Techniques for targeting erosion control and riparian rehabilitation in the Mount Lofty Ranges. Report to Land & Water Australia

[摘要] Executive Summary:This report presents assessment techniques for setting catchment-scale priorities for improving water quality and riparian condition in the Mount Lofty catchments.Separate priorities are provided for erosion contorl to reduce catchment sediment yields, and for protection and rehabilitation of riparian vegetation to enhaance riparian condition.The assessments are supported by independent data.Sediment budgets are modelled in the south Para, Torrens and upper Onkaparinga catchments of the Mount Lofty Ranges using the SedNet model.The budgets include assessments of spatial variation in hillslope, gully and riverbank erosion, as well as sediment transport and loss in reservoirs and overbank deposition.Gully erosion is predicted to be the largest sediment source in these catchments, and hillslope and riverbank erosion are also important.Management actions for reducing sediment loads are most effective when targeted to erosion hotsports.The management action with the best cost/benefit ratio is targeted riparian revegetation in hotspots of bank erosion, and highly active gully erosion.The second priority management actions include installation of riparian filter strips in hotspots water supply storages are presented, to assist targeting hotspot areas.The sediment budgets presented here provide a higher resolution of assessment than that previously provided by the National Land and water Resources Audit, and they also conclude that hillslope erosion is relatively less important as a sediment source in the Mount Lofty Ranges.The condition of existing riparian vegetation is assessed by relating tree cover data to site measurements of riparian condition made using the Rapid Appraisal of Riparian Condition (RARC).The regional assessment of riparian condition is used to develop priorities for improving riparian condition, based on the principle that it is more efficient (cheaper) to protect riparian areas in good condition before rehabilitating riparian areas in poor condition.The priorities are thus to protect the least degraded sections first.In this report, no attempt is made to integrate the priorities for riparian condition with the priorities for reducing sediment yields.

[发布机构] CSIRO

[学科分类] 地球科学(综合)