Terrastop™ silt fences use fabric as an entrenched interceptor to control pollution caused by silt-laden construction site stormwater run-off.

Problem

Many construction, forestry and farming activities result in disturbed or bare ground that is vulnerable to weather erosion. The silt-laden run-off, plus site debris and other pollutants, often contaminate surrounding land, rivers, streams, lakes and drains - resulting in significant environmental diffuse pollution and potentially costly fines.

However, due to the on-going nature of such work, it is generally not possible to protect exposed surfaces until the project is complete. So stormwater from such sites represents a major non-point source of diffuse water pollution in the UK.

Solution

Terrastop™ Premium is a special, high-quality, permeable, technical filter fabric for stormwater surface run-off pollution management. It can be installed as an entrenched vertical entrapment fence, and is designed to intercept and detain stormwater run-off, trapping harmful silt through settlement and filtration before it leaves the site.

Terrastop™ Premium and HighFlow silt fences, offer a proven, practical, economic and effective method to reduce stormwater run-off pollution from such locations. While Terrastop™ Basic offers a budget option for low-risk, small-scale projects, with less stringent environmental requirements such as domestic use.

The benefits of the silt fence are increasingly becoming recognised in Britain: The Environment Agency / SEPA Pollution Prevention Guidelines (PPG5) now recommend the use of silt fences to reduce silt transport from exposed ground and stock piles; and research at The James Hutton Institute, using Terrastop silt fencing, demonstrated that even after post-harvest contour grubbing of potato fields an estimated 80 tonnes of soil containing 60-70kg phosphate-P contaminants was trapped from a 17ha field [Dr Andy Vinten].

Silt fences have also been used extensively in other countries for many years, and their proven performance (Intercepting up to 86% of suspended solids [Horner et al 1990]) has made them a standard Best Management Practice on a diverse range construction projects, while in-depth research and practical experience has identified the most important characteristics for effective results.

Kirsty Liddon’s Edinburgh University Dissertation “Prevention of Diffuse Pollution from Active Forestry Harvesting Sites:” concluded “the Hy-Tex [Terrastop Premium] material appears to be the most suitable material for use as sediment retention as it has the most consistent performance between differing soil types retaining the highest volumes of sediment for both gley and peat solutions.”

Features and benefits

  • Burial depth and max silt height marker lines

  • Top tying-off + tensioning ribbon

  • Fibrous weft yarn provides excellent filtration (Premium)

  • Proven performance

  • Traps harmful silt via settlement and filtration

  • Purpose designed for application

  • High tensile strength

  • UV-stabilised

  • Non fraying reinforced edges

  • High-quality weave

  • Exceptional balance of permeability vs filtration

Specifications

Feature

Terrastop™ Premium (Terrasilt GR180)

Terrastop™ HighFlow

Terrastop™ Basic (Terrasilt GR90)

Tensile Strength

22kN/m

32kN/m

32kN/m

Puncture Resistance (CBR)

3,500N

3,700N

1,600N

Permeability (ISO 11058)

21 l/m².s

(45 l/m².s to AS 3706.9)

190 l/m².s

21 l/m².s

Opening Size (ISO 11058)

180µm

320µm

310µm

Weight

200g/m²

145g/m²

88g/m²

Material

1000µ thick, green/black, 400kLy UV stabilised, polypropylene, tear resistant non-fraying edges.

1000µ thick, green/black, 400kLy UV stabilised, polypropylene, tear resistant non-fraying edges.

500µ thick, green/black, 400kLy UV stabilised, polypropylene, tear resistant non-fraying edges.

Roll Size

0.75 x 100m

1.00 x 100m

0.75 x 100m

Other Key Features:

Fibrous weft yarn, burial depth and max silt height marker lines, top tying-off + tensioning ribbon.

Burial depth and max silt height marker lines, top tying-off + tensioning ribbon.