Geospatial Assessment of Trophic Status From a Dam Under Significant Agricultural Drainage at the Mid-Anatolia, Türkiye

The population of Anatolia is continuously growing and developing and it is under the deep influence of global warming. It is increasingly evident that more fresh water will be needed for drinking, irrigation and domestic use. This study aims to assess the water quality and trophic status of a dam (Bayramhacılı dam lake) under excessive agricultural irrigation threat using spatial and multivariate statistical analysis. In the study, the periodic changes in the eutrophic state of the dam lake were determined using global index categories, Carlson Trophic Status Index (CTSI = 66.7), Burns Trophic Level Index (BTLI = 6.4), and Shu Trophic State Index (STSI = 65.6). The two periodical averages of total phosphorus (TP), total nitrogen (TN), biological oxygen demand (BOD), (chemical oxygen demand (COD) and chlorophyll a (Chl_a) concentrations, which serve as an indicator of anthropogenic nutrient input, were determined to be 0.23, 31.28, 1.83, 8.99 and 48.1 µg/L, respectively. Trophic index distribution maps demonstrate that the dam’s surface water displays considerable alterations, particularly during the dry season. This evidence supports the implementation of a local management model that addresses the issue of eutrophication. It is therefore imperative that on-site measures are taken without delay.