The European Water Framework Directive requires the qualification of a good ecological status for water bodies. Lake Mondsee of Austria has repeatedly failed to reach a good ecological status due to phosphorus emissions from non-point source (NPS) pollution. NPS pollution of phosphorus emissions within landscapes dominated by grassland have an effect on water quality. The Agricultural Non-Point Source (AGNPS) pollution modeling program was used to develop a model for determining phosphorus emissions within Koppl catchment. The identification of critical source areas (CSA) through NPS pollution modeling provides data pertaining to landscape regions susceptible to NPS phosphorus emissions. The targeting of CSA through NPS pollution modeling will further aide in the remediation and restoration of watersheds affected by an overabundance of phosphorus loading into open water bodies. The information can be used to help decision support systems in the reduction of phosphorus emissions and identify landscapes more susceptible to the release of greater phosphorus emissions.

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Koppl catchment is located within the greater Mondsee watershed (264 km2) in the Austrian Federal District of Salzburg. Koppl is 5.9 km2 in size and is dominated by agricultural land use. In 2000, the European Union established the Water Framework Directive (WFD). This legislation was put in place for environmental and water quality monitoring within watersheds. During the years 2002, 2003 and 2009 there is a noticeable increase of P loading into the Mondsee catchment. Mondsee presently has not recovered from high P emissions loading into the lake. This brought upon concern of environmental degradation and eutrophication of the karst lakes of Mondsee watershed. NPS pollution has been targeted as the proprietor of P emissions.  

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AnnAGNPS is the annualized version of AGNPS. It is a continuous process-based modeling program that was developed under the AGNPS suite. The program can be used to model NPS pollution of P emissions and discharge through the development of cell sub-catchment zones and river network routes. The challenges for combating ecological standards within Mondsee pertain to both societal and environmental parameters. Societal impact pertains to agricultural practices (nutrient emissions) whilst environmental impacts include meteorological, soil erosion and hydrological processes within the Mondsee watershed. Among the nutrient emissions, the limiting nutrient Phosphorus (P) has become prevalent within Mondsee Lake. The overabundance of P concentrations within a body of water causes ecological degradation overtime (Vollenweider, 1968; Vollenweider, 1976). As confirmed by Klug et al. (2015), nutrient emissions predominately occur during the spring freshet and heavy rainfall events. During these time periods, hydrological processes transport P throughout a watershed. Haufe (2014) has analyzed the snowmelt distribution of while Kerschbaumer (2014) analyzed the spatial distribution of P emissions during heavy rainfall events in the Mondsee watershed. Klug & Oana (2015) have analyzed weather forecasts and Klug et al. (2015) operationalized the environmental measurements within the catchment zone. However, a spatial modeling analyses using the Agricultural Non-Point Source (AGNPS) program to verify P transport and emissions during meteorological events has not been conducted within the sub-catchment zones of the Mondsee. Under the use of the program ANGPS an NPS pollution model for identifying CSA of phosphorus emissions was developed in this thesis work.