Predicting Wetland Occurrence in the Arid to Semi—Arid 1 Interior of the Western Cape, South Africa, for Improved 2 Mapping and Management

As for drylands globally, there has been limited effort to map and characterize such wetlands in the Western Cape interior of South Africa. Thus, the study assessed how wetland occurrence and type in the arid to semi-arid interior of the Western Cape relate to key biophysical drivers, and, through predictive modelling, to contribute towards improved accuracy of the wetland map layer. Field-verified test areas were selected to represent the aridity gradient, rainfall seasonality, hydrogeomorphic (HGM) types and physiographic zones encompassed in the study area. The arid areas of the Karoo physiographic zones had: (1) a low (<1%) proportional area of wetland; (2) an almost complete absence of seepage slope wetlands; (3) ephemeral depressions, all non-vegetated; and (4) much of the wetland associated with valley bottoms confined within a channel. The less arid mountain zones had: (1) a much higher (>3%) proportional area of wetland; and (2) wetlands being predominantly hillslope seepages, but also including valley bottom wetlands. A spatial probability surface of wetland occurrence was generated based on the statistical relationship of verified wetland presence and absence data points with a range of catchment-scale predictor variables, including topographic metrics and hydrological/climatic variables. This layer was combined with raster images of most likely HGM type within the landscape to provide a final product of wetland occurrence, attributed by HGM type. Vulnerabilities of the wetlands were identified based on key attributes of the different wetland types, and recommendations were provided for refining the wetland map for the Western Cape.

Danube Delta - a unique place in Europe

At the end of a flowing route that exceeds 2,860 km, through an impressive catchment area that covers more than 80% of Europe, the Danube, the second largest river in Europe, intersects the Black Sea forming the delta which is known as one of the great wetlands of the planet. The stretches of water and land formed here offer good living conditions to many species of plants and animals. The purpose of this study was to create several maps that present these aspects of the Danube Delta wetland using a set of GIS technologies. Since the GIS technology is an important tool in the analysis of geographic areas, we managed to obtain the following maps: hypsometric, slope, slope orientation and flood direction. Since September 1990, the Danube Delta Biosphere Reserve has been recognised internationally as a wetland; specifically, the Danube Delta Biosphere Reserve has been recognised internationally as a wetland, especially for water birds habitat. The value of the World Heritage Site of the Danube Delta Biosphere Reserve was recognised in December 1990 by including more than half of its surface into the World Cultural and Natural Heritage List. Keywords: Danube Delta, flood accumulation, natural heritage, slope, wetlands.

Cooling Effect of Crushed Rock-Based Embankment along the Chaidaer-Muli Railway

This paper presents an experimental study of the cooling effect of crushed rock-based embankment on slope wetlands along the Chaidaer-Muli Railway. The result shows that only the embankment shady side can be effectively cooled down in a warm permafrost region and the crushed rock-based embankment can cool the entire embankment in a cold permafrost region. The crushed rock-based embankment cannot eliminate the problems from the south-north slope. Slope wetland can influence the temperature field of the crushed rock-based embankment. On the uphill side, it will lead to degradation in some cases and development of permafrost in other cases, which depends on the topsoil water content and ground surface runoff. On the downhill side, it always leads to the warming of permafrost. For crushed rock-based embankment constructed on slope wetlands, it is necessary to adopt other stronger measures to eliminate the sunny-shady slope problems.