Global Climate Change Could Impact U.S. Water Supply

The Pew Center on Global Climate Change says climate change is likely to impact both the availability and quality of the U.S. water supply.

A Pew study, ?Water Resources and Global Climate Change,? concludes that as climate change alters precipitation, evapotranspiration and runoff in the U.S., these changes are likely to affect the magnitude, frequency, and costs of extreme weather events, as well as water supply.

Eileen Claussen, executive director of the center, said, ?Recent floods and droughts have reminded everyone that the climate and our nation?s water supply are inextricably linked.

?This study shows that as the climate changes, so will its impact on our water supply.?

The paper said while some specifics are difficult to predict, several consistent impacts can be identified. For example, in mountainous watersheds, higher temperatures will increase the ratio of rain to snow, accelerate the rate of spring snowmelt, and shorten the overall snowfall season, leading to more rapid, earlier, and greater spring runoff.

In arid regions, there is likely to be greater flux in the water supply, while higher temperatures fuel an increased demand for water. In other areas, new instances of flooding and droughts also will impact the availability of water.

?An adequate and safe water supply is an essential component to our health, environment, communities and economy. These new findings demonstrate that climate change will not only impact the quantity of our water supply, but the quality as well,? Claussen said.

The paper said that while higher water flows could improve water quality in some streams, the increased runoff of pollutants and saltwater intrusion could accompany a climate change induced sea-level rise.

The study notes steps can be taken to prepare for water supply changes. It said in addition to reviewing options for adapting and expanding the existing infrastructure, including reservoirs and dams, there are opportunities to develop water marketing and trading strategies and improve the management of water systems.

Claussen said that although steps can be taken to prepare U.S. water supplies for climate change, the key action would be to reduce the greenhouse gas emissions that cause climate change.

Great Lakes

Environmental Protection Agency Administrator Carol Browner has proposed to restrict direct discharges of the most toxic chemicals into the Great Lakes.

Great Lakes

The chemicals, known as ?bioaccumulative chemicals of concern? (BCCs), include mercury, polychlorinated biphenyls or PCBs, dioxin, chlordane, DDT and mirex.

Great Lakes

Browner proposed to phase-out the discharges of BCCs into ?mixing zones? ?areas of the lakes where discharges of toxic chemicals are allowed to mix with receiving waters and dilute.

Great Lakes

The EPA proposal would ban new discharges of BCCs into mixing zones in the Great Lakes Basin and would phase out the use of existing mixing zones for BCCs in the Great Lakes Basin over 10 years.

Great Lakes

The governors of Indiana, Michigan, Minnesota, and Wisconsin already have eliminated mixing zones for BCCs in the Great Lakes Basin.

Great Lakes

EPA said its action will ensure that mixing zones for BCCs in the Great Lakes Basin also are prohibited in the states of Illinois, New York, Ohio and Pennsylvania.

Great Lakes

?It is anticipated that the proposal would reduce mercury from direct water discharges, like outfall pipes, into the Great Lakes by up to 90 percent,? EPA said.

Great Lakes

Browner also said she is directing EPA staff to work closely with state and local government, industry, environmental and public health groups, and other partners to review the use of mixing zones for bioaccumulative toxic chemicals to determine if they should be phased out nationwide.

Great Lakes

In 1995, EPA and the Great Lakes states agreed to a comprehensive plan to restore the health of the Great Lakes. The Great Lakes Initiative includes criteria for states when setting water quality standards for 29 pollutants, including BCCs. The 1995 guidance prohibited the use of mixing zones for BCCs.

Great Lakes

The iron and steel industry challenged the plan in federal court, and in June 1997, the U.S. Court of Appeals in the District of Columbia upheld most of the guidance, but vacated the BCC mixing zone prohibition and remanded the provision to EPA for further consideration.

Great Lakes

EPA said its latest proposal reinstates that provision for environmental and public health reasons, based on evidence that BCCs presents a significant potential risk to human health, aquatic life and wildlife.

Baltimore Settlement

Federal and state officials have announced a proposed multi-million dollar settlement in a lawsuit against the city of Baltimore over water pollution violations at the Ashburton drinking water filtration plant and Patapsco sewage treatment plant.

Baltimore Settlement

The city agreed to improve operations at both plants, pay a $1 million fine, and conduct three special environmental projects costing an estimated $2.5 million.

Baltimore Settlement

The lawsuit, filed in December 1997, alleged the Ashburton plant chronically exceeded limits in its Clean Water Act permit for the discharge of chlorine, aluminum, and suspended solids.

Baltimore Settlement

It also alleged the Patapsco plant exceeded permit limits in several categories. It also alleged the city failed to properly report its discharges to state and federal authorities.

Baltimore Settlement

In settling the lawsuit, the city installed a new dechlorination system and removed solids from the Ashburton plant and replaced major parts of the Patapsco plant?s sewage treatment system.

Baltimore Settlement

The city also will build a $1.3 million facility to capture and treat stormwater runoff from a section of Anne Arundel County; will build a $600,000 pollution control facility at Gwynns Run; and spend $600,000 to dispose of debris and trash dumped into Gwynns Falls on the Patapsco River.

Enforcement Cases