18 research outputs found

    A GIS Approach to Quantify Impact of Flooding on Shallow Groundwater Levels in the Wakool Irrigation District - Final Draft

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    Environmental degradation associated with shallow saline watertables is a major threat to the sustainability of agricultural industry throughout the Murray-Darling Basin. Located in the western part of the Murray Valley of NSW, the Wakool Irrigation District has experienced a history of water table rise, including likely contribut ions from widespread flooding. The community is interested in scientific evidence quantifying the impact of flooding on the shallow groundwater, in order to target management actions to control water table rise and salinity in this area. This study estimates the spatial and temporal impact of flooding on shallow groundwater for the Wakool Irrigation District through an extensive GIS analysis based on a large amount of piezometric data monitored over many years. By compiling the piezometric data into a GIS database and analyzing the data in a GIS application, we are able to quantify the net recharge caused by flooding and to visualize the spatial extent of the impact of flooding on the shallow water table reflected by water table change. The results show that flooding has a significant impact on the shallow groundwater. The floods during the record wet period of 1973-75 caused a net recharge of around 116x103 ML (0.52ML/ha in average) at the stage when water table rise reached its maximum value around December 1975. Apart from the magnitude of flooding, the amount of the net recharge caused by a single flood event is also related to the initial water table before the flood, which affects the shallow groundwater storage capacity. The higher the initial water table is, the less the shallow groundwater storage capacity will be, and consequently there will be less room for the net recharge, as shown during the 1973-75 floods. More frequent flooding such as the one experienced in 1981, whose recurrence interval is estimated as around 1 in 10 years, could result in 42.68x103 ML or an average of 0.19ML/ha net recharge at the stage around maximum water table mound, given the initial average water table depth being at 4.28m. There are strong connections between the local rainfall, flood, and water table change, suggesting that the floods happened in this area are normally due to both upstream and local rainfall. The major flood recharge areas within the Wakool area are mainly located along the Edward – Niemur River system. The groundwater recession following a flooding is affected by a number of factors, such as the initial water table depth, the climate conditions, the management actions, and etc

    Quantifying Impact Of Rainfall On Shallow Groundwater Table In The Wakool Irrigation District, NSW

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    Water table rise and salinity are major threats to the sustainability of agriculture in the Wakool area. In order to improve groundwater and salinity management in the Wakool area, it is necessary to quantify impact of both climate and management on shallow groundwater table. Rainfall as a major climate indicator and hydrology component plays an important role in regional hydrology and environment, as well as in water table change. This study attempts to quantify the impact of rainfall as a major climate indicator on shallow groundwater in the Wakool area based on the piezometric data in this area and the rainfall data in a wider area. GIS techniques have been extensively used in this study for data processing and analysis, especially for generating the spatial distributions of rainfall and groundwater table over the study period, for analyzing the spatial extent of groundwater table changes, and for calculating relevant volumes for various time intervals. This study has developed a method for isolating the impact of climate on shallow watertables. The method has been proven particularly effective in assessing the impact of rainfall for summer seasons which are the major irrigation periods in the study area. Statistical relationships were established to understand and quantify the impact of climate represented by rainfall on groundwater tables for different seasons in the year. The statistical relationships between rainfall and groundwater storage change derived from this study revealed some interesting bench mark rainfall figures: • For summer seasons, the bench mark rainfall is around 200mm, above which, it will likely to have an addition effect on groundwater storage; below which, it will likely to have a reduction effect on groundwater storage; • For the winter season, that bench mark rainfall is around 170mm The results of this study indicate that climate represented by rainfall, which is also a major source of flood, has a significant impact on the shallow groundwater tables in the Wakool area, as the correlations (R2) between rainfall and water table change are in the range of 0.7~0.9 for all the time intervals considered

    Hydro-climatic and Economic Evaluation of Seasonal Climate Forecasts for Risk Based Irrigation Management

