Journal articles on the topic 'Runoff Victoria'

To see the other types of publications on this topic, follow the link: Runoff Victoria.

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Runoff Victoria.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Holland, J. E., T. H. Johnston, R. E. White, and B. A. Orchard. "An investigation of runoff from raised beds and other tillage methods in the high rainfall zone of south-western Victoria, Australia." Soil Research 50, no. 5 (2012): 371. http://dx.doi.org/10.1071/sr11200.

Full text
Abstract:
For many years, the poor physical and hydraulic properties of the soils in south-western Victoria have restricted crop production due to waterlogging. In this region of predominantly winter rainfall, raised beds have become popular with farmers to overcome these difficulties; however, little has been reported on the hydrology of raised beds compared with other tillage systems for cropping in the rain-fed environment of south-western Victoria. This study measured rainfall characteristics, runoff volumes, and soil properties such as the soil water content, bulk density, and hydraulic conductivity for three tillage treatments (raised beds, conventional cultivation, and deep cultivation) over 6 years on a Sodosol at a field site near Geelong, Victoria. Runoff was regressed against rainfall variables such as the amount per event, hours of rainfall, rainfall intensity, and maximum rainfall intensity to determine the significance of any differences between the treatments. The relationship between runoff and rainfall amount was best described with an exponential model. Raised beds significantly increased the amount of runoff relative to the other treatments when above-average rainfall was received, but there was little difference in runoff in years of below-average rainfall. No consistent effect of runoff on crop biomass was detected nor could any differences in runoff be attributed to differences in soil water content, hydraulic conductivity, and bulk density between treatments. The most important factor appeared to be the furrows between the raised beds, which acted as conduits for the flow of surface water during the larger storm events. During such events, runoff is an important hydrological process in cropping land in south-western Victoria.
APA, Harvard, Vancouver, ISO, and other styles
2

van, Rees H., and RC Boston. "Evaluation of Factors Affecting Surface Runoff on Alpine Rangeland in Victoria." Rangeland Journal 8, no. 2 (1986): 97. http://dx.doi.org/10.1071/rj9860097.

Full text
Abstract:
A 'portable' rainfall simulator was used on alpine soils on the Bogong High Plains in Victoria, to determine the relationship of surface runoff to soil moisture, rainfall intensity, slope and the percentage of the area lacking vegetation cover (bare ground). A strong inverse relationship (R' = 0.64) existed between total runoff and antecedent soil moisture conditions. The other factors, within the range evaluated in these experiments (bare ground 0 to 33'70, rainfall intensity 37 to 97 mm/hr and slope 6 to 23%) had no significant influence on runoff. Time to runoff initiation was influenced by antecedent soil moisture, slope and rainfall intensity ( ~ ~ ~ 0 . 7 1 ) . It was found that time to runoff decreased as the soils dried, and the slope and rainfall intensity increased. The percentage of bare ground had little influence on the time to runoff initiation. These results show that differences in grassland condition, including large differences in the percentage of bare ground, had little influence on either surface runoff or on the time to runoff initiation. The single most important factor influencing runoff rates was the antecedent moisture content of the soil. This factor is generally outside management control.
APA, Harvard, Vancouver, ISO, and other styles
3

Charles, Stephen P., Francis H. S. Chiew, Nicholas J. Potter, Hongxing Zheng, Guobin Fu, and Lu Zhang. "Impact of downscaled rainfall biases on projected runoff changes." Hydrology and Earth System Sciences 24, no. 6 (June 8, 2020): 2981–97. http://dx.doi.org/10.5194/hess-24-2981-2020.

Full text
Abstract:
Abstract. Realistic projections of changes to daily rainfall frequency and magnitude, at catchment scales, are required to assess the potential impacts of climate change on regional water supply. We show that quantile–quantile mapping (QQM) bias-corrected daily rainfall from dynamically downscaled WRF simulations of current climate produce biased hydrological simulations, in a case study for the state of Victoria, Australia (237 629 km2). While the QQM bias correction can remove bias in daily rainfall distributions at each 10 km × 10 km grid point across Victoria, the GR4J rainfall–runoff model underestimates runoff when driven with QQM bias-corrected daily rainfall. We compare simulated runoff differences using bias-corrected and empirically scaled rainfall for several key water supply catchments across Victoria and discuss the implications for confidence in the magnitude of projected changes for mid-century. Our results highlight the imperative for methods that can correct for temporal and spatial biases in dynamically downscaled daily rainfall if they are to be suitable for hydrological projection.
APA, Harvard, Vancouver, ISO, and other styles
4

Rwetabula, J., F. De Smedt, and M. Rebhun. "Prediction of runoff and discharge in the Simiyu River (tributary of Lake Victoria, Tanzania) using the WetSpa model." Hydrology and Earth System Sciences Discussions 4, no. 2 (April 23, 2007): 881–908. http://dx.doi.org/10.5194/hessd-4-881-2007.

Full text
Abstract:
Abstract. A spatially distributed hydrologic model (WetSpa) is used to estimate daily river water discharge in the Simiyu river a tributary of Lake Victoria, Tanzania. The model combines topography, landuse and soil maps, and observed daily meteorological time series to predict discharge hydrographs and the spatial distribution of hydrological parameters in the catchment. The elevations in the catchment range from 2000 to 1100 m at the outlet, with average slope of 1.4%. The dominant landuse types are, wasteland, grassland, bushland, cultivated land, and a very small area is covered by surface water. The dominant soil types are sandy loam, followed by sandy clay loam, clay loam, clay, loam and sandy clay. There are two distinctive seasons in the Simiyu catchment. Short rains mainly in November, December and January, and long rains in March to May, resulting in a total average annual precipitation of 700 to 1000 mm. The annual potential evapotranspiration is about 1300 mm, and the river discharge at the catchment outlet ranges from 0 to about 200 m3/s. Global parameters of the model are calibrated using three years of daily observed discharge values measured at the mouth of the river at Lake Victoria. The estimated average travel time of the runoff to the outlet of the catchment is about 2.4 d and maximum 8 d for the most remote areas. The model results also show that the surface runoff and interflow provide respectively 38.6% and 61.4% of the total runoff, while the contribution of groundwater drainage is nil. The absence of groundwater drainage is probably due to the high evaporation demand of the atmosphere, which accounts for about 90% of the total precipitation being lost by evapotranspiration. The annual water balance estimated with the model reveals that the total outflow to Lake Victoria is about 500×106 m3 per year, which occurs mainly in the wet seasons, i.e. from March to May and from November to January. The volume of runoff produced by agricultural land amounts to about 9% of the total runoff annually.
APA, Harvard, Vancouver, ISO, and other styles
5

Khan, S. I., P. Adhikari, Y. Hong, H. Vergara, R. F Adler, F. Policelli, D. Irwin, T. Korme, and L. Okello. "Hydroclimatology of Lake Victoria region using hydrologic model and satellite remote sensing data." Hydrology and Earth System Sciences 15, no. 1 (January 14, 2011): 107–17. http://dx.doi.org/10.5194/hess-15-107-2011.

Full text
Abstract:
Abstract. Study of hydro-climatology at a range of temporal scales is important in understanding and ultimately mitigating the potential severe impacts of hydrological extreme events such as floods and droughts. Using daily in-situ data over the last two decades combined with the recently available multiple-years satellite remote sensing data, we analyzed and simulated, with a distributed hydrologic model, the hydro-climatology in Nzoia, one of the major contributing sub-basins of Lake Victoria in the East African highlands. The basin, with a semi arid climate, has no sustained base flow contribution to Lake Victoria. The short spell of high discharge showed that rain is the prime cause of floods in the basin. There is only a marginal increase in annual mean discharge over the last 21 years. The 2-, 5- and 10- year peak discharges, for the entire study period showed that more years since the mid 1990's have had high peak discharges despite having relatively less annual rain. The study also presents the hydrologic model calibration and validation results over the Nzoia basin. The spatiotemporal variability of the water cycle components were quantified using a hydrologic model, with in-situ and multi-satellite remote sensing datasets. The model is calibrated using daily observed discharge data for the period between 1985 and 1999, for which model performance is estimated with a Nash Sutcliffe Efficiency (NSCE) of 0.87 and 0.23% bias. The model validation showed an error metrics with NSCE of 0.65 and 1.04% bias. Moreover, the hydrologic capability of satellite precipitation (TRMM-3B42 V6) is evaluated. In terms of reconstruction of the water cycle components the spatial distribution and time series of modeling results for precipitation and runoff showed considerable agreement with the monthly model runoff estimates and gauge observations. Runoff values responded to precipitation events that occurred across the catchment during the wet season from March to early June. The spatially distributed model inputs, states, and outputs, were found to be useful for understanding the hydrologic behavior at the catchment scale. The monthly peak runoff is observed in the months of April, May and November. The analysis revealed a linear relationship between rainfall and runoff for both wet and dry seasons. Satellite precipitation forcing data showed the potential to be used not only for the investigation of water balance but also for addressing issues pertaining to sustainability of the resources at the catchment scale.
APA, Harvard, Vancouver, ISO, and other styles
6

Hughes, JMR, and B. James. "A hydrological regionalization of streams in Victoria, Australia, with implications for stream Ecology." Marine and Freshwater Research 40, no. 3 (1989): 303. http://dx.doi.org/10.1071/mf9890303.

Full text
Abstract:
Annual, monthly, low and peak flow data were used to classify and ordinate 138 stream gauges in Victoria. Sixteen hydrological variables were used and low-flow and entire-flow regionalizations were derived. The low-flow regionalization was spatially indistinct and therefore unusable, but the entire-flow regionalization produced five distinctive and spatially significant regions. Least-squares relationships were calculated between mean annual runoff, catchment area and coefficient of variation of annual flows, and the 16 variables. Rivers in the dry western districts of Victoria exhibit high variability of annual, monthly and peak flows, and low specific low flows. The converse is true for rivers in the western highlands of Victoria. Stream regionalizations are a useful tool for stream ecologists, and may be used for generating hypotheses, for detecting representative rivers and for producing baseline stream surveys.
APA, Harvard, Vancouver, ISO, and other styles
7

Cooke, JW. "Effect of fallowing practices on runoff and soil erosion in south-eastern Australia." Australian Journal of Experimental Agriculture 25, no. 3 (1985): 628. http://dx.doi.org/10.1071/ea9850628.

