This training was prepared by the U.S. Department of Agriculture (USDA) team of Otto Gonzalez-USDA Foreign Agricultural Service (Team Leader), Jon Fripp (Civil Engineer) and Chris Hoag (Wetland Plant Ecologist)-USDA Natural Resources Conservation Service (Civil Engineers). Fripp and Hoag were the primary authors of this material. The U.S. AID provided funding support for the USDA team. 9 Introduction to Gabion Construction

Gabions are also good to use if: 1 - A required stone or riprap size is larger than what is available. 2 - A vertical wall is needed Check Dams can be built with many different types of materials Rock Logs Metal Concrete Gabions others

What is a gabion? Answer: A gabion is a big wire box full of small stone.

The wire baskets can be purchased or locally constructed

The Basket is construct so it can be folded into a box Edges need thicker wire (hem) Hem

The hem is used to tie the box together Hem

Woven wire should be 0.3 cm (0.115 inch) thick Woven opening should be 8 to 12 cm Hem should be 0.4 cm (0.153 inch) thick Should not exceed 1 m without an inside wall Inside wall

Straight edges

Assembly of the baskets includes fastening the edges and inside wall before placing

Lace the hems on the sides with wire Double half-hitches at spacing between 8 to 15 cm. Lacing wire is 0.2 cm

HITCH SPACING

LACING WIRE The hems must be tightly held together

DOUBLE HALF HITCH Double Half Hitch Clove Hitch

LACING BASKETS WITH WIRE NOT this!

Can use rings to quickly assemble

Use a machine to close ring

A cheaper way is to use a “Clute”

It is not as strong so use more

Unless you have a big crane, it is best to place the basket then fill with stone

Stone Size The stone must be larger than the opening of the wire mesh

These stones are too small The basket may not hold them

Can use smaller stone in middle But the stones on the outside must larger than the opening Workers may mix this up so be careful. Need good supervision

Fill in layers Place internal wires every 0.5 meter

Place Stones carefully on the outside so that the face is uniform. Basket should be full but not buldging

Assemble Gabions Like a Brick Wall Like this

Not like this

Plants can be placed between gabions

Do you see anything wrong in this picture? Test time! Answer: lacing

Do you see anything wrong in this picture? Answer: Rock size too small on surface

What is the problem here? Answer: not filled completely, also some rocks are too big and some too small

Do you see anything wrong in this picture? Answer: Nothing, but joints are close, but overlapping joints are hard to achieve

Do you see anything wrong in this picture? Answer: Nothing, good joints, rock size, fill

Do you see anything wrong in this picture?

The End