SALT LAKE CITY — Blame it on the pioneers and the historical diversions from a trio of rivers.

The waters of the Great Salt Lake have shrunk by 48 percent and its levels diminished by 11 feet since pioneers first arrived in 1847.

A white paper exploring the impacts of water development on the Great Salt Lake and Wasatch Front was released late Wednesday, providing a cautionary message on further development that warrants a strong examination of the benefits, and the costs.

"There’s no doubt about it, Great Salt Lake is shrinking,” said Wayne Wurtsbaugh, lead author of the paper and a professor in Utah State University's Department of Watershed Resources and the USU's Ecology Center.

"Though we’ve witnessed droughts and floods in recent decades, impacts of water diversions have decreased the lake’s level by 11 feet."

Why should you care? Researchers say there is a lot to consider before any additional diversions take place, specifically dust pollution from a greater exposed lake bed, impacts to industrial users on the lake, including brine shrimp harvesters, recreational impacts, and jeopardizing the environmental benefits the lake, its wetlands and uplands provide to as many as 5 million birds.

Wurtsbaugh collaborated with USU's Sarah Null and Peter Wilcock, Craig Miller of the Utah Division of Water Resources, Maura Hahnenberger of Salt Lake Community College and Frank Howe of USU and the Utah Division of Wildlife Resources for the paper, which was published on the university's Quinney College of Natural Resources’ home page Wednesday.

The paper tracks the fluctuations on the terminal lake’s levels since 19th century pioneer settlement and details the declines that have happened over time due to agricultural, industrial and other diversions from rivers that flow into the lake.

Development of the Bear River Project, warns the Utah Division of Water Resources, will drop the lake an additional 8.5 inches and expose another 30 square miles of lake bed.

The project is in its early study stages to determine if it is feasible, and the potential impacts are among chief components of the analysis. While authorities initially projected the diversion would have needed to be in place by 2015 — that timeline has been extended to 2040 or beyond.

Critics have already lined up with harsh opposition to the proposed diversion, which would funnel 220,000 acre feet from the Bear River to transform it into drinking water for populations along the Wasatch Front to meet growth.

"Great Salt Lake is already at near historic lows, stressed by years of drought," said Steve Erickson, policy advocate with the Utah Audubon Society. "Further depleting the waters of the lake could have enormous consequences for industries that rely upon its waters, for bird and wildlife habitat and for air quality, as receding shorelines expose alkali and likely contaminated soils that will become airbone in big winds."

This latest research, however, is likely to be another resource for critics to point to as a reason to kill the project before the first bit of water ever flows to a tap.

"The logic is straightforward: If less water is delivered to the lake, the lake level must drop. This is an inevitable consequence of ever-increasing water consumption," it said.

With net river inflows already reduced by 39 percent since the 19th century, the paper warns of a "dry" Great Salt Lake that could occur, similar to California's Lake Owens in 1926 that dried up following excessive diversions on the Owens River.

As a result of the now-dead lake, the city of Los Angeles logged $1.3 billion in dust mitigation expenses since 2000, a number that is expected to eclipse more than $2 billion in the next two years to combat what has become one of the largest sources of particle pollution in the United States.

"Because most of Utah’s population is located near Great Salt Lake, health impacts from exposed lake bed could potentially affect even more people," the paper warns.

Diversions and drought are already causing dust impacts from the lake, particularly in the Salt Lake City area, which witnessed a monumental dust storm in August of 2015. Researchers say an additional 550 square miles of lake bed is exposed from the time when pioneers arrived, giving rise to concerns over health impacts to respiratory systems.

The paper also cites:

Already low levels forcing the dredging of the Great Salt Lake Marina at a cost of $1.5 million

Threats to the $57 million brine shrimp industry from receding lake levels

Disappearing freshwater areas along Farmington and Bear River bays that are prime nesting habitat for water fowl, jeopardizing a $70 million waterfowl hunting industry

Expensive fixes industry is already making to access the water or pump brine to their facilities

Overall, the lake pumps $1.3 billion into Utah's economy, the paper stresses, and has become entrenched in the history and culture of the state.

Its value to Utah requires a careful approach to any subsequent diversions, said Todd Adams, deputy director of the Utah Division of Water Resources.

“There are competing interests related to water because there is a limited supply, but it is important that we take a balanced approach in our decisionmaking," he said. "That includes fully analyzing any effort that impacts the Great Salt Lake.”

Email: amyjoi@deseretnews.com

Twitter: amyjoi16