Full text
Abstract:
The effect on runoff and soil loss of four methods of preparation of fallow was investigated at each of three sites in north-central Victoria. There was a chemical fallow treatment (uncultivated) and three scarified treatments (smooth, medium and rough cultivation). When the results from the three sites were combined, there was 10.7 mm runoff from the uncultivated treatment, 5.1 mm from the smooth, 0.8 mm from the medium and 0.3 mm from the rough scarified treatments. Soil loss from the uncultivated treatment was 103 g/m2 compared with 87 g/m2 from the smooth, 22 g/m2 from the medium and 13 g/m2 from the rough treatment. The concentration of sediment in the runoff was negatively correlated (R2 = -0.56 to -0.98) with runoff. It ranged from 1.21% (w/w) for the uncultivated to 5.06% (w/w) for the rough scarified treatment. The results show that a regimen of minimum scarification to produce a rough surface, and then use of herbicides to control weeds, reduces soil loss compared with either an uncultivated or a smoothly cultivated soil surface.
APA, Harvard, Vancouver, ISO, and other styles
8

Weatherley, A. J., B. F. Quin, K. B. Dassanayake, and J. S. Rowarth. "Runoff losses from irrigated dairy pastures treated with phosphorus fertilisers of differing solubility in south-eastern Australia." Soil Research 49, no. 7 (2011): 633. http://dx.doi.org/10.1071/sr11156.

Full text
Abstract:
In response to increasing concern about environmental quality, water authorities in many countries are imposing legislation limiting phosphorus (P) concentrations in water, which is having an impact on farming practice. This experiment investigated the agronomic effects and runoff losses associated with different forms of P fertiliser applied to an irrigated dairy pasture (soils were Vertic Calcic Red Chromosols; average Olsen P, 50 mg P/kg) in north-central Victoria, Australia. Single superphosphate (SSP), a sulfurised diammonium phosphate, or partially acidulated phosphate rock was surface-applied at 50 kg P/ha in March 2005 to a border-check, flood-irrigated dairy pasture (ryegrass–white clover) ten days before a scheduled irrigation. Dissolved reactive P (DRP) and total P (TP) were measured in runoff from whole bays on one replicate and from microplots on all three replicates for a period of 9 weeks. In all runoff events and all treatments, concentrations of DRP and TP in runoff greatly exceeded water quality guidelines for acceptable limits (0.045 mg P/L). The SSP resulted in significantly higher concentrations of P in runoff than the less water-soluble fertilisers. Even after the fifth irrigation, runoff from all fertilisers still exceeded the control. These results suggest that: (i) P fertilisers should not be applied in high-risk situations as insurance against yield loss; (ii) the current recommendation of withholding irrigation for 3 days after fertiliser application is insufficient to prevent potentially significant losses occurring; and (iii) runoff losses were dependent on the type of fertiliser applied, with a smaller proportion of P applied as sulfurised DAP lost in runoff.
APA, Harvard, Vancouver, ISO, and other styles
9

Saffarpour, Shabnam, Andrew W. Western, Russell Adams, and Jeffrey J. McDonnell. "Multiple runoff processes and multiple thresholds control agricultural runoff generation." Hydrology and Earth System Sciences 20, no. 11 (November 11, 2016): 4525–45. http://dx.doi.org/10.5194/hess-20-4525-2016.

Full text
Abstract:
Abstract. Thresholds and hydrologic connectivity associated with runoff processes are a critical concept for understanding catchment hydrologic response at the event timescale. To date, most attention has focused on single runoff response types, and the role of multiple thresholds and flow path connectivities has not been made explicit. Here we first summarise existing knowledge on the interplay between thresholds, connectivity and runoff processes at the hillslope–small catchment scale into a single figure and use it in examining how runoff response and the catchment threshold response to rainfall affect a suite of runoff generation mechanisms in a small agricultural catchment. A 1.37 ha catchment in the Lang Lang River catchment, Victoria, Australia, was instrumented and hourly data of rainfall, runoff, shallow groundwater level and isotope water samples were collected. The rainfall, runoff and antecedent soil moisture data together with water levels at several shallow piezometers are used to identify runoff processes in the study site. We use isotope and major ion results to further support the findings of the hydrometric data. We analyse 60 rainfall events that produced 38 runoff events over two runoff seasons. Our results show that the catchment hydrologic response was typically controlled by the Antecedent Soil Moisture Index and rainfall characteristics. There was a strong seasonal effect in the antecedent moisture conditions that led to marked seasonal-scale changes in runoff response. Analysis of shallow well data revealed that streamflows early in the runoff season were dominated primarily by saturation excess overland flow from the riparian area. As the runoff season progressed, the catchment soil water storage increased and the hillslopes connected to the riparian area. The hillslopes transferred a significant amount of water to the riparian zone during and following events. Then, during a particularly wet period, this connectivity to the riparian zone, and ultimately to the stream, persisted between events for a period of 1 month. These findings are supported by isotope results which showed the dominance of pre-event water, together with significant contributions of event water early (rising limb and peak) in the event hydrograph. Based on a combination of various hydrometric analyses and some isotope and major ion data, we conclude that event runoff at this site is typically a combination of subsurface event flow and saturation excess overland flow. However, during high intensity rainfall events, flashy catchment flow was observed even though the soil moisture threshold for activation of subsurface flow was not exceeded. We hypothesise that this was due to the activation of infiltration excess overland flow and/or fast lateral flow through preferential pathways on the hillslope and saturation overland flow from the riparian zone.
APA, Harvard, Vancouver, ISO, and other styles
10

Schreider, S. Yu, P. H. Whetton, A. J. Jakeman, and A. B. Pittock. "Runoff modelling for snow-affected catchments in the Australian alpine region, eastern Victoria." Journal of Hydrology 200, no. 1-4 (December 1997): 1–23. http://dx.doi.org/10.1016/s0022-1694(97)00006-1.

Full text
APA, Harvard, Vancouver, ISO, and other styles
11

YU. SCHREIDER, S., A. J. JAKEMAN, and A. B. PITTOCK. "MODELLING RAINFALL-RUNOFF FROM LARGE CATCHMENT TO BASIN SCALE: THE GOULBURN VALLEY, VICTORIA." Hydrological Processes 10, no. 6 (June 1996): 863–76. http://dx.doi.org/10.1002/(sici)1099-1085(199606)10:6<863::aid-hyp376>3.0.co;2-8.

Full text
APA, Harvard, Vancouver, ISO, and other styles
12

Nash, David, and Craig Murdoch. "Phosphorus in runoff from a fertile dairy pasture." Soil Research 35, no. 2 (1997): 419. http://dx.doi.org/10.1071/s96039.

Full text
Abstract:
Losses of phosphorus (P) from grazed pastures in runoff can significantly reduce the water quality in streams draining agricultural catchments. Many preventative strategies depend for their success on the association of the P with large soil particles (>0·45 mm). We investigated the forms of P in runoff from a dairy pasture of high fertility. A 3·6-ha paddock at Darnum in West Gippsland, Victoria, was set up to measure runoff volume and rainfall, and to sample runoff water. Runoff from the site was restricted to 3 months in late winter and spring. Total runoff for 1994 of 660 m3 had an average total P concentration of 5·2 mg/L. Runoff from a single storm system over 8 days in early November accounted for 56% of the total runoff volume and 69% of the P lost. Of the total P in the runoff, 93% passed through a filter with 0·45-µm pores and 91% was reactive in an ascorbic acid–molybdate medium, without digestion; 89% of the P was both reactive in the ascorbic acid{molybdate medium and in the <0·45-µm fraction. There was no apparent relationship (P > 0·05) between P concentration and soil cover. In the Darnum catchment, the major runoff events occurred when the soil was saturated. The low settling velocities of materials <0·45 µm and the amount of P moving in larger storms would suggest that buffer strips and riparian zones are unlikely to decrease P losses substantially from dairy pastures in this area. Further, since erosion is unlikely to be the major process by which P is lost, control measures which simply limit erosion will be similarly ineffective at preventing P losses under the conditions that prevailed in this study.
APA, Harvard, Vancouver, ISO, and other styles
13

Swamikannu, X., D. Radulescu, R. Young, and R. Allison. "A comparative analysis: storm water pollution policy in California, USA and Victoria, Australia." Water Science and Technology 47, no. 7-8 (April 1, 2003): 311–17. http://dx.doi.org/10.2166/wst.2003.0704.

Full text
Abstract:
Urban drainage systems historically were developed on principles of hydraulic capacity for the transport of storm water to reduce the risk of flooding. However, with urbanization the percent of impervious surfaces increases dramatically resulting in increased flood volumes, peak discharge rates, velocities and duration, and a significant increase in pollutant loads. Storm water and urban runoff are the leading causes of the impairment of receiving waters and their beneficial uses in Australia and the United States today. Strict environmental and technology controls on wastewater treatment facilities and industry for more than three decades have ensured that these sources are less significant today as the cause of impairment of receiving waters. This paper compares the approach undertaken by the Environmental Protection Authority Victoria for the Melbourne metropolitan area with the approach implemented by the California Environmental Protection Agency for the Los Angeles area to control storm water pollution. Both these communities are largely similar in population size and the extent of urbanization. The authors present an analysis of the different approaches contrasting Australia with the USA, comment on their comparative success, and discuss the relevance of the two experiences for developed and developing nations in the context of environmental policy making to control storm water and urban runoff pollution.
APA, Harvard, Vancouver, ISO, and other styles
14

McCaskill, M. R., A. M. Ridley, A. Okom, R. E. White, M. H. Andrew, D. L. Michalk, A. Melland, W. H. Johnston, and S. R. Murphy. "SGS Nutrient Theme: environmental assessment of nutrient application to extensive pastures in the high rainfall zone of southern Australia." Australian Journal of Experimental Agriculture 43, no. 8 (2003): 927. http://dx.doi.org/10.1071/ea03020.

