Water Resources Engineering (WRE) connects engineering hydrology and hydraulics with global, economic, environmental, and societal issues. Our student Catherine Sobchuk makes the connection between WRE and economic and environmental issues here… On January 24th, 2013, Brandon Loomis of The Arizona Republic reported the news entitled, “Grand Canyon flood experiment restores beaches on the USA Today online news site. The news relates to the WRE domain of hydrology, specifically the effects of artificial flooding of the Grand Canyon by Glen Canyon Dam. In brief, this article reports on the efforts and effects of replenishing the sand bars along the Colorado River that have eroded since the dam’s completion. The river washes sediment away to Lake Mead, and upstream sediment is unavailable to replace it because it is blocked by the Glen Canyon Dam. The flooding of the dam allows the blocked sediment to flow along the river and churns up additional sand from the bottom of the river, replenishing the eroded sand bars. The experimental flooding is executed by the U.S. Bureau of Reclamation and monitored throughout the year by the Grand Canyon Monitoring and Research Center (GCMRC). Some conservationists believe the flooding of the dam is not doing enough for the sand bars, and that alternative actions should be taken to transport sediment down the river. These options include breaching the dam, transporting sediment around it, or giving up altogether. The results from this flood will not be fully known until later in the year, but so far the targeted sand bars have grown, while others have not grown as much. The article goes in depth about the benefits the sand bars have to the environment, the potential economic effects, but does not discuss the testing or monitoring techniques. The GCMRC would need to monitor how the sand bars grow and erode and how the habit around the sand bars change. This article intended to focus on the effects of the experimental flooding, but it would have benefited from describing how the sand bars would be monitored.

 

WRE is an interdisciplinary field that involves the management of hydrologic and hydraulic systems to reduce negative impacts and maximize positive impacts. The flooding of the Colorado River at the Glen Canyon Dam would have beneficial impacts on the environment in the river system, but the flooding and its alternatives also have negative economic impacts on the surrounding community. The flooding is meant to provide “young endangered humpback chubs a shelter from the river…a windborne source of cover for uphill archaeological sites and a purchase for vegetation.” This would increase the fish numbers and diversity and promote the growth of a variety of vegetation along the sand bars, potentially returning the river to pre-dam conditions. However, when the dam is bypassed, the Colorado River Energy Distributors Association reported about $1.4 million in power generation was lost, a serious economic cost. There is also the economic cost of more than $100 million if the alternative pipeline is built to transport sediment around the dam. To determine if the environmental benefits outweigh the economic costs, a cost-benefit will have to be conducted. The environmental benefits can be measured by determining how much money people would be willing to pay to visit the site if it was back to pre-dam conditions and by determining the price of any other environmental benefits. This is then compared to the costs of breaching the dam or building a pipeline to complete the analysis. After all of the results are collected and analyzed, the GCMRC will be able to determine if the experimental flooding has the intended effects and therefore, if it should be continued.

Figure 1: The Colorado River is flooded November 19, 2012 from bypass tubes at Glen Canyon Dam in Page, Arizona.

Figure 1: The Colorado River is flooded November 19, 2012 from bypass tubes at Glen Canyon Dam in Page, Arizona.

 

References

Loomis, Brandon. “Grand Canyon flood experiment restores beaches.” USA Today. Gannett, 2013. Web. 15 Apr. 2013. <http://www.usatoday.com/story/news/nation/2013/01/24/ grand-canyon-flood-experiment-restores-beaches-habitat/1863483/>.

 

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