Landscape images taken on May 2, 2026, of the Tully Valley mudboils near Onondaga Creek in LaFayette. Credit: Mike Roy | Central Current

The downstream waters of the Onondaga Creek hardly suggest vitality — but Sid Hill remembers well-worn pathways leading to clearer waters.

For the Onondagas, the creek intertwined with sustenance and ceremony. All along the clear waters, trails led down to the creek’s banks, worn from regular use. Fishermen left their poles leaning in the crooks of fork sticks near preferred angling spots. Even in winter, fish could be seen swimming beneath the creek’s frozen surface.

Long before becoming the Tadodaho (spiritual leader) of the Onondaga Nation, a young Hill learned to swim in the creek where just about everyone learned to swim, he said, a favorite swimming hole off a country road in the Tully Valley. 

Springtimes would see Hill’s uncles netting bigger fish off a dam on the creek, bringing home their yield to be cleaned, fried and eaten at family gatherings. It was a spring ritual, Hill said, to pick wild onions, leeks and natural medicines found growing near the water.

But those rituals don’t happen anymore.

“Three generations now, haven’t done that. You don’t see the paths,” said Hill. “You go down to the creek there, and there’s no paths run. You don’t see these fork sticks sticking up.”

For over half a century, the once-clear creek has run brown with silt and sand that oozes above ground through holes called mudboils.

Across 35 years, various working groups, task forces, and teams of experts and public officials have researched, simulated, implemented and altered plans to mitigate the salty silt degrading Onondaga Creek. Past remediation efforts have addressed certain mudboils, only to be derailed by the emergence of new mudboils elsewhere.

The ongoing problem has no solution near in sight, while the Onondagas’ practices along the creek have been lost to the mire.

Onondagas noticed impacts on the creek’s clarity by the 1950s, when Hill, now 75 years old, and his generation were still kids. That decade also saw the peak of brining operations in the valley. The creek had become continuously turbid, and state investigators documented mudboils in the area. By the early 1970s, the Onondaga Creek was visibly muddy year-round from mudboil activity. Brining operations ended in 1988. When the mines stopped pumping brine to Syracuse factories, underground pressure increased — and so did the mudboils.

The 1991 collapse of the Otisco Road Bridge into the creek prompted initial efforts to solve the mudboil problem. The valley also experienced landslides that distributed sediment into the creek, including the 1993 landslide that spread 15 feet of mud across a 1500-foot area. For the next 15 years, mitigation efforts reduced the mudboils’ discharge from an average of 30 tons a day to half a ton a day. 

But the emergence of “rogue” mudboils outside the mitigation measures effectively undid much of the previous work to reduce the amount of silt flowing into the creek. The result was a creek whose flow resembled the turbid waters of 1991.

In 2014, the Nation and other stakeholders hoped a forthcoming study from a newly formed mudboil technical advisory group might identify a lasting solution. 

Over a decade later, scientists are still researching the viability of proposed mitigation plans, and the Onondaga Nation is still waiting for clarity.

‘Between a rock and a mudboil’

Tully Valley mudboils were first documented in the late 19th century, including in a 1899 Post- Standard article describing a “sand and water volcano.” The valley is one of the only places on Earth where mudboils have been documented, and scientific research suggests they have likely occurred for thousands of years.

A causal relationship between regional salt mining and modern mudboil output has yet to be proven, but the extractive operations of Allied Chemical (now Honeywell) have altered the land above and beneath the creek, according to United States Geological Survey reports. 

In 2015, a research paper commissioned by the Onondaga Nation and published by Chazen Companies found “a preponderance of evidence linking these phenomena to brine mining activities.”

Honeywell through Director of Communications Caitlin Leopold declined a Central Current reporter’s request for an interview for this story.

For nearly a century, Allied conducted solution salt mining in the Tully brine fields, extracting over pumped water into underground salt caverns, creating brine and pumping it to the surface. The operations carved vacuums below the Tully Valley, causing land subsidence and creating sinkholes. Above the creek, hillsides are slashed with numerous rock fissures, gaping cracks in the ground that opened as a direct result of the salt mining operations.

The USGS in 2009 reported over 400 such fissures, some with depths of over 50 feet. 

A rock fissure, one of hundreds slashing the slopes of the Tully Valley, photographed in September 2019. Credit: Courtesy of Joe Heath

Water, especially during and after big storms, slips through the fissures and into the underground cavities. As freshwater passes through the salt caverns, it becomes briny. The influx of surface water and resulting brine strains aquifers and creates upward pressure.

Mudboils form when it burbles out of a volcano-like mixture of sand and clay, a mudboil.

The sediment discharges into tributaries and eventually merges with the waterway downstream of the creek’s pristine headwaters. The mudboils’ mucky output renders the water brackish and brown.

Once in the creek, the silt flows through Syracuse — where some Southside residents have had to purchase flood insurance because of seasonal flooding — eventually reaching Onondaga Lake. The mudboils account for 67% of all sediment in Onondaga Lake, according to findings presented in 2025 to the Onondaga County Legislature by OEI. 

“We’re between a rock and a mudboil,” said Bill Kappel, a retired geologist who studied the mudboils for decades. “It’s very tough to suggest what could be done, but if you want to talk about the nature of the Onondaga Nation, getting rid of the sediment in the creek would go a long way.”

‘In perpetuity…’

A long-term solution has eluded experts for 35 years — but not for lack of effort. 

The collapse of the Otisco Bridge in 1991 served as the inciting incident for the ensuing 35 years of research into the issue.

