fg

Subscribe2


 

Volume X |

Floodplains – Links between Countries and Landscapes

Abstract: The primary function of floodplains remains to be to ensure the safe passage of flood waves. As flood control problems are serious along some river sections, this also requires international cooperation. In landscape ecology, floodplains perform two related functions: they are riparian buffer zones (vital for maintaining river water quality) on the one hand and ecological corridors (ensuring connectivity and high biodiversity) on the other. Floodplain wetlands play an important part of the ecological integrity of riverine ecosystems as they fundamentally influence the ecological status of adjacent water bodies. It is all the more important since along most of its length the Danube crosses densely inhabited areas with intensive agriculture, large-scale industries and well-developed communication networks. Consequently, environmental pressure on the active and protected floodplains is of considerable extent and sharp conflicts arise between different land use types. Land use types promoting the fulfilment of the riparian buffer zone function must have priority. Unfortunately, only restricted sections of the Danubian floodplain are retained in seminatural conditions. In the Danube catchment 80% of the former wetlands are now disconnected and cannot fulfil their nature conservation role. The national NATURA 2000 networks are so much dependent on seminatural riparian ecosystems that they cannot be efficient without floodplain restoration measures. Predictable climate change tendencies (increasing drought liability) are also a threat to the survival of floodplains as ecological corridors. Remediation efforts are necessary along extensive floodplain sections and better connectivity is identified as an important target. According to the Danube River Basin District Management Plan (ICPDR 2009, p. 76):”The ICPDR’s basin-wide vision is that floodplains/wetlands in the entire DRBD are re-connected and restored. The integrated function of these riverine systems ensures the development of self-sustaining aquatic populations, flood protection and reduction of pollution in the DRBD”.

Volume X |

Geohazard Assessment in the Eastern Serbia

Abstract: The territory of eastern Serbia is characterized by a variety of igneous, sedimentary and metamorphic rocks formed through different paleogeographic developments. As a result of varied natural conditions, the region is vulnerable to various geohazards, such as earthquake, landslide, excessive erosion, flood, rockfall, cave collapse and subsidence. The occurrence of any geohazard depends on the intensity of the process causing it. An assessment of each type of hazard or combination of all hazards is necessary for this region of Serbia which accommodates major power-generation, industrial and mining facilities and has rich mineral resources. Depopulation of eastern Serbia reduces the ability of local communities to invest in the hazard control works. This assessment of the geohazards begins with the reference to the available seismic maps and proceeds with the research in the landslide, potential flood and excessive erosion hazards, then rockfall and rock collapse. Research results suffice to prepare a generalized geohazard map of eastern Serbia showing areas vulnerable to particular natural hazards and to estimate a total area endangered by hazardous processes. The purpose of this work is to locate and classify areas of potential hazards on which future protective actions may be based.

Volume X |

Application of Object Based Image Analysis for Glacial Cirques Detection. Case Study: The Ţarcu Mountains (Southern Carpathians)

Abstract: Geomorphologic mapping is an important fact in many research studies and the traditional methods are time consuming and expensive. This paper aims to develop a semi-automated rule-based method for the detection of glacial cirques for a test area located in the Ţarcu Mountains (Southern Carpathians) in an object-oriented approach. In this study we have established the morphometric characteristics of the glacial cirques developed in a particularly geomorphologic context at the edge of planation surfaces, using a 10 m horizontal resolution DEM (Digital Elevation Model). The parameters extracted from DEM (i.e. curvature) were further used in segmentation and classification process. Also, other factors were introduced in the rule set, as the context regarding neighboring objects like planation surfaces to the target class. The most important factor in segmentation was the curvature and to choose an appropriate scale factor we have used the available ESP (Estimation of Scale Parameter) tool. The results achieved were very close to the field reality, except for some areas where there are large negative landforms such as gullies and torrents, which were identified as objects belonging to glacial cirques class and also some roches moutonnées with high positive curvature values, objects that could be filtered manually by the user based on previous field knowledge and ancillary data such as orthophotoplans and the geomorphologic map of glacial relief in the Ţarcu Mountains. For further research, we intend to identify the characteristic thresholds for morphometric parameters that can be integrated in a set of rules in order to detect and classify other type of landforms in the alpine domain of the Ţarcu Mountains.

Volume X |

Glacial and Periglacial Relief in the Făgăraş Mountain, with Special Focus on the Vâlsan River Basin

Abstract: The glacial modeling has created two well individualized geomorphologic landscapes in the Transylvanian Alpes: Borăscu, characterized by the large extension of the platform and high peaks, and Făgăraş, where cirques were multiplied and have developed until they reduced the platform to a very sharp ridge (gipfelflur). The layout of the main ridge on the West-East direction and the overall morphography of the two slopes, the northern one short and steep and the southern long, with gentle slopes, were also reflected in the way of development of glaciers in the Quaternary. In the Vâlsan basin there are distinguished some particularities of the glacial landform. Thus, the glacial landform of this sector of the Făgăraş Mountains is characterized by a small steep (200-300 m) which favored the development of a long glacial valley with gentle slopes and led to the forming of the moraines at the glacial valley floor. The Vâlsan glacial cirque is at 2300 m altitude, is small and has small lakes. The bottom of the cirque is flat and is predominantly grafted on mica-schist and gneisses. The Vâlsan glacial valley is North-South oriented and has several glacial thresholds. The slopes surrounding the Vâslan valley are symmetrical, being affected by torrents and avalanches. Other characteristic landforms are: narrow glacial crests, glacial replats ridges, nunataks and moraines. The frost wedging caused the residual relief represented by sharp ridges, peaks, landforms of accumulation, debris cones, glacis, stone arches, protalus ramparts. Overall, the Vâlsan glacial valley is a typical valley where the intensive post-glacial processes have hidden most of the features resulting from the glaciers action, which kept the characteristic „U” shape and the glacial replats appear from place to place under glacises and rock debris.

Volume X |

Typological and Morphometric Characteristics of the Glacial Cirques in Doamnei River Basin (Făgăraş Massif)

Abstract: The Doamnei River basin, situated on the southern slope of the Făgăraş Massif, is a proper field to study the glacial landforms, because it preserves the two types of glacial landscape identified by Emm. De Martonne even since 1907 for the Meridional Carpathians: the Făgăraş glacial landscape (typical alpine landscape) and the Borăscu glacial landscape. This paper intends to explain some theoretical and practical aspects regarding the correct definition and identification of glacial cirques, and to provide a glacial typology that includes morphological, genetic and topographic criteria. The paper also contains a geomorphologic map (the result of a more extensive analysis) of the glacial landforms in the Doamnei River basin (with 7 glacial complexes, isolated glacial cirques, glacio-nival cirques), the periglacial landforms and the Borăscu erosion surface.