What is the primary purpose of using a water quality model like QUAL2K in an EIA for wastewater discharge?

The primary purpose of using a water quality model like QUAL2K in an EIA for wastewater discharge is to predict the impact of the discharge on the receiving water body's water quality. QUAL2K is a river and stream water quality model that simulates the transport and fate of pollutants. By inputting data on the characteristics of the wastewater discharge (e.g., flow rate, pollutant concentrations) and the physical, chemical, and biological characteristics of the receiving water body (e.g., flow rate, temperature, nutrient levels), the model can predict how the discharge will affect water quality parameters such as dissolved oxygen, nutrient concentrations, and pollutant levels downstream. This allows environmental professionals to assess whether the discharge will cause violations of water quality standards or harm aquatic life. For example, the model can predict how the discharge of treated sewage into a river will affect dissolved oxygen levels, which are essential for fish survival. The results of the modeling are used to inform decisions about wastewater treatment requirements, discharge limits, and mitigation measures to protect water quality.