Stream quality is determined through a combination of physical, chemical, and biological assessments. Physical assessments evaluate stream characteristics like flow rate, temperature, and sedimentation. Chemical assessments involve testing water samples for various parameters such as pH, dissolved oxygen, and nutrient levels. Biological assessments focus on the presence and abundance of aquatic organisms, including invertebrates and fish, which indicate the health of the stream ecosystem. These assessments are used collectively to gauge stream health and identify potential pollution sources or other environmental concerns.«Morphometry and sediment dynamics of the churiya river area, siwalik range in nepal»