The quick answer
If you need a cofferdam to isolate a bridge work area from a flowing creek, river or drain so you can repair it in the dry, Apex Envirocare hires, supplies and installs the Aqua-Barrier™ water-inflated cofferdam system Australia-wide. As the exclusive Australian representative for Aqua-Barrier, Apex Envirocare holds barriers in stock in 1.8 m and 2.4 m heights, delivers them to site, and can provide on-site installation supervision and technical support. A 2.4 m barrier at the standard 25% freeboard limit holds back roughly 1.8 m of water — enough to dewater most abutment, pier and deck-repair work zones under a bridge.
Why a water-inflated cofferdam suits bridge repairs
Bridge repairs almost always mean working next to — or in — a watercourse. Abutment underpinning, pier patching, scour protection, bearing replacement and concrete repairs all need a dry, stable work area, but the creek or river doesn't stop flowing while you work. A cofferdam is how you separate the two.
Traditional sheet-pile or earthen cofferdams are slow, expensive to install and remove, and they penetrate the bed — which is a problem in a sensitive or hard-bottomed watercourse, and a headache when it comes time to demobilise. The Aqua-Barrier water-inflated cofferdam takes a different approach:
- It sits standalone on the bed. No piling, no bed penetration, no anchoring. The barrier is a heavy-duty PVC tube that you lay out, then fill with water. Its own weight and footprint hold it in place.
- It fills from the site's own water — including saltwater, so tidal and estuarine bridge sites are fine.
- It's reusable many times and the PVC is infield-repairable, so a puncture on site doesn't end the job.
- Units overlap at any angle to build length, corners and enclosed work cells around a pier or abutment.
Because there's no driven pile and no excavation, install and removal are fast, and the bed is left as it was found. That's a genuine advantage on bridge sites where you're working around existing structures and don't want to disturb the foundations.
How the enclosure works around a bridge
For a single abutment or a section of the deck, you typically run a barrier out from the bank, across the front of the work zone, and back — forming a U or a full cell that shuts the water out. Once the enclosure is sealed, the trapped water inside is pumped out (dewatered) and your crew works on dry ground. When the repair is finished, the enclosure is dewatered externally, the barriers are deflated, rolled and removed, and flow returns to normal.
Apex Envirocare's own dewatering and water-diversion crews do this work routinely, so the cofferdam hire can come with the plant and know-how to actually run the isolation — not just the equipment dropped at the gate.
Getting the size right: freeboard, depth and flow
The single most important thing to get right before you hire is whether the barrier suits your water depth and flow. The Aqua-Barrier system runs on a 25% freeboard rule — the water you're holding back should be no more than about 75% of the barrier height.
- 1.8 m barrier — holds back roughly 1.35 m of water.
- 2.4 m barrier — holds back up to roughly 1.8 m of water and sediment combined.
These two heights are the standard sizes Apex Envirocare stocks and recommends, and they cover the great majority of creek, drain and river bridge repairs. Custom heights are available where a deeper site genuinely needs them, but that's the exception rather than the rule.
A few limits are worth knowing up front so you hire the right solution:
- Deep water. If your water is deeper than about 1.8 m, the standard barrier can't be used at the required freeboard — you'll need a taller/custom barrier or an engineered solution.
- Fast flow. At or above about 0.9 m/s (3 ft/s) current, the barrier needs extra freeboard and engineering sign-off. Many bridge sites are on slow to moderate flow, but flood-prone rivers need a proper assessment.
- Unstable ground, steep or very uneven beds, and wave or dynamic loads — slick or weak soils, excess slope, or wave action all warrant a site assessment and possibly external support before deployment.
- It's a temporary works solution, not a substitute for an engineered permanent dam.
Apex Envirocare will size the barrier against your measured water depth, bed conditions and flow rather than guessing — which is what keeps the enclosure sealed and your crew safe once the water's held back.
Working in a sensitive or tidal watercourse
Many bridges cross environmentally sensitive water — foreshores, estuaries, wetlands. Because the Aqua-Barrier sits on the bed with no piling and no bed penetration, and because it can fill with the site's own water including saltwater, it's well suited to sensitive foreshore and sediment-retention work where you can't be driving piles or disturbing the bed.
Apex Envirocare used exactly this approach for sediment retention on the Swan River foreshore for the Camfield Drive Extension with Laing O'Rourke at Burswood, aligning its methods to WA DWER requirements on that sensitive-foreshore project. That's the kind of in-stream, low-disturbance isolation the system is built for.
Why hire through Apex Envirocare
Apex Envirocare is a wholly Australian owned and operated environmental works contractor with 20+ years in business and is the exclusive Australian representative for the Aqua-Barrier water-diversion system. That matters for a bridge-repair buyer for a few concrete reasons:
- Stock and supply. Barriers are held in stock in the standard 1.8 m and 2.4 m heights, so you're not waiting on an overseas order.
- Self-performing crews. Apex Envirocare runs its own crews and plant and can supply the cofferdam plus the water diversion, dewatering and technical support around it — or lease you the equipment with on-site installation supervision if you're self-delivering.
- National reach. Apex Envirocare operates Australia-wide and mobilises to remote and mine sites nationally, and is headquartered in Western Australia.
- Trusted by blue-chip clients. Mainroads WA, John Holland, Water Corporation, BHP, Rio Tinto and SA Water are among the organisations Apex Envirocare works with across dredging, desludging and water-diversion projects — including civil and roadworks contractors doing exactly this kind of in-stream structural work.
What to have ready when you enquire
To get a fast, accurate recommendation, have these details ready:
- Water depth at the work zone (and how much it varies).
- Flow velocity or whether the watercourse is slow, moderate or flood-prone.
- Bed conditions — rock, sand, silt, slope, evenness.
- The footprint you need to isolate — length, corners and whether you're enclosing a pier, an abutment or a stretch of the channel.
- Whether it's tidal / saltwater and whether the site is environmentally sensitive.
- Access for delivery and how long the isolation needs to stand.
With those, Apex Envirocare can confirm the right barrier height, the layout, and whether your site sits inside the standard envelope or needs a custom/engineered approach — then hire or supply the Aqua-Barrier and support the works.
