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New Guidance Available for Incorporating Climate Change Impacts to Inland Hydrology in Civil Works Studies, Designs, and Projects

Published May 29, 2014
HARTWELL, Ga. - Water rushes through 12 spillway gates at the U.S. Army
Corps of Engineers' Hartwell Dam in the early morning hours of July 9, 2013.
The Corps activated the spillway gates to release excess water after heavy
rainfall the night before caused the reservoir to reach its maximum flood
storage capacity of 665 feet per mean sea level. During peak discharge, the
Corps released 74,000 cubic feet per second (cfs) of water through the
Hartwell Dam. This amount includes 32,000 cfs passing through the five
turbines (for hydropower generation) and 42,000 cfs passing through 12
spillway gates. Other than routine spillway gate tests, it was the first
time the spillway gates had been opened at the Hartwell Dam since Aug. 18,
1994. The only other occasion was on March 8, 1964. Photo by Doug Young.

HARTWELL, Ga. - Water rushes through 12 spillway gates at the U.S. Army Corps of Engineers' Hartwell Dam in the early morning hours of July 9, 2013. The Corps activated the spillway gates to release excess water after heavy rainfall the night before caused the reservoir to reach its maximum flood storage capacity of 665 feet per mean sea level. During peak discharge, the Corps released 74,000 cubic feet per second (cfs) of water through the Hartwell Dam. This amount includes 32,000 cfs passing through the five turbines (for hydropower generation) and 42,000 cfs passing through 12 spillway gates. Other than routine spillway gate tests, it was the first time the spillway gates had been opened at the Hartwell Dam since Aug. 18, 1994. The only other occasion was on March 8, 1964. Photo by Doug Young.

ALEXANDRIA, VIRGINIA. The U.S. Army Corps of Engineers (USACE) has released new guidance on how to incorporate climate change information in hydrologic analyses in accordance with the USACE overarching climate change adaptation policy. USACE policy requires consideration of climate change in all current and future studies to reduce vulnerabilities and enhance the resilience of our water-resource infrastructure.
 
The Engineering and Construction Bulletin (ECB) 2014-10 (pdf, 195 KB),  issued 2 May 2014 and expiring 2 May 2016, outlines concepts and goals, provides guidance and provides an example to support incorporation of new science and engineering products and other relevant information about specific climate change and associated impacts in hydrologic analyses for new and existing USACE projects.

The bulletin establishes a procedure to perform a qualitative analysis of potential climate threats and impacts to USACE hydrology-related projects and operations. The method consists of a two phase process that first conducts an initial screening-level qualitative analysis to identify whether climate change is relevant to the project goals or design. If climate change is relevant to the project goals or designs, the second phase requires an evaluation of information gathered about impacts to the important hydrologic variables and the underlying physical processes such as changes in processes governing rainfall runoff or snowmelt. The information should be used to help identify opportunities to reduce potential vulnerabilities and increase resilience as a part of the project's authorized operations and also identify any caveats or particular issues associated with the data. The information gathered in the second phase can be included either in risk registers or separately in a manner consistent with risk characterization in planning and design studies, depending on the project phase.

The guidance applies to all Civil Works applies to all hydrologic analyses supporting planning and engineering decisions having an extended decision time frame, except for operational hydrologic studies for water management or to dam safety. Changes other than climate threats that affect inland hydrology will continue to be evaluated in the manner described in current USACE guidance.

The ECB was issued by Mr. James Dalton, Chief of the HQUSACE Engineering & Construction Community of Practice and was prepared under the direction of Mr. Jerry Webb, leader of the Hydrologic, Hydraulic & Coastal Engineering Community of Practice. The authors of the bulletin included Dr. David Raff (formerly of USACE IWR, now with the U.S. Bureau of Reclamation), and Dr. Kate White and Dr. Jeff Arnold of USACE IWR.