Case Study

Storm Pipe Repair and Rehabilitation in Delray Beach, Fla.

Delray, Fla.

HOA

Pipe Failure

A residential community in Delray Beach, Fla., experienced a sinkhole forming in an active roadway, a sign of catastrophic failure in an aging 36-inch corrugated metal storm pipe beneath the surface. AQUALIS was contracted to investigate the failure and restore the pipe’s hydraulic capacity, its ability to carry stormwater without backing up the system, and what the team found underground changed the repair plan. That shift demonstrated the value of data-driven, adaptive fieldwork.

The Problem

The pipe was old, corrugated metal, buried beneath an active roadway and running close beside an 8-inch water main and a handful of other utility lines. Through cracks, water was able to seep out of the pipe and carry sediment with it, leaving voids underground. Above ground, as the soil slowly eroded away, a depression began to form, what engineers call a surficial subsidence feature. It eventually opened into a full sinkhole. Sediment had also built up inside the pipe itself, narrowing the space water had to move through. That buildup increased hydrostatic pressure, the force of built-up water pushing against the pipe walls, making the problem worse every time it rained.

Getting to the pipe was not simple. The dig site was tight, squeezed between the water main, overhead power lines and a roadway residents needed open around the clock. Based on the pipe’s age, the initial read on the situation pointed to slow, steady wear: rust, separated joints, decades of use finally catching up.

Preparing pipe for the instillation of concrete collar

Backfilling excavated area; compacted in lifts

Compacting asphalt to match existing grade

Digging In

Before repairs started, the team had to remove the groundwater that would interfere with the repair. Crews installed a ring of well points, narrow borings that allow water to be pulled out of the ground. As the site was in an area with a high-water table, this, was a crucial step. As crews dug underground, they would hit the water that naturally occurs. That risked hydraulic heaving, where water pressure pushes soil upward and destabilizes the excavation, potentially exacerbating the current erosion and sinkhole. Removing this water before the dig reduced complications down the line. To keep the water out, pumps were installed to continually draw out any water during the repair, approximately a week in total. From there, they used hydro-excavation, a non-destructive digging method that uses pressurized water instead of mechanical bucket excavation. It exposed the pipe gently enough not to disturb the water main running right next to it. Since the pumps were already running, this was a logical shift that again simplified the process.

However, once ground was broken, the plan changed almost immediately, and the team adjusted without losing time. The trench box the crew had brought to shore up the walls of the excavation would not fit in the space available. Instead, the team engineered a custom shoring solution on-site: a wall of steel sheets along both sides of the trench, held apart with adjustable steel bars. The setup could be built in place around the water main and conduits instead of dropped in as one fixed-size piece.

What the Pipe Actually Showed

Once the pipe was fully uncovered, the damage did not match the original assumption. This was not decades of slow decay. It was a single, isolated impact: a break about 3 feet long and as much as 20 inches wide, caused by a drilling operation for unrelated utility work that had nothing to do with the storm system itself. The rest of the pipe was in good condition.

The difference in the root cause is crucial to properly remediating the site. A pipe failing from age usually needs a much bigger fix, often a full section replacement or a structural liner running well past the damage. A pipe with one isolated point of damage from an outside cause needs something else entirely. AQUALIS field crews are trained to confirm the actual cause before designing a repair, which is what let the team here match the fix to the real problem instead of overcorrecting damage that was not there.

The Fix

With water lines, overhead utilities and a roadway that needed to stay open all crowding the work zone, the crew built a custom wood form at the damaged section and poured a concrete collar around it to reinforce the pipe. The collar went in over the course of one day and cured for three days before the trench could be filled back in.

The trench was filled back in layer by layer with fresh material;, each layer compacted before the next went on. The steel sheet piling came out once everything had settled, and the road got new asphalt to match what was there before.

Results

A camera run through the pipe afterward confirmed the repair held and the rest of the system was sound. The team confirmed the actual cause before repairing it, so the fix matched the real damage instead of what the initial assessment expected, sparing the property unnecessary digging and downtime. That kind of attention to detail is standard practice for AQUALIS on every project. The road is open again, and underneath it, the pipe is doing exactly what it is supposed to do.