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Hampton Forest Slash Barrier

Debris Flow & Shallow Landslide Protection - Hampton Forest Slash Barrier 2021

Looking downstream at the completed structure

Debris Flow & Shallow Landslide Protection - Hampton Forest Slash Barrier 2021

Looking Upstream - Installing the support ropes

Debris Flow & Shallow Landslide Protection - Hampton Forest Slash Barrier 2021

Looking downstream at the completed structure which is hardly visible

Debris Flow & Shallow Landslide Protection - Hampton Forest Slash Barrier 2021

Mid construction

Debris Flow & Shallow Landslide Protection - Hampton Forest Slash Barrier 2021

The contractor Rock Control installing the ring mesh

 

Year of installation

2021

Initial situation

The best management of slash material is at the source. However, even with the best practices, unforeseen extreme weather events can mobilise tree waste and debris into river channels which can cause significant damage to downstream assets. Historically in New Zealand forestry slash-catching barriers are built in-house with various combinations of rope, railway irons and recycled steel members which are then secured back to the bank with deadman anchors.  These structures are effective at stopping small volumes of slash material but risk catastrophic failure from overload subsequently releasing a large volume of material downstream at once. Rayonier Matariki Forests wanted to be proactive and set a new protection benchmark by installing a Geobrugg 1:1 tested and engineered solution, common in Europe but a first in NZ. Although designed for an extreme weather event, the intention is that the barrier is never significantly impacted through slash management at the source and then it can then be dismantled and used at another similar location.

Description

A VX140-H4 was installed in the river channel near the boundary of the 800ha catchment. The barrier height and location were chosen to utilise the large upstream catchment area for log and debris accumulation. The location also has good access for future maintenance/clearing if required. The VX140-H4 System (140kN/m²) was selected to provide sufficient capacity for both the static and dynamic loads of debris and driftwood (slashing) events. Wire rope anchors were used to transfer the loads back into the ground and provide design redundancy should some bank erosion occur. Edge protection was also installed on the top rope to protect the structure in the event of overtopping.

Contractor

Rock Control

Protected object

Other

Your local contact

Kevin H. Coyle
 

Kevin H. Coyle

Regional Manager Northeast

Natural Hazards
Hydraulic Engineering
Geobrugg North America, LLC,3 Beaudet Terr,Columbia CT 06237 / United States Regional Manager Northeast

E-Mail

Saleh Feidi
 

Saleh Feidi

Regional Manager California

Natural Hazards
Hydraulic Engineering
Geobrugg North America, LLC,8921 Emperor Ave.,San Gabriel, California 91775 / United States Regional Manager California

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John Kalejta
 

John Kalejta

Regional Manager Central US

Natural Hazards
Hydraulic Engineering
Geobrugg North America, LLC,3215 67th Avenue Pl,Greeley CO 80634 / United States Regional Manager Central US

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Bob Lyne
 

Bob Lyne

Regional Manager Southeast

Natural Hazards
Hydraulic Engineering
Geobrugg North America, LLC,8004 Windspray Drive,Summerfield NC 27358 / United States Regional Manager Southeast

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Pierce Runnels, Civil Engineer
   

Pierce Runnels

General Manager Geobrugg North America

Natural Hazards
Geobrugg North America, LLC,22 Centro Algodones , Civil Engineer General Manager Geobrugg North America

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Tim Shevlin
 

Tim Shevlin

Sales Director

Natural Hazards
Geobrugg North America, LLC,Salem OR 97302 / United States Sales Director

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