CPD Specifier May 2015 issue September 2014 | Page 40

Outdoor Engineering

Flood protection
and erosion prevention.
Where do we go from here?
The severe storms and widespread flooding of winter and early spring 2014 have
highlighted the vulnerability of our coastal and low lying communities and the
importance of making sure appropriate flood protection and erosion prevention
measures are in place.
CPD Specifier reflects on the recent storms and floods which caused so much disruption
and asks “What resources can industry provide to help prevent it happening again?”
Rutland Water
At Rutland Water, the largest reservoir by surface area in England,
engineers installed the company’s Enkamat A20 erosion prevention
matting on the waterside embankment slopes to prevent water scour
caused by wind-blown waves.

It is widely recognised that the building and maintenance of adequate
protective embankments and erosion prevention measures are crucial
priorities if a repeat of the recent devastation to coastal and flood-plain
communities is to be prevented.
Engineers and manufacturers have their work cut out to address these
challenges and one company at the sharp end of erosion protection and
watercourse management is Oxford based Maccaferri.

Enkamat is a high performance, three-dimensional matting made of
polyamide monofilaments pre-filled with bitumen bound mineral filter of
dense stone chippings. At 22mm thick and with a weight of 20kg/sqm,
Enkamat A20’s composition and solid mass provides an immediate
erosion protection. Its open, woven texture allows vegetation to grow
through its structure, resulting in a naturally vegetated slope within a few
months.

Best know for the ubiquitous wire mesh Gabion Basket system, the
company has developed hugely and is now a world leader in innovative
environmental engineering solutions with expertise in erosion control and
river training, retaining walls and soil reinforcement, coastal protection,
and other related disciplines.

The system has been widely used on river or canal banks, lakes and
reservoirs throughout Europe and is designed to be resistant to the wave
action caused by small ships and pleasure craft passing by.

Over recent years the company has provided creative and cost efficient
solutions to a variety of water related engineering challenges. Here we
take a look at a handful of examples.

Boscastle
At the pretty sea-side Devon village of Boscastle, the scene of devastating
flash flood in 2004, Engineers Halcrow used over 7000sq metres of
Maccaferri wire mesh, Reno Mattress units and Mac Mat R geomats in
planned remedial work to reinforce and protect embankments of the River
Valency, which runs through the village to the sea.
Reno Mattresses are large flat wire cages, similar to gabions, lined with
filter fabric and filled with site won fill material. At Boscastle, they were
overlain with Mac Mat R, a three dimensional mesh reinforced geomat.
Together they create a hard, durable embankment protection system
capable of withstanding extreme flow velocities and impact from waterborn debris.
Embankment reinforcement
Simplicity, durability and speed of construction have made stone filled
Gabions the default material for embankments stabilisation and erosion
protection. Their physical mass and open, free draining composition gives
them enormous structural strength and res