Full text
Abstract:
To assess the risks and benefits of more intensive pasture management, 2 or 3 treatments with contrasting fertiliser regimes were selected from each site of the Sustainable Grazing Systems national experiment. The assessment used soil coring data, modelling and runoff nutrient concentration data.Soil acidification rates were estimated from the simulated nitrate leaching and product removal estimated from the stocking rates at each site. Much higher acidification rates were estimated at sites in Victoria and southern Western Australia than in northern New South Wales. This was because of a lower level of nitrate leaching in summer-dominant rainfall environments coupled with lower stocking rates. Simulations showed highest nitrate leaching on annual pastures, but that a phalaris pasture could reduce this, and a kikuyu pasture could almost fully control leaching.The concentration of P in surface runoff was related to soil P status at the 4 southern sites, indicating that greater use of P fertiliser would increase P movement into waterways. There was no relationship between soil P status and P in surface runoff at the northern New South Wales sites, and across all sites there were no relationships between P fertility and runoff N levels. Concentrations of P and N in runoff greatly exceeded stream water quality guidelines, even on treatments where only minimal P had been applied as fertiliser. There was also evidence of high spatial variation in surface runoff generation, with surface runoff from some plots less than 5% of the streamflow in nearby reference streams. There is therefore scope to control P concentrations in streams by retiring from production the parts of the landscape that generate high quantities of surface flow, but to intensify production on areas that produce little runoff.
APA, Harvard, Vancouver, ISO, and other styles
15

Kiem, A. S., and D. C. Verdon-Kidd. "Towards understanding hydroclimatic change in Victoria, Australia – why was the last decade so dry?" Hydrology and Earth System Sciences Discussions 6, no. 5 (October 1, 2009): 6181–206. http://dx.doi.org/10.5194/hessd-6-6181-2009.

Full text
Abstract:
Abstract. Since the mid-1990s Victoria, located in southeast Australia, has experienced severe drought conditions characterized by streamflow that is the lowest on record in many areas. While severe decreases in annual and seasonal rainfall totals have also been observed, this alone does not seem to explain the observed reduction in flow. In this study, we investigate the large-scale climate drivers for Victoria and demonstrate how these modulate the regional scale synoptic patterns, which in turn alter the way seasonal rainfall totals are compiled and the amount of runoff per unit rainfall that is produced. The hydrological implications are significant and illustrate the need for robust hydrological modelling, which takes into account insights into physical mechanisms that drive regional hydroclimatology, in order to properly understand and quantify the impacts of climate change (natural and/or anthropogenic) on water resources.
APA, Harvard, Vancouver, ISO, and other styles
16

Kiem, A. S., and D. C. Verdon-Kidd. "Towards understanding hydroclimatic change in Victoria, Australia – preliminary insights into the "Big Dry"." Hydrology and Earth System Sciences 14, no. 3 (March 8, 2010): 433–45. http://dx.doi.org/10.5194/hess-14-433-2010.

Full text
Abstract:
Abstract. Since the mid-1990s the majority of Victoria, Australia, has experienced severe drought conditions (i.e. the "Big Dry") characterized by streamflow that is the lowest in approximately 80 years of record. While decreases in annual and seasonal rainfall totals have also been observed, this alone does not seem to explain the observed reduction in flow. In this study, we investigate the large-scale climate drivers for Victoria and demonstrate how these modulate the regional scale synoptic patterns, which in turn alter the way seasonal rainfall totals are compiled and the amount of runoff per unit rainfall that is produced. The hydrological implications are significant and illustrate the need for robust hydrological modelling, that takes into account insights into physical mechanisms that drive regional hydroclimatology, in order to properly understand and quantify the impacts of climate change (natural and/or anthropogenic) on water resources.
APA, Harvard, Vancouver, ISO, and other styles
17

De Mora, S. J., R. F. Whitehead, and M. Gregory. "Aqueous geochemistry of major constituents in the Alph River and tributaries in Walcott Bay, Victoria Land, Antarctica." Antarctic Science 3, no. 1 (March 1991): 73–86. http://dx.doi.org/10.1017/s0954102091000111.

Full text
Abstract:
Two geochemical surveys of the major constituents of the Alph River, situated in Walcott Bay, Victoria Land, were undertaken in the austral summer of 1987–88. At the same time, tributaries and the runoff from various glaciers were investigated. The Alph River has an average total dissolved solids (TDS) concentration of 63.5 mgl−1, approximately half that of average world river water. The chemical composition is dominated by Na+ and HCO−3. Glacial melt waters have very low TDS but chemical weathering over the course of a few kilometres causes solute concentrations in the tributaries to exceed those of the Alph River. The composition of the streams is variable, but often Ca2+ is the principal cation. Enrichment factor and mass balance calculations indicate that the salts in the Alph River and its tributaries have a substantial non-marine component. Chemical weathering of calcite, mirabilite, gypsum and halite contribute solutes to the aquatic system. A “Gibbs Plot” [TDS versus Na:(Na+Ca) weight ratio] indicates that water samples from direct glacial runoff fall outside the world water envelope. They have low solute levels but enhanced Ca2+ concentrations, resulting from the aeolian deposition and subsequent dissolution of calcitic material.
APA, Harvard, Vancouver, ISO, and other styles
18

Sheridan, G. J., and C. J. Rosewell. "An improved Victorian erosivity map." Soil Research 41, no. 1 (2003): 141. http://dx.doi.org/10.1071/sr02030.

Full text
Abstract:
The impact of raindrops on the soil surface and surface water runoff are two of the agents of soil detachment and sediment transport. The magnitude of these erosion processes is a function of the erosive potential, or erosivity of a rainstorm. The erosivity of rainfall is commonly quantified using the R factor developed for the universal soil loss equation. R is the average of the annual sum of the individual storm erosivity values and can be estimated from published relationships between the storm energy and the rainfall intensity. Currently the most likely source of R-values in Victoria is a hand-drawn contour map produced more than 20 years ago by an expert panel and published in an out-of-print handbook. A new R-value contour map for Victoria is presented, developed from current empirical relationships between rainfall intensity–frequency–duration and R. The R contours vary in value across the state by about a factor of 4, from <800 MJ.mm/ha.h.year in the north-west, to >2700 MJ.mm/ha.h.year in the eastern ranges. The new map improves the resolution and accuracy of erosivity values for Victoria, especially in steeper, forested areas, and will assist in the prediction and modelling of erosion and water quality.
APA, Harvard, Vancouver, ISO, and other styles
19

Wood, M. L., and L. Finger. "Influence of irrigation method on water use and production of perennial pastures in northern Victoria." Australian Journal of Experimental Agriculture 46, no. 12 (2006): 1605. http://dx.doi.org/10.1071/ea05197.

Full text
Abstract:
The irrigation of pasture for the dairy industry accounts for a large proportion of Australia’s total irrigation water use, particularly in the Murray–Darling Basin. Most pasture is irrigated using the border-check method. The dairy industry is under increasing pressure to use water more efficiently in response to water market reforms and restrictions on future irrigation water availability, creating interest in the potential of alternative irrigation methods. A field experiment was conducted at Tatura, Victoria, Australia between July 2000 and July 2002 to quantify the differences in water use, perennial pasture production and pasture composition under border-check, surge, sprinkler and subsurface drip irrigation. The experiment aimed to assess each irrigation method as it would perform under farm best management practices. Measurements included applied water, tailwater runoff, soil water status, dry matter production and botanical composition. This experiment found that sprinkler and subsurface drip irrigation used on average 2 ML/ha.year (17–23%) less water than border-check irrigation while maintaining or increasing pasture production, consequently having a significantly higher water use efficiency. Surface runoff was significantly reduced under sprinkler and subsurface drip irrigation. Surge irrigation had no advantages over border-check. Although some differences in pasture composition were observed between irrigation treatments, the trends were inconsistent from one season to the next. The high water use by gravity fed irrigation methods is attributed to a combination of higher evaporation and groundwater accessions.
APA, Harvard, Vancouver, ISO, and other styles
20

Kizza, Michael, Allan Rodhe, Chong-Yu Xu, and Henry K. Ntale. "Modelling catchment inflows into Lake Victoria: uncertainties in rainfall–runoff modelling for the Nzoia River." Hydrological Sciences Journal 56, no. 7 (October 2011): 1210–26. http://dx.doi.org/10.1080/02626667.2011.610323.

Full text
APA, Harvard, Vancouver, ISO, and other styles
21

Mathers, Nicole J., and David M. Nash. "Effects of tillage practices on soil and water phosphorus and nitrogen fractions in a Chromosol at Rutherglen in Victoria, Australia." Soil Research 47, no. 1 (2009): 46. http://dx.doi.org/10.1071/sr08106.

