PITTSBORO — When Tom Colson spotted a great blue heron at Jordan Lake recently, he was first delighted, then horrified.

The bird was standing on a mat of trash so thick it couldn't fish.

Colson, a Raleigh environmental consultant and hobby wildlife photographer, investigated more closely and found an even worse situation. Near where the Haw River flows into the lake, a half dozen shallow coves resemble floating landfills, collecting debris washed down the river over the years.

Jordan Lake is popular with boaters, fishermen and swimmers. It's also a source of drinking water. Near the northern end of the lake, the towns of Cary and Apex draw water and pump it to residents' taps, and other communities such as Durham and Orange County may use it in the future. Although those communities have treatment plants that purify the water, the National Resources Defense Council cautions that good drinking water starts with lakes, streams and reservoirs that are protected from pollution.

Storm runoff is a main source of problems. At the south end of Jordan Lake, where the Haw enters, acres of tires, basketballs, plastic bottles, prescription bottles, quart oil containers, barrels and coolers float in a foul stew of human-generated refuse in backwater coves. More debris litters the banks.

"I got out of the boat and that's when I realized how extensive and massive the distribution is," said Colson, 35, who estimated there were 50 acres of trash. "I was completely dumfounded. It makes me think about what kind of society I live in where people casually toss trash out the window or let trash cans overflow."

Colson sent e-mail with photos to several government agencies asking if they knew about the trash. This summer, he took groups of people and government officials to see the trash, and he is recruiting volunteers for a cleanup day next month.

Craig Shoe, U.S. Army Corps of Engineers operations manager for B. Everett Jordan Lake, said the corps is aware of the trash but doesn't have the manpower to clean it up. The Haw River is the primary feeder of the lake; and whenever it rises, it washes in trash.

"When we get high flows, it just flushes trash and debris off the river banks into the lake," Shoe said. "The problem with trash and debris is not hidden from us at all. It's the manpower, time and expense."

That is where volunteers play a valuable role, Shoe said. At a cleanup day in March, for example, 43 volunteers removed 250 bags of garbage and more than 100 tires from the shoreline adjacent to the visitor's center near the dam.

The littered areas to be cleaned up in October are remote and more accessible by boat than land. Colson is seeking volunteers, including some with boats, to help ferry the trash to collection bins.

Fred Royal, director of environmental resources for Chatham County, said a visit to the litter-strewn lake banks was a wake-up call.

"We went to the area in boats several times and decided it was significant enough to warrant a cleanup," Royal said. "It's years of accumulated trash and debris, including tires."

A cleanup of one cove is planned on Oct. 18 near Robeson Boat Ramp. That will give organizers an idea how long it would take to clean up the entire area. Chatham County will provide a trash collection bin and weigh how much is collected.

"We're doing a small-scale cleanup of the smallest cove to see how the logistics work, how much trash we get, how effective it is," Royal said.

Elaine Chiosso, the Haw Riverkeeper and executive director of the Haw River Assembly, said she had been involved with shoreline cleanups for 20 years but was still shocked when she saw the trash accumulated in the coves.

"I've been out on the lake for a long time, but never seen anything like this," Chiosso said. "This trash is kind of a reminder that a river flows and brings with it everything that comes out of the storm sewers."

wade.rawlins@newsobserver.com or (919) 829-4528