Pond Water Source for Irrigation on Steep Slopes

Abstract

Existing technologies have been tailored to deliver cost-effective irrigation on a railway embankment and excavated steep slopes (referred to as batters) within a semiarid environment. Irrigation is to aid the establishment of 100% grass cover within a few weeks to mitigate soil erosion problems. It is based on water sourced from a temporary excavated pond plus the use of a solar powered pump and a drip irrigation system. Railway batter erosion remediation is timed for the wet summer season when irrigation can be used to supplement natural rainfall. For a given irrigation demand and catchment area, critical (minimum) pond volume is estimated from regional charts developed for ungauged catchments. About 20% of the critical volume is added to account for evaporation losses and dead storage. Also, seepage losses need to be considered if the soil is medium to coarse textured and if the pond is not lined with an impermeable material. Initial results are very encouraging with a cost estimate of AU$2.74/m² of batter area treated (irrigated). Irrigation unit cost is expected to decrease with a larger scale irrigated batter area and the refinement of technologies and installation procedures. Although irrigation methodologies were developed for railway embankments and excavated slopes, they can also be used for erosion control on steep slopes such as road embankments or excavated slopes and earth dam side slopes.