Modelling nutrient loads and eutrophication assessment of lake YahuarcochaPullas Guarderas, Nathan Andrés (Avtor) Atanasova, Nataša (Mentor) Krzyk, Mario (Komentor) Pacini, Nicola (Komentor) master thesiseutrophicationVollenweiderphosphorus loadingmassbalancesurface run-offnonpoint source pollutionanthropogenic activitybest management practices (BPMs)4r nutrient managementcircular economywastewater treatmentconstructed wetlandsphosphorus cycleAlthough significant rehabilitation efforts have been carried out in the past to enhance the ecological and chemical status of Lake Yahuarcocha, it continues to experience considerable pressure from its surrounding environment. In this master's thesis, we examined and modeled the origins of nutrient loads from the contributing areas as well as the sources that directly impact the lake. To achieve this, we developed a model to estimate nutrient loadings from the watershed. Following the Kirchner-Dillon formulation, the model was used to predict the mean phosphorus concentration ([P]) based on the balance between external loading and hydraulic characteristics. We considered phosphorus to be the sole limiting factor affecting the quality of the lake. In our analysis we considered point and dispersed pollution sources. The model was calibrated by refining the Phosphorus Export Coefficients for various land use categories to better reflect the specific conditions of the Yahuarcocha micro-basin. Initially, these coefficients were based on general values from literature, but they were adjusted during the calibration process to bring the predicted lake concentration within an acceptable <20% difference of the observed monitoring data. The calibrated model identified surface runoff as the largest source of phosphorus loading, accounting for almost 70% of the total load. This is primarily a result of agricultural activities within the watershed. The model also highlighted that anthropogenic inputs and runoff enhance the lake's internal nutrient load, a critical factor that significantly contributes to algal blooms. To achieve a mesotrophic state (target 20 μg P/L), the allowable total phosphorus (TP) load for the lake is estimated to be ≈ 795 kg P per year. The current total P load of 5,301 kg P per year overpasses this allowable load by approximately 7.65 times. In response to these findings, we propose a multi-faceted set of recommendations. These measures are designed to not only reduce nutrient loads at their source but also foster a more sustainable development of the tourism-dependent community.[N. A. Pullas Guarderas]20262026-06-17 08:45:07Magistrsko delo/naloga183663sl