MARANA, Ariz. -- Trekking across Arizona's stunning desert landscapes is one of the most popular forms of recreation in the state, and the Central Arizona Project (CAP) Trail System provides access for thousands of hikers and cyclists.

The trails are built along portions of the CAP's canal system, and cover dozens of miles, primarily in urban and suburban areas. The trail system is a cooperative effort of the CAP, the U.S. Bureau of Reclamation and the cities and counties along the pathways.

Ryan Johnson, engineering services manager for the Central Arizona Project, said the trails have been in place for many years.

"The trail system was originally envisioned by the Bureau of Reclamation, probably as far back as 1973," Johnson explained. "It's totally for public use. Anyone can use it, of course, and then it intersects and ties in with other trailheads that counties and cities have developed."

Johnson pointed out the system continues to grow. A new CAP trailhead will be dedicated in the Pima County town of Marana Saturday, adding 30-plus miles of maintained pathways to the trail system.

The trails are designed for hiking, jogging, equestrian use, bicycling, and in-line skating on paved portions, but Johnson said motorized vehicles are not allowed. He added because CAP is a public utility, it does not use taxpayer funds, but coordinates with the Bureau of Reclamation and local officials to build and maintain the system.

"I think the most interesting feature about the canal is that it interconnects and ties in with other city and county features, like parks and other bigger trail systems," Johnson remarked. "It is a good thing for the trail, a good thing for the community."

Most of the trails run along portions of CAP's 330-mile long distribution canal network, with completed or planned sections in Pima, Pinal and Maricopa counties.

The Great Lakes hold about one-fifth of the Earth's fresh water, but a new report indicates they're getting saltier - and says that's reason for concern.

Lake Michigan used to sit at a salinity level of one to two milligrams of chloride per liter of lake water. Now, that concentration has risen to nearly 15 milligrams per liter.

Hilary Dugan, an assistant professor in the Center for Limnology at University of Wisconsin-Madison, said it's still a relatively low level for a water body as large as Lake Michigan. But rising chloride levels could pose problems for plants and animals in the smaller lakes and tributaries that feed into it.

"If anything, we're just hurting those native freshwater species that are adapted to, you know, Wisconsin waters that basically have no salt in them," said Dugan. "And now, you know, we've increased the salt ten-, hundredfold, depending on what body of water we're looking at."

She said salt levels have to hit roughly 250 milligrams per liter to pose a serious risk to plants, animals and humans, and notes virtually all the chloride pollution is from road salt.

Dugan added that people can reduce pollution in lakes and streams this winter by limiting their use of salt on roads, driveways and sidewalks.

Unlike other chemical pollutants, Dugan said salt pollution isn't irreversible. She explained that over the course of their life cycle, lakes and streams will gradually flush it out of their system.

"Salt stays dissolved in water, and so lakes and rivers will naturally flush themselves out," said Dugan. "So what it takes to reduce the salinity is just to stop the amount of salt that's going into these bodies of water."

The report found about 70% of the salt flowing into Lake Michigan comes from just five of the body's 300 tributaries.

Dugan said if nothing's done to address the issue, salt concentration in the lake will rise by about one milligram per liter, every two to three years.

A fund created seven years ago in the wake of Clark County's violation of the Clean Water Act is helping improve salmon habitat and cleaning up stormwater in the Columbia River.

Clark County was sued more than a decade ago for approving weaker pollution regulations for entities like big box stores and subdivisions. After losing in court, the county agreed to one of the largest citizen-enforcement penalties in Washington state history: $3 million.

Jan Hasselman, a Seattle-based senior attorney for Earthjustice who worked on the case, said that money didn't go to Washington, DC.

"What we agreed instead was that the county would pay into a local fund for salmon habitat restoration," said Hasselman. "That fund is overseen by biologists and professionals that make sure the money addresses the most important problems."

The penalty helped create the Clark County Clean Water Restoration Fund, which, along with matching investments, funded 25 water restoration projects in the region.

Hasselman said stormwater is the number one source of water pollution in Washington state.

The Lower Columbia Fish Recovery Board picked and distributed funds to projects. Denise Smee, program manager with the board, said they've implemented a variety of programs.

"We worked with partners for reducing oil leaks from automobiles, the don't drip and drive program," said Smee. "They worked with landowners and homeowners to facilitate repairs on stormwater facilities, failing septic systems."

The projects have led to the planting of more than 80,000 trees to improve stormwater quality. It's also supported K-12 education programs, providing classroom and field instructions for more than 7,700 students. Smee said those programs have had a big impact on students.

"It's always a huge increase in the kids' knowledge but also their interest in the subject matter," said Smee. "A lot of them, after these projects, are interested in going into natural resources or the environmental field or working with those kinds of positions and jobs."

Many of the projects to help clean up stormwater and improve salmon habitat will continue for the next several years.

CHEYENNE, Wyo. -- Wyoming and other western states are projected to see multiple years in a row without any snow as soon as 35 years out if efforts to rein in fossil-fuel emissions fail to meet global targets, according to a new report.

Almost 75% of water use in western states comes from snowpack.

Matt Rice, southwest regional director for the group American Rivers, said the report should be a red flag for water managers and policymakers to make plans now for a future with a lot less water.

"How do we build resilience in this new more arid future for the West?" Rice questioned. "It's important to make sure that we have the ability to keep water in rivers, to dedicate water to the environment, for fish, for wildlife."

Rising temperatures already have cut snowpack by 20% below 1950s levels, and researchers project by century's end, the vast majority of years -- up to 94% -- will see little or zero snowfall. Loss of snow will not just close ski resorts. Scientists already have linked vanishing snowfall to more frequent and catastrophic wildfires.

The first sector likely to see water restrictions will be agriculture.

Rice said investments are needed to help farmers and ranchers retool for more efficient irrigation and conservation, because no one wants to see a mass dry-up on lands across the West.

"And it's not like when you remove water that land comes back with native grasses and plants and shrubs," Rice cautioned. "This is oftentimes land that has been irrigated for 100-plus years, and to take water off of it, it creates a kind of 'deathscape.'"

Recommendations for adaptation include monitoring weather patterns to avoid flooding by capturing increasingly intense, if less frequent, downpours to refill aquifers. While conflicts over water rights have a long history in western states, Rice noted the issue traditionally has cut across political boundaries.

"As scarcity increases, my fear is that it will digress into a partisan issue, or rural versus urban, when it comes to water," Rice stressed. "These challenges are so significant that we can't afford not to all be in this together."