construction and refurbishment of earthen irrigation channel banks

ank and the crest. The EBM then acts to stabilise the inside batter face andincrease freeboard, if required.Non-coring methods of repair increase the bank width by re-forming the bank withEBM while leaving the bank’s core intact.This method is illustrated in Figure 20.10.Bank re-forming with EBM is typically carried out as follows:1. channels are selected for bank re-forming according to the suitability andavailability of EBM.2. the channel is drained and the EBM is de-watered as much as possible.3. topsoil is stripped from crest and stockpiled4. any hollows encountered in the inside batter are filled with good clay fill, ifavailable5. EBM is excavated from the bottom of the channel and placed onto the insidebatter and crest of bank, then shaped so that the inside batter is at a maximumslope of 1:3 and the crest is restored to a trafficable width.Re-establish freeboardInside batterstabilisationwith EBMThe top of the originalbank is not pulleddown below runninglevel of channel31Some material is left inthe bed of the channelas a sealFigure 20.10Profile after EBM Stabilisation6. Material is left to dry7. Crest of bank is rotary-hoed8. The crest is shaped and trimmed with a bulldozer or grader.9. Protective cover (refer Section 17) replaced on crest (if no access) and outsidebatter.10. A layer of protective granular material is placed on the waterface if required.11. Access track is constructed.12. Longitudinal fencing is installed if protection is required.Limitations of method• Need to use with a degree of caution. G-MW has found, depending on suitabilityof EBM, and the deterioration conditions acting on the bank, that the life of thebank may be extended by 10-15 years. However the life extensions have variedConstruction and Refurbishment of Earthen Channel Banks August 2002 - Edition 1.0 20-17