Assessment of water quality of Lake Viroi after the reconstruction of the park

Abstract

Albania is a reach country in water natural resource and one of them is "Mëma e Viroit" in the region of Gjirokastra. This is a karstic water source and it is approved as natural monument. The Lake Viroi is an important water ecosystem, with ecological, economic and environmental values. The anthropogenic and natural impacts are very significant indicators for eutrophication process of this lake. There is a good database for the environmental indicators and eutrophication of this ecosystem, which were assessed during the years 2011-2015. The park was under restoration during the year 2016 and it was a demand to assess water quality of lake after its restoration. The main objective of this study was to compare water quality of the lake before and after lake restoration and to propose the measures for water quality improvement. Water samples were collected during the year 2018, in accordance with the standard methods and were analyzed for chemical parameters by using ISO standard methods. The analyzed parameters were estimated according to the Water Framework Directive (WFD 2000/60 /EC) on the quality of surface waters. The values of trophic index (TSI) for Lake Viroi was calculated based on the total Phosphorus and total Nitrogen. The results showed that the amount of main nutrients as Nitrogen and Phosphorus continues to be at "High" and "Good" level. The trophic status of the lake varies from "oligotrophic" based on total Phosphorus values, to oligo-mesotrophic based on total Nitrogen values.