Colorado River

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At the beginning of the 18th century, more than 110 million tons of sediment was transported by the Colorado River every year all the way to the Gulf of California (National Parks Conservation Association, 2011). The river was very unpredictable because of the constant flooding and the constant running dry. Because of the flooding, it transported huge amounts of sediment down river that created marshlands, deltas, and lagoons with very diverse wildlife habitats. Even when the flooding didn’t occur, large amounts of sediment were transported along the river because the currents were so strong. After the dam construction, the floods that were so unpredictable, were captured and stored within the lakes that were created, and water was dispensed as needed for irrigation to farms. Even during the summer months and the driest of droughts, there was water available to be transported or dispensed to the cities and to the farms for irrigation. The normally natural flowing sediment, which consisted of silt, mud, and sand, now has nowhere to go and will either pile up at the dams or settles within the center of the lakes that have been created. Sediment absorbs the chemical compounds and nutrients in the water and if the sediment gets trapped behind the dams then many of the nutrients carried within the sediment will get trapped too. Those chemical and nutrients are “important for the growth of phytoplankton, important photosynthesizing organisms and key components of the aquatic food chain” (National Parks Conservation Association, 2011). The constant movement of rocks and sediment can reduce the diversity of insects and other small organisms. Certain surfaces can provide attachment sites for periphytom and algal filaments which are a source of food for some species (Osmundson et al, 2002). These surfaces can also provide areas for fish to lay their eggs and help keep them safe until they hatch. They can also provide safe areas for fish to hide from their predators. By changing the flow of water in the river the nonnative fish have thrived.

It has been noted by Mark R. Vinson (2001) that attempts in restoring native species that are implemented long after the constructions of dams generally are not effective because any new communities of species may have a considerably better tolerance to the new operation. The Bonytail chub, Razorback Sucker, Colorado Pikeminnow, and the Humpback Chub are the four species that are currently at the most risk of becoming endangered. In the lower Colorado River regions many efforts have been made to restore some of the natural habitats. Many have campaigned to allow more water to flow farther down the river and they have also planted many endangered mesquite trees. Unfortunately, their efforts may have come a little too late because it doesn’t seem to be working and their voices doesn’t seem to be heard.

The damming of the Colorado River has been for the greater good of humans, but unfortunately Mother Nature is the one that is paying the price. The river is now under the control of man to provide water and hydroelectricity to humans. The ecosystem of the river has been altered by humans and these disruptions have resulted in some species becoming endangered and extinct. There is one positive aspect of the many dams that have been built and that is the clean production of energy that provides electricity, hydroelectric power.

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References

National Parks Conservation Association (2011). National parks of the colorado river basin: water management, resource threats, and economics. Retrieved June 18, 2012, from http://www.npca.org/about-us/center-for-park-research/colorado_river_basin/Colorado-River-Report.pdf

Cunningham, W. P., Cunningham, M. A., (2009). Principles of environmental science: inquiry and applications (5th ed.). Boston: McGraw-Hill.

Kaufman, R.K., Cleveland, C.J. (2008). Environmental science. New York, NY: McGraw-Hill Companies.

Minckley, W.L., Marsh, P., Deacon, J.E., Dowling, T.E., Hedrick, P.W., Matthews, W.J., Mueller, G., (2003). A conservation plan for native fishes of the lower colorado river. BioScience, Vol. 53, No.3. Retrieved June 5, 2012 from http://www.jstor.org/stable/10.1641/0006-3568%282003%29053%5B0219%3AACPFNF%5D2.0.CO%3B2

Mueller, G.A., Marsh, P.C., (2002). Lost, a desert river and its native fishes: a historical perspective of the lower colorado river. USGS/BRD/ITR—2002-0010

Osmundson, D.B., Ryel, R.J., Lamarra, V.L., Pitlick, J., (2002). Flow-sediment-biota relations: implications for river regulation effects on native fish abundance. Ecological applications, Vol. 12, No. 6. Retrieved June 5, 2012 from http://www.jstor.org/stable/3099934

Vinson, M.R., (2001). Long-term dynamics of an invertebrate assemblage downstream from a large dam. Ecological Applications, Vol. 11, No.36. Retrieved June 5, 2012 from http://www.jstor.org/stable/3061112