THAT'S HARD TO DISPUTE. My only teensy gripe with Carothers's system is that it funnels most of the degrading labor onto one guy: me.

A poo captain's day is long and hard, and it usually begins at first light, when he gets up with the rest of the crew. On this particular expedition, the routine is pretty standard: While Andre, Billie, Milty, Bronco, and Monte fix breakfast and clean the dishes, I focus on my duties as the trip's turd-transport specialist.

I start by rounding up my 16 pee pails—small plastic paint cans, purchased at Home Depot, which I place in front of the passengers' tents every night so they won't have to stumble off to the groover after dark. Then I stuff whatever garbage I can scrounge into a trash bag and drench it with liquid bleach to prevent the Jackass from turning into a floating fly farm. Today marks the end of our first week on the river, so I also perform a quick inventory to confirm that we have an adequate supply of toilet paper (one roll per person for every five days), Clorox crystals, hand soap, air freshener, and, most important, empty rocket boxes. (I carry a total of 11 to see us through a 19-day trip, with a one-groover safety margin.) Finally, I check the day-tripper—two smaller ammo cans containing a roll of TP, a jar of hand soap, and about four pounds of Feline Pine kitty litter. This system is for clients who cannot avoid using the toilet during the day.

Around 7:30, as the crew starts dismantling the kitchen, it's time for me to encourage everyone to finish groovering. This is demeaning, but it's also a bit of a power trip. When I yell "Last call on the groover!" what I'm really telling people is "No matter how important you are, I'm about to revoke your bathroom privileges for the next eight hours." It doesn't matter that Steve sits on the board of the New York Stock Exchange or that Maureen is a highly placed official at the Commerce Department. It also doesn't matter that Ben pounds nails in Portland or that Emily, who runs a crane at the docks in Port Arthur, Texas, has been saving pennies for most of her adult life to afford this trip. In the eyes of the groover, everyone is created equal.

Everyone except me, of course. When the passengers are finished, I'm the guy who gets to grab a guide, dash up through the tamarisk trees, and break down the system.

If the groover is getting full, I lift it and drop it on the sand a time or two to "settle" things—being extremely careful not to compress the contents too tightly. (After baking in the sun for another two weeks, the contents of a compressed rocket box can cement to form what we call poo glue, which will be almost impossible to remove at the Wildcat Hill Wastewater Treatment Plant, in Flagstaff.) Then I shower the inside with a furious deluge of Clorox crystals, which helps beat back the odor. We cart the toilet seat down to the river with the riser and urine bucket, where the urine is dumped in the water and all components get a thorough scrubbing. Finally, we seal the lid and begin the Morning Poo Parade.

This can be embarrassing. As we haul our load toward the beach, the passengers spot us coming and conversation often grinds to a halt. Someone might break the silence with a remark such as "Stand back, here comes Groover Boy!" Other times, there is a subdued chuckle punctuated with a joke like "Hey, did you know that Grand Canyon poop boatmen never die—they just smell that way?"

Ha-ha, I laugh, that's really funny. Then I pretend to stumble, which sends everyone running down the beach screaming.

As the guides hoist the components onto my front deck, I leap aboard and start tying everything down, often rigging double and triple backups to ensure that nothing goes flying out. It's a complex operation—I use nearly 40 cam straps to properly anchor the pee bucket, the 16 pee pails, the riser, the three bags of toilet paper, the garbage, the groover seat, and the rocket boxes, plus all my Clorox and cleaning supplies.

When the lashing is done, I'm surrounded by a mountain of trash and toilet products. You're probably familiar with those wheeled carts used by folks who clean the bathrooms at airports and hospitals? Well, that's what the Jackass looks like, with one big difference. When I'm finished rigging, I have to row the goddamn thing through some of the biggest commercial whitewater in North America.