SLOPES WITH VEGETATIVE MATRIX

The planting of a slope composed primarily of topsoil is limited to the selection of a seed-type having suitable herbaceous and shrublike properties, provided that the quality of the soil itself is appropriate for the growth and preservation of vegetation. It’s also true, however, that topsoil, during the initial phase of planting, is easily subjected to washout and surface erosion brought about by rainfall, its consequential rilling, and by wind activity. Such phenomena can induce significant loss of soil and the consequential formation of moderately deep furrows. All this occurs due to the barrenness and fragility of the vegetation during its first phase of growth and consequentially, to the reduced penetration of the root system into the substrate.

BANKS FOR EARTHEN CANALS AND WATERWAYS

Earthen canals and waterways in general are continuously exposed to erosion and flooding from rainfall, runoff and surface runoff, both on the canal bed and their banks. Under these conditions, the concentrated forces produced by the velocity can cause the formation of holes, longitudinal and transversal furrows and undercutting at the base. The subsequent sliding of earth down the embankment onto the canal bed can also affect the hydraulic properties of the canal itself.

A dense vegetative plant covering on the bed and banks of the canal guarantees an effective defence considering that it increases the profile roughness (subsequently reducing the flow velocity), the sedimentation of suspended solid particles and prevents the detachment of soil. The formation of plant growth covering is accelerated by using a three-dimensional TENAX MULTIMAT geomat which, due to its flexibility, is easy to place on both the bed and banks of the dry canal.

Ashford (GB): Erosion protection of a surface water drainage channel with TENAX MULTIMAT geomats

Ashford (GB): Grass growth established three months after hydroseeding

Anchored to the slopes and base by means of U shaped anchors, the geomat is filled with topsoil and seeded. The planting process allows the roots of the grass to firmly anchor themselves to both the three-dimensional structure and the underlying soil, together forming permanent protection.

Even before vegetation begins to grow, TENAX MULTIMAT geomat is capable of drastically reducing the quantity of soil erosion from slopes and above all it eliminates the formation of rivulets and furrows.

Full-scale tests performed at the University of Utah (USA) have demonstrated that the limit of water velocity, below which erosion of the bank and the base does not occur, greatly increases when the channel is protected by TENAX MULTIMAT geomats.