The US Environmental Protection Agency’s (EPA) Office of Water has made available for comment a review draft of the National Water Program Strategy: Response to Climate Change. The draft document represents the National Water Program’s initial effort to identify potential impacts of climate change for clean water and drinking water programs and define actions to respond to these impacts, which may include: increases in certain water pollution problems; changes to availability of drinking water supplies; and significant collective impacts on coastal areas.
The draft strategy proposes 46 specific actions that the National Water Program will take to respond to climate change in areas including adaptation, research, mitigation, and education. Only those actions that can be initiated in FY 2008 or 2009 with an assumption of level funding are included in the draft Strategy.
The National Water Program is a cooperative effort by Federal, State, Tribal, and local governments to implement core laws, including the Safe Drinking Water Act and the Clean Water Act, intended to protect and to improve the quality of the Nation’s waters.
Some of the primary effects of climate change for water resources include:
Air and water temperature increases. Warmer air temperatures are expected to have several impacts on water resources including diminishing snow pack and increasing evaporation, which affects the seasonal availability of water. A key impact of warmer air temperatures is warmer water temperatures. Some impacts of warmer water temperatures are shifts in aquatic species distribution and population; reduced oxygen levels; increased concentrations of come pollutants; and promotion of algal blooms and increased bacteria and fungi content.
Changes in Levels and Distribution of Rainfall and Snowfall. Changing precipitation patterns are expected to have several impacts on water resources including: more pollution and sedimentation due to runoff; increased urban flood risks creating additional design challenges and costs for stormwater management; affects on water quality; and increases or decreases of net water supplies.
Storm Intensity Increases. The primary impacts of increasing storm intensity on water resources is coastal and inland flooding, complicated in the case of coastal storms by storm surges. Many of these impacts will vary regionally and can be influenced by other factors such as the level of development in the watershed.
Sea Level Rise. The primary impact of sea level rise on water resources is the gradual inundation of natural systems and human infrastructure in coastal and estuarine areas. Inundation impacts include: wetland displacement; accelerated coastal erosion; changes in water quality; and sea level rise increases the vulnerability of coastal areas to flooding during storms.
Impacts of sea level rise other than inundation include: rising sea level increases the salinity of both surface water and ground water through salt water intrusion; if sea level rise pushes salty water upstream, then the existing water intakes might draw on salty water during dry periods; and salinity increases in estuaries can harm aquatic plants and animals that do not tolerate high salinity.
Changes in Coastal/Ocean Characteristics. Changes in ocean characteristics are expected to have several impacts on coastal and ocean resources including: the inhibition or slowing of the biological production of corals, as well as calcifying photoplankton and zooplankton within the water column; ocean acidification and its affects on corals, pelagic ecosystems and the marine food web; salinity increases in estuaries.
The document notes that likely responses to climate change include development of alternative methods of energy production that reduce emissions of greenhouse gases and sequester carbon generated by energy production. These too can have impacts on water resources. Suggested impacts on water resources from changes in energy generation or carbon sequestration include:
Thermoelectric power plants that generate electricity using fossil or nuclear power require significant amounts of water, and will be vulnerable to fluctuations in water supply.
Deep ocean sequestration might harm marine organisms, and requires studies on the response of biological system in the deep sea to added CO2.
Sequestration of carbon in “biological” forms, (i.e., preserving forests, no-till agriculture and related land management practices) may have water quality benefits by encouraging practices that reduce the amount of stormwater runoff and the pollution levels in the runoff. While land restoration will have positive environmental impacts, conversion of floodplains and wetlands to agriculture could hamper ecological function (reduced water recharge, bioremediation, nutrient cycling, etc.
Demand for biofuels is also likely to have impacts on water including increasing land in agricultural production, resulting in increased risk of runoff of sediments, nutrients, and pesticides. Production of biofuels also uses significant amounts of water.
The report outlines five general goals for the National Water Program response to climate change impacts on water resources:
Goal 1: Water Program Mitigation of Greenhouse Gases: use water programs to contribute to greenhouse gas mitigation;
Goal 2: Water Program Adaptation to Climate Change: adapt implementation of core water programs to maintain and improve program effectiveness in the context of a changing climate;
Goal 3: Climate Change Research Related to Water: strengthen the link between EPA water programs and climate change research;
Goal 4: Water Program Education on Climate Change: educate water program professionals and stakeholders on climate change impacts on water resources and programs; and
Goal 5: Water Program Management of Climate Change: establish the management capability within the National Water Program to engage climate change challenges on a sustained basis.
National Water Program Strategy: Response to Climate Change (Review Draft, March 2008)