Carmel Accidentally Got Another Geist Reservoir. Now Who Is Watching the Water?

HOOSIER ENQUIRER INVESTIGATION | Nearly 9 billion gallons poured into an operating Martin Marietta quarry after historic flooding reversed Blue Woods Creek, destroyed the Hazel Dell Parkway bridge and threatened critical sewer infrastructure. Officials appear to have prevented a much larger catastrophe. Now comes an unprecedented cleanup—and some questions that deserve public answers.

CARMEL, Ind. — Less than two weeks ago, the Martin Marietta Carmel Sand and Gravel operation along Hazel Dell Parkway was producing the basic materials Indiana uses to build roads, bridges, homes and other infrastructure. Today, it looks like a lake, of fish hatchery.

And not a particularly small one. Carmel officials estimate that historic August flooding sent nearly 9 billion gallons of water into the enormous excavation—roughly comparable to the amount of water in Geist Reservoir, according to Carmel City Engineer Bradley Pease. The number is almost difficult to comprehend: nine billion gallons represents roughly 27,600 acre-feet and about 75 billion pounds of water sitting where workers and heavy equipment recently operated.

The immediate emergency appears to have been contained through a remarkable around-the-clock response involving Carmel employees, private contractors, Hamilton County, state officials and the Indiana National Guard. Crews moved hundreds of truckloads of aggregate and concrete, while Black Hawk helicopters lowered enormous sandbags into the damaged corridor as officials raced to prevent a potentially catastrophic diversion of the White River.

They succeeded. But stopping the emergency and cleaning it up are two very different things.

Carmel now faces a problem unlike almost anything in its recent history: How do you safely remove nearly 9 billion gallons of floodwater from an operating industrial quarry and return that water to the White River? And when that operation begins, who will independently verify what is in the water and whether it is safe to discharge?

Those aren't accusations. They are the questions that naturally follow one of the most extraordinary infrastructure events central Indiana has experienced in decades.

When a Creek Started Flowing the Wrong Way

Understanding what happened requires appreciating how dramatically the flood altered the landscape.

Blue Woods Creek normally carried water toward the White River near Hazel Dell Parkway south of 106th Street. During the historic flooding, the swollen White River effectively reversed that relationship. Water surged backward through the creek corridor toward the Martin Marietta excavation, cutting through soil and vegetation with enough force to radically alter the terrain.

An area beside the creek that had been roughly 30 feet higher and covered with mature trees was scoured away. The Hazel Dell Parkway bridge suffered catastrophic damage and has been declared a total loss. Hamilton County subsequently prohibited recreational use of the White River because officials feared someone could be swept through the altered channel, into the destroyed bridge area or toward the quarry. Commissioner Christine Altman warned residents that the current had become powerful and unpredictable.

For a time, officials confronted an even more frightening possibility. The concern wasn't merely that the quarry was filling with water. The White River itself appeared capable of establishing a substantially new route into the enormous excavation.

During an Aug. 17 Carmel City Council meeting, officials discussed river flows measured in millions of gallons per minute and the possibility that continued erosion could create an even larger pathway toward Hazel Dell. The implications went well beyond Martin Marietta's flooded property because beneath the original creek bed were force mains carrying wastewater toward Carmel's treatment system.

Those weren't minor pipes. City officials said the threatened infrastructure carries roughly 90% of Carmel's treated wastewater flow. If erosion had exposed and ruptured those mains, raw sewage potentially could have entered the quarry and ultimately the White River downstream toward Indianapolis. Carmel Utilities Director Lane Young publicly discussed constructing a bypass as officials confronted that possibility.

The threat was serious enough that downstream utilities were preparing for it. Citizens Energy Group told Mirror Indy that if wastewater reached the White River, it was prepared to increase upstream monitoring and adjust treatment or water supplies as necessary to continue meeting federal drinking-water requirements. Fortunately, that nightmare didn't materialize. Carmel says the wastewater main remained intact, no sewage entered the river, drinking water remained safe and no boil-water advisory was issued.

That is an important part of this story. Sensationalizing what could have happened would obscure what emergency crews actually accomplished. They appear to have prevented an already serious disaster from becoming substantially worse.

Four Hundred Trucks and Black Hawk Helicopters

The engineering response sounds more like something from a disaster movie than an Indianapolis suburb.

According to Carmel, crews ultimately constructed a concrete-and-aggregate dam using more than 400 truckloads of material. The intervention reduced water flow by more than 90%, buying engineers enough time to protect the threatened wastewater infrastructure and allowing the Indiana National Guard to establish a secondary barrier. Guard crews then used Black Hawk helicopters to place 73 sandbags weighing 2,000 pounds apiece.

Consider the scale of that response: more than 400 truckloads of material, 73 one-ton bags, military helicopters, heavy equipment, utility crews, police, firefighters and private contractors, all mobilized because a creek that normally emptied into the White River suddenly became a pathway capable of sending the river toward a giant industrial excavation.

