Turf reinforcement

Turf reinforcement mats (TRM) may be required in swales which are designed to convey higher velocity events. Most TRM are made of synthetic fibres and intended as a permanent part of the construction (unlike a temporary erosion control blanket). Mats should be applied with soil fill technique:

1. Grade the swale and smooth the top soil, removing any debris and large rocks,
2. Seed with turf grass mixture,
3. Dig 150 mm anchor trench at the top of the channel,
4. Secure blanket into the trench with staples every 300 mm. Backfill and compact soil into the trench,
5. Unroll mat in the direction of flow. Staple as recommended by manufacturer,
6. Overlaps should be 150 mm and stapled. Upstream mat should always overlay the downstream mat,
7. Anchor the bottom end of the channel in a similar fashion to the top,
8. Apply 15-20 mm of topsoil over the TRM, without the use of heavy machinery which can tear the mat and/or compact the soil,
9. An erosion control blanket may be applied to protect the surface through the first one or two years,
10. Irrigate until turf grass is established.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.