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Geomorphology

Volume X |

Human-Induced Environmental Changes and Floodplain Restoration Necessity along the Danube, on the Drobeta-Turnu Severin – Bechet Sector

Abstract: The present paper aims at analysing the human-induced transformations that took place in the Drobeta-Turnu Severin – Bechet sector of the Danube Floodplain during the last two centuries. The research started from the need to obtain a real and comprehensive database concerning the extension, the nature and the characteristics of the topographic-hydrographical, edaphic and biologic structures appeared or modified under human influence, their relation with the changes occurred at the level of the land use and their present functionality. Special attention was paid to the latter transformations occurred after 1989. The primary types of topographical and hydrographical changes resulted from the geomorphic human activity in the Danube Floodplain are analysed in relation with the land use within this unit. The analysis of the environmental transformations in the floodplain sector started from cartographic and statistical materials that are relevant for the 19th-21st centuries. For the post-communist period, the valorisation of the Corine Land Cover database allowed for a more detailed analysis of the land use dynamics. The data thus obtained was checked and updated with field observations and measurements, which are mandatory given the fact that the cartographic database shows deficiencies and it is partially outdated.

Volume X |

The Dynamics of Forest Areas in the Vâlsan Basin

Abstract: This case study refers to forest area dynamics within the Vâlsan Basin, situated between his affluents: Mierlei Valley and Bunești Valley in 1904-2004 period. The dynamics was shown by maps on a temporal scale especially in reference years as 1904, 1973, 1981, 1994, 2004. Forest cover from our study area has been decreased substantially because of the impact of human activities. We can conclude at the end of our paper that forest ecosystems had lost the natural equllibrium, and barely can realize the protective and hydrological function, in the context of declaring our study a natural reserve.

Volume IX |

The Ancient City of Callatis and the Neotectonic Movements

Abstract: Southeastwards of Mangalia, 6 – 7 meters under the sea level, on a surface of about two hectares, there were discovered vestiges of the ancient fortress of Callatis. The settlement known since the 4th century B.C. had almost a millenary existence, but it is not known when it ceased to exist and what causes triggered it. Different suppositions were made and, among them, the telluric causes are plausible. The Southern Dobroudja Platform is penetrated by mobile faults and the compartment of Mangalia is affected by a negative neotectonic movement that gets accentuated towards southeast, where the epicentres of earthquakes with repeated manifestation have been observed. The negative movement rate is 3 – 4 mm/year and, cumulated during the 15 centuries that passed since the disappearance of the city of Callatis, it could explain the depth at which the vestiges of the settlement are presently located.

Volume IX |

The Analysis of the Relief Fragmentation Features within the Bălăciţa Piedmont

Abstract: Within the Bălăciţa Piedmont there are to be distinguished two areas with specific features, which correspond to the Danube catchment and to the Jiu drainage area. Both in the case of the drainage density, as well as in that of the relief energy, the distribution of the value classes correlated with the two catchments underlines major differences, but also certain resemblances, situation which is explained by the evolution time, the base level, the flow direction in relation with the structure and the lithological and climatic homogeneity. The analysis of the data enabled the quantification of the relief energy and of the drainage density within the Bălăciţa Piedmont, as well as the correlation of the two parameters in report to the main catchments. The computation and representation methods for the two indicators of the relief fragmentation (i.e. the depth and the density) allowed for a quantitative interpretation (the identification of five value classes), as well as for a spatial interpretation (the grouping of the values depending on the two collecting rivers: the Danube and the Jiu). The aggregation of the influence factors on the two main drainage areas is mostly due to the fact that the Danube catchment extended its area in the detriment of the Jiu catchment, the three more important tributaries (the Blahniţa, the Drincea and the Desnăţui) catching sectors within the upper course of the tributaries of the Jiu. The analysis of the relief fragmentation within the Bălăciţa Piedmont shows that this unit is on different evolution stages. The complexity of the fragmentation is closely connected to the maturity degree of the valleys and to the morphogenetic complexes imposed by the paleogeographical evolution.

Volume IX |

The Dynamics of the Present Processes within the Sărăţel Catchment Area

Abstract: The Sărăţel catchment displays a territory mostly located in the molasse area of the Buzău Subcarpathians. The physical-geographical characteristics, as well as the social-human impact, created a complete geomorphologic system, in which the present geomorphologic processes register accentuated dynamics. Starting with the year 2002 until 2008 there were monitored areas with significant impact on the landscape, among the most important processes under study being the landslides, the torrents, the ravines and the creep.