Advances in steep slope (batter) erosion control

Embankments and cuttings are integral parts of rail and road networks that support the economy of every country including Australia. Water induced erosion from the steep slopes (batters) of these civil engineered structures costs tax-payers in terms of ongoing operation and maintenance of the land transport networks. Also the environment is degraded and sediments transported from sites have the potential to pollute the nearby water bodies downstream. This paper provides an overview of advances made in Queensland, Australia, to mitigate the erosion problems of railway formation batters. Our research effort has been focused on strategies to aid quick establishment of grasses on the batters. The strategies include defining the topsoil quality of the batters, modification of batter topsoils to provide a conducive growth medium for the grasses, and seed treatment including pre-germination to accelerate the germination process. Provision of a cheap mulch to protect grass seeds/ seedlings and ameliorants from washout by high intensity and short duration rainfall events is another strategy. Development of a cost-effective drip irrigation system that sources water from either an existing pressurised water main or a temporary excavated pond/ dam (with solar pump) to supplement the unpredictable natural rainfall ia a major strategy. It has been established that the target of 60% grass cover reduces erosion by over 90% compared with the bare scenario. The plot-scale verification work and experiences have already been successfully incorporated into large scale railway projects such as the 110 km Bauhinia Regional Railway Project spur line construction.