scholarly journals A computer model to estimate seepage rates from automated irrigation distribution channels during periods of shutdown

2014 ◽  
Vol 16 (6) ◽  
pp. 1302-1317 ◽  
Author(s):  
A. Moavenshahidi ◽  
R. Smith ◽  
M. Gillies
Keyword(s):  
Computer Model ◽  
Direct Method ◽  
Rapid Expansion ◽  
Control Structures ◽  
Test Methodology ◽  
South Wales ◽  
Level Data ◽  
Water Level Data ◽  
Eastern Australia ◽  
Channel Control

Within the last 10 years throughout south-eastern Australia, there has been a rapid expansion of modernisation efforts by irrigation companies that has included installation of automatic control structures, the so-called total channel control (TCC) technology. TCC includes supervisory control and data acquisition technology, which results in production of integrated databases utilising real time measurements of flow and water depth throughout the whole system. Pondage tests are acknowledged as the best direct method for seepage measurement and the recorded water level data from automated systems during periods of gate closure can be treated as pondage test data. This paper presents the development and operation of a new computer model that applies pondage test methodology to automated channel control data during periods of shut down in order to estimate seepage rates in different channel reaches. The Coleambally Irrigation Area (CIA) in southern New South Wales was chosen as the case study, as it is one of the first irrigation districts in the world to be automated. The methodology was tested using the TCC data of the entire CIA during the 2010–11 season and was demonstrated to be successful in identifying all pondage conditions throughout the entire network as well as estimating the seepage rates for each gauge, pondage and pool.

scholarly journals Long-Term Dataset of Tidal Residuals in New South Wales, Australia

Data ◽  
2021 ◽  
Vol 6 (10) ◽  
pp. 101
Author(s):  
Cristina N. A. Viola ◽  
Danielle C. Verdon-Kidd ◽  
David J. Hanslow ◽  
Sam Maddox ◽  
Hannah E. Power
Keyword(s):  
Water Level ◽  
Extreme Events ◽  
New South ◽  
New South Wales ◽  
Causal Processes ◽  
South Wales ◽  
Level Data ◽  
Water Level Data ◽  
Height Datum

Continuous water level records are required to detect long-term trends and analyse the climatological mechanisms responsible for extreme events. This paper compiles nine ocean water level records from gauges located along the New South Wales (NSW) coast of Australia. These gauges represent the longest and most complete records of hourly—and in five cases 15-min—water level data for this region. The datasets were adjusted to the vertical Australian Height Datum (AHD) and had the rainfall-related peaks removed from the records. The Unified Tidal Analysis and Prediction (Utide) model was subsequently used to predict tides for datasets with at least 25 years of records to obtain the associated tidal residuals. Finally, we provide a series of examples of how this dataset can be used to analyse trends in tidal anomalies as well as extreme events and their causal processes.

scholarly journals Model Based Assessment of the Reflection Behavior of Tidal Waves at Bathymetric Changes in Estuaries

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 489
Author(s):  
Vanessa Sohrt ◽  
Sebastian S.V. Hein ◽  
Edgar Nehlsen ◽  
Thomas Strotmann ◽  
Peter Fröhle
Keyword(s):  
Cross Sectional ◽  
High Agreement ◽  
Tidal Waves ◽  
Level Data ◽  
Water Level Data ◽  
Abrupt Changes ◽  
Water Effects ◽  
Potential Impact ◽  
Tidal Constituents ◽  
Harmonic Components

Estuaries are often modified by human activities. Adjustments in the morphology of an estuary have a potential impact on the hydrodynamics and on the reflection behavior of the tide. The influence of such system changes on the complex tidal regime with a large number of superimposed tidal constituents is not fully understood yet. The reflection properties of estuaries that are characterized by abrupt changes in geometry are systematically investigated on the basis of simplified estuary model approaches to improve the understanding of the oscillation and reflection behavior of tidal waves in estuaries. The reflection coefficients at abrupt cross-sectional changes are determined by two different methods, i.e., an analytical energy-based approach and a hydrodynamic numerical (HN) model. Comparisons indicate a high agreement of the results of the different methods when evaluating the reflection coefficient. The tidal constituents are reflected at partial and total reflectors and amplified by shoaling depending on the water depths, the height of the bottom step and the horizontal constriction. A harmonic analysis of simulated water level data partly shows the formation and amplification of higher harmonic components as a result of shallow water effects. The interaction with reflectors results in an increasing amplification of the tidal constituents and the tide.

Grain protein responses to nitrogen applied to wheat growing on a red earth

1991 ◽  
Vol 42 (5) ◽  
pp. 735 ◽  
Author(s):  
JF Angus ◽  
RA Fischer
Keyword(s):  
Ammonium Nitrate ◽  
Theoretical Background ◽  
Yield Response ◽  
Grain Protein ◽  
Fertilizer N ◽  
South Wales ◽  
Eastern Australia ◽  
Red Earth ◽  
Subsequent Crop ◽  
Urea Ammonium Nitrate

Dryland wheat was fertilized with ammonium nitrate or liquid urea-ammonium nitrate at the time of sowing or about 3 months later (generally at the terminal-spikelet stage) on a well-drained site near Harden on the south-west slopes of New South Wales. The experiments continued from the second to the fifth year (1981-1984) of the cropping phase of a crop-pasture rotation. The maximum agronomic efficiencies for yield in the four consecutive years were 19, 4, 23 and 25 kg grain per kg of applied nitrogen (N). The three large responses were obtained in wetter than average seasons and the small response was obtained during drought. In the last three years of the study the yield response to nitrogen at the terminal-spikelet stage was found to be close to but slightly less than that for N applied at sowing. In those years the agronomic efficiencies for the late-applied N were 0, 22 and 22. The apparent recovery of fertilizer N in the above-ground parts of the crop at maturity was up to 70% of the fertilizer applied in the year of sowing, and, after the drought during which there was little uptake of fertilizer N, up to 62% by the subsequent crop. The fertilizer efficiencies in the non-drought years were higher than generally reported in south-eastern Australia, and indicate potential for profitable delayed application of N fertilizer to wheat. Grain-protein responses were variable from year to year and are discussed against a simple theoretical background of the amount of N applied and grain-yield response.

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