Distrustful of snarled federal relief efforts and moved to make a personal gesture, an army of maverick volunteers is funneling aid through back channels to the bayou region, complicating overtaxed relief efforts.

A week after Hurricane Katrina flattened the Gulf Coast, Americans have contributed more than a half-billion dollars to disaster aid, nearly double what they gave in the same period after the Sept. 11, 2001, attacks. Accompanying the cash has come a flood of clothing, toys and food, offers of housing, transport and entertainment, taken into the region by Good Samaritans with little or no experience in disaster relief.

But from donated evacuation buses that come home empty, to the mountain of used clothing that disrupted food distribution in a Baton Rouge, La., shelter, charities say home-grown aid is touching but often not helpful.

"When nobody directs the effort [at the federal level], you end up with a ton of well-intentioned folks who want to help but have no idea how," said Trent Stamp of Charity Navigator, a charity rating service. "That's a recipe for disaster. We've been telling people since day one that the real way to help with this disaster is to write a check, because they're just not prepared at the other end to receive goods."

Alan Courtemanche, a tae kwon do instructor from Leesburg, discovered that when he arrived in Gulfport, Miss., on Sunday night. He had his brother Michael in tow, as well as a trailer full of water, food and diapers donated by his students at Gold's Gym in Sterling.

"There is no order," Courtemanche said, speaking on his cell phone from Gulfport. "Nobody knows who is in charge or what to do to help out."

The brothers finally found a center that accepted their delivery.

"The Red Cross is saying, 'We don't want freelance people bringing supplies down here,' " Courtemanche said. "The Red Cross and FEMA are absolutely in denial. They're saying, 'Send money.' How many times have you chewed on a dollar bill when you're hungry?"

Charities say their warnings are as much for the safety of the volunteers as for the convenience of the relief organizations.

"You don't know what you're going to find when you arrive. There are inaccessible areas," said Lesly Simmons, spokeswoman for American Red Cross headquarters in Washington. "Conditions are difficult. It is incredibly hot. They may be encountering areas where there is no gas available."

Also, trained volunteers could be diverted from counseling victims or other important tasks by having to stop and unload unexpected donations, she said. "If you just arrive with truckloads they're not expecting, it takes people away from doing other work."

At Catholic Charities headquarters in Alexandria, for instance, a small mountain of donated goods has appeared in the lobby, far from where such goods are needed. "Money can buy this stuff, and money is flexible," said spokeswoman Shelley Boysiewicz.

Still, the instinct to do something tangible runs deep for many of those in the impromptu relief efforts.

"Sending in a check to the Red Cross -- what have I done?" asked Pam Weinberg, who helped organize a drive in Frederick. "I think there's a mechanism inside all of us, when we see this much suffering, we need to go into action. I think people want to work."

Weinberg and four friends launched a kitchen-table effort to fill industrial-size paint buckets with personal care items, flashlights and duct tape -- and drive three truckloads of them today from Maryland to Picayune, Miss. "We never even asked for money," Weinberg said. "We asked for these products."

After a Web-based call for donations, the group filled a warehouse near Frederick with 1,500 five-gallon "Buckets Full of Hope."

Kelly Tidwell, a Lorton resident and electrician, recalled the uncertainty he experienced after Sept. 11, 2001, after taking a truckload of respirators, batteries and gloves intended for rescue workers to an anonymous donation center in a Northern Virginia business park.

"In the back of my mind, I couldn't be sure it had actually been received by the people who needed it," Tidwell said. "When this happened, I wanted to make sure it got where it needed to go. More of a grass-roots effort."

So yesterday, Tidwell was driving south with a friend and a flatbed trailer with five tons of supplies. The supplies -- donated by members of the Neighbors Great Falls community listserv -- included a generator, 100 cases of water and more than 50 cases of food and baby formula.

On Capitol Hill, as lawmakers demand an inquiry into the federal government's handling of the disaster, lobbyist Campbell Kaufman has been directing back-channel aid efforts. A Baton Rouge native, Kaufman was ready to climb into a friend's Explorer and drive supplies from Alexandria to the bayou on the day of the hurricane. But reason took hold, and Kaufman decided to stay put long enough to send out a mass e-mail to Capitol Hill contacts requesting donations and help.

Those pleas grew into a do-it-yourself relief effort scheduled to head to Louisiana on Saturday. By last night, Kaufman had two 24-foot rented trucks parked near his offices on Independence Avenue, ready to be packed full of water and food.

"This was the quickest and most effective way to positively help," Kaufman said. "There are a lot of fundraisers going on around here. But our focus is to get supplies to people now. You avoid red tape that way."

Staff writers Jacqueline L. Salmon in Baton Rouge and Fredrick Kunkle in Frederick contributed to this report.