Reduce Stormwater Runoff with Green Walls & Permeable Pavements

There is more focus today on designing natural structures that offer stability as well as environmental benefits. As concern for runoff and flooding potential grows, engineers are rethinking how their designs can contribute to stormwater and mitigation initiatives without compromising their project’s performance.

Earth retention structures, commonly used in civil construction works, have spilled over onto sites with irregular topography, especially related to transportation upgrades. Retention walls are used in place of simple earth slopes, generally dictated by the severity of grade change and the availability or cost of land within the project site. Concrete cribs and steel sheet piles are typical wall structures, but they aren’t low environmental impact solutions and they don’t promote stormwater infiltration.

Living Retaining Walls Offer Design Versatility, Low Environmental Impact

A natural alternative is GEOWEB vegetated 3D geocellular walls.  GEOWEB walls offer green aesthetics through living plantings—as well as flexibility of design for a variety of wall configurations (e.g. gravity, reinforced, steepened slopes) and conformance to native landscapes.

The unique feature of geocellular walls is their horizontal terraces and exposed outer fascia cells at the wall set-back. This open fascia creates a natural environment for selected sustainable vegetation to grow and is also highly permeable–acting as a multitude of planting pots where rainwater can infiltrate, rather than run off onto hard pavements. Their stormwater benefit is ideally suited for Low Impact Development (LID) and Green Infrastructure (GI) design.

Permeable Pavements Capture Stormwater at its Source

With increases in surface runoff from new construction and expanding hard pavements, the capacity of existing stormwater systems are being pushed beyond their limits. As a result, environmental regulations limiting runoff continue to increase the demand for access roads, parking areas, road shoulders and walkways that are porous.

Land development initiatives such as GI and LID are also helping to escalate the use of low environmental impact products to reduce stormwater naturally at its source.  Porous and permeable pavements offer immediate infiltration at the point of contact—not only reducing runoff, but reducing the size/need for stormwater infrastructure.  Gravel pavers contain open-graded aggregate for fast infiltration without any traffic restrictions.  Even the pavement layer acts as stormwater detention. Grass pavers are designed to protect turf from damage caused by occasional traffic.  Both can receive runoff from adjacent hard pavements, and store predicted stormwater in the base for natural percolation.

Design Support & Resources for Walls & Pavements

Selection of retaining wall type is influenced by a number of criteria (e.g. surcharge loadings, wall height and batter, soil conditions, space accessibility).  A free project evaluation from the manufacturer helps determine design feasibility.

A downloadable porous pavement interactive tool is also available to help designers determine best options for site conditions, stormwater requirements, and expected use.

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