Ten people set out in kayaks at dawn Saturday and bobbed and splashed down a murky 1.5-mile stretch of the upper Los Angeles River, offering a paddle experience like no other in the city.

The L.A. Conservation Corps members were on a reconnaissance mission to confirm that the route through the San Fernando Valley’s Sepulveda Basin was clear of potential hazards a week before the start of the 2nd annual Paddle the Los Angeles River program.

The scenery was captivating and, for the most part, serene as the flotilla skimmed over lazy currents of water the color of chocolate milk and smelling like old socks in the hardest working wetlands in Los Angeles.

The 70-foot channel has for years operated as a flood-control channel, wildlife sanctuary and escape valve for treated waste water befouled with chemicals and trash. Now, the soft-bottom swath of weedy islands, dense brush and willows draped with fast-food wrappers, plastic bags and clothes is one of the newest summer attractions in town.

As they maneuvered past discarded shopping carts and tree stumps, egrets and hawks flushed from trees leaning over the section of river that runs between Balboa and Burbank boulevards, about 17 miles northwest of downtown. Blue herons squawked angrily at the intruders.

Anglers stared, perhaps wondering how far the riders had traveled.

On a bluff, a woman pointed curiously at the vessels, then shouted, “Watch out for the treacherous rapids just up ahead! Just kidding!”

An hour into the journey, Pablo Cardosa, the Conservation Corps’ program manager, said, “The water’s a little lower than I expected. Otherwise, I think we’re going to be in pretty good shape this year with our paying customers.”

Corps’ spokesman Mike Mena agreed. “Most folks will be pleased with the peaceful flows and lush greenery.”

Hope of transforming this portion of the river into a recreation area led to unlikely bedfellows — the city of Los Angeles, the Army Corps of Engineers, the for-profit L.A. River Expeditions and nonprofits including the River Project, Friends of the River, Urban Semillas and the Conservation Corps — to forge the plan allowing paying customers a chance to paddle it under tightly controlled conditions.

The first legal trips down the river in seven decades launched last August after the Army Corps issued the license allowing the Conservation Corps to operate the program on weekends. Its 290 tickets sold out in 10 minutes.

This year, the program will be handled by two operators — the Conservation Corps and L.A. River Expeditions — and expanded to accommodate 2,000 participants over a nine-week season ending Sept. 29.

Trips are being offered by the Conservation Corps on Tuesday through Saturday at a cost of $50 per person for a two-hour excursion, and $25 per person for a one-hour trip. Tickets go on sale Tuesday (https://www.paddlethelariver.org).

L.A. River Expeditions (https://www.lariverexpeditions.com) will offer trips Sunday and Monday at similar prices.

The program is restricted to summer months as a safety precaution. That is because the river recedes in the summer but explodes into dangerous torrents with the first rains of winter.

louis.sahagun@latimes.com