Summary and Final Tasks

Summary

Watersheds are basic organizational units that comprise a landscape, ranging in size from a tiny area that drains to a pond or an enormous area, such as the Amazon River Basin. Earth's surface is characterized by an incredible diversity of watersheds, and while most contain some representation of each of the various pathways of the water cycle illustrated in figure 3, the most prominent pathways vary from landscape to landscape. Most watersheds larger than 1 km2 form a stream channel that drains surface water, with larger watersheds containing entire networks of hierarchically-organized channels. These channel networks are incredibly important ecosystems, providing connectivity in terms of routing water, nutrients and sediment and providing habitat for a wide array of organisms. It is no wonder that early and modern human societies have developed in such close proximity to streams and rivers. But as we saw in this module and will continue to explore in the next module, these ecosystems exhibit immense variability, at times providing insufficient amounts of water and at other times providing far too much! As a result, humans have a long history of developing means to control rivers and streams, which has had both positive and negative impacts. Better understanding these impacts is paramount to building a better, more sustainable future.

Reminder - Complete all of the Module 3 tasks!

You have reached the end of Module 3! Double-check the to-do list on the Module 3 Roadmap to make sure you have completed all of the activities listed there before moving on to Module 4!

References and Further Reading

Brierley, G. and Fryirs, K.A. (2005) Geomorphology and River Management: Applications of the River Styles Framework. Blackwell Publishing Company.

Horton, R. E. (1945). Erosional development of streams and their drainage basins; hydrophysical approach to quantitative morphology. Geological society of America bulletin, 56(3), 275-370.

Leopold, L. B., & Wolman, M. G. (1960). River meanders. Geological Society of America Bulletin, 71(6), 769-793.

Montgomery, D. R., & Buffington, J. M. (1997). Channel-reach morphology in mountain drainage basins. Geological Society of America Bulletin, 109(5), 596-611.

Schottler, S. P., Ulrich, J., Belmont, P., Moore, R., Lauer, J., Engstrom, D. R., & Almendinger, J. E. (2014). Twentieth century agricultural drainage creates more erosive rivers. Hydrological Processes, 28(4), 1951-1961.

Strahler, A. N. (1957). Quantitative analysis of watershed geomorphology. Civ. Eng, 101, 1258-1262.