and the classes of each alternative as well. After weighing the criteria and alternatives, the weighted overlay analysis was used to determine the final vulnerability map in the form of contours and statistical data. The difference between this software and similar ones is that people with a low level of knowledge in the area of earthquake crisis management can use it to determine and estimate the seismic vulnerabilities of their houses. This visualized operational forecasting software provides an applicable tool for both government and people to make quick and correct decisions to determine higher priority structures for seismic retrofitting implementation.