UKIAH – The trail of trash led down the bank of a dry creek to a camp site where two homeless men were drinking vodka and lounging on mattresses under the Orr Street bridge.

They were surrounded by refuse — human waste, charcoal briquettes, clothing and piles of empty booze bottles — a sample of the pollution occurring in creeks and along rivers throughout the state. It’s an old problem that officials say is an increasing threat to urban waterways.

Volunteer groups periodically remove the messes but it doesn’t last and the impacts are deepening as the transient population grows, according to police, county and city officials and even some of the creek dwellers.

“Homeless are everywhere now,” said Mitchell Howie, a bearded, red-haired man who said he began living under bridges after the Ukiah homeless shelter closed a month ago for financial reasons. Howie said he became homeless after losing his job trimming and felling trees some months ago. Even Howie’s attempts to clean up the creek where he was staying have proved fruitless.

“Every creek looks just like this. Worst I’ve ever seen it,” said Howie’s companion, who said he’s been homeless for 30 years. He refused to give his name.

The latest winter homeless count in Ukiah, held in 2013, did not reflect an increase in the population but police say they’re seeing more people and that criminal incidents involving homeless people are rising. Transient-related police calls increased by 25 percent between 2011 and 2013, when there were 1,388 calls. They include assaults, aggressive panhandling and dog bites.

Ukiah Police Chief Chris Dewey said the population is at its highest during summer months, not in January, when the homeless counts take place.

Transients aren’t the only ones trashing creeks and rivers, said state Fish and Wildlife biologist Scott Harris. He recalled 15 years back finding a 6-foot-tall pile of garbage in the creek behind one Ukiah residence. The damage documented at legal and illegal marijuana growing operations throughout the North Coast has also been extensive, leading one state official to call it the “worst environmental crime” in a generation.

Regular cleanups have sought to keep pace with the transient use of waterways. The efforts include annual projects along the Russian River and creeks in the Ukiah area.

Mendocino County Supervisor John McCowen, however, doesn’t wait for organized cleanups. He regularly patrols area creeks, telling illegal campers they need to move elsewhere. He then hauls away the debris. He often does it on his own, and other times with help, including assistance from Ukiah police and the Mendocino Solid Waste Management Authority.

He is well known in homeless circles as a result.

“You McCowen?” Howie’s companion demanded to know as the supervisor perused the Orr Street encampment last week in preparation for a cleanup.

McCowen said rivers and creek beds are not acceptable places for them to live and pollute.

“I maintain they do not have to be in the most sensitive areas of the environment,” McCowen said.

Ukiah City Councilman Phil Baldwin agrees.

“It’s gotta be stopped,” he said.

But it should be handled in ways that are ethical and compassionate, Baldwin said.

The encampments also must be addressed in ways that comply with the law, Police Chief Dewey said.

“The city of Ukiah must find a balance between effective cleanup procedures and ensuring the rights of individuals are protected,” he said.

He noted a case in which the American Civil Liberties Union sued the city of Fresno for clearing out a homeless encampment. A federal court found the city violated the homeless people’s constitutional rights when it seized their belongings. The 2008 settlement cost Fresno $2.3 million.

ACLU attorney Alan Schlosser said if city officials clear out homeless encampments, they must first give adequate notice, preferably 72 hours, so they can collect their belongings. And if property is seized, it can’t immediately be thrown in a dumpster. There should be a process for storing the property so that people can later claim their belongings, he said.

Dewey said he and the city’s attorney are revisiting Ukiah’s ordinance on illegal camping to ensure it can stand up to scrutiny.

Dewey also is soliciting the help of the public to figure out how to best deal with the transient issue.

The Ukiah City Council will be discussing homeless issues at its Sept. 3 meeting, Baldwin said.

You can reach Staff Writer Glenda Anderson at 462-6473 or glenda.anderson@pressdemocrat.com. On Twitter @MendoReporter.