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61.
Is irrigated agriculture in the Murray Darling Basin well prepared to deal with reductions in water availability? 总被引:1,自引:0,他引:1
Yongping WeiJohn Langford Ian R. WillettSnow Barlow Clive Lyle 《Global Environmental Change》2011,21(3):906-916
The “Big Dry”, a prolonged dry period in Australia from 1997 to 2009, dried out much of the Murray-Darling Basin (MDB) and resulted in large agricultural losses and degraded river ecosystems. Climate projections are that dry conditions in the MDB are likely to be more regular and severe than ever before, and recent policy initiatives are likely to reduce consumptive water use and redirect water to ecosystem management. This paper aims to develop an understanding of the interactions between water policy and irrigation practices by deriving lessons from drought management in irrigated agriculture of the MDB during the Big Dry, and furthermore, to draw out lessons to enhance the preparedness of irrigated agriculture for a future drier climate and reduced water availability. Reviews of irrigation farmers’ practices, attitudes and capacity to manage during prolonged droughts in the MDB, and the evolution of agricultural water policy in Australia since 1990 were made. It is clear that farmers could be better prepared to deal with a drier climate if their water management practices, e.g. irrigation methods and soil moisture measuring tools are improved, if the impediments to the uncertainty of water allocation and low water availability could be overcome, and if well-targeted research and extension could assist farmers to use water more wisely. It is also clear that Australian water policy could be better prepared in terms of assisting irrigated agriculture to deal with a drier climate. Key areas are reduction of barriers and distortions to water trading, optimizing the environmental water allocation, and seeking mutual benefits between environmental water allocation and irrigated agriculture, improvement of the cost-effectiveness of investments in water supply infrastructure, facilitating carryover and capacity sharing at larger scales, and provision of accurate, accessible and useful water information at different scales. An approach to irrigation practice and water policy is proposed based on past experience and potential opportunities. The approach is a set of linked strategies for more robust agricultural production and a more sustainable environment under a drier climate and reduced water availability. 相似文献
62.
James Marcus Bishop Weizhong Chen Adel Hasan Alsaffar Hussain Mahmoud Al-Foudari 《Estuaries and Coasts》2011,34(6):1246-1254
Discharge of the Shatt Al-Arab is believed to be a dominating component of the northern Arabian Gulf’s ecology and largely
responsible for productivity of Kuwait’s fisheries. With major construction of dams on the Tigris and Euphrates Rivers in
Turkey, river discharge has been substantially reduced, and flooding essentially eliminated. We attempted to relate river
flow and shrimp landings indirectly by correlating 19 years of salinity and temperature data from Kuwait’s waters with corresponding
annual shrimp landings. For green tiger prawns (Penaeus semisulcatus), the combination of October salinities and January temperatures provided the best correlation (r = 0.67) with landings in the following shrimping season. For the combined landings of jinga and kiddi shrimps (Metapenaeus affinis and Parapenaeopsis stylifera, respectively), December salinity during season and May temperature prior to season resulted in the best correlation (r = 0.87). Landings of these two species also correlated well with spring and summer temperatures. Under normal conditions,
late winter or early spring temperatures prior to fishing season influence recruitment of the green tiger prawn, whereas December
salinities during harvest season influence the abundance of jinga–kiddi shrimps. With further reductions in the Shatt Al-Arab
discharge and the elimination of flood events, Kuwait’s shrimp landings will most likely decrease over time. 相似文献
63.
China and Japan’s June 2008 agreement in principle on maritime cooperation in the East China Sea raised hopes of a significant breakthrough in the parties' complex and long-standing disputes in the area. Subsequent progress towards the realisation of a legally binding, formal treaty on, for example, offshore petroleum joint development has been slow to materialise. In fact, the area under dispute appears to have become more rather than less extensive. This paper examines competing maritime and sovereignty claims in the East China Sea together with progress towards maritime cooperation in the context of overlapping jurisdictional claims. The paper identifies some of the key challenges that need to be overcome in realizing a functioning joint resource management regime in the East China Sea. 相似文献
64.
