The variations of physico-chemical parameters during summer in Lake Erenciuc from the Danube Delta (Romania)

Abstract

Lake Erenciuc is situated in the Danube Delta (Romania) and was created in the abandoned riverbed of the Sfântu Gheorghe arm. It is the largest meander lake in Romania. During spring–summer, the physico-chemical parameters of water have been measured in seven lake sampling points and one at the Sfântu Gheorghe branch, which supplies the lake through Erenciuc channel. The area around Lake Erenciuc belongs to the category of strictly protected areas within the Danube Delta Biosphere Reserve. The following water quality parameters were measured: temperature (T: °C); pH (pH units); Luminescent Dissolved Oxygen (LDO: mg dm−3); Dissolved Oxygen saturation (DO: %); water tension (U: mV); Electrical Conductivity (EC: μS cm−1); Total Dissolved Solids concentration (TDS: mg dm−3). The recorded values are easily differentiated across the entire length of the elongated lake path, especially between inflow (upstream) and outflow (downstream). The parameters recorded during the spring–summer period, with high flow rates and high water levels, demonstrate good lake water quality, especially oxygenation. The study also demonstrates that high waters refresh and recalibrate the water quality in isolated lake basins.

Temporal and Vertical Relations between Various Environmental Factors in the Largest Lake of Łęczna-Włodawa Lake District (Eastern Poland)

“…A pH inter-annual distribution in lake waters may be related to wet and dry periods or to snow meltdown [47], due to low pH value of both rain and snow. DO and pH correlations, observed in our study, often occur in temperate lakes [48]. However, pH and DO correlations with NH 4…”

UAV and field survey investigation of a landslide triggered debris flow and dam formation in Eastern Carpathians

“…Moreover, since the present case study will be included together with other examples in an upcoming European landslide dams database, the delineation of geomorphological features to obtain accurate morphometrical values was achieved according to a specific datacollection template (Mihu-Pintilie and Dufresne, 2023) (Figure 4E). The summary of this data-collection includes informations related with: 1) Landslide triggered debris-flow data: type, trigger, total volume, deposit area, length, crown elevation, toe elevation, total drop height, total runout length, horizontal runout length in 2D and 3D, travel angle, distance scarp to river (Cruden and Varnes, 1996;Hungr et al, 2014); 2) LDF dam data: dam type (Costa and Schuster, 1988), dam volume, dam material composition, dam height, dam-surface lowest elevation, dam length, dam width, downstream and upstream slope of the dam (Fan et al, 2020); 3) Făgețel Lake data: elevation of lake surface, area, length, mean and maximum width, major axis, small axis, form coefficient, perimeter length, sinuosity coefficient, volume and volume coefficient, mean and maximum depth (Mihu-Pintilie, 2018b; Romanescu et al, 2018b). As presented in the introduction section, during the summer of 2010, significant heavy rainfall impacted the northeastern part of the Goșmanu Massif, leading to several flash floods along the Iapa Valley.…”

“…However, due to the mass movement type, together with the dam's lithological characteristics and the fact that it formed a long-term lake, the Iapa LDF is quite unique in the landscape of the Eastern Carpathians. Usually, the other examples of landslide dams that did not fail after a few days have been formed by rock slides, which confer high stability due to the lithological composition and morphological characteristics (Mihu-Pintilie, 2018a;Romanescu et al, 2018b).…”

“…The main trigger was the heavy rains that impacted the entire region during the May-July period of 2010 (Romanescu et al, 2017;Romanescu et al, 2018a), but the high density of the forest paths and extensive deforestation in the Limpedea logging area have also a significant contribution in geomorphological process that affect the southern slope of the Drumul Chinezilor ridge. However, the most interesting aspect related to the Iapa landslide triggered debris flow (Iapa LDF) is that of more than 20 large landslide dams formed due to extreme hydroclimate conditions in the Carpathian Mountains, investigated and reported in various studies (Năstase, 1949;Ciornei, 1959;Tövissi, 1964;Pop, 1970;Decei, 1981;Ichim and Rădoane, 1996;Ilinca and Gheuca, 2011;Șerban et al, 2012;Romanescu et al, 2013;Mihu-Pintilie, 2014a;Mihu-Pintilie et al, 2014b;Stoleriu et al, 2014;Mihu-Pintilie et al, 2016;Lesenciuc et al, 2017;Mihu-Pintilie et al, 2018a;Romanescu et al, 2018b), the Iapa LDF event is the singular one in the Eastern Carpathians that has formed a long-term lake (more than 10 years) due to a debris flow-slide dam (Table 1).…”