Anglers opt for travel when water looks fishy.

• Position: Interview with Daniel Phaneuf - Brief Article - Statistical Data Included

Sparkling trout steams and clear lakes are the raw materials of North Carolina's $17.4 billion-a-year travel-and-tourism industry and recreational spending by residents. Daniel Phaneuf, assistant professor of agricultural and resource economics at N. C. State University, studied their economic value.

BNC: How vital is clean water?

Phaneuf: Recreational fisheries in North Carolina generate about $1 billion a year, and this study shows people will drive to sites where they expect better quality water. If we have debris washing up on the beach or decreased catch rates in a lake or river, people don't go there.

What was behind your study?

The N.C. Water Resources Research Institute, located here on campus, sponsored it. In economics, we talk about market goods, like a loaf of bread, and non market goods, things we care about and that have a cost but that the market does not provide. We can't go to a store and buy a fishing trip. Obviously, water quality is a nonmarket good, but the debate usually focuses on the cost side. My study looks at what recreational users are willing to pay for water quality. That's the benefits side.

You use an economic model you call "travel cost." What's that?

The study looks at the 58 watersheds in North Carolina and EPA standards for phosphorus, ammonia and dissolved oxygen. Then it looks at where people go on 14.7 million annual fishing trips in the state. It assumes that if all things were equal, you'd drive the shortest distance with the smallest cost. But all things aren't equal, so you bypass a place close to home to reach one with better characteristics. We were able to show people were willing to pay extra to travel to watersheds with higher quality and that they avoid those with lower quality.

What were the extremes?

By way of example, from 1990 through 1997, the lower Catawba watershed containing Charlotte had 55% of its phosphorous readings in excess of the EPA criteria. The upper French Broad watershed, containing Asheville, had 24% of its readings in excess.

So, how much is clean water worth?

Qualitatively, we could make a list that would include such things as health, aesthetics and even the bequest motive, which is how much we value saving clean water for later. But this study was limited to the recreation side and the value of water-quality improvement to recreation uses, including boating, fishing, swimming and viewing. The numbers I came up with show reduced phosphorus levels are worth $2.87 extra...