This course teaches students to develop, apply, and critically evaluate surface water quality models, focusing on the response of natural and engineered aquatic systems to pollutants and environmental factors. Students will first learn to model generic substances in various aquatic settings (e.g., rivers, lakes) with processes like reaction, settling, diffusion, dispersion, volatilisation, and advection. Next, the course will cover the complex dynamics of specific water quality constituents commonly managed, such as dissolved oxygen, nutrients, temperature, and algae. Students will use the STELLA Systems Modelling software to simulate water quality processes and gain an understanding of water quality parameters, chemical and biological transformations, mathematical modelling, and computational simulation. By the end of the course, students will be equipped with modelling skills essential for assessing water quality impacts and solving real-world environmental engineering challenges.