Gheorghe Romanescu, Alin Mihu-Pintilie, Cristian Trifanov and Cristian C. Stoleriu
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.