Why is it more effective to manage an entire watershed as compared to a single water source?

Managing an entire watershed allows for a holistic approach that considers interconnected water sources, land use practices, and ecosystem health, leading to better water quality and quantity management. By addressing issues at the watershed level, it helps prevent pollution and degradation of water sources upstream, benefiting downstream communities and ecosystems. Additionally, watershed management can enhance overall resilience to factors like climate change and extreme weather events.