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    This work is focused in the Murrumbidgee catchment to help understand the value of the seasonal forecasts to rice based cropping systems. The key activities of this project include: • An overview of water allocation in the Murrumbidgee Valley • Evaluation of commonly used seasonal forecasting methods used to predict rainfall • Development of a novel water allocation model on the basis of seasonal forecasts and historic allocation data • Economic analysis of the benefits from better irrigation forecasts in irrigated catchments The key findings include: • The current system of announcing allocations does not take into account seasonal climate forecasts of rainfall and flows in the catchment. End of the season allocations are made too late and pose a serious financial risk to farmers due to inadequate information being available at the start of the summer cropping period • The SST correlations with inflows to dams has provided promising results, which can be used to forecast flows to dams with lead times of around 1 year • Artificial Neural network (ANN) approaches which can learn from historic model simulations and SST predictions can be a way forward to link climate forecasts with risk management. Results of the ANN model show good correlations with the historic water allocation trends over any given season. This tool can be used to make informed cropping risk decisions • Irrigators utilising allocation forecast information can minimise the opportunity cost of forgone agricultural production. Undertaking decision analysis, it was estimated that the net benefit of allocation forecasts to the irrigators of the CIA is between 50,000and50,000 and 660,000 per year (equivalent to 0.68/haand0.68/ha and 8.56/ha). This was assuming that the CIA irrigators are collectively risk averse as their risk preference is unknown As part of this project a stakeholder workshop on climate variability, climate change and adaptation in the Murrumbidgee Basin was organised, to examine research ideas on climate research for efficient irrigation management. Participants included a number of interested participants from irrigation companies, NSW Agriculture, Department of Infrastructure Planning and Natural Resources (DIPNR), Murray Darling Basin Commission (MDBC) and the local community. There is a tremendous interest in climate and water issues due to the recent drought. The farming community needs tools which can link climate forecasts with smarter agricultural water management using a risk based approach. The key barrier to the adoption of existing climate forecast tools is their lack of proven utility and the risk adverse attitude of water allocation agencies

    Effect of Different Cultivation Patterns on Amomum villosum Yield and Quality Parameters, Rhizosphere Soil Properties, and Rhizosphere Soil Microbes

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    The forest–medicinal plant management system has benefited the commercial production of Amomum villosum. However, little is known about the influence of different forestlands on the cultivation of A. villosum. The present study investigated the potential differences in the A. villosum yield and quality parameters, rhizosphere soil properties, and rhizosphere soil microbiota between a rubber plantation (RP) and a natural secondary forest (NSF). No significant differences in yield or rhizosphere soil properties of A. villosum were observed between RP and NSF, although most of the A. villosum yield parameters, the rhizosphere soil physicochemical properties, and soil enzyme activities were higher in NSF than in RP. Furthermore, the 38 volatile components had significantly higher relative abundances in NSF than in RP. Furthermore, the alpha diversity indices for the microbiota communities in the A. villosum rhizosphere soil indicated that the richness of the bacterial and fungal communities was significantly higher in NSF than in RP. These findings suggest that NSF conditions may be more appropriate than RP conditions for growing A. villosum. The data generated in this study may be useful for increasing the production of high-quality A. villosum via the exploitation of natural environments

    Failure Mechanism and Residual Stress Analysis of Crystal Materials for the Thermal Battery

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    This paper investigates the thermal battery as a research topic. We conducted an in-depth analysis of various thermal battery aspects, such as the cathode material CoS2 and electrolyte material morphology, crystal type, and interface state changes before and after service. The aim was to explore the core reaction and main failure mechanisms of the thermal battery. Prior to the reaction, the thermal battery cathode and electrolyte material consisted of pure-phase CoS2 and a composition of MgO-LiF/LiBr/LiCl. After service, the cathode and electrolyte of the single thermal battery exhibited significant morphological alterations caused by the presence of a molten state. The cathode transformed from CoS2 to Co3S4 and Co9S8 together with the presence of a marginal quantity of Co monomers visible throughout the discharge process, which was confirmed by means of XRD and XPS analyses. After the reaction, the electrolyte material was primarily made up of LiF, LiBr, and LiCl while the crystal components remained largely unaltered, albeit with apparent morphological variations. As was deduced from the thermodynamic analysis, the cathode material’s decomposition temperature stood at 655 °C, exceeding the working temperature of the thermal battery (500 °C) by a considerable margin, which is indicative of outstanding thermal durability within the thermal battery’s operational temperature range. Furthermore, the discharge reaction of the positive electrode was incomplete, resulting in reduced CoS2 residue in the thermal battery monomer after service. The reaction yielded a combination of Co3S4, Co9S8, and small amounts of Co monomers, indicating possible inconsistencies in the phase composition of the pole piece during the reaction process. In this study, we examine the distribution of residual stress in the thermal battery under various operating conditions. The simulation results indicate that exposure to a 70 °C environment for 2 h causes the maximum residual stress of the battery, which had an initial temperature of 25 °C, to reach 0.26 GPa. The thermal battery subjected to an initial temperature of 25 °C exhibited a maximum residual stress of 0.42 GPa subsequent to a 2-hour exposure to a temperature of −50 °C