After the bridge’s collapse, scientists at the USGS in Oct. 1991 began studying what they called the Mudboil Depression Area — the part of the valley where mudboils were occurring and nearby surface land was sinking as a result. 

Ed Michalenko, the president of OEI, has worked to address the mudboils for decades, said that the efforts to control the silt discharge at its source succeeded in mitigating most silt output for about 15 years.

“From ‘93 to about the 2008, 2009 timeframe, the source controls worked very well. We had a dam around what was called the main depression area,” Michalenko said. “Most of the sediments that were in there was, at the time, about 30 tons a day coming up, and less than half a ton was released to the creek with those controls.”

The dam around the Mudboil Depression Area slowed the flow of the discharge, providing more time for the silt to settle on the creekbed. Other controls involved rerouting a major tributary to feed into the creek south of the MDA, and the drilling of depressurization wells.

Onondaga Nation Tadodaho Sid Hill and OEI president Ed Michalenko in August 2018 inspect a mudboil on the edge of a cornfield. Credit: Courtesy of Joe Heath

But the emergence of a rogue mudboil in late 1996 ultimately undermined previous remediation; a depressurization well, containment berm, and relocation of a stream succeeded for years in mitigating the rogue mudboil’s discharge. But by 2010, the mudboil had sunk those efforts into the ground.

The dilemma resembled the starting point of mudboil mitigation efforts. The OEI has compared the decades of mudboil mitigation attempts to a game of whack-a-mole.

After spending his working life studying mudboils, and contributing expertise to studies after his retirement, USGS geologist Bill Kappel does not believe that any permanent solution to the mudboils exists. 

Kappel characterized the mudboils as a long-term obstacle to be navigated, rather than a short-term ordeal to be endured. 

Even though he doesn’t think the mudboils themselves can be completely eliminated, Kappel said he believes there are viable options that could mitigate mudboils’ most negative impacts.

Michalenko agrees with Kappel that, if a clear solution to the mudboils exists, it remains out of sight to those who have dedicated time, effort, and resources seeking it. 

Comparing the mudboils to a disease, Michalenko said that a “cure” to the mudboils would require controlling the source of the issue through hydrogeologic intervention.

“We can deal with the symptoms and try to stop the sediment flow into the creek,” Michalenko said. “But at this point, we don’t have a remedy to shut off mudboils.”

Michalenko is optimistic that a workable solution to the mudboils’ worst “symptoms” is near. 

One “water control” plan would see the OEI and its partners introducing more beavers to the creek ecosystem. Similar wildlife management programs in Europe have demonstrated that beavers can provide low-cost, long-term benefits for some natural restoration initiatives, Michalenko said.

“The beavers are doing work,” Michalenko said. “They’re not taking money.”

Mudboil near former Otisco Road Bridge, pictured on July 15, 2024. Credit: Courtesy of Joe Heath

Michalenko hopes to conduct a study within the next two years to determine the feasibility of beaver dams for creek mitigation.

Meanwhile, the USGS in April released a report outlining the viability of a mitigation plan that would divert tributaries to flow to in which silt could settle. USGS’s investigation found the plan would be challenging to implement, and that necessary excavation for certain proposed relocation channels could cause instability and even risk forming new mudboils.

Kappel suggested the biggest challenge now isn’t finding the best mitigation method, but funding it. Any effective long-term plan will not be cheap, and will need to be maintained “in perpetuity,” Kappel said.

OEI has not had much success in landing environmental remediation grants.

“I think a lot of the agencies look at the mudboils as irreparable,” Michalenko said, in part because solutions are likely more attractive to potential funders than perpetual maintenance.

‘Clean it up’

Onondaga Nation lead counsel Joe Heath believes Honeywell, which still owns the land where the mudboils continue to belch sediment into the creek, should help finance long-term mitigation and seek a permanent solution to the Tully Valley mudboils, no matter the cost.

Heath and Hill hope that forthcoming research from the USGS may find more evidence to support the link the Chazen report identified between Allied’s past solution salt mining, and the valley’s mudboils. If it does, they believe that could support a lawsuit against Honeywell.

“Certain corporations used the valley and the lake for a century, and made tremendous profits, and should be held responsible,” Heath said. “That’s what we all apply to our children: You made a mess, please clean it up.”

An excerpt from a 2009 U.S. Geological Survey report on the Tulley mudboils. Credit: Courtesy of USGS
An image of the Mudboil Depression Area from May 2, 2026. Credit: Mike Roy | Central Current

Without intervention, the mudboils will continue to disrupt the Onondaga Nation’s cultural traditions, exacerbate native wildlife populations and threaten to dull remediation work at the lake, a federal Superfund site and at one point the most polluted body of water in the nation.

As the waiting game reaches its 35th year, the cultural artery’s clear waters have become a thing of memory, and aging Onondagas have watched the creek customs that defined their childhoods slide into a similar murk.

They recall a pristine creek, one where fish like brook trout were so abundant that a fisherman could cross the creek atop them. 

Now, that natural bridge is gone.

The degradation of Onondaga Creek is a continuation of past injustice, Hill said. When Hill grew up in Onondaga, the Nation had long ago lost all formal contact to its traditional seat of power, Onondaga Lake. He fears the creek is consigned to the same fate.

“We lost connection to the lake,” Hill said. “Now, we’ve lost connection to the creek.”

Read more of Central Current’s coverage

Patrick McCarthy is a staff reporter at Central Current covering government and politics. A graduate of Syracuse University’s Maxwell and Newhouse Schools, McCarthy was born and raised in Syracuse and...