Floods are the most destructive natural phenomenon, by the total number of casualties, and value of property damage, compared to any other type of natural disaster. However, some of the most destructive flash floods are related to dam breaches or complete collapses, that release the large amounts of water, affecting inhabited areas. Worldwide, numerous dams have almost reached or surpassed the estimated construction life span, and pose an increasing risk to structure stability. Considering their continuous degrading state, increasing rainfall aggressiveness, due to climatic changes, technical error, or even human error, there are numerous, potential causes, for which dams could develop breaches and completely fail. This study aims to portray a comparative perspective of flood impact, with real-life consequences, measured by quantifiable parameters, generated from computer simulations of different breach sizes. These parameters include the total flooded surface, water velocity, maximum water depth, number of affected buildings, etc. The analysis was undergone by means of HEC-RAS based 2D hydraulic modeling and GIS, depending on high-accuracy Lidar terrain data and historical hydrological data. As a case study, Drăcșani Lake with the associated Sulița earthfill embankment dam was chosen, being one of the largest and oldest artificial lakes in Romania.

The aim of this study was to determine the effects of main factors and interactions on the color removal performance from dye solutions using the electrocoagulation process enhanced by adsorption on Granular Activated Carbon (GAC). In this study, a mathematical approach was conducted using a two-level fractional factorial design (FFD) for a given dye solution. Three textile dyes: Acid Blue 74, Basic Red 1, and Reactive Black 5 were used. Experimental factors used and their respective levels were: current density (2.73 or 27.32 A/m²), initial pH of aqueous dye solution (3 or 9), electrocoagulation time (20 or 180 min), GAC dose (0.1 or 0.5 g/L), support electrolyte (2 or 50 mM), initial dye concentration (0.05 or 0.25 g/L) and current type (Direct Current—DC or Alternative Pulsed Current—APC). GAC-enhanced electrocoagulation performance was analyzed statistically in terms of removal efficiency, electrical energy, and electrode material consumptions, using modeling polynomial equations. The statistical significance of GAC dose level on the performance of GAC enhanced electrocoagulation and the experimental conditions that favor the process operation of electrocoagulation in APC regime were determined. The local optimal experimental conditions were established using a multi-objective desirability function method.

The Putna-Vrancea Natural Park (PVNP) is one of the wildest mountain areas in Romania and is home to internationally important species of flora and fauna. Although the park’s area is covered by forests, the last two centuries have seen several major transformations. The aim of this article is to present a historical approach to the development of habitat areas within the PVNP, with an attempt to show both the situation before and after the establishment of its protection regime. The changes in the forest area were identified using available cartographic material from 1789, 1895, 1957, 1975, 2005, and 2018. The analysis of forest distribution according to different classes of natural factors (altitude, slope, soil type, and lithology) highlighted the early 20th century when forest cover decreased at low altitudes and slopes. However, anthropogenic factors were responsible for almost all changes. The specific socio-economic system of the Vrancea Mountains, according to which the forest was and still is owned by the inhabitants of several villages, led to periods of deforestation: burning to increase the area of pastures and the unsustainable exploitation of wood by some companies that had been granted this right by the owners. In the 1960s and 1970s, the mountain pastures were reforested, and in the last 20 years, the mountain pastures have been transformed into forests. Although the use of old maps for this type of analysis has certain limitations, the results obtained provide insight into the causes of the transformation of forest landscapes in some areas of the PVNP.