    Medicinal Plant Root Exudate Metabolites Shape the Rhizosphere Microbiota

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    The interactions between plants and rhizosphere microbes mediated by plant root exudates are increasingly being investigated. The root-derived metabolites of medicinal plants are relatively diverse and have unique characteristics. However, whether medicinal plants influence their rhizosphere microbial community remains unknown. How medicinal plant species drive rhizosphere microbial community changes should be clarified. In this study involving high-throughput sequencing of rhizosphere microbes and an analysis of root exudates using a gas chromatograph coupled with a time-of-flight mass spectrometer, we revealed that the root exudate metabolites and microorganisms differed among the rhizosphere soils of five medicinal plants. Moreover, the results of a correlation analysis indicated that bacterial and fungal profiles in the rhizosphere soils of the five medicinal plants were extremely significantly or significantly affected by 10 root-associated metabolites. Furthermore, among the 10 root exudate metabolites, two (carvone and zymosterol) had opposite effects on rhizosphere bacteria and fungi. Our study findings suggest that plant-derived exudates modulate changes to rhizosphere microbial communities

    Directly Using Li<sub>2</sub>CO<sub>3</sub> as a Lithiophobic Interlayer to Inhibit Li Dendrites for High-Performance Solid-State Batteries

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    Garnet solid electrolytes have attracted great interest due to their wide electrochemistry window and high ion conductivity. However, the lithiophobic Li2CO3 generated on the garnet surface results in a huge interfacial resistance and interface incompatibility. Herein, different from the extensive removal or conversion strategies, the Li2CO3 on the surface of Li6.5La3Zr1.5Ta0.5O12 (LLZTO) is directly used as a lithiophobic layer to suppress Li dendrite growth, and the lithophilic Li-In-F composite is used as the anode. The Li symmetrical half-cell with a Li2CO3 interlayer is stably cycled for 6500 h without Li dendrite formation, a much longer time than for the half-cell without a Li2CO3 interlayer (2334 h), showing a much higher interfacial stability. Moreover, the full cell based on LiFePO4 and LiNi0.8Co0.1Mn0.1O2 cathode shows a stable cycling performance and high rate capability (LiNi0.8Co0.1Mn0.1O2, 94%@100th cycle@1C; LiFePO4, 90%@500th cycle@2C). This study provides a distinct way of converting disadvantages into advantages and solving the Li|LLZTO interfacial issues

    Effects of Different Altitudes on Coffea arabica Rhizospheric Soil Chemical Properties and Soil Microbiota

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    Coffee is one of the most valuable agricultural commodities worldwide, second only to oil in terms of international trade. Coffea arabica L. is a widely cultivated and economically important crop that is responsible for about 90% of the global production of coffee. In this study, we selected five C. arabica cultivation sites at different altitudes to clarify the effects of altitude on rhizospheric soil physical&ndash;chemical characteristics and microbial communities. The samples collected at low altitudes were more nutrient-deficient and acidic than the soil samples collected at medium&ndash;high altitudes. The Proteobacteria-to-Acidobacteria ratio increased from lower altitudes to medium&ndash;high altitudes. Additionally, although Ascomycota was the dominant fungal phylum, it was unaffected by the altitude. Furthermore, the alpha richness and diversity of the bacterial and fungal communities were higher at medium&ndash;high altitudes than at low altitudes. Moreover, the redundancy analysis indicated that microbial phyla were closely associated with pH. These findings suggest that C. arabica should be cultivated at medium&ndash;high altitudes, which is conducive to sustainable management and the production of high-quality C. arabica beans

    Effects of Different Altitudes on <i>Coffea arabica</i> Rhizospheric Soil Chemical Properties and Soil Microbiota

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    Coffee is one of the most valuable agricultural commodities worldwide, second only to oil in terms of international trade. Coffea arabica L. is a widely cultivated and economically important crop that is responsible for about 90% of the global production of coffee. In this study, we selected five C. arabica cultivation sites at different altitudes to clarify the effects of altitude on rhizospheric soil physical–chemical characteristics and microbial communities. The samples collected at low altitudes were more nutrient-deficient and acidic than the soil samples collected at medium–high altitudes. The Proteobacteria-to-Acidobacteria ratio increased from lower altitudes to medium–high altitudes. Additionally, although Ascomycota was the dominant fungal phylum, it was unaffected by the altitude. Furthermore, the alpha richness and diversity of the bacterial and fungal communities were higher at medium–high altitudes than at low altitudes. Moreover, the redundancy analysis indicated that microbial phyla were closely associated with pH. These findings suggest that C. arabica should be cultivated at medium–high altitudes, which is conducive to sustainable management and the production of high-quality C. arabica beans
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