Water Resources Engineering (WRE) connects engineering hydrology and hydraulics with global, economic, environmental, and societal issues. Our student, Kalon Riehle, makes this connection here…

This post is based on the article “How to Set a River Free: Rethinking the Obsolete Dams Clogging America’s Rivers”, from Rapid Magazine, in the summer 2015 issue. This is an important issue within hydrology and hydraulics because dams provide significant services to society, including flood control, water reservoirs, and hydro-electric power. However they also have significant negative consequences, including blocking fish migration, de-watering river beds, limiting recreation opportunities, and preventing sediment transport. Additionally, the extended age of many dams means that many present safety hazards due to poor design and/or structural degradation. Thus “restoring some rivers reaches to free-flowing conditions may restore substantial environmental benefits, but at some economic cost” (Null et al., 2014, p. 121)

The article “How to Set a River Free” is targeted towards whitewater kayakers, who generally favor free-flowing rivers and dam removal. Therefore it largely focuses on how to overcome the financial and policy hurdles that impede dam removal. It presents 4 case studies from around the country, detailing the unique hurdles to removal, and how those hurdles were overcome. Thus, the article seems to undervalue all the services that dams provide, and only looks at the issue from the narrow stake-holder perspective of the whitewater kayaker. This is narrow perspective forgivable, given the targeted audience of the magazine. (However, it should be noted that in some instances dams provide a positive benefit to whitewater enthusiasts, in the form of scheduled, weekend releases of known flow-rates of water to facilitate recreation, particularly in the hot, dry summer months.)

From a decision making perspective, the article largely ignores the preceding, critical questions of “When should a dam be removed?”, and its corollary “When should a dam remain in place?”  When considering aging dams, policy makers must realize that “decisions concerning dam removal or retention are challenging because they involve tradeoffs, diverse stakeholders, and increasing public safety concerns” (Zheng et al., 2013, p. 65). The complex needs and desires of all stakeholders must be considered in the decision making process. And, since the needs of the various stakeholders will often conflict, methods of prioritization and mediation are absolutely necessary.

In summary, decisions regarding what to do with an aging, dangerous dam are multi-dimensional questions that include economic, environmental, and societal impacts for a diverse group of stakeholders. “Because dams may serve multiple purposes or their removal may have many types of impacts, dam risk management should consider a wide range of abandonment, repair, and removal options and their associated trade-offs” (Zheng, p. 65). While articles in pop literature may present the issues from the narrow perspective of their target readership, decision makers must seek to understand the potential effects on all stakeholder groups. Then they must synthesize these conflicting desires into a cohesive plan that prioritizes the most critical considerations while mitigating the negative impacts to all stakeholders to the maximum extent possible.

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Figure 1: Removal of the Pine Meadow Ranch Dam on Whychus Creek, Oregon (Schulman, 2015, p. 33)

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Figure 2: To Keep the Large Boundary Dam (above) in operation, owner Seattle City Light helped fund the removal of Mill Pond Dam on Sullivan Creek (Schulman, p. 34)

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Figure 3: Sullivan Creek after the removal of Mill Pond Dam ((Schulman, p. 35)

URL: http://www.rapidmedia.com/rp/rapidmag_earlysummer15/

 

Reference List

Null S, Medellín-Azuara J, Escriva-Bou A, Lent M, Lund J. Optimizing the dammed: Water supply losses and fish habitat gains from dam removal in California. Journal Of Environmental Management [serial online]. April 1, 2014;136:121-131. Available from: ScienceDirect, Ipswich, MA. Accessed January 21, 2016.

Schulman N. How to Set a River Free: Rethinking the Obsolete Dams Clogging America’s Rivers. Rapid Magazine. Summer 2015; 30-35.

Zheng P, Hobbs B. Multiobjective portfolio analysis of dam removals addressing dam safety, fish populations, and cost. Journal Of Water Resources Planning And Management [serial online]. 2013;(1):65. Available from: Academic OneFile, Ipswich, MA. Accessed January 21, 2016.

 

 

 

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