Mauro A. Di Vito Elena Zanella Lucia Gurioli Roberto Lanza Roberto Sulpizio Jim Bishop Evdokia Tema Giuliana Boenzi Elena Laforgia 《Earth and Planetary Science Letters》2009,277(3-4):408-421
Public works in progress in the Campanian plain north of Somma-Vesuvius recently encountered the remains of a prehistoric settlement close to the town of Afragola. Rescue excavations brought to light a Bronze Age village partially destroyed and buried by pyroclastic density currents (PDCs) of the Vesuvian Pomici di Avellino eruption (3.8 14C ka BP) and subsequently sealed by alluvial deposits. Volcanological and rock-magnetic investigations supplemented the excavations.Careful comparison between volcanological and archaeological stratigraphies led to an understanding of the timing of the damage the buildings suffered when they were struck by a series of PDCs. The first engulfed the village, located some 14 km to the north of the inferred vent, and penetrated into the dwellings without causing major damage. The buildings were able to withstand the weak dynamic pressure of the currents and deviate their path, as shown by the magnetic fabric analyses. Some later collapsed under the load of the deposits piled up by successive currents. Stepwise demagnetization of the thermal remanent magnetization (TRM) carried by potsherds embedded in the deposits yields deposition temperatures in the order of 260–320 °C, fully consistent with those derived from pottery and lithic fragments from other distal and proximal sites. The fairly uniform temperature of the deposits is here ascribed to the lack of pervasive air entrainment into the currents. This, in turn, resulted from the lack of major topographical obstacles along the flat plain.The coupling of structural damage and sedimentological analyses indicates that the currents were not destructive in the Afragola area, but TRM data indicate they were still hot enough to cause death or severe injury to humans and animals. The successful escape of the entire population is apparent from the lack of human remains and from thousands of human footprints on the surface of the deposits left by the first PDCs. People were thus able to walk barefoot across the already emplaced deposits and escape the subsequent PDCs. The rapid cooling of the deposits was probably due to both their thinness and heat dissipation due to condensation of water vapour released in the mixture by magma–water interaction. 相似文献
65.
Jinesh C. Jain M. Paul Field Clive R. Neal James C. Ely Robert M. Sherrell 《Geostandards and Geoanalytical Research》2000,24(1):65-72
Inductively coupled plasma-mass spectrometry is well suited for the precise, accurate and rapid determination of rare earth elements in most geological samples. However, determination of rare earth elements in certain mantle-derived materials, without applying preconcentration techniques, remains problematical due to low natural concentrations (generally < 1 ng g−1 ). Consequently, USGS reference materials DTS-1 (a dunite) and PCC-1 (a partially serpentinized harzburgite) have only suggested rather than recommended values for the rare earth elements in reference material compilations. We compared results obtained using two ICP-MS instruments: a U-5000AT ultrasonic nebuliser coupled to a PQ2+ quadrupole ICP-MS and an ELEMENT sector field ICP-MS equipped with a MCN-6000 microconcentric desolvating nebuliser, with the suggested literature values for these two reference materials. Precision and accuracy of analytical methods employed by both instruments were demonstrated by excellent relative standard deviations (< 2%) and inter-laboratory agreement (< 5%) for numerous analyses of BHVO-1 and BIR-1, which are well established with rare earth elements contents at the μg g−1 level. Repeat analyses of DTS-1 and PCC-1 at each laboratory indicate that each method is generally precise to better than 5% at sub-g g−1 levels. Furthermore, values from both instruments generally agree to within 10%. Our DTS-1 and PCC-1 values agree reasonably well with selected data reported in the literature (except for Ce and Sm in DTS-1) but exhibit poorer agreement with reported compilation values. With the demonstrated level of precision and accuracy, we contend that these new values for DTS-1 and PCC-1, generated by two different instruments, are the best estimates of the true whole-rock composition of these samples reported to date. 相似文献
66.
Tumbure Akinson Bretherton Mike R. Bishop Peter Hedley Mike J. 《Natural Resources Research》2020,29(3):1561-1570
Natural Resources Research - The physical and chemical characteristics of mined phosphate rock will vary temporally as the location and nature of the ore body changes and as the type of equipment... 相似文献
67.
68.
Clive Blacknell 《Geological Journal》1981,16(4):287-297
Particle size, pebble shape, pebble fabric, discharge and flow velocity data are used to introduce a model of sandy gravel formation in Welsh gravel-bed rivers. The development of contact-imbrication of the typically very bladed and very platy cobbles and larger pebbles subsequently acts to significantly affect the depositional modes and patterns of small pebbles and sand particles. An important distinction is drawn between sand deposition, which can occur at or below the bed surface, and pebble and cobble deposition, which is merely a surface phenomenon. 相似文献
69.
Ambiguity in parameter identification represents a potentially serious limitation to the application of models of surface water acidification. Previous work has concentrated on manipulation of two of the three factors affecting model identifiability, namely model structure and estimator properties. A new technique is proposed which uses different modes of response within the data to improve parameter identification. Preliminary results, obtained using the Birkenes model of surface water acidification, appear to show promise. The technique is robust in recovering model parameters from synthetic data, with and without error, and in assimilating problems of structural error. 相似文献
70.
William J. Chaplin Yvonne Elsworh Rachel Howe George R. Isaak Clive P. McLeod Brek A. Miller H. B. Van Der Raay Sarah J. Wheeler Roger New 《Solar physics》1996,168(1):1-18
Since 1981 we have been operating the Birmingham Solar-Oscillations Network (BiSON), a global network of resonant-scattering spectrometers, observing the low-l solar p modes. Here we discuss historical developments, culminating in the establishment of a 6-station network in 1992 September, and the subsequent performance of that network. The data record of each station from 1992 to 1994 has been analysed in terms of weather and equipment breakdowns. Our early experience suggests that the best long-term coverage possible with a 6-station network is limited in practice to about 80%, which falls short of previous predictions. 相似文献