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Water Intrusion (water + intrusion)
Kinds of Water Intrusion Selected AbstractsSWICA,2 M3: Second Conference on Salt Water Intrusion in Coastal Aquifers: Monitoring, Modeling, and ManagementGROUND WATER, Issue 3 2004Luis E. Marin No abstract is available for this article. [source] Hydrogeological and Hydrogeochemical Studies for Salt Water Intrusion on the South Coast of Laizhou Bay, ChinaGROUND WATER, Issue 1 2000Yuqun Xue Sea water intrusion has occurred on the east and southeast coasts of Laizhou Bay, China, since the 1970s (Wu et al. 1993). In 1981, on the adjacent south coast, the intrusion of salt water originating from brine was observed. In this area, the salt water intrusion was caused by the excessive pumping of fresh water in aquifers. Moreover, the simultaneous pumping of fresh water and salt water/brine formed a complicated ground water flow field. The data obtained from observation wells were used to analyze the origin of the salt water and brine, and the genesis of the bicarbonate/sodium water zone. All data suggest that the brine originated from ancient sea water, and that the bicarbonate/sodium water was formed by cation exchange. The variations of chemical compositions along representative flowpaths and the relationships between such variations and salt water intrusion were also discussed. [source] Remediation of Sea Water Intrusion: A Case StudyGROUND WATER MONITORING & REMEDIATION, Issue 3 2001Ioannis K. Tsanis Sea water intrusion and remediation in the Upper Floridan Aquifer in South Carolina is simulated using the finite-element model SUTRA developed by the U.S. Geological Survey. A sensitivity analysis of the effect of the hydrogeologic parameters on the sea water recharge and seepage velocities is performed. An increase in confining unit and/or in aquifer conductivity results in an increase of the sea water recharge. An increase in aquifer porosity results in a decrease of the sea water recharge. Among the three remedial techniques simulated,reduced aquifer withdrawals, an injection well, and a combined injection and capture well,the reduced aquifer withdrawals and injection well are the best methods for preventing sea water intrusion. [source] Transport of larval jack mackerel (Trachurus japonicus) estimated from trajectories of satellite-tracked drifters and advective velocity fields obtained from sequential satellite thermal images in the eastern East China SeaFISHERIES OCEANOGRAPHY, Issue 6 2002Hee-Yong Kim Abstract Transport processes of jack mackerel (Trachurus japonicus) larvae in the waters off the west coast of Kyushu in the eastern East China Sea, have been investigated using satellite-tracked surface drifters and consecutive satellite thermal images. Trajectories of drifters describe northward flows over the continental shelf, eastward flows of the Kuroshio south-west of Kyushu, and a weak clockwise gyre off the west coast of Kyushu. In particular, the clockwise gyre causes the entrainment of jack mackerel larvae into the waters off the west coast of Kyushu. Consecutive satellite thermal images help to elucidate the northward warm water intrusion from the Kuroshio front south-west of Kyushu. Particle trajectories using sea surface current fields computed with the Maximum Cross Correlation (MCC) technique also reveal that the transport of jack mackerel larvae into the nursery ground off the west coast of Kyushu caused by the anti-cyclonic gyre and the warm streamers are an important process for successful recruitment. [source] Inverse Modeling of Coastal Aquifers Using Tidal Response and Hydraulic TestsGROUND WATER, Issue 6 2007Andrés Alcolea Remediation of contaminated aquifers demands a reliable characterization of hydraulic connectivity patterns. Hydraulic diffusivity is possibly the best indicator of connectivity. It can be derived using the tidal response method (TRM), which is based on fitting observations to a closed-form solution. Unfortunately, the conventional TRM assumes homogeneity. The objective of this study was to overcome this limitation and use tidal response to identify preferential flowpaths. Additionally, the procedure requires joint inversion with hydraulic test data. These provide further information on connectivity and are needed to resolve diffusivity into transmissivity and storage coefficient. Spatial variability is characterized using the regularized pilot points method. Actual application may be complicated by the need to filter tidal effects from the response to pumping and by the need to deal with different types of data, which we have addressed using maximum likelihood methods. Application to a contaminated artificial coastal fill leads to flowpaths that are consistent with the materials used during construction and to solute transport predictions that compare well with observations. We conclude that tidal response can be used to identify connectivity patterns. As such, it should be useful when designing measures to control sea water intrusion. [source] Hydrogeological and Hydrogeochemical Studies for Salt Water Intrusion on the South Coast of Laizhou Bay, ChinaGROUND WATER, Issue 1 2000Yuqun Xue Sea water intrusion has occurred on the east and southeast coasts of Laizhou Bay, China, since the 1970s (Wu et al. 1993). In 1981, on the adjacent south coast, the intrusion of salt water originating from brine was observed. In this area, the salt water intrusion was caused by the excessive pumping of fresh water in aquifers. Moreover, the simultaneous pumping of fresh water and salt water/brine formed a complicated ground water flow field. The data obtained from observation wells were used to analyze the origin of the salt water and brine, and the genesis of the bicarbonate/sodium water zone. All data suggest that the brine originated from ancient sea water, and that the bicarbonate/sodium water was formed by cation exchange. The variations of chemical compositions along representative flowpaths and the relationships between such variations and salt water intrusion were also discussed. [source] Remediation of Sea Water Intrusion: A Case StudyGROUND WATER MONITORING & REMEDIATION, Issue 3 2001Ioannis K. Tsanis Sea water intrusion and remediation in the Upper Floridan Aquifer in South Carolina is simulated using the finite-element model SUTRA developed by the U.S. Geological Survey. A sensitivity analysis of the effect of the hydrogeologic parameters on the sea water recharge and seepage velocities is performed. An increase in confining unit and/or in aquifer conductivity results in an increase of the sea water recharge. An increase in aquifer porosity results in a decrease of the sea water recharge. Among the three remedial techniques simulated,reduced aquifer withdrawals, an injection well, and a combined injection and capture well,the reduced aquifer withdrawals and injection well are the best methods for preventing sea water intrusion. [source] Stack unit mapping of coastal aquifer to predict and control sea water intrusion using remote sensing and a geographical information systemHYDROLOGICAL PROCESSES, Issue 17 2003J. Moses Edwin Abstract Aquifers are inherently susceptible to contamination and coastal aquifers in specific are highly vulnerable to sea water intrusion. For efficient planning and management of coastal aquifers in Kayalpattu and Tiruchopuram villages, which extend over 4·05 km2, it is essential to delineate and predict the extent of intrusion into the shallow aquifer. Management of ground water in coastal aquifers is composed of major elements that should be properly evaluated, and special attention is given to the sea water intrusion problem. Different data, like hydro-geomorphological and depth-wise iso-apparent resistivity, are integrated spatially using a geographical information system. The stack-unit mapping approach is used to delineate the zones with iso-apparent resistivity of less than 10 , m have been found to be increasing in areal extent with reference to depth. Copyright © 2003 John Wiley & Sons, Ltd. [source] The marine copepod, Pseudocalanus elongatus, as a mediator between climate variability