Mayor Sue Finkam described the response as an example of "Hoosier ingenuity." In this instance, the phrase seems justified. The more interesting question is what happens after the helicopters leave and emergency improvisation gives way to months of environmental and civil engineering.

That is where this story is heading now.

Nine Billion Gallons Have to Go Somewhere

Martin Marietta still lists Carmel Sand and Gravel at 11010 Hazel Dell Parkway as an aggregate operation. Its product is exactly the kind of material Indiana will need as communities repair roads, bridges and other infrastructure damaged by the storms. Mayor Finkam has also pointed to the economic impact on quarry employees who suddenly found their workplace underwater.

Leaving the quarry as Carmel's newest lake therefore isn't the plan. The water has to come out.

Carmel Utilities Director Lane Young has said draining the excavation could require approximately 90 to 100 days, with the water ultimately discharged back into the White River in a measured and controlled process coordinated with state and federal agencies.

The arithmetic illustrates the extraordinary scale. Removing 9 billion gallons evenly over 100 days would require an average of about 90 million gallons per day, or approximately 62,500 gallons every minute, 24 hours a day. Compress the operation to 90 days and the average approaches 100 million gallons per day, nearly 69,500 gallons every minute.

The actual pumping schedule almost certainly won't be uniform. Pump capacity, permits, weather, White River levels, sediment and water-quality requirements will determine how quickly water can safely be removed. But those calculations demonstrate why the operation can't be compared with pumping out a flooded basement—or even an ordinary commercial property.

This is industrial-scale dewatering.

The Water Came From the River. That Doesn't Automatically Mean It Can Simply Go Back.

At first glance, the solution seems obvious. The water largely came from the White River system, so pump it back into the White River.

Hydrologically, that makes sense. Environmentally, it requires more scrutiny.

The water has now spent days inside an active industrial excavation where quarry machinery was submerged during the flood. Heavy equipment can contain diesel fuel, hydraulic fluids, lubricants, coolants and other petroleum products. Officials have said they haven't observed a petroleum sheen on the surface, which is encouraging, but Carmel Utilities Director Lane Young acknowledged that the machinery below the water remains part of the environmental equation.

“We’re hopeful that whatever containers the petroleum was in have held,” Young told IndyStar, adding that water-quality testing will be part of the process.

That distinction is important. The absence of a visible sheen is good news, but it isn't the same thing as a laboratory result. There is currently no evidence establishing that a significant petroleum release occurred inside the quarry, and the public shouldn't be frightened with unsupported claims of contamination. At the same time, billions of gallons of floodwater sitting above submerged industrial equipment shouldn't simply be presumed clean because pollution isn't visible from shore.

What Carmel has is not an established contamination crisis. It has a contamination risk that should be tested, measured and publicly documented.

Before large-scale discharge begins, residents should know what parameters are being tested. Petroleum hydrocarbons would be an obvious consideration because of the submerged machinery, but turbidity, suspended solids, pH and other constituents associated with floodwater and quarry operations deserve attention as well.

Testing also shouldn't necessarily end with a single sample before the first pump is turned on. Conditions inside a deep quarry can change as the water level falls. Sediment can be disturbed, machinery can shift or become exposed, and water at different depths may have different characteristics. If dewatering lasts three months or longer, the monitoring regime should be designed for three months or longer.

And the results should be available to the public.

This Has Happened Before—But Not Quite Like This

Flooded quarries are not unprecedented. In fact, engineers sometimes deliberately use enormous excavations for flood control.

One of the most dramatic examples is outside Chicago, where the Thornton Quarry was incorporated into the region's massive flood-control system. It can hold nearly 8 billion gallons of stormwater and sewage during major events, after which the water is pumped to a treatment facility.

The comparison is fascinating because the capacity is remarkably similar to the amount now sitting in Carmel. But the difference is more important than the similarity: Thornton was deliberately engineered to flood. Carmel Sand and Gravel wasn't.

The Chicago project required extensive engineering, enormous gates and work to control the movement of water through the quarry. Other communities have similarly studied quarries for water storage only after evaluating their geology and the potential effects on water chemistry. A Maryland quarry examined as a possible Washington-area water-storage facility was estimated to hold about 8 billion gallons, and engineers conducted extensive testing before treating it as a potential reservoir.

In those places, engineering came first and water came second.

Carmel received the water first.

Now the engineering has to catch up.

Don't Forget What Is Underneath the Water

The submerged machinery raises the most obvious environmental questions, but there is another issue that deserves attention as the quarry is drained: groundwater.

Large excavations interact with surrounding groundwater systems. Depending upon local geology and hydraulic connections, removing enormous quantities of water can alter surrounding conditions. That does not mean Carmel is about to experience failing wells, subsidence or sinkholes, and there is no current evidence establishing any such outcome.

It does mean that nearly 9 billion gallons is too much water to remove without understanding how the excavation interacts with surrounding groundwater.

