We have passed the halfway point in our weekly examination of the 14 top science questions that President Barack Obama and Governor Mitt Romney need to address as part of their quests to lead the United States for the next four years. Question #8 tackles increasing concerns about the health of the U.S. freshwater supply.

Scientific American is partnering in this election-year project with ScienceDebate.org, which developed the questions and has gotten the candidates to supply written answers. SA's editors will be grading the responses for our November issue (available mid-October). As you go through the answers below, you'll see why a live debate on science issues--in which followup questions can be asked--makes a lot of sense. (Are you listening, Governor Romney and President Obama?)

First some background: The major users of water in the U.S. are agriculture and thermoelectric power generation, followed by the general public.

Addressing water issues strategically is made more complicated by the fact that different parts of the country have different problems with fresh water (on the surface, in the ground and in the sky). The Southwest, for example, is struggling with continuing drought and heat waves while the general trend in the Northeast over the past few years has been too much water--in the form of tropical storm-like deluges.

The Water Wars that have pitted communities all along the Colorado River and other parts of the West against each other throughout the past 100 years are projected to get much, much worse--despite recent notable declines in demand in some areas. The rate at which water is being withdrawn from the ground is outstripping the natural replacement rate.

The U.S Geological Survey and the federal government's Global Change Research Program produce regular, reliable reports detailing the issues and their impact here and here.

Against this backdrop and the growing urgency of the freshwater problems in the U.S. and a wealth of scientific data documenting the problem, there has been fairly little news coverage in the presidential election of the need for major changes in how we as a country use our natural water resources. How do communities negotiate their conflicting needs? How do they identify and implement programs that will benefit everyone by reducing the stress on oversubscribed water supplies? How does all of this get paid for?

With its question on fresh water, ScienceDebate is trying to get voters to pay more attention to the issue. So, without further ado, here is the question and President Obama and Governor Romney's answers.

8. Fresh Water. Less than one percent of the world’s water is liquid fresh water, and scientific studies suggest that a majority of U.S. and global fresh water is now at risk because of increasing consumption, evaporation and pollution. What steps, if any, should the federal government take to secure clean, abundant fresh water for all Americans?

Barack Obama:

I am working to ensure the integrity of the water Americans rely on every day for drinking, swimming and fishing, and that support farming, recreation, tourism and economic growth. My Administration released a national clean water framework aimed at developing a comprehensive approach to protecting the health of America’s waters. Through partnerships with communities around the country, we are working to improve water quality, restore rivers and critical watersheds, and we are making headway in ensuring that our nation’s waters best serve its people.

To help with water scarcity concerns in the West and elsewhere, I am supporting water conservation programs. My administration has awarded 92 grants to water conservation projects that will save enough water for an estimated 950,000 people. We are also working collaboratively with communities around the country on how to best manage freshwater resources in a changing climate, in order to ensure adequate water supplies and protect water quality.

Having clean water isn’t enough if people don’t have access to it, which is why we are also working to improve access to clean water for rural American’s and border counties. Already, my administration has invested in 5,100 water and waste water community infrastructure projects to safeguard the health of 18 million rural residents and support 135,000 jobs. This past summer, we also streamlined the process to improve water quality along the US-Mexico border that previously didn’t have the right water facilities to ensure clean water.

By working together, we can continue to build on these achievements and find more efficient ways to use the water available, conserve where we can, protect jobs, and secure safe drinking water for all Americans today and for years to come.

Mitt Romney:

America has made extraordinary environmental progress in recent decades thanks to the laws that protect our air and water. But while these laws have served us well, they have not been modernized in over twenty years and are now significantly out of date. Our communities and businesses must contend with excessively costly and inflexible approaches that impose unnecessary economic constraints and trigger inevitable litigation. The result is to delay progress that could be achieved, and to leave communities and natural resources worse instead of better off.

I will modernize the federal laws and regulations governing water use to enable smarter, more collaborative, more flexible, and more cost-effective approaches that welcome state and local participation as partners and leaders. A combination of incentives, market-based programs, and cooperative conservation measures will improve the water quality of our lakes, rivers, streams and coastal environments. Through a renewed focus on research and technology in both the private and public sectors, America can meet the growing challenge of maintaining and improving the nation's drinking water and sanitation infrastructure.

Click to see the answers to all 14 science questions from Gov. Mitt Romney and President Barack Obama.

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