Concrete Scour Aprons

Concrete Scour Aprons

Get a project estimate today:

Concrete Scour Aprons

Get a project estimate today:

Cast a custom concrete scour apron with HYDROTEX fabric forms for the casting of concrete.

Adding scour aprons to any dam, mining, or other facility is easy with custom-made HYDROTEX fabric-formed concrete mattresses.

Our products can also be used to meet other common scour protection requirements such as bridge pier scour protection, prop scour protection, and rubble mound structure foundations.

How is HYDROTEX used to cast scour aprons?

The Problem

Scour can happen anywhere, especially at the base of locks, dams, and port quay walls. Left unattended, such scour can cause damage to the surrounding infrastructure, limiting its effectiveness and lifespan. Don’t leave these vulnerable areas to the mercy of the severe hydraulic events they experience.

The Solution: HYDROTEX Fabric Forms for the In-Situ Casting of Concrete

Effectively prevent critical failure of costly dam, port, or mining infrastructures by casting a concrete scour protection mattress with HYDROTEX fabric formworks for the casting of concrete.

This mattress is placed underwater at the base of locks, dams, and quay walls, permanently remediating and protecting against severe scour.

Best HYDROTEX Fabric Forms for Casting a Scour Apron

Articulating Block Concrete Mat on Slope

HYDROTEX® Articulating Block

HYDROTEX Uniform Section

HYDROTEX® Uniform Section

HYDROCAST® Armor Units

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Scour Aprons for Dams

HYDROTEX fabric-formed concrete mats are perfect to cast scour aprons.

These scour aprons can help you prevent erosion at conduits or anywhere else in or around the dam.

Scour aprons are especially useful at maintaining healthy soil conditions and providing a buffer between the original soil and the dam’s man-made structures. Installation is simple: lay out the geosynthetic panels on the area you’d like to protect, then pump with fine aggregate concrete.

Scour aprons are typically needed for:

Lock and dam

Related Solutions

HYDROCAST® Formworks

HYDROCAST® (HC) Formworks

Synthetex specializes in manufacturing engineered, project-specific fabric formworks for the casting-in-place of concrete armor units and structures for a spectrum of underwater applications.  For more than 25 years, engineering, contractor, and government clients around the world have relied on HYDROCAST® to design and fabricate the special concrete formworks they need for their projects.  They know Synthetex will deliver only the highest quality products, materials, and workmanship—guaranteed.

As leading specialists in the fabrication of fabric formworks for underwater casting of concrete structures, Synthetex offers engineered solutions such as custom armor units for spillway aprons, bulkheads, tunnel and pipe plugs, and more.  Our expertise includes working with nearly every component and material used in concrete formworks today, including high-strength polyester and Kevlar® fabrics and sewing threads, and steel and high tenacity polyester reinforcement cables.  With newly expanded manufacturing capabilities, we’re able to offer end-to-end solutions in-house, delivering finished products that are designed and built to perform.

HYDROCAST® fabric formworks provide low-cost in situ concrete alternatives to natural rock and precast concrete where they are not possible or practical.  Cast-in-place, concrete armor units and structures eliminate the requirement for heavy lift cranes for placement, where rock riprap and precast concrete blocks may require lifts of tens of thousands of pounds.  As with our concrete grout bags, HYDROCAST® can be positioned and filled with concrete from the surface in shallow water or by divers in deeper water.  Since the flexible fabric forms are cast-in-place, they intimately adapt to variations in the subgrade or bottom contours.  Installations do not require dewatering, a crucial advantage in emergency repair of scour aprons.

Synthetex worked closely with the U.S. Army Corps of Engineers and Bergmann Associates for the design of fabric forms for the underwater casting of armor units for the scour aprons of two Ohio River locks and dams. The concrete armor units ranged in sizes, up to 36 ft long x 18 ft wide x 6 ft high, and weights in excess of 10 tons each.  The specification of a fabric formwork that can be deployed underwater and then pumped full with concrete avoided the lifting of the massive armor units.

Heavy-duty, puncture-resistant formworks designed to meet pumped concrete pressures were placed into reusable steel frames and lowered into place in rows and columns.  As the frameworks were lowered they were filled with water to offset buoyancy and to inflate the formwork to its rectangular dimensions.  As concrete was pumped into the formwork an equal volume of water was displaced. The flexible bottom allowed intimate contact with the uneven subgrade. And, all of this is performed entirely under water and constructed on a slope.

HYDROCAST® concrete grout bags meet the requirements for a reliable and economical cast-in-place alternative to traditional rock (riprap) and precast concrete for the armoring of sand-filled geocontainers.

Applications for HYDROCAST® custom fabric formed concrete units:

  • Concrete armor units for dam scour aprons
  • Concrete armor units for the main primary protection of breakwaters, levees, and dikes
  • Artificial concrete reefs
  • Concrete armor units as the protection of sand-filled geocontainers
  • Pipeline and tunnel closures
  • Concrete quay walls and seawalls
  • Concrete sealing of large mineshafts and tubes

Ronald Stive, Director of Projects, Maritime and Waterways at Royall Haskoning DHV, has reported a trend toward using sand packed into geocontainers at the core of a breakwater, a solution that could be ten times cheaper than traditional rock.