The White River itself should also dictate the pace of pumping. An additional discharge that represents a relatively small portion of river flow during high-water conditions could become proportionally much more significant during a dry autumn. A sensible dewatering plan therefore shouldn't simply establish a date by which Martin Marietta wants the quarry empty. The river, water quality and engineering conditions should determine the rate.

The 90-to-100-day estimate should be understood as exactly that: an estimate, not a deadline nature is obligated to respect.

Then Comes the Question Nobody Escapes: Who Pays?

The emergency brought together an impressive collection of public and private entities. Hamilton County owns the destroyed bridge. Carmel maintains Hazel Dell Parkway. Martin Marietta owns and operates the quarry. Carmel Utilities has critical infrastructure in the affected corridor. State agencies and the Indiana National Guard participated in the emergency response, while federal assistance could eventually become part of the recovery picture.

Those overlapping responsibilities worked remarkably well while the river was raging. They become considerably more complicated when the invoices begin arriving.

Hamilton County officials are already working toward replacement of the Hazel Dell Parkway bridge, a project they hope can be completed by the end of 2027 for less than $10 million. Quarry dewatering, environmental testing, riverbank reconstruction, utility protection and restoration of Martin Marietta's operation are separate costs.

The public deserves a clear accounting of which expenses belong to Martin Marietta, Carmel, Hamilton County, state government, federal disaster assistance and insurers. Asking that question doesn't assign blame for a historic flood. It is simply what taxpayers should expect after a disaster involving millions of dollars of public infrastructure.

The same principle applies to the bridge itself. Engineers now know something about the White River and Blue Woods Creek that wasn't theoretical two weeks ago. They have watched an extreme event physically rewrite the landscape. Whatever replaces the Hazel Dell bridge should be designed around what engineers learned from this flood rather than merely recreating what existed before it.

Did the Quarry Also Save Part of Carmel?

There is an intriguing question hidden inside all the destruction: Did the quarry inadvertently protect other parts of Carmel by absorbing billions of gallons of floodwater?

A nearly 9-billion-gallon excavation represents an extraordinary amount of temporary flood storage. Water entering the quarry was, at least temporarily, water that wasn't continuing somewhere else. That doesn't make the event beneficial; the destruction of the bridge, loss of quarry operations and threat to sewer infrastructure demonstrate the enormous costs.

But it does make the hydrology worth studying.

How much higher would the White River have risen elsewhere if the quarry hadn't accepted that volume? Would surrounding neighborhoods or downstream properties have experienced additional flooding? Did the quarry reduce the flood peak, or did the altered channel create other problems that outweighed any temporary storage benefit?

Those are questions engineers can model after the emergency has passed. The answers could matter enormously for future flood planning along the White River corridor.

The quarry may turn out to have been both one of Carmel's biggest flood casualties and one of its largest accidental flood-control structures.

The Public Should Be Able to Watch the Water Leave

Carmel officials have been highly visible throughout the emergency, issuing updates, holding briefings and explaining the infrastructure response. That transparency should continue when the story becomes less visually dramatic and more technically complicated.

The public should eventually be able to see the approved dewatering plan, identify the agencies authorizing the discharge, understand the maximum pumping rates and review baseline and continuing water-quality results. If petroleum or another contaminant is detected, residents should know the concentration and what corrective action follows. If groundwater monitoring is required, those results should be available as well. And taxpayers should eventually receive a comprehensible accounting of which recovery costs are public and which belong to private parties.

Those records may demonstrate that the quarry water presents little environmental difficulty. That would be excellent news and precisely why the information should be published.

Transparency isn't something government needs only when something has gone wrong. It is also how government proves that something is being done right.

There is much to praise about Carmel's response so far. City employees worked around the clock. Contractors moved hundreds of truckloads of material. National Guard helicopters placed one-ton sandbags with extraordinary precision. Engineers improvised barriers while the White River was still trying to carve itself a new route through Hamilton County. The wastewater infrastructure remained intact, sewage didn't enter the river, drinking water remained safe and a frightening worst-case scenario was avoided.

That was the emergency phase. What follows will be slower, less dramatic and potentially more consequential for understanding how Carmel prepares for the next historic flood.

Nearly 9 billion gallons now sit inside a hole that was never supposed to become a lake. An operating aggregate facility is underwater, a bridge is gone, the river and creek have carved a landscape that didn't exist two weeks ago, and a massive pumping operation could continue well into the fall.

The appropriate response isn't panic, and it isn't blind reassurance either. Carmel has an opportunity to make this recovery a model of transparent environmental engineering: test the water, establish safe discharge limits, monitor the river, publish the results and explain who is paying for the work. Young offered perhaps the simplest description of the enormous job ahead:

“We’re basically putting the river back where it belongs but doing it in a measured and controlled way.”

That is exactly what Carmel should do. Measure it, control it—and let the public see the measurements.