Full text
Abstract:
Phosphorus (P) and nitrogen (N) exports from cropping areas can be greater than those from uncropped areas. Conservation farming methods, involving minimal tillage and full stubble retention, offer significant benefits to grain cropping, but may increase nutrient concentrations in surface (i.e. 0–20 mm) soils, resulting in increased risks of nutrient mobilisation and loss. The effects of tillage and stubble management on soil nutrients that are potentially mobilised into runoff from a long-term trial site at Rutherglen (established in 1981) were investigated. On 2 different sampling dates (February and August 2006) soils from the 0–20, 20–50, and 50–150 mm depths were collected from 3 treatments: conventional cultivation with stubble burning (CCb); direct drill with stubble burning (DDb); and direct drill with stubble retained (DDr). In 2004, the trial was sown with wheat (Triticum aestivum cv. Dollarbird), followed by faba beans in 2005 (Vicia faba L.) and wheat again in 2006. In August 2006, a rainfall simulation experiment was also conducted on these sites. All nutrient concentrations decreased with depth to 150 mm in all treatments, when both sampling dates were analysed together. This indicated that soil nutrient stratification was occurring in all 3 treatments. The CCb treatment only displayed differences between the 0–20 and 20–50 mm depths for soil organic C and ammonium-N. DDr significantly increased some nutrient concentrations in the 0–20 mm soil depth compared with the CCb treatment, including CaCl2-extractable P (0.76 and 0.50 mg/kg, for DDr and CCb, respectively), total N (1.23 and 1.00 g/kg, for DDr and CCb, respectively), and nitrate-N (12.6 and 8.63 mg/kg, for DDr and CCb, respectively), while the ammonium-N concentration was greater under CCb (9.71 mg/kg) than DDr (6.46 mg/kg). Being water-soluble, CaCl2-extractable P and nitrate-N are more likely be mobilised into streams from the 0–20 mm depth, where they are highly bioavailable and may contribute to increased eutrophication. Direct drilling with stubble retention contributed a greater proportion of particulate P and N to TP (Total P) and TN (Total N) in surface runoff than either of the burnt systems. Particulate P accounted for 75%, 67%, and 83% of TP in surface runoff from the CCb, DDb, and DDr treatments, respectively. However, the highly bioavailable dissolved reactive P (DRP) was the dominant form of dissolved P, with concentrations exceeding the recommended guidelines of 0.05 mg P/L in the lowlands of south-east Australia. Total N (0.44, 0.68, and 0.73 mg N/L for DDr, DDb, and CCb, respectively) in surface runoff was dominated by nitrate-N and also exceeded current Australian guidelines of 0.5 mg N/L, except for TN from the DDr treatment. These results would indicate that P, particularly the non-dominant but highly bioavailable form of DRP, exported from these systems is more likely to adversely affect catchment water quality than N exports. The increase in surface runoff volumes and nutrient loads from the CCb treatment observed in this study indicate that DDr systems have increased soil infiltration properties and retained nutrients within the soil–plant system. Therefore, direct drilling with stubble retention in the high rainfall zone cropping areas of north-east Victoria is more likely to retain nutrients on-site and improve soil fertility than burning stubble and cultivating the soil.
APA, Harvard, Vancouver, ISO, and other styles
22

Bronge, Christian. "Hydrology of Tierney Creek, Vestfold Hills, Antarctica." Polar Record 35, no. 193 (April 1999): 139–48. http://dx.doi.org/10.1017/s0032247400026486.

Full text
Abstract:
AbstractThe discharge in Tierney Creek from proglacial Chelnok Lake was recorded during the summer of 1987–1988. In addition, air temperature, water temperature, and radiation were recorded. Multiple linear regressions revealed that discharge could be predicted from recorded radiation and air temperature in late summer. In early summer, other factors such as wind must also be taken into account. Long-term discharge fluctuations displayed response times that decreased during the runoff season due to the opening of the meltwater channels on the ice-margin. During parts of the runoff season, flow variations were modulated by nocturnal freezing in the creek, a phenomenon still more pronounced in Onyx River in the Dry Valleys of Victoria Land. Hydrologically, Tierney Creek resembled Onyx River, but, in the Onyx, the flow pattern was more exclusively determined by low air temperatures than it was in Tierney Creek. In the Dry Valleys, streams whose lengths, gradients, and discharges are of the same magnitude as those of Tierney Creek, also display similar recession coefficients and time lags between flow peak and insolation peak.
APA, Harvard, Vancouver, ISO, and other styles
23

Khan, S. I., P. Adhikari, Y. Hong, H. Vergara, T. Grout, R. F. Adler, F. Policelli, D. Irwin, T. Korme, and L. Okello. "Observed and simulated hydroclimatology using distributed hydrologic model from in-situ and multi-satellite remote sensing datasets in Lake Victoria region in East Africa." Hydrology and Earth System Sciences Discussions 7, no. 4 (July 22, 2010): 4785–816. http://dx.doi.org/10.5194/hessd-7-4785-2010.

Full text
Abstract:
Abstract. Floods and droughts are common, recurring natural hazards in East African nations. Studies of hydro-climatology at daily, seasonal, and annual time scale is an important in understanding and ultimately minimizing the impacts of such hazards. Using daily in-situ data over the last two decades combined with the recently available multiple-years satellite remote sensing data, we analyzed and simulated, with a distributed hydrologic model, the hydro-climatology in Nzoia, one of the major contributing sub-basins of Lake Victoria in the East African highlands. The basin, with a semi arid climate, has no sustained base flow contribution to Lake Victoria. The short spell of high discharge showed that rain is the prime cause of floods in the basin. There is only a marginal increase in annual mean discharge over the last 21 years. The 2-, 5- and 10-year peak discharges, for the entire study period showed that more years since the mid 1990's have had high peak discharges despite having relatively less annual rain. The study also presents the hydrologic model calibration and validation results over the Nzoia Basin. The spatiotemporal variability of the water cycle components were quantified using a physically-based, distributed hydrologic model, with in-situ and multi-satellite remote sensing datasets. Moreover, the hydrologic capability of remote sensing data such as TRMM-3B42V6 was tested in terms of reconstruction of the water cycle components. The spatial distribution and time series of modeling results for precipitation (P), evapotranspiration (ET), and change in storage (dS/dt) showed considerable agreement with the monthly model runoff estimates and gauge observations. Runoff values responded to precipitation events that occurred across the catchment during the wet season from March to early June. The hydrologic model captured the spatial variability of the soil moisture storage. The spatially distributed model inputs, states, and outputs, were found to be useful for understanding the hydrologic behavior at the catchment scale. Relatively high flows were experienced near the basin outlet from previous rainfall, with a new flood peak responding to the rainfall in the upper part of the basin. The monthly peak runoff was observed in the months of April, May and November. The analysis revealed a linear relationship between rainfall and runoff for both wet and dry seasons. The model was found to be useful in poorly gauged catchments using satellite forcing data and showed the potential to be used not only for the investigation of the catchment scale water balance but also for addressing issues pertaining to sustainability of the resources within the catchment.
APA, Harvard, Vancouver, ISO, and other styles
24

Dugan, H. A., P. T. Doran, B. Wagner, F. Kenig, C. H. Fritsen, S. A. Arcone, E. Kuhn, N. E. Ostrom, J. P. Warnock, and A. E. Murray. "Stratigraphy of Lake Vida, Antarctica: hydrologic implications of 27 m of ice." Cryosphere 9, no. 2 (March 4, 2015): 439–50. http://dx.doi.org/10.5194/tc-9-439-2015.

Full text
Abstract:
Abstract. Lake Vida, located in Victoria Valley, is one of the largest lakes in the McMurdo dry valleys and is known to contain hypersaline liquid brine sealed below 16 m of freshwater ice. For the first time, Lake Vida was drilled to a depth of 27 m. Below 21 m the ice is marked by well-sorted sand layers up to 20 cm thick within a matrix of salty ice. From ice chemistry, isotopic composition of δ18O and δ2H, and ground penetrating radar profiles, we conclude that the entire 27 m of ice formed from surface runoff and the sediment layers represent the accumulation of surface deposits. Radiocarbon and optically stimulated luminescence dating limit the maximum age of the lower ice to 6300 14C yr BP. As the ice cover ablated downwards during periods of low surface inflow, progressive accumulation of sediment layers insulated and preserved the ice and brine beneath, analogous to the processes that preserve shallow ground ice. The repetition of these sediment layers reveals hydrologic variability in Victoria Valley during the mid- to late Holocene. Lake Vida is an exemplar site for understanding the preservation of subsurface brine, ice, and sediment in a cold desert environment.
APA, Harvard, Vancouver, ISO, and other styles
25

Zafari, Najibullah, Ashok Sharma, Dimuth Navaratna, Varuni M. Jayasooriya, Craig McTaggart, and Shobha Muthukumaran. "A Comparative Evaluation of Conceptual Rainfall–Runoff Models for a Catchment in Victoria Australia Using eWater Source." Water 14, no. 16 (August 16, 2022): 2523. http://dx.doi.org/10.3390/w14162523.

Full text
Abstract:
Hydrological modelling at a catchment scale was conducted to investigate the impact of climate change and land-use change individually and in combination with the available streamflow in the Painkalac catchment using an eWater Source hydrological model. This study compares the performance of three inbuilt conceptual models within eWater Source, such as the Australian water balance model (AWBM), Sacramento and GR4J for streamflow simulation. The three-model performance was predicted by bivariate statistics (Nash–Sutcliff efficiency) and univariate (mean, standard deviation) to evaluate the efficiency of model runoff predictions. Potential evapotranspiration (PET) data, daily rainfall data and observed streamflow measured from this catchment are the major inputs to these models. These models were calibrated and validated using eight objective functions while further comparisons of these models were made using objective functions of a Nash–Sutcliffe efficiency (NSE) log daily and an NSE log daily bias penalty. The observed streamflow data were split into three sections. Two-thirds of the data were used for calibration while the remaining one-third of the data was used for validation of the model. Based on the results, it was observed that the performance of the GR4J model is more suitable for the Painkalac catchment in respect of prediction and computational efficiency compared to the Sacramento and AWBM models. Further, the impact of climate change, land-use change and combined scenarios (land-use and climate change) were evaluated using the GR4J model. The results of this study suggest that the higher climate change for the year 2065 will result in approximately 45.67% less streamflow in the reservoir. In addition, the land-use change resulted in approximately 42.26% less flow while combined land-use and higher climate change will produce 48.06% less streamflow compared to the observed flow under the existing conditions.
APA, Harvard, Vancouver, ISO, and other styles
26

Ghofrani, Zahra, Victor Sposito, and Robert Faggian. "Modelling the impacts of blue-green infrastructure on rainfall runoff: a case study of Eastern Victoria, Australia." International Journal of Water 13, no. 2 (2019): 151. http://dx.doi.org/10.1504/ijw.2019.099514.

