Asphalt Specialists In Hydraulic Engineering


Coastal Protection
Dam Waterproofing
Dam Erosion Protection
Dam Spillway Protection
Ports & Harbours

Flood Alleviation

River Yare
Bodmin Town Leat

Rivers Blackwater, Crouch & Colne

Fingringhoe Ranges
River Training
Scour Protection
Underwater Impact Protection
Strengthening Rock Structures
Landfill Linings
Offshore Services

Rivers Blackwater, Colne and Crouch, Essex

Historically, high quality farmland in this area has been protected by clay embankments generally armoured with a layer of Essex Blocks (115mm thick) jointed with hot-poured mastic. Essex Blocks perform very well under moderate wave attack, where the embankment is stable, and where the slope lengths are not too long. Where blocks are loosened and removed - in areas of settlement or relatively high wave attack - failure is rapid and progressive. With high annual maintenance costs for the most exposed or unstable areas, our client, the (then) National Rivers Authority sought a more cost-effective solution using Lean Stone Asphalt (LSA)/Open Stone Asphalt (OSA).

  • Essex blocks stripped off the embankment and placed to protect the toe
  • 150mm LSA placed as filter and regulating layer
  • 150mm OSA armour placed in situ over LSA, following all shapes and contours
  • Over 10 sections completed since 1989
  • All sections maintenance-free to date
Blackwater     Blackwater

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