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Please use this identifier to cite or link to this item: http://www.lsln.net.au/jspui/handle/1/13338
Type: journalArticle
Title: Before and after riparian management: sediment and nutrient exports from a small agricultural catchment, Western Australia
Authors: McKergow, L. A.
Weaver, D. M.
Prosser, I. P.
Grayson, R. B.
Reed, A. E. G.
Year: 2003
Citation: Volume: 270
Issue: 3-4
Abstract: Riparian vegetation can trap sediment and nutrients sourced from hillslopes and reduce stream bank erosion. This study presents results from a 10-year stream monitoring program (1991-2000), in a 6 km2 agricultural catchment near Albany, Western Australia. After 6 years, a 1.7 km stream reach was fenced, planted with eucalyptus species and managed independently from the adjacent paddocks. Streamflow, nutrient and sediment concentration data were collected at the downstream end of the fenced riparian area, so there are data for before and after improved riparian management. Suspended sediment (SS) concentrations fell dramatically following improved riparian management; the median event mean concentration (EMC) dropped from 147 to 9.9 mg l-1. Maximum SS concentrations dropped by an order of magnitude. As a result, sediment exports from the catchment decreased following improved riparian management, from over 100 to less than 10 kg ha-1 yr-1. Observations suggest that this was the result of reduced bank erosion and increased channel stability. Riparian management had limited impact on total phosphorus (TP) concentrations or loads, but contributed to a change in phosphorus (P) form. Before improved riparian management, around half of the P was transported attached to sediment, but after, the median filterable reactive P (FRP) to TP ratio increased to 0.75. In addition, the median FRP EMC increased by 60% and the raw median FRP concentration increased from 0.18 to 0.35 mg l-1. These results suggest that there was a change in the dominant P form, from TP to FRP. Changes in total nitrogen (TN) following improved riparian management were less clear. There were reductions in TN concentrations at high flows, but little change in the loads or EMC. This study demonstrates the benefits of riparian management in reducing stream bank erosion, but suggests that in catchments with sandy, low P sorption soils, there may be limitations on the effectiveness of riparian buffers for reducing P and N exports.
URL: http://www.sciencedirect.com/science/article/pii/S002216940200286X
URL: http://www.lsln.net.au/jspui/handle/1/13338
ISSN: 0022-1694
DOI: 10.1016/S0022-1694(02)00286-X
Journal Title: Journal of Hydrology
Geo Location: -35.0238227,117.8847286
Location: Albany West Australia Australia
Appears in Collections:Hunter Local Land Services

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