Chapter 15 - Human Impacts on River Dynamics

Summary

This chapter examines how rivers respond to human impacts. It introduces the concept of the Anthropocene, the notion that society has produced a new geologic epoch dominated by human change of the environment, as the context for discussion. A distinction is made between indirect impacts on rivers, which involve changes in land cover or climate, and direct impacts, which involve human modification of river channels. Cycles of erosion and deposition within river systems are discussed in relation to land clearing, implementation of agriculture, different stages of urbanization, and hydraulic mining. The potential impacts of climate change on rivers are also explored. Direct impacts on rivers include channelization, construction of dams, and in-channel mining. The ways in which direct and indirect human impacts on rivers lead to transient geomorphological responses are explored through the concepts of the channel evolution model and aggradational-degradational episodes.