HOPEWELL -- The James River just got a checkup, and the patient looked pretty healthy.

Thank the drought.

"For water quality, yeah, it's good," said Chuck Frederickson, as he ran a series of water tests Friday aboard his boat just upriver from Hopewell.

With little rain to wash fertilizers and other pollution into the river, the James now is generally clearer and richer in oxygen than normal, Frederickson said.

"The question now is: How do we keep the water quality up at these levels when it does rain?"

Frederickson is the James' riverkeeper -- part scientist, part educator. He works for the James River Association, an environmental group.

On Wednesday through Friday, Frederickson and volunteers conducted a three-day checkup of the James. Frederickson performed tests for such measures of river health as clarity, dissolved oxygen, temperature and chlorophyll, which indicates the presence of algae.

By truck and by boat, he checked nearly 200 miles of the 340-mile river, from rural Bent Creek near Lynchburg to industrialized Newport News.

Frederickson worked Friday from just above the Osborne Landing in eastern Henrico County to a spot near the Herring Creek in Charles City County.

Near the landing, after performing various tests using electronic sensors, Frederickson dropped into the river a black-and-white disk that gauges clarity. When it disappears, you measure the distance to the surface.

"This is my favorite tool," he said. "It's low-tech."

The water was clear for about 3 feet, about twice the average for that spot during the wet summer of 2003.

Clear water allows sunlight to penetrate deeper, fostering the growth of river grasses that fish need to hide in.

In the James above Richmond, Frederickson found spots where the river was clear for 6 to 7 feet. He also found some new grasses growing, a great sign for the James.

Natural waters are complicated, however, and in some ways the drought has hurt the James.

Aboard Frederickson's boat Friday were Virginia Commonwealth University biologist Paul Bukaveckas and graduate students Brent Lederer and Matt Beckwith.

They are studying the relationship of nutrients such as nitrogen to troublesome algae. The nutrients, from sewage-treatment plants and other sources, nourish the algae.

At Hopewell, the James becomes wider and shallower. That allows more light to get to the algae, helping them grow. That's bad because the algae take oxygen from the river when they die.

Dry weather means a lower flow of fresh water that would flush out the nutrients. For that reason, there has been considerable algae growth around Hopewell.

"The river did become more clear during the summer," Bukaveckas said, "but it was not as clear as it should have been, because of the algae."

The algae growth around Hopewell did not create much of a stir because it was not as visible -- in part because of the type of algae -- as some well-publicized outbreaks this summer in streams near the coast.

As Frederickson, Bukaveckas and the students worked the James, the river looked its best. A bald eagle flew by, and egrets stood like delicate white statues in the shallows. A VCU scientist in another boat showed off the remains of a sturgeon, killed by a boat, that was at least 9 feet long.

The James is coming back from years of abuse, but more needs be done, particularly to fight pollution that washes in during rains, Frederickson said.

A few minutes later, a light rain began to fall.

Contact Rex Springston at (804) 649-6453 or rspringston@timesdispatch.com