A watershed is a good example of how the living and nonliving things within anecosystem depend upon each other. Altering a watershed will affect all the living things within that watershed. People can alter a watershed by paving over land and constructing buildings. This will affect how water flows over the land and may cause harmful materials to flow directly into the water. This will have an effect on the organisms that depend on the water for survival. For example, some fish feed on organisms in the water. Polluted water may cause these organisms to die, leaving the fish with no food. This is why we must understand these relationships and protect our water resources. You share your watershed with all other living things within the ecosystem.