“What we have noticed in the past ten years in our port and breakwater projects is that all around the world, people are in a hurry,” he noted. “They don’t accept that these types of structures will take years to design and to construct, so they are always looking for alternative ways to do it faster.

“Secondly, there is a trend to go into deeper water, and into areas where you don’t have quarries nearby and you may have problems where the seabed isn’t stable enough or there’s seismic activity. In these remote areas, you have to look for alternative designs to the traditional rubble mound type of breakwater, because of the fact that the materials are too far away or too costly to bring in.”

HYDROTEX® Uniform Section

Uniform Section (US) Concrete Linings

Uniform Section (US) Concrete Linings

Uniform Section (US) Concrete Linings are similar to traditional concrete slope paving.  They create a solid, high-quality concrete lining with a relatively low hydraulic resistance and uniform cross-section.  Uniform Section linings are used to reduce the infiltration or exfiltration of aggressive waste and chemical fluids into or out of open channels and basins.  They are also used to reduce exfiltration in arid regions where open channels and basins require watertight linings.

Uniform Section Concrete Linings are resistant to leachate and most chemicals.  They protect geosynthetic liners from mechanical damage, exposure to UV light, and freeze-thaw cycles.  These self-supporting, high-strength linings permit construction on steep side slopes and replace the conventional use of clay or sand as liner protection. Placement of the forms and concrete filling can be performed without the use of equipment on the liner.  The tensile strength and abrasion resistance of the fabric protect the liner from the pumped concrete.


HYDROTEX® Articulating Block

Articulating Block (AB) Concrete Linings

Articulating Block (AB) Concrete Linings

Articulating Block Mats form cable-reinforced concrete block mattresses that resist erosive forces. They are often constructed where a revetment is exposed to frontal attack by wave action.

AB Mats are typically used to protect coastlines, canals, rivers, lakes, reservoirs, underwater pipelines, bridge piers, and other marine structures from propeller wash, ship wakes, wind waves, currents, and high velocity flows. They are also used in environmental construction for landfill caps, down chutes, and collector channels.

The AB fabric form consists of a series of compartments linked by an interwoven perimeter. Grout ducts interconnect the compartments, and high-strength revetment cables are installed between and through the compartments and grout ducts.

Once filled, the AB Mats become a mattress of pillow-shaped, rectangular concrete blocks. The interwoven perimeters between the blocks serve as hinges to permit articulation. The cables remain embedded in the concrete blocks to link the blocks together and facilitate articulation.


Submit a Request for an Articulating Block Specification

We’ll get back to you within 1-2 business days. All specifications are available in both nylon and polyester configurations.

Submit a request for a technical specification

We’ll get back to you within 1-2 business days. All specifications are available in both nylon and polyester configurations.

HYDROTEX® Filter Point

HYDROTEX Articulating Block

HYDROTEX Uniform Section

HYDROTEX Filter Band

HYDROTEX Enviromat

Emsworth Lock and Dam, Back Channel Left Abutment Stabilization and Scour Protection

Emsworth Lock and Dam, Back Channel Left Abutment Stabilization and Scour Protection

Allegheny County, Pennsylvania, USA

Emsworth Locks and Dams are located on the Ohio River immediately downstream from the city of Pittsburgh, Pennsylvania. The back channel dam and locks are located on Neville Island, Pennsylvania, at river mi 6.4. The dam length is 960 ft (293 m) and the water depth exceeds 30 ft.

During low-flow conditions the loss of the pools of the Ohio, Monongahela and Allegany Rivers, at the point of Pittsburgh, would cease all navigation. Shippers using Emsworth had estimated that loss of the dam would increase transportation costs by $130 million annually.

The $32 million U.S. Army Corps of Engineer’s Contract W911WN08B0007 was awarded to Trumbull Construction in July of 2008. Synthetex was brought into the project, working closely with the U.S. Army Corps of Engineers and Bergmann Associates for the design of formworks for the underwater casting of armor units for the scour aprons on both the Main and Back Channels of the Emsworth Locks and Dams. The concrete armor units ranged in sizes up to 32 ft x 18 ft x 6 ft and weights in excess of 15000 lb each. Prior to the installation of the HYDROCAST® Concrete Bag Scour Protection downstream of the dam, there were 10 ft (3.0 m) deep scour holes and 65% of the existing stone scour protection was in a failed state. Due to the extreme corroded state of the dam gates, failure of any one of seven lift gates would most likely cause a portion of the stilling basin to fail and possibly undermine the dam. The dam had been categorized as Dam Safety Action Class 1, urgent and compelling.

The scour protection measures consisted of grading, placing bedding stone, and installing HYDROTEX® concrete-filled bags downstream of the existing dam for six individual bays.  During the project, approximately 10000 yd³ (7600 m³) of concrete was placed in more than 200 individual armor units with no lost time for more than three years.

Owner:U.S. Army Corps of Engineers
Engineer:U.S. Army Corps of Engineers / Bergmann Associates
Contractor:Trumbull Construction
Installation:2008 – 2014

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