The thesis examines the implementation of the EU Water Framework Directive in two river basins in Denmark. It assesses how climate change considerations can be integrated into the development of cost-effective action programs. For one river basin, the effects of climate change on nitrate leaching into waterways were modeled, showing a 25% increase. Alternative action measures were then analyzed to reduce nutrient loads in a cost-effective way while adapting to climate change impacts. For the other river basin, a novel bioenergy concept using food waste and manure for biogas production was evaluated, finding it could significantly reduce greenhouse gas emissions and nutrient loads to waterways. The thesis demonstrates how addressing targeting, synergies and costs can help meet Water Framework Directive objectives