Final answer:
Stream flow can be determined by factors such as topography, elevation, and prevailing winds. In the case of southwest stream flow, it is typically observed in regions where the prevailing winds are from the southwest.
Step-by-step explanation:
The direction of stream flow is usually determined by studying factors such as topography, elevation, and prevailing winds. In the case of southwest stream flow, it is typically observed in regions where the prevailing wind directions are from the southwest. This can be influenced by specific geographic features, such as mountain ranges or coastlines, which can affect the movement of air masses and the resulting wind patterns. For example, in India, the southwest summer monsoon brings moisture from the Arabian Sea to South Asia, resulting in southwest stream flow in some regions.
In the context of the specific question, without additional information or context, it is not possible to definitively determine why stream flow is stated as southwest. It would be important to consider the specific location and factors that influence stream flow in that particular area.