Author:
Carroll C.,Connolly R. D.,Freebairn D. M.,Francis J.,Silburn D. M.,Simpson B.
Abstract
Sedimentation in the drainage network of the Emerald Irrigation Area (near
Emerald, Queensland), as a result of erosion from irrigated farms, is a
serious problem. Deposited sediment changes the hydraulic characteristics of
the drains causing flooding and is difficult and expensive to remove. We used
the GLEAMS erosion model to simulate a range of management strategies aimed at
reducing sedimentation in the drains by reducing erosion at the bay/field
scale or retaining eroded sediment on-farm.
GLEAMS was set up and tested using data measured at the rainfall simulator (12
m2), furrow (0·2–0·3 ha), and bay
(20–30 ha) scales. Comparisons of measured with predicted sediment
transport indicated the model accurately reproduced effects of several
management treatments on sediment transport and the size distribution of
eroded sediment at the bay scale. To reproduce accurately size distribution of
eroded sediment, though, an important parameter, clay content of surface soil,
had to be substantially distorted from measured values. GLEAMS was used to
simulate sediment transport from a typical farm producing irrigated cotton.
Management strategies simulated included conventional (bare), stubble
retained, cover in the tail-drain, drip irrigation, and addition of a
silt-trap and storage.
The most effective management strategies for reducing erosion and sediment
transport at the bay scale were stubble retained and drip irrigation. Stubble
retained+drip irrigation almost eliminated sediment transport. Addition
of a silt-trap and storage with conventional management reduced sediment
transport off-farm by 45%. Use of a silt-trap with improved field
management further reduced sediment transport. Erosion and sediment transport
at the bay scale was sensitive to changes in the furrow/tail-drain layout.
Changes in the furrow/tail-drain layout from the original design should be
undertaken carefully so as not to increase sediment transport off-farm.
Subject
Earth-Surface Processes,Soil Science,Environmental Science (miscellaneous)
Cited by
19 articles.
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