Clean and grade the base of the slope or stream banks to create a level and compact soil surface. Place a stabilizer board (3/4” plywood cut to the lift height) vertically on the outside face of the base lift. Lift height usually varies from 9” to 18” depending upon desired slope, soil type, flow velocity, etc. and must be determined by the engineer. Secure the stabilizer board using 2” x 2” wood stakes or #4 rebar pins. In case of a stream banks, KoirLog™s can be used along the toe of the banks for additional stability (Fig 1)
Unroll KoirWrap™ parallel to the stream banks or face of the slope as the case may be. Ensure that the secondary layer (jute fabric) is on top. Drape KoirWrap™ over the stabilizer board so that it forms a 900 angle where the inner face of the stabilizer board meets the soil surface. Keep a minimum embedment length of 3’ as shown in Fig.2. Anchor KoirWrap™ using 2” x 4” wedge stakes at 3’ spacing along the stabilizer board and along the edge of KoirWrap™. Backfill with a well graded mixture of rock and soil (Fig 2).
Compact soil to the required degree of compaction specified by the engineer. Spread native seeds on the portion of the lift that will be exposed to sunlight. Stretch KoirWrap™ over the compacted soil and extend towards the slope. Anchor KoirWrap™ using wedge stakes at 3’ spacing in a key trench. This base lift forms the foundation for the upper lifts and provides adequate stability to the slope. Spread 2” to 3” layer of the soil on the top surface of KoirWrap™ and place live self-rooting cuttings (Fig 3).
Repeat the same procedure for the upper lifts. Native soil without rock can be used as backfill for upper lifts. Offset each lift 3” to 36” from the previous lift as specified on the plans (Fig 4).
On the topmost lift, spread topsoil, seed and fertilizer. Cover the topsoil with KoirMat™ or an erosion control blanket as appropriate. Container seedlings or plant plugs can be inserted through the KoirWrap™ along the horizontal benches (Fig 5).
A combination of KoirMat™ 700 (or KoirMat™ 900) and C400 (or KoirPad™ 640) can be used in place of KoirWrap™ 1000. In such cases the KoirMat™ layer should be laid down first followed by the layer of C400 or KoirPad™ 640. When wrapping the soil, both layers are to be drawn together as tightly as possible around the soil.