Final answer:
Surface water is owned publicly by state governments, who regulate its use to serve various public and environmental needs and prevent the tragedy of the commons. Watersheds are critical as they funnel precipitation into these surface water bodies that make up our community water systems.
Step-by-step explanation:
Surface water is publicly owned by the state government, and its usage is regulated based on its value for various uses such as public water supply, protection of fish, and wildlife, recreation, agriculture, industry, and navigation. Authorities are responsible for determining if a water body is suitable for these uses, considering factors including physical, chemical, and biological characteristics, geographical setting, scenic qualities, and economic considerations. This falls under the concept of public goods or common goods, which may necessitate government regulation to avoid the tragedy of the commons, where individuals deplete resources due to lack of ownership. Community water systems, serving many people, often rely on surface water from watersheds that collect precipitation and channel it into rivers, lakes, or reservoirs.