Full text
APA, Harvard, Vancouver, ISO, and other styles
27

Faggian, Robert, Victor Sposito, and Zahra Ghofrani. "Modelling the impacts of blue-green infrastructure on rainfall runoff: a case study of Eastern Victoria, Australia." International Journal of Water 13, no. 2 (2019): 151. http://dx.doi.org/10.1504/ijw.2019.10020979.

Full text
APA, Harvard, Vancouver, ISO, and other styles
28

Cheruiyot, CK, and VS Muhandiki. "Modeling of runoff pollution load in a data scarce situation using swat, Sondu watershed, Lake Victoria Basin." Ethiopian Journal of Environmental Studies and Management 8, no. 5 (August 4, 2015): 494. http://dx.doi.org/10.4314/ejesm.v8i5.3.

Full text
APA, Harvard, Vancouver, ISO, and other styles
29

Noor, Farhana, Orpita U. Laz, Khaled Haddad, Mohammad A. Alim, and Ataur Rahman. "Comparison between Quantile Regression Technique and Generalised Additive Model for Regional Flood Frequency Analysis: A Case Study for Victoria, Australia." Water 14, no. 22 (November 11, 2022): 3627. http://dx.doi.org/10.3390/w14223627.

Full text
Abstract:
For design flood estimation in ungauged catchments, Regional Flood Frequency Analysis (RFFA) is commonly used. Most of the RFFA methods are primarily based on linear modelling approaches, which do not account for the inherent nonlinearity of rainfall-runoff processes. Using data from 114 catchments in Victoria, Australia, this study employs the Generalised Additive Model (GAM) in RFFA and compares the results with linear method known as Quantile Regression Technique (QRT). The GAM model performance is found to be better for smaller return periods (i.e., 2, 5 and 10 years) with a median relative error ranging 16–41%. For higher return periods (i.e., 20, 50 and 100 years), log-log linear regression model (QRT) outperforms the GAM model with a median relative error ranging 31–59%.
APA, Harvard, Vancouver, ISO, and other styles
30

Carter, MR, and GR Steed. "The effects of direct drilling and stubble retention on hydraulic properties at the surface of duplex soils in north-eastern Victoria." Soil Research 30, no. 4 (1992): 505. http://dx.doi.org/10.1071/sr9920505.

Full text
Abstract:
Soil hydraulic properties in the sandy clay loam surface horizon of duplex soils were assessed under cultivated, stubble burnt (CCB); direct drilling, stubble burnt (DDB); and direct drilling, stubble retained (DDR) systems for three wheat-lupin rotations, established from 7 to 10 years, in north-eastern Victoria. Disc permeameters were used to determine sorptivity and steady state infiltration in each rotation. A rainfall simulator was used on the 10 year rotation to characterize saturated infiltration and surface soil stability. Cultivation caused an increase in soil bulk density and decreased organic C at the soil surface. Application of a -40 mm water supply potential removed macropore flow from the infiltration process and mainly characterized water flow in the soil matrix. Differences in sorptivity among tillage treatments at this potential mainly reflected initial soil moisture, rather than soil structure. Sorptivity measured on soil cores was related (T = 0.74, P = 0.01)= to sorptivity measured in the field. Under Rainfall simulation , DDR increased sorptivity, wetting depth and time to runoff, and decreased runoff rate and sediment loss, compared with DDB and CCB. Overall, steady state infiltration rate was controlled over time by the permeability of lower soil horizons. The combination of disc permeameter and rainfall simulation measurements provided a useful description of unsaturated and saturated infiltration under field conditions. The DDR system improved the potential for saturated infiltration, maximized rainfall storage in the surface horizon, and increased the stability of macroporous infiltration.
APA, Harvard, Vancouver, ISO, and other styles
31

Dugan, H. A., P. T. Doran, B. Wagner, F. Kenig, C. H. Fritsen, S. Arcone, E. Kuhn, N. E. Ostrom, J. Warnock, and A. E. Murray. "27 m of lake ice on an Antarctic lake reveals past hydrologic variability." Cryosphere Discussions 8, no. 4 (July 23, 2014): 4127–58. http://dx.doi.org/10.5194/tcd-8-4127-2014.

Full text
Abstract:
Abstract. Lake Vida, located in Victoria Valley, is one of the largest lakes in the McMurdo Dry Valleys. Unlike other lakes in the region, the surface ice extends at least 27 m, which has created an extreme and unique habitat by isolating a liquid-brine with salinity of 195 g L−1. Below 21 m, the ice is marked by well-sorted sand layers up to 20 cm thick, within a matrix of salty ice. From ice chemistry, isotopic abundances of 18O and 2H, ground penetrating radar profiles, and mineralogy, we conclude that the entire 27 m of ice formed from surface runoff, and the sediment layers represent the accumulation of fluvial and aeolian deposits. Radiocarbon and optically stimulated luminescence dating limit the maximum age of the lower ice to 6300 14C yr BP. As the ice cover ablated downwards during periods of low surface inflow, progressive accumulation of sediment layers insulated and preserved the ice and brine beneath; analogous to the processes that preserve shallow ground ice. The repetition of these sediment layers reveals climatic variability in Victoria Valley during the mid- to late Holocene. Lake Vida is an excellent Mars analog for understanding the preservation of subsurface brine, ice and sediment in a cold desert environment.
APA, Harvard, Vancouver, ISO, and other styles
32

Brault, Marc-Olivier, H. Damon Matthews, and Lawrence A. Mysak. "The importance of terrestrial weathering changes in multimillennial recovery of the global carbon cycle: a two-dimensional perspective." Earth System Dynamics 8, no. 2 (June 30, 2017): 455–75. http://dx.doi.org/10.5194/esd-8-455-2017.

Full text
Abstract:
Abstract. In this paper, we describe the development and application of a new spatially explicit weathering scheme within the University of Victoria Earth System Climate Model (UVic ESCM). We integrated a dataset of modern-day lithology with a number of previously devised parameterizations for weathering dependency on temperature, primary productivity, and runoff. We tested the model with simulations of future carbon cycle perturbations, comparing a number of emission scenarios and model versions with each other and with zero-dimensional equivalents of each experiment. Overall, we found that our two-dimensional weathering model versions were more efficient in restoring the carbon cycle to its pre-industrial state following the pulse emissions than their zero-dimensional counterparts; however, in either case the effect of this weathering negative feedback on the global carbon cycle was small on timescales of less than 1000 years. According to model results, the largest contribution to future changes in weathering rates came from the expansion of tropical and mid-latitude vegetation in grid cells dominated by weathering-vulnerable rock types, whereas changes in temperature and river runoff had a more modest direct effect. Our results also confirmed that silicate weathering is the only mechanism that can lead to a full recovery of the carbon cycle to pre-industrial levels on multimillennial timescales.
APA, Harvard, Vancouver, ISO, and other styles
33

Bethune, M., and Q. J. Wang. "A lysimeter study of the water balance of border-check irrigated perennial pasture." Australian Journal of Experimental Agriculture 44, no. 2 (2004): 151. http://dx.doi.org/10.1071/ea03049.

Full text
Abstract:
The dairy industry is a major user of water in northern Victoria and southern New South Wales. Water is typically applied to pasture using the border-check irrigation system. The border-check system is largely gravity driven and thus energy efficient. However, deep drainage can potentially be high because the system allows only limited control over the depth of water applied in each irrigation event. For this reason, heavy soils are regarded as the most suitable for border-check irrigation. This study quantified net deep drainage (deep drainage less capillary rise) under border-check irrigated pasture on a Goulburn clay loam soil. Additionally, the study investigated the extent to which irrigation frequency and watertable conditions influence water use, dry matter production and deep drainage. The water balance and dry matter production were monitored over 2.5 years in a lysimeter facility in northern Victoria. The Goulburn clay loam is representative of the heavier textured soils used for border-check irrigation of pasture in northern Victoria. The average measured net deep drainage was 4 mm/year. This indicates that relatively small levels of net deep drainage can be achieved under well-managed border-check irrigation on a Goulburn clay loam soil. Net deep drainage losses were greatest following winter, when rainfall exceeded pasture water use for an extended period. Increasing the interval between irrigation events resulted in reduced plant water use, infiltration of irrigation water, rainfall runoff and pasture production. However, increasing the interval did not impact on net deep drainage or water use efficiency. Depth of watertable had a relatively minor impact on the water balance.
APA, Harvard, Vancouver, ISO, and other styles
34

McFarlane, DJ, and JW Cox. "Management of excess water in duplex soils." Australian Journal of Experimental Agriculture 32, no. 7 (1992): 857. http://dx.doi.org/10.1071/ea9920857.

Full text
Abstract:
Excess water in duplex soils can be removed by drains. In soils in which drainage is impractical, some success has been obtained by deep ripping and by gypsum amendment. These practices can increase profile storage or drainage. Interceptor drains are suitable for duplex soils with slopes of more than about 1.5%. On more gentle slopes, relief drains are used to remove excess water. Subsurface tube and mole drains have been used successfully to drain cereal crops in Victoria, but in Western Australia open drains are preferred because they can carry storm runoff as well as seepage waters. The greatest cost of open drains is the land removed from production. Over 35% of the rain falling during the growing season has been removed by drains in Victoria and Western Australia in wet years. Drainage was almost entirely downslope of monitored interceptor drains in Western Australia, which is not predicted from the theory. Simulation of water levels between drains and of drain flows using the DRAINMOD model indicated significant, preferred pathways for water flow to drains. The pathways explain the predominantly downslope effect of interceptor drains and the wide drain spacings which can be used. Deep ripping and the incorporation of gypsum can reduce waterlogging in some soils, but has had no effect in several others. The effect of deep ripping on recharge is unclear. Drains may decrease groundwater recharge, water and wind erosion, and soil structure decline. Their effect on phosphate export from catchments is unclear.
APA, Harvard, Vancouver, ISO, and other styles
35

Kanda, Edwin K., Job R. Kosgei, and Emmanuel C. Kipkorir. "Simulation of organic carbon loading using MIKE 11 model: a case of River Nzoia, Kenya." Water Practice and Technology 10, no. 2 (June 1, 2015): 298–304. http://dx.doi.org/10.2166/wpt.2015.035.

