The Department of Water and Sanitation's water quality guidelines for aquatic ecosystems, published as Volume 7 of the South African Water Quality Guidelines series. Establishes Target Water Quality Ranges (TWQRs) for physical, chemical, and biological parameters critical to freshwater ecosystem health. Covers toxic constituents (heavy metals, pesticides, phenols), system variables (dissolved oxygen, pH, temperature, turbidity, TDS), and non-toxic inorganic constituents (nutrients, salinity indicators). Provides both Chronic Effect Values (CEVs) and Acute Effect Values (AEVs) for key parameters. Includes guidance on site-specific application, natural background concentrations, and interpretation of water quality data in the context of ecological condition. Directly supports the water quality driver component of the EcoClassification system and Resource Quality Objectives under the National Water Act.