12. Conclusions

Although most of the lakes in Romania are anthropic, there are relatively numerous standing waters, but the actual natural lakes, according to the universal definition, are rare. The north-eastern part of Romania is characterised by a lack of water, because of which many ponds were built as early as the 14th century. There are numerous types of lakes, natural dam lakes (Red (Roşu), Cuejdu, Ştiol, etc.); volcanic (Saint Anne); fluviatile limans (Ostrov, Mârleanu, Vederoasa, etc.); lagoons (Razim, Sinoie, Siutghiol, etc.), of subsidence (Movila Miresii) etc. The best-known natural dam lake is the Red Lake (10.5 meters deep) formed in 1837, in the Haghimaşul Mare Mountains. The Red Lake catchment basin has a surface of 40.59 km2, and it is drained by typical, high mountain rivers, such as Suhard, Licoş, Vereschiu, Oaia etc. A detailed morpho-metric analysis of the hydrographic basin has been conducted, in order to emphasise the main ecologic elements. Using modern equipment (eco-drill, topometric total station, high precision multi-parameter, etc.), detailed measurements have been taken for the morph-bathymetric elements and for the physical–chemical parameters of the water. Therefore, the main cartographic results obtained refer to slope value and orientation, hypsometry, river classification according to Horton Strahler system etc. Deforestations have accelerated the erosion rate, contributing to the silting process of the Red Lake. The largest deforested surfaces were registered between 1989 and 2001. The maximum clogging rate has reached 1.5 – 1.6 meters (2.8 – 3 cm/year), mostly between 1957 and 2010. All physical–chemical parameters of the water have fluctuations depending on seasons and morpho-bathymetric layers. From a trophic point of view, the Red Lake is included in the meso-eutrophic (nutrients) and ultra-oligotrophic (biologic) categories. The Red Lake has existed for a very long time. The current silting rate is relatively low, which contributes by rising the lifespan of the lake. Several structural and non-structural measures have been applied, to reduce silting, and the most recommended ones refer to lowering soil erosion inside the hydrographic basin, which would also be adopted to maintain biodiversity and the general landscape of this area.