The purpose of longitudinal structures. Longitudinal structures are hydraulic structures with their length parallel to the river flow. These structures are often built on, or supporting, existing natural banks and typically extend for a considerable distance.They are used for a variety of purposes, such as:
- erosion control
- control of meandering
- containment of the normal flow channel
- flood protection
Counteracting natural forces in water courses. A trained water course reduces land-loss caused by erosion, yet the inherent strong longitudinal or transverse currents can still erode the river banks or the toe of the banks making them unstable. Therefore the river bank protection solution must be sufficiently robust and well-designed to counteract these forces.
Steep channel banks: Mass gravity bank retention
Supporting steep banks while protecting against erosion. When the channel bank is overly steep and destabilised by erosion, a structure is required to retain the bank as well as provide on-going erosion protection: flexible double twist hexagonal mesh gabion walls or Terramesh® reinforced soil systems are often used. A flexible system is essential in these testing conditions, along with suitable corrosion protection on the wire used in the gabions. Heavily galvanised wire with an additional polymer coating, in accordance with local regulations, are required.
Shallow channel banks: Bank protection
Erosion protection is required, even for stable banks. When the channel bank is geotechnically stable, a simple erosion protection solution may be appropriate. Without this protection, the slope may gradually erode and steepen over time, until it becomes unstable.
Our solutions are tailored to your needs. We offer a graded, logical range of hydraulic erosion protection techniques so that the level of intervention is appropriate to the erosion risk you face; Natural BioMac® biodegradable biomats; man-made MacMat® reinforced and unreinforced 3-D geomats and traditional double twist steel wire-based products gabions and Reno Mattresses.
Our natural engineering solutions. We also offer natural engineering techniques. Soil bioengineering is based on the combination of man-made materials and plants: the man-made materials provide immediate and ongoing protection to the local situation and create ideal conditions for the natural re-vegetation of the slope. The roots of the vegetation are anchored firmly in the erosion protection.
Our multi-purpose, high tech design software. Our engineers use our design software, Mac.R.A. 1 and Mac.R.A. 2 in order to design channels, longitudinal and transverse structures.
These enable us to rapidly perform preliminary hydraulic studies to evaluate the bank protection (Mac.R.A. 1) or the transverse weir (Mac.R.A. 2) required. An open library of products enables a combination of man-made and natural solutions to be considered.