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Volume XV |

The Assessment of Artificial Water Surfaces Regeneration in Stachinez Swamps Protected Area by Using Remote Sensing and In–situ Data

Abstract: The Satchinez Swamps, a remnant of the swamps once specific for Banat Plain, is an ornithological reserve since 1942 and the habitat of many protected bird species. Draining works conducted in the seventies affected the reserve by decreasing the water surface area. Thirty-five years later, hydro-technical works aiming to restore the former aquatic surfaces within the buffer zone were conducted. Thus, in 2005 a water delivery canal from the discharge canal of Satchinez reservoir towards Balta Mare was built. The objective of this study is to assess the efficiency of the hydrological works carried out in 2005 by using temporal analysis of some normalized difference indexes derived from satellite images, in relation to precipitation data (recorded at Timisoara meteorological station) as an indicator for wetland restoration. We used geospatial data from different time periods: historical maps (1953, 1962 and 1984), orthophotos (1963, 1970, 2005 and 2012), oblique airphotos (2004) and 38 Landsat satellite scenes (1984-2015), two images per year, for the dry season respectively for the rainy season. We noticed a slight increase of the Normalized Difference Vegetation Index (NDVI) in Balta Mare and on the relict watercourse of Sicsău stream, which shows the expansion of reed and suggests an increase in soil moisture. During the dry season, for the period before the restoration works (1984 – 2004) there is a strong, very significant correlation between Normalized Difference Water Index (NDWI) and precipitations (r =0.7008, p = 0.0011). After 2005, this correlation no longer occurs (r = -0.1083, p <0.05), which demonstrates that precipitations are not the main water supply for Balta Mare anymore. For the 1984 – 2015 period, during rainy months the Modified Normalized Difference Water Index (MNDWI) indicate the presence of water in Balta Mare, but during the dry months, it demonstrates the lack of water which underlines the temporary character of this pond and confirms the field observations. We conclude that the restoration did not succeed in the rebuilding of the former water surfaces of Balta Mare, but has an effect in increasing the underground water level in this area followed by reed extension.

Volume XIV |

Snow avalanche tracks mapping within Bâlea glacial valley (the Făgăraș Mountains) using semi-automated detection methods

Abstract: Mapping of snow avalanche tracks based on topographic maps, aerophotos and field data to achieve inventories for the whole mountaineous areas in Romania is an important step in snow avalanche risk assessment and other related geomorphic processes. This requires experience and it is a time consuming process. In the absence of field data, the process of snow avalanche tracks mapping is influenced by the subjectivity of those who digitize.
Thus, we propose a semi-automated method for detection of snow avalanche tracks based mainly on geomorphometric parameters that can be extracted from the Digital Elevation Model (DEM) like slope gradient, plan and profile curvature, mean curvature, runoff.
In this study we used an object based analysis to detect snow avalanche tracks in central part of the Făgăraș Mts. This approach has two steps, segmentation and classification. First, we segmented the area based on plan curvature (which is the most important parameter that describes these snow avalanche tracks) in order to obtain objects. In the process of classification we added other conditions such as fuzzy function for slope gradient, thresholds for altitude and runoff and a shape index of objects. The results obtained were very close to the mapped tracks using digitizing techniques. The maps resulted from the classification were compared to the those resulted from digitizing in both number of objects and spatial agreement of the class of objects. There was a very good fit in case of the number of objects and total area of objects. The method could be improved if we apply on high resolution DEMs and also on more case studies with different topography and existing vector database.

Volume XI |

Trends in land cover change in abandoned mountain pastures. A case study: Măgura Marga Massif (the Southern Carpathians)

Abstract: Grazing was the main activity of the inhabitants of the region, so that on an area of only 750 hectares, 16 sheepfolds existed simultaneously. In the last 20 years, mountain pastures were gradually abandoned a fact which led to some changes in land cover, mainly close to timberline. The aim of this paper is to identify general trend of land cover change using change – detection methods based on Landsat TM imagery for 1988 – 2011 time interval. Detailed analysis based on field research and high resolution air photos was also made for the areas with highest land cover changes. The analysis of the historical maps allowed a better understanding of the land cover transformations in the last 70 years. The results showed that the general trend in pastures area for the last 23 years is the biomass gain. Even if this phenomenon has a low and medium magnitude, it is a dominant one, appearing on more than 88% of the pastures area. Moderate intensity changes are explained due to the relatively short time interval since pastures were abandoned. Major changes occurred in some areas: on the southern slopes, because of the specific topoclimate, in areas where the anthropogenic timberline was lowered at very low altitudes and in the areas near the spruce timberline. There are also areas where there are no obvious changes of the timberline. These occur more frequently on the northern and western slopes, near the beech forest timberline. In the study area, the timberline is still anthropogenic, but if the current trend of forest regeneration continues, the timberline will change to a climatic one.

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 |

Features of the Ski Area from the Romanian Banat

Abstract: The Romanian Banat is endowed with an important mountain area composed of the Banatului Mountains and the north-western part of the Retezeat-Godeanu Range, i.e. Ţarcu – Muntele Mic. The purpose of our paper is to make an account of the features of the two important ski areas within this mountain area: Ţarcu – Muntele Mic and Semenic. Their structure evolved over time according to the local and regional interest, but also due to more recent activities of the Romanian investors. Our research concluded that both ski domains have a great natural potential to sustain winter-sports and to further develop what today are two very small resorts. They have a low capability of attraction due to the small capacity of the pistes and to the fact that each resort has only two ski-lifts. In both cases the access is rather limited and as far as accommodation is concerned in both cases it is disproportional in relation with the provisioned capacity of the ski pistes. Having these aspects in view, we conclude that these resorts do not represent as yet a major attraction, especially due to the fact that there are undercapitalized and underdeveloped for the raising demand of the regional market for winter-sports. On the other hand in both cases projects have already been blue-printed by the aforementioned investors which are waiting to be undertaken for development.