Emerging Climate Change Impacts on Freshwater Resources: A Perspective on Transformed Watersheds


June 16, 2009


Alan Covich



Reading time

2 minutes

As climate change occurs, the prospect of more intense flooding and drought—and a coincident decline in the quality of water in lakes, rivers, and estuaries—demands that states and communities prepare for the inevitable disruptions in adequate supplies of freshwater, according to an RFF analysis on the topic.

The RFF Report, “Emerging Climate Change Impacts on Freshwater Resources: A Perspective on Transformed Watersheds,” by Alan P. Covich of the University of Georgia, notes that “cascades of interconnected and cumulative impacts will alter regional hydrology and ecosystem capacities to supply reliable sources of high-quality freshwater.”

Covich examines six case studies in which regional planners have implemented adaptation policies to deal with a variety of freshwater contingencies. The areas studied include the Colorado River watershed, the Boston Metropolitan Region, New York City, the Flint River in Georgia, Everglades restoration in Florida, and the San Joaquin River in southern California.

“The main effects on freshwater resources are likely to consist of greatly increased uncertainty in maintaining sufficient local and regional supplies of high-quality water to meet demands for municipal, industrial, and agricultural needs,” Covich writes, “while also sustaining natural ecosystem services.”

The report is one in a series issued as part of a major RFF project on domestic adaptation policy.

Excerpts from the report:

  • “Evidence suggests that the volumes of water stored in lakes and rivers are declining because of decreases in long‐term average precipitation and runoff as well as increased rates of evaporation.”
  • “Various types of climatic impacts will have distinct differences in the associated public health risks that can increase the costs of dealing with either very high or very low flows. These extreme flows also affect biodiversity and sustainability of essential ecosystem services.”
  • “Many communities have a high capacity to adapt to climate changes by minimizing their economic losses resulting from extreme events and long‐term trends. The ways in which they decide to supplement their water supplies during droughts and to store water during floods can be informed by a step‐wise, integrative adaptive process similar to other types of adaptive management.”
  • “It has been clear for decades that the social complexities of the responses by individuals and communities increase with scarcity, but long‐term planning and governmental agreements are required for interbasin transfers and these negotiations often take detailed discussions of options. The needs for regional sharing of water will probably increase as different locations experience high variability in precipitation. The adaptive capacity to transfer surplus water from one watershed to another (i.e., to one that lacks water in any given year) will probably increase if the political and economic complexities can be resolved.”


Alan Covich

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