Full text
Abstract:
River Nzoia is the largest river draining into the Kenyan portion of Lake Victoria. This river receives both point sources of pollution from industrial and municipal wastes, and non-point sources from agricultural runoff in the catchment. The objective of this study was to simulate dissolved oxygen (DO) and biochemical oxygen demand (BOD) of the middle section of River Nzoia using MIKE 11 model. The model was calibrated using discharge and water quality data for 2009 and validated with March–April 2013 data. The model performance was good with coefficient of determination (R2) values of between 0.845 and 0.995, Nash–Sutcliffe efficiency values of between 0.748 and 0.993 and percent bias of less than 10 for both calibration and validation of electrical conductivity (EC), DO and BOD. EC and BOD values were lower for April compared to March which could be attributed to dilution during high flows. DO values were above the recommended minimum level of 4 mg/l in all the sections of the river in the wet period but some sections had lower than 4 mg/l during low flow period. The government agencies such as Water Resources Management Authority and National Environment Management Authority should enforce the effluent standards to ensure that industries and wastewater treatment plants adhere to the maximum allowable limit for BOD and also improve their treatment efficiencies of wastewater plants so as to improve the quality of River Nzoia which is important in the overall management of the Lake Victoria basin.
APA, Harvard, Vancouver, ISO, and other styles
36

Benyon, Richard, Shane Haydon, Rob Vertessy, Tom Hatton, George Kuczera, Paul Feikema, and Patrick Lane. "Comment on Wood et al. 2008, 'Impacts of fire on forest age and runoff in mountain ash forests'." Functional Plant Biology 37, no. 12 (2010): 1187. http://dx.doi.org/10.1071/fp10141.

Full text
Abstract:
Wood et al. (2008; FPB 35) concluded their measurements of evapotranspiration (ET) in Eucalyptus regnans F.Muell. forest at Wallaby Creek, Victoria showed that ET differs only slightly between regrowth and oldgrowth, contrary to the findings of previous research. We assert that the conclusions of Wood et al. are invalid and argue that Wood et al. substantially overestimated annual transpiration and rainfall. Monthly whole-forest ET measured by Wood et al. using eddy covariance in a 296-year-old stand sum to ~700 mm year–1; consistent with rainfall of 721 mm year–1 recorded nearby by the Bureau of Meteorology. However, the Wood et al. conclusions were based on 1077 mm annual transpiration at this site, which appears to be estimated from a few months of heat pulse velocity measurements. Transpiration alone cannot be 54% higher than whole-forest ET because the latter includes transpiration, rainfall interception and evaporation from the forest floor. We believe Wood et al. made errors in scaling heat pulse velocities to whole-stand annual transpiration. Their rainfall of 1175 mm year–1 averages 62% higher than at three Bureau of Meteorology and Melbourne Water sites nearby. The paper also contains inaccuracies in reporting of the literature and numerous other errors.
APA, Harvard, Vancouver, ISO, and other styles
37

Zhang, Shihao, Junhe Tan, Junhang Liu, Jiaqi Wang, and Ata Tara. "Suitability Prediction and Enhancement of Future Water Supply Systems in Barwon Region in Victoria, Australia." Land 11, no. 5 (April 23, 2022): 621. http://dx.doi.org/10.3390/land11050621.

Full text
Abstract:
Intensive agricultural production accompanied by the climate change impacts in post-Colonial rural landscapes have continuously increased the demand for water resources and coastal areas, showing an unprecedented water supply crisis. By taking extreme weather conditions and rainfall events for future trends, a resilient water storage facility for the landscape requires the collaborative approach of natural systems and simulation modelling techniques to develop sustainable future scenarios. In this study, an ecological suitability model is used to identify potential sites for the construction of multi-purpose dams. As part of the model structure, multi factors are classified using the patterns of changing landscapes, and then weighted overlay analysis is conducted on a Geographic Information System (GIS) platform. Compared to previous studies, this paper derives its principal impact parameters and projections based on historical land cover information. The suitability maps that are generated visually guide the geographical location of the multi-purpose dams and indicate the areas from highly suitable to least suitable, clarifying the possibility of building blue infrastructure alongside the waterways in west-central Barwon. The workflow proposes a resilient water system based on existing land characteristics and measures that future water storage capacity will be a valid increase of approximately 1.5 times. This strategy alleviates water scarcity during the dry season to benefit traditional agricultural activities. Digital calculations are utilized to demonstrate the feasibility of the experimental results, providing a methodology for regulating the distribution and supply of river flows throughout the year while retaining runoff in a hierarchical pattern at precipitation periods.
APA, Harvard, Vancouver, ISO, and other styles
38

Das, Sushil K., Amimul Ahsan, Md Habibur Rahman Bejoy Khan, Muhammad Atiq Ur Rehman Tariq, Nitin Muttil, and Anne W. M. Ng. "Impacts of Climate Alteration on the Hydrology of the Yarra River Catchment, Australia Using GCMs and SWAT Model." Water 14, no. 3 (February 1, 2022): 445. http://dx.doi.org/10.3390/w14030445.

Full text
Abstract:
A rigorous evaluation of future hydro-climatic changes is necessary for developing climate adaptation strategies for a catchment. The integration of future climate projections from general circulation models (GCMs) in the simulations of a hydrologic model, such as the Soil and Water Assessment Tool (SWAT), is widely considered as one of the most dependable approaches to assess the impacts of climate alteration on hydrology. The main objective of this study was to assess the potential impacts of climate alteration on the hydrology of the Yarra River catchment in Victoria, Australia, using the SWAT model. The climate projections from five GCMs under two Representative Concentration Pathway (RCP) scenarios—RCP 4.5 and 8.5 for 2030 and 2050, respectively—were incorporated into the calibrated SWAT model for the analysis of future hydrologic behaviour against a baseline period of 1990–2008. The SWAT model performed well in its simulation of total streamflow, baseflow, and runoff, with Nash–Sutcliffe efficiency values of more than 0.75 for monthly calibration and validation. Based on the projections from the GCMs, the future rainfall and temperature are expected to decrease and increase, respectively, with the highest changes projected by the GFDL-ESM2M model under the RCP 8.5 scenario in 2050. These changes correspond to significant increases in annual evapotranspiration (8% to 46%) and decreases in other annual water cycle components, especially surface runoff (79% to 93%). Overall, the future climate projections indicate that the study area will become hotter, with less winter–spring (June to November) rainfall and with more water shortages within the catchment.
APA, Harvard, Vancouver, ISO, and other styles
39

Bamutaze, Y., J. Wanyama, B. Diekrugger, M. Meadows, and H. Opedes. "Dynamics of surface runoff and soil loss from a toposequence under varied land use practices in Rwizi catchment, Lake Victoria Basin." Journal of Soil and Water Conservation 72, no. 5 (2017): 480–92. http://dx.doi.org/10.2489/jswc.72.5.480.

Full text
APA, Harvard, Vancouver, ISO, and other styles
40

Ridley, A. M., B. P. Christy, R. E. White, T. McLean, and R. Green. "North-east Victoria SGS National Experiment site: water and nutrient losses from grazing systems on contrasting soil types and levels of inputs." Australian Journal of Experimental Agriculture 43, no. 8 (2003): 799. http://dx.doi.org/10.1071/ea02090.

Full text
Abstract:
Water and nutrient losses, pasture and animal production were measured for a prime lamb enterprise at Maindample (rainfall 750 mm/year) and a wool enterprise at Ruffy (rainfall 671 mm/year) in north-east Victoria from 1998 to 2000. Each site comprised 3 paddock-scale treatments: control, unsown pasture receiving about 5�kg�phosphorus (P)/ha.year; medium input, sown pasture (about 10 kg P/ha.year); and high input, sown pasture (≥22 kg P/ha.year). Sown pastures were based on phalaris (Phalaris aquatica L.) at Maindample and cocksfoot (Dactylis glomerata L.) at Ruffy, and sheep were set stocked. Pastures at Maindample created a larger soil water deficit (commonly about 120 mm) compared with Ruffy (about 70 mm) in summer. Maximum soil water deficit at Maindample occurred under the high input pasture and was about 30 mm greater than the medium or control treatments. Phalaris content ranged between about 200 and 1300 kg DM/ha, between 10 and 70% of total composition (commonly about 20%). In contrast, at Ruffy the control, which had 20–40% native grasses (Austrodanthonia and Microlaena) achieved the greatest soil water deficit, about 25 mm greater than for sown pastures. Cocksfoot persisted poorly at the acid soil at Ruffy. Small differences in green leaf area over summer (about 200 kg DM/ha) between treatments could generate the soil water deficit differences over the summer.The most striking result was the markedly different pathways of water loss between surface losses and deep drainage at the 2 sites, which was of greater consequence than the effect of pasture type. At Maindample, on average, 166 mm of water was lost annually (22% of rainfall) with 110 mm of this as surface runoff. At Ruffy, annual water loss was 128 mm (19% of rainfall) with 110 mm of this total water loss estimated as loss through deep drainage.Phosphorus losses were low in all treatments (≤1 kg P/ha.year), and nitrate-N (NO3-N) losses (7–12 kg N/ha.year) were comparable with previous work. Concentrations of P in water were highest from the high treatments at both sites, averaging 0.91 and 0.83 mg P/L in surface runoff from Maindample high and Ruffy high treatments, respectively. Average soil water NO3-N concentrations ranged from 3 to 26 mg N/L. Both P and N concentrations were higher than acceptable for aquatic health.Environmental risks in terms of water and nutrient losses could be either higher or lower for sown than unsown pastures, depending upon soil type, botanical stability, persistence and the soil water extracting ability of the pasture. Results indicated that better environmental outcomes could be achieved if soil types were targeted for particular land uses. High management skills are needed if grazing enterprises are to be both profitable and have lower off-site impacts.
APA, Harvard, Vancouver, ISO, and other styles
41

Hoffman, Matthew J., Andrew G. Fountain, and Glen E. Liston. "Near-surface internal melting: a substantial mass loss on Antarctic Dry Valley glaciers." Journal of Glaciology 60, no. 220 (2014): 361–74. http://dx.doi.org/10.3189/2014jog13j095.

Full text
Abstract:
AbstractThe McMurdo Dry Valleys, southern Victoria Land, East Antarctica, are a polar desert, and melt from glacial ice is the primary source of water to streams, lakes and associated ecosystems. Previous work found that to adequately model glacier ablation and subsurface ice temperatures with a surface energy-balance model required including the transmission of solar radiation into the ice. Here we investigate the contribution of subsurface melt to the mass balance of (and runoff from) Dry Valley glaciers by including a drainage process in the model and applying the model to three glacier sites using 13 years of hourly meteorological data. Model results for the smooth glacier surfaces common to many glaciers in the Dry Valleys showed that sublimation was typically the largest component of surface lowering, with rare episodes of surface melting, consistent with anecdotal field observations. Results also showed extensive internal melting 5–15 cm below the ice surface, the drainage of which accounted for ~50% of summer ablation. This is consistent with field observations of subsurface streams and formation of a weathering crust. We identify an annual cycle of weathering crust formation in summer and its removal during the 10 months of winter sublimation.
APA, Harvard, Vancouver, ISO, and other styles
42

Lawson, A. R., K. L. Greenwood, and K. B. Kelly. "Irrigation water productivity of winter-growing annuals is higher than perennial forages in northern Victoria." Crop and Pasture Science 60, no. 5 (2009): 407. http://dx.doi.org/10.1071/cp08243.

Full text
Abstract:
The dairy industry in Victoria, Australia, uses more than half the state’s irrigation water, mainly for growing pasture. Information on the comparative water use of forage systems would be useful for dairy farmers aiming to optimise their forage production under conditions of limited water availability. However, there are few data comparing water use under similar management and weather conditions. This paper reports on an experiment which measured and compared the production, water use, and water productivity (forage removed per unit water input) of a range of 6 border-check irrigated forage systems (3 perennial, 2 annual, and a double-cropped) and 1 spray irrigated, annual forage system, used by the dairy industry in northern Victoria. Forage removal was highest from the perennial pastures, lucerne, double-cropped and Persian clover systems in both 2005 and 2006. Irrigation water inputs in 2005 were comparable with average values reported in the literature and were closely related to the length of the growing season, with around 800–850 mm used for the perennial pastures and 340–440 mm used for the border-check irrigated annual pastures. Irrigation water inputs in 2006 were substantially higher than in 2005, reflecting the drought conditions that prevailed throughout most of Victoria, with 1100–1200 mm used for the perennial species and 450–700 mm used by the border-check irrigated annual pastures. These irrigation water requirements highlight considerable year-to-year variation as low-rainfall years are usually high-evaporation years. Irrigation water productivity (WP) was greater for the annual than for the perennial systems. In 2005, irrigation WP was 30–37 kg DM/ha.mm for the annual pastures compared with 21–27 kg DM/ha.mm for the perennial and double-cropped systems. In the drier year of 2006, irrigation WP was higher for the short-season annuals than for the other forage systems. When rainfall, runoff, and changes in soil water content were included in the calculation of total WP, there were no consistent differences in the total WP of the annual and perennial systems in either year. These findings show that under conditions of limited irrigation water availability, farmers will be able to grow more forage using winter-growing annual systems than perennial systems. However, other factors such as nutritive characteristics, cost of production, and cost of transferring feed also need to be considered when deciding which forages to grow.
APA, Harvard, Vancouver, ISO, and other styles
43

Chang, Tak, Amin Talei, Lloyd Chua, and Sina Alaghmand. "The Impact of Training Data Sequence on the Performance of Neuro-Fuzzy Rainfall-Runoff Models with Online Learning." Water 11, no. 1 (December 29, 2018): 52. http://dx.doi.org/10.3390/w11010052.

Full text
Abstract:
The learning algorithms in many of conventional Neuro-Fuzzy Systems (NFS) are based on batch or global learning where all parameters of the fuzzy system are optimized off-line. Although these models have frequently been used, they suffer from a reduced flexibility in their architecture as the number of rules need to be predefined by the user. This study uses a Dynamic Evolving Neural Fuzzy Inference System (DENFIS) in which an evolving, online clustering algorithm, the Evolving Clustering Method (ECM), is implemented. This study focused on evaluating the performance of this model in capturing the rainfall-runoff process and rainfall-water level relationship. The two selected study catchments are located in an urban tropical and in a semi-urbanized area, respectively. The first catchment, Sungai Kayu Ara (23.22 km2), is located in Malaysia, with 10-min rainfall-runoff time-series from which 30 major events are used. The second catchment, Dandenong (272 km2), is located in Victoria, Australia, with daily rainfall and river stage (water level) data from which 11 years of data is used. DENFIS results were then compared with two groups of benchmark models: a regression-based data-driven model known as the Autoregressive Model with Exogenous Inputs (ARX) for both study sites, and physical models Hydrologic Engineering Center–Hydrologic Modelling System (HEC–HMS) and Storm Water Management Model (SWMM) for Sungai Kayu Ara and Dandenong catchments, respectively. DENFIS significantly outperformed the ARX model in both study sites. Moreover, DENFIS was found comparable if not superior to HEC–HMS and SWMM in Sungai Kayu Ara and Dandenong catchments, respectively. A sensitivity analysis was then conducted on DENFIS to assess the impact of training data sequence on its performance. Results showed that starting the training with datasets that include high peaks can improve the model performance. Moreover, datasets with more contrasting values that cover wide range of low to high values can also improve the DENFIS model performance.
APA, Harvard, Vancouver, ISO, and other styles
44

Zalnezhad, Amir, Ataur Rahman, Mehdi Vafakhah, Bijan Samali, and Farhad Ahamed. "Regional Flood Frequency Analysis Using the FCM-ANFIS Algorithm: A Case Study in South-Eastern Australia." Water 14, no. 10 (May 17, 2022): 1608. http://dx.doi.org/10.3390/w14101608.

Full text
Abstract:
Regional flood frequency analysis (RFFA) is widely used to estimate design floods in ungauged catchments. Both linear and non-linear methods are adopted in RFFA. The development of the non-linear RFFA method Adaptive Neuro-fuzzy Inference System (ANFIS) using data from 181 gauged catchments in south-eastern Australia is presented in this study. Three different types of ANFIS models, Fuzzy C-mean (FCM), Subtractive Clustering (SC), and Grid Partitioning (GP) were adopted, and the results were compared with the Quantile Regression Technique (QRT). It was found that FCM performs better (with relative error (RE) values in the range of 38–60%) than the SC (RE of 44–69%) and GP (RE of 42–78%) models. The FCM performs better for smaller to medium ARIs (2 to 20 years) (ARI of five years having the best performance), and in New South Wales, over Victoria. In many aspects, the QRT and FCM models perform very similarly. These developed RFFA models can be used in south-eastern Australia to derive more accurate flood quantiles. The developed method can easily be adapted to other parts of Australia and other countries. The results of this study will assist in updating the Australian Rainfall Runoff (national guide)-recommended RFFA technique.
APA, Harvard, Vancouver, ISO, and other styles
45

Bakyayita, G. K., A. C. Norrström, and R. N. Kulabako. "Assessment of Levels, Speciation, and Toxicity of Trace Metal Contaminants in Selected Shallow Groundwater Sources, Surface Runoff, Wastewater, and Surface Water from Designated Streams in Lake Victoria Basin, Uganda." Journal of Environmental and Public Health 2019 (May 23, 2019): 1–18. http://dx.doi.org/10.1155/2019/6734017.

Full text
Abstract:
The levels, speciation of elements, and toxicity of selected trace metals as well as other parameters in selected surface water, shallow groundwater sources, landfill leachate, and associated surface runoff in the Lake Victoria basin, Uganda, were studied. The WHO guidelines, Ugandan standards, Canadian guidelines and Swedish EPA were used for assessment. The shallow groundwater was acidic with pH values below 6.5. The pH, dissolved organic carbon, flouride, and sulphate levels for all springs were below the guideline values although 52.8% was contaminated with nitrates while 39% was contaminated with chloride ions. Some surface water samples had levels of major elements, such as iron, chromium, aluminium, and manganese, above the guideline values. Speciation studies showed that 74% of the metal ions was bound to dissolved organic matter in surface water, whereas in landfill leachates, the dominant ionic species was metal hydroxides or fulvic acid bound. Risk analysis based on the Swedish EPA showed varied risks of negative effects in 30%–76% of the sample sites ranging from high to increased risk in surface water, whereas the results from modelling sorption data using the Bio-met tool showed potential risk to toxicity effects of Cu2+, Ni2+, Zn2+, and Pb2+ in 15.3%–30.8% surface water samples and 8.3%–62.5% groundwater samples.
APA, Harvard, Vancouver, ISO, and other styles
46

Potter, Nicholas J., Francis H. S. Chiew, Stephen P. Charles, Guobin Fu, Hongxing Zheng, and Lu Zhang. "Bias in dynamically downscaled rainfall characteristics for hydroclimatic projections." Hydrology and Earth System Sciences 24, no. 6 (June 8, 2020): 2963–79. http://dx.doi.org/10.5194/hess-24-2963-2020.

Full text
Abstract:
Abstract. Dynamical downscaling of future projections of global climate model outputs can provide useful information about plausible and possible changes to water resource availability, for which there is increasing demand in regional water resource planning processes. By explicitly modelling climate processes within and across global climate model grid cells for a region, dynamical downscaling can provide higher-resolution hydroclimate projections and independent (from historical time series), physically plausible future rainfall time series for hydrological modelling applications. However, since rainfall is not typically constrained to observations by these methods, there is often a need for bias correction before use in hydrological modelling. Many bias-correction methods (such as scaling, empirical and distributional mapping) have been proposed in the literature, but methods that treat daily amounts only (and not sequencing) can result in residual biases in certain rainfall characteristics, which flow through to biases and problems with subsequently modelled runoff. We apply quantile–quantile mapping to rainfall dynamically downscaled by the NSW and ACT Regional Climate Modelling (NARCliM) Project in the state of Victoria, Australia, and examine the effect of this on (i) biases both before and after bias correction in different rainfall metrics, (ii) change signals in metrics in comparison to the bias and (iii) the effect of bias correction on wet–wet and dry–dry transition probabilities. After bias correction, persistence of wet states is under-correlated (i.e. more random than observations), and this results in a significant bias (underestimation) of runoff using hydrological models calibrated on historical data. A novel representation of quantile–quantile mapping is developed based on lag-one transition probabilities of dry and wet states, and we use this to explain residual biases in transition probabilities. Representing quantile–quantile mapping in this way demonstrates that any quantile mapping bias-correction method is unable to correct the underestimation of autocorrelation of rainfall sequencing, which suggests that new methods are needed to properly bias-correct dynamical downscaling rainfall outputs.
APA, Harvard, Vancouver, ISO, and other styles
47

White, R. E., B. P. Christy, A. M. Ridley, A. E. Okom, S. R. Murphy, W. H. Johnston, D. L. Michalk, et al. "SGS Water Theme: influence of soil, pasture type and management on water use in grazing systems across the high rainfall zone of southern Australia." Australian Journal of Experimental Agriculture 43, no. 8 (2003): 907. http://dx.doi.org/10.1071/ea02239.

Full text
Abstract:
Eleven experimental sites in the Sustainable Grazing Systems (SGS) national experiment were established in the high rainfall zone (HRZ, >600 mm/year) of Western Australia, Victoria and New South Wales to measure components of the water balance, and pathways of water movement, for a range of pastures from 1997 to 2001. The effect of widely spaced river red gums (Eucalyptus camaldulensis) in pasture, and of belts of plantation blue gums (E. globulus), was studied at 2 of the sites. The soil types tested ranged from Kurosols, Chromosols and Sodosols, with different subsoil permeabilities, to Hydrosols and Tenosols. The pasture types tested were kikuyu (Pennisetum clandestinum), phalaris (Phalaris aquatica), redgrass (Bothriochloa macra) and annual ryegrass (Lolium rigidum), with subterranean clover (Trifolium subterraneum) included. Management variables were set stocking v. rotational grazing, adjustable stocking rates, and level of fertiliser input. Soil, pasture and animal measurements were used to set parameters for the biophysical SGS pasture model, which simulated the long-term effects of soil, pasture type, grazing method and management on water use and movement, using as inputs daily weather data for 31 years from selected sites representing a range of climates. Measurements of mean maximum soil water deficit Sm were used to estimate the probability of surplus water occurring in winter, and the average amount of this surplus, which was highest (97–201 mm/year) for pastures in the cooler, winter-rainfall dominant regions of north-east and western Victoria and lowest (3–11 mm/year) in the warmer, lower rainfall regions of the eastern Riverina and Esperance, Western Australia. Kikuyu in Western Australia achieved the largest increase in Sm compared with annual pasture (55–71 mm), while increases due to phalaris were 18–45 mm, and those of native perennials were small and variable. Long-term model simulations suggested rooting depth was crucial in decreasing deep drainage, to about 50 mm/year for kikuyu rooting to 2.5 m, compared with 70–200 mm/year for annuals rooting to only 0.8 m. Plantation blue gums dried the soil profile to 5.25 m by an average of 400 mm more than kikuyu pasture, reducing the probability of winter surplus water to zero, and eliminating drainage below the root zone. Widely spaced river red gums had a much smaller effect on water use, and would need to number at least 14 trees per hectare to achieve extra soil drying of about 50 mm over a catchment. Soil type affected water use primarily through controlling the rooting depth of the vegetation, but it also changed the partitioning of surplus water between runoff and deep drainage. Strongly duplex soils such as Sodosols shed 50% or more surplus water as runoff, which is important for flushing streams, provided the water is of good quality. Grazing method and pasture management had only a marginal effect in increasing water use, but could have a positive effect on farm profitability through increased livestock production per hectare and improved persistence of perennial species.
APA, Harvard, Vancouver, ISO, and other styles
48

Young, Kathy L., W. Robert Bolton, Ånund Killingtveit, and Daqing Yang. "Assessment of precipitation and snowcover in northern research basins*." Hydrology Research 37, no. 4-5 (August 1, 2006): 377–91. http://dx.doi.org/10.2166/nh.2006.021.

Full text
Abstract:
In 2004, a workshop was held to collect and synthesize the water balance data from 39 northern research basins (NRB) in Victoria, BC, Canada. One of the recommendations from the meeting was a need to review systematically each component of the water balance for these northern basins in order to identify spatial and temporal trends and to address significant knowledge gaps. Here, we assess the methodologies for measuring snow and rain in these northern basins; examine the temporal and spatial patterns of snow accumulation both during and at the end-of-the winter; consider ablation patterns and comment on the occurrence of extreme events. Our evaluation indicates that northern hydrologists still employ a variety of gauges and approaches to both measure and correct precipitation. For the NRB, rainfall contributions dominate in lower latitudes while snowfall gains importance with higher latitudes and altitude. Occurrence of large water bodies, topography (i.e. aspect, slope) and vegetation influence precipitation amount and its distribution across the landscape. Only two NRB studies showed a declining trend in snowcover (SWE). Snow is still considered the most important input of water in these northern basins, but extreme summer precipitation events (both rain and snow) have triggered higher magnitude floods than seasonal snowmelt runoff. Glacierized basins are sensitive to summer snowfalls and low winter snow storage. Both have the potential to dampen or enhance melting despite warmer or cooler air temperatures. Standardized gauges, approaches and continued monitoring of the NRB is encouraged.
APA, Harvard, Vancouver, ISO, and other styles
49

Burkitt, L. L., D. R. Small, J. W. McDonald, W. J. Wales, and M. L. Jenkin. "Comparing irrigated biodynamic and conventionally managed dairy farms. 1. Soil and pasture properties." Australian Journal of Experimental Agriculture 47, no. 5 (2007): 479. http://dx.doi.org/10.1071/ea05196.

Full text
Abstract:
Ten paired irrigated dairy farms under biodynamic (BD) and conventional (CV) management were compared over a 4-year period (1991–94). The paired farms were located in the irrigation districts of northern Victoria and southern New South Wales and were matched for soil type, climate, cattle breed and farm area. Farms had been practising BD principles for an average of 16 years before the commencement of the study and had not received phosphorus (P) fertiliser for an average of 17 years. The effects of farm management on soil chemical and biological properties and the nutritive properties and botanical composition of pasture were examined at varying sampling times during the study. Soil Olsen extractable P concentrations were consistently 2–3 times higher under CV management at various sampling depths (mean = 22 mg/kg, 0–10 cm), and were generally marginal under BD management in the surface 10 cm (mean = 8.5 mg/kg). Low soil extractable P concentrations were also reflected in consistently lower mean pasture P concentrations under BD management (0.25 compared with 0.35% on CV farms). Lower soil and pasture P concentrations under BD management were the result of a large negative P balance across BD farms (–17 kg P/ha.year). A mean negative P balance under BD management was a result of low P imports (2 kg P/ha.year) in comparison with large quantities of P (19 kg P/ha.year) effectively lost from the farming system through animal products, estimated losses in water runoff and slowly reversible soil P reactions. These results suggest that greater P imports are required to ensure the future sustainability of BD dairy pasture farming systems. There were few differences in soil biological properties, with earthworm weights significantly higher under CV management, but no difference in soil organic carbon, humus concentration, the weight of the organic mat or microbial biomass, between the two management systems.
APA, Harvard, Vancouver, ISO, and other styles
50

Burkitt, L. L., C. J. P. Gourley, and P. W. G. Sale. "Phosphorus auditing cannot account for all of the phosphorus applied to different pasture soils." Soil Research 42, no. 1 (2004): 89. http://dx.doi.org/10.1071/sr03025.

Full text
Abstract:
Five field sites established in the high rainfall zone of southern Victoria were used to examine the downwards vertical movement of phosphorus (P) fertiliser on soils which ranged in P sorption capacity. Fertiliser was applied either as a single application of 280 kg P/ha at the beginning of the experiment (April 1998), or as 35�kg�P/ha reapplied every 6 months (totalling 210 kg P/ha by the end of the third year). Soil cores were sampled in June 2001 to a depth of 40 cm, and soil at depths of 0–5, 5–10, 10–20, 20–30, and 30–40 cm was analysed for a range of soil properties and total P concentration.Total P concentration changed very little down the profile, indicating that there was minimal vertical movement of P fertiliser below the 10 cm layer of 5 pasture soils following the single application of 280 kg P/ha or 35 kg P/ha reapplied every 6 months. Soils with low to moderate surface P sorption capacity showed a trend for higher total P concentrations at depth. However, quantitative relationships between vertical P movement and soil properties at depth were poor. A P audit resulted in variable recovery of the applied P (45–128%) in the surface 40 cm at each of the 5 sites. Consistently low P recoveries were achieved at one site, where the surface soil had a high P sorption capacity. Some applied P may have bypassed the high P sorbing surface layers at this site through macropore flow and moved beyond the 40 cm sampling zone, or have been lost to surface runoff. These results question the usefulness of P audit or mass-balance methods for accounting for P movement in a pasture-based system, as spatial heterogeneity of soil properties, both horizontally and vertically, was high in the current study.
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography