CASE STUDY: TRADER RIDGE DITCH REPAIR

THE PROBLEM

The Trader Ridge conveyance ditch collected runoff from the surrounding industrial area. Three culverts emptied into the ditch over several years, causing the vegetated channel to erode.

In addition, the spring freshet each year compounded the ditch’s erosion problems, washing topsoil and clay downstream.

The cost of the annual repairs of the ditch were no longer sustainable, and with the risk of water line infrastructure becoming exposed, a permanent erosion control solution was required.

THE SOLUTION

After initial consultation, the project team met a few times to discuss the viability of the fabric formed concrete for this application. Stakeholder concerns were addressed, Synthetex fabric formwork was selected and a plan for installation and completion was developed.

Based on the provided survey data, the Synthetex engineering team created a panel layout drawing. Once approved, Synthetex manufactured and shipped (12) Enviromat FX 100 (1”) panels, custom fabricated to support vegetation and to fit the channel dimensions.

The installed cost of the HYDROTEX fabric formed concrete project was

very competitive, including earthwork, product, grout, installation and supervision.

Other options were considered including articulating concrete block and a concrete cloth product, but both proved to be more expensive.

Site was graded, top soiled and seeded. A straw/coconut blanket was stapled in place. Formwork panels were pulled into place, according to detailed drawings supplied by Synthetex. All culvert protrusions were cut and sewn on site to insure intimate contact with the channel base and the culvert. A high flow, high strength fine aggregate cement grout was pumped into the fabric formwork, filling two millwidths at a time. An approximate 75m3 was pumped in a total of 4 days to complete the project. On-site product installation support and supervision was supplied by Synthetex. Engineer review and project management was supplied by Helix Engineering Ltd. Specification generation and project sale by Cross Country Canada. In addition, there was open collaboration throughout the entire project from start to finish, making it a very successful installation.

PROJECT SUMMARY

Project Name: Trader Ridge Ditch Repair

Project Owner: County of Grande Prairie

Location: Grande Prairie, Alberta, Canada

Project Type: Channel Armoring

Project Engineer: Helix Engineering

HYDRAULIC INFORMATION

Max Water Depth: 0.9m

Max Water Velocity: 1m/sec or 3.0m³/sec

SOLUTION

HYDROTEX® Fabric Formwork Enviromat FX-100 (1” thick) vegetated mat

Coverage area: 2,162 m²

Concrete Volume: 75m³

Installation Time: 4 days