Here's a question: If you had to fill a small bottle with water from the Potomac River, where would you go? What would you do?

This was the challenge put to guests invited to a gala hosted by the Potomac Conservancy, a local environmental group. As reported in the Washington Post, the guests had to bring their water to the event and tell how they got it.

At the dinner, the awful truth came out: One busy businessman sent his housekeeper; another commissioned his teenaged daughter so he wouldn't risk soiling his suit. And so it went, one sheepish story after the other.

As a river geek, getting a bottle of river water for me is no more challenging than ordering a cup of coffee at Starbucks. But that's me. It may be different for you.

Does it really matter?

According to Bill Dennision, it matters a lot.

"We need more people who know about nature firsthand," he said at a recent meeting of the National Capital Section of the American Water Resources Association at the Rockville headquarters of the Interstate Commission on the Potomac River Basin. 

Lanky, lean and bearded, Dennison had the look of someone who can dunk a bottle in the Potomac without missing a beat. Although a scientist himself, working out of University of Maryland's Center for Environmental Science, he believes that a big part of his job is to encourage what he calls "citizen scientists." To this end, he created a website on the Chesapeake Bay and its tributaries with a wealth of colorful visuals and environmental updates.  

Knowledge about nature gives people the power to protect it, Dennison said.

"People acting on their own can solve problems without government and without laws," he said.

Their power comes by combining what they learn at the water's edge with their knowledge of local developers, farmers, or even neighbors, who might need a little neighborly coaxing to do the right thing.

A week later, at the World Wildlife Federation, I heard Dennison's views reaffirmed by no less than the 2009 winner of the Nobel Prize in economics.

In her talk, Elinor Ostrom, of Indiana University, insisted that ordinary people working on their own can protect common pool resources, such as forests and streams that belong to the community as a whole. Given the right conditions, people will "self-organize" for the common good, she said.

Based on decades of detailed studies, mostly in poor countries, Ostrom's work refutes the conventional view that people are hopelessly greedy, taking what they can get from nature, wherever they can get it, until nothing remains.

Modest in words and dress, Ostrom believes the power of the ordinary person, no matter if they are desperately poor, isolated from governmental authority and lacking scientific information of any kind.

So what do the successes and failures of farmers in Nepal and fishermen in Baja California have to do with our own Potomac River and the privileged communities along its shores?

After her talk, Ostrom gave me her answer: Despite all our layers of government, our laws and regulations, our scientific data and our many conservation groups, we still need that essential ingredient — the power of the people.  

"People who use the river are the most effective force for protecting it," she said.

It's both people's own knowledge of the river and — as she has found in her studies — their knowledge of how others are using it, both good and bad. It's a little like a neighborhood watch.

So grab a bottle and find some special place along the shore to fill it up. It's kind of like shaking hands with a new friend.