Hydrological Variability Impact on Eutrophication in a Large Romanian Border Reservoir, Stanca–Costesti

Abstract

Climate change represents one of the major challenges of our century with great potential to alter water quality, and hence, find suitable solutions becomes a must. Stanca–Costesti reservoir is one of the most important in Romania and one of the most affected by the hydrologic variability. The studies regarding the trophic state of this reservoir are few, even if there are some environmental issues in its hydrological basin that could be further investigated. According to the National Administration “Apele Romane” (ANAR) yearly reports, the Stanca–Costesti reservoir is, from the trophic state point of view, an oligotrophic lake. The current research is based on chemical and some biological data collected over 10 years (ANAR) for the trophic state of the Stanca–Costesti reservoir, using the Carlson index. The research investigates the hydrological data and spans over 10 years that were classified into three categories, namely: wet year, normal year, and dry year and the influences generated by the contrasting weather (flow and temperature changes) on the trophic state of the lake. The research findings show that the trophic state of the lake is directly influenced by the hydrological variability, namely evolving to a hypertrophic status due to concentrations of nutrients. Moreover, over the years, according to ANAR data, the water quality in the reservoir alternated. Hence, at times, the quality of the water was poor, with possible negative influences on water usage. As a consequence, we proposed that the water quality be verified monthly, and this should be done by means of a more reliable method, such as a multiparameter index or multicriteria analysis.

Overview of the Eutrophication in Romanian Lakes and Reservoirs

“…This map Figure 4, where the 20 lakes and reservoirs from the analyzed works are a the bigger the circle, the higher the number of studies on that specific reser of the lakes/reservoirs and their corresponding number is presented in Ap studies deal with lakes and reservoirs in hilly and plain areas, where the water bodies is more vulnerable. Considering the results of the national In ent Pollution Control Project, which specifies the area susceptible to pollu ents, it can be noticed that only a few lakes and reservoirs (5,8,9,13) are zones. Also, the project does not present any data for the Danube Delta o coast [39].…”

“…Most studies deal with lakes and reservoirs in hilly and plain areas, where the trophic state of water bodies is more vulnerable. Considering the results of the national Integrated Nutrient Pollution Control Project, which specifies the area susceptible to pollution with nutrients, it can be noticed that only a few lakes and reservoirs (5,8,9,13) are placed in clean zones. Also, the project does not present any data for the Danube Delta or the Black Sea coast [39].…”

“…Eutrophication represents an anthropogenic pollution, requiring interdisciplinary knowledge to understand the phenomenon. Thus, in the specialized literature, the phenomenon of eutrophication is associated with limnology [11], agronomy [12], hydrology [13], climate science [4,14] water biology [15], and even social sciences [16,17]. The eutrophication of inland waters is currently prevented, managed, and remedied through management practices of aquatic ecosystems or land adjacent to them [18].…”

Methodology for assessing the geoecological state of landscape-lake systems and their cartographic modelling (case study of Lake Bile, Rivne Nature Reserve, Ukraine)

“…Limnological studies of recent years reflect only certain aspects of the complex landscape and limnological approach to the study of lakes. They are related to: 1) zonal regulation of the protection areas of the Olsztyn Lake basin, taking into account the slope coefficients of the relief (Hakuć-Błażowska, Cymerman 2011); 2) restoration of lake shores based on landscape ecology (Boromisza et al 2014); 3) assessments of the ecological consequences of hydromorphological loads on European lakes (Poikane et al 2020) and assessments of the ecological state of lakes in natural parks whose watersheds are located at different geomorphological levels (Paszteleniec, Kutyła 2015); 4) changes in water resources under the influence of natural and anthropogenic factors (Choiński et al 2016); 5) natural and anthropogenic conditions of fluctuating lake water levels (Nowak, Ptak 2019); 6) assessments of anthropogenic pollution of lakes based on the content of heavy metals in bottom sediments (Ignatavičius et al 2022); 7) correlations between water quality in reservoirs and land use within the watershed basin (Dumitran et al 2020;Česonienė et al 2021); 8) monitoring of the lake water quality according to the data of RSE (Ciężkowski et al 2022;Fesiuk et al 2022). Such a variety of approaches is natural since the development of landscape science and limnology is based on different fundamental concepts.…”

Carbon footprint of Vidraru hydropower development

“…The second largest Romanian reservoir, Stanca-Costesti, was subject of analysis related to hydrological variability impact on eutrophication [13] and even of the evaluation of GHG emissions using 7 models from literature, among which G-res [14]. The results show GHG emissions varying from 567.34 gCO2e/kWh to 19.06 gCO2e/kWh using G-res.…”