- Biogeography (19)
- Climatology (36)
- Environment (77)
- Geomorphology (58)
- GIS and Remote Sensing (19)
- Human and economic geography (63)
- Hydrology (57)
- Regional geography (45)
- Tourism (42)
- Various (37)
Abstract: Soil erosion is recognized as one of the most serious soil threats in Bulgaria. The paper presents assessments of soil erosion factors and risk in the catchment of the Dzhebelska River (Eastern Rhodopes), Bulgaria. The assessments are based on the USLE approach, which was adapted for Bulgarian conditions and integrated with GIS. It is established that about 45% of the territory of the Dzhebelska River catchment are characterized with rains with an average erosivity between 600 and 800 MJ mm/ha h y. Largest percentage share (47%) of the lands in the catchment area is characterized by medium to high susceptibility to erosion (0.03-0.04 t ha h / MJ ha mm). Almost half of the lands in the studied catchment are with a slope above 15°. Significant share of land (32.5%) is with high potential risk of erosion (100-200 t/ha y). Due to the largest percentage share of forestland (57%), lands with actual erosion risk below 3 t/ha y cover about 58 % of the catchment area, while these with a risk above 40 t/ha y cover about 15%.
Abstract: Water transparency is a primary indicator used to evaluate the status of marine ecosystems. Although a subjective measure, Secchi Depth (ZSD) is one of the “oldest” and most widely used optical parameters in studies that focus on surface water clarity, with probably millions of observations available in the last century. As recent satellite observa-tions do not cover such extended periods from the past, a comprehensive understanding of the spatio-temporal dy-namics of water transparency requires consistent historical data. In this regard, the present study aims to integrate in-formation from archives of in situ ZSD measurements available for the entire Black Sea. Several potential sources were investigated. Among them, two were identified to have historical measurements of ZSD in the Black Sea, SeaDataNet and Black Sea Ecosystem Processes and Forecasting / Operational Database Management System (NATO SfP ODBMS). A database with all available observations was aggregated for this study, containing a total of 5100 records between 1960 and 2016. The analysis of the spatial variability of ZSD was performed based on a square grid of 30 km x 30 km covering the entire Black Sea region. For each cell, statistics such as the average and the number of ZSD measurements were calculated. Moreover, the spatial and temporal homogeneity of the in-situ observations are assessed and dis-cussed.
Abstract: The purpose of this study is to analyze gully erosion processes and their management in the Trivale Forest Park. Although the inclusion of gullies in the category of risk phenomena is still debated, due to their spatial extent and evolution, both longitudinally and vertically, they can pose concern to woody vegetation by altering slope stability. This is the case of the Trivale Forest Park, situated in Pitești city, where gully erosion has been affecting tree growth and recreational activities, such as hiking or cycling, which has led to the implementation of erosion control measures and hydrotechnical structures. By carrying out field observations and cartographic analyses, the research has/proposes/seeks to support two objectives: firstly, to establish the impact of erosion processes on the valleys’ and slopes’ balance by evaluating the type of erosion processes and resulting features and secondly, to assess the exposure of the Trivale Forest area to erosional forms, by using GIS and the frequency ratio (FR) techniques. The results of the multicriteria analysis highlighted, in good agreement with the field observations, the areas most susceptible to slope erosion processes.
Abstract: Water samples for chemical analyses have been collected from impenetrable karst springs and from water flows intercepted by caves within the area of Sohodol valley. The analyzed inorganic constituents were noticed to belong to two distinct categories. One category included solutes of variable concentrations, likely related to local allochtonous inputs (Al, NO3) and to local occurrences of decaying organic matter (PO4, NO3), such solutes being hence irrelevant in terms of regional patterns of rock weathering. The other category of solutes (Ca, Mg, Na, K, Sr, Ba, Rb, Fe, HCO3 and SiO2) proved to have concentrations that did not differ between two interconnected water flows (e.g., impenetrable karst springs that discharged from a common water body; a cave stream connected to an impenetrable karst spring). Accordingly, the concentrations of this second group of constituents represented reliable chemical fingerprints of a particular karst watershed. And implicitly, water flows having contrasting concentrations of such solutes were conjectured to belong to distinct karst watersheds, which likely differed in terms of chemical composition of the karstifiable rocks, and/or of the impervious rocks which provided allochtonous recharge to the concerned karst drainage systems.
Abstract: The study presents a detailed geomorphological characterization of the volcanic mountains of Transcarpathia. Materials of previous geological researches, including the Transcarpathian geological exploration expedition, supplemented by the results of our own field researches, are systematized. Based on the analysis of relief forms and taking into account geomorphological and tectonic factors, Vyhorlat-Gutyn morphostructure of the second order is divided into morphostructures of the third order: Poprychny, Antaliv-Synyatska, Velykyi Dil, Tupy and Oash, which in turn are divided into morphostructures of lower orders. The Mukachevo morphostructure of the second order is composed of the following morphostructures of the third order: Beregovo hills, Kosino-Biganski hills, volcanic remains (Shalanka, Chorna Gora). Based on a detailed analysis of the collected materials, it was determined that the main role in shaping the modern relief of volcanic mountains belongs to channel and temporary water flows and weathering processe; consequently, river valleys and weathering surfaces were formed, which are the most important morphosculptures. On the basis of morphological and structural-lithological approach, as well as own field research, a geomorphological map of the volcanic mountains mountains of Transcarpathia on a scale of 1: 100,000 was compiled.
© 2009- 2026 Forum geografic
Designed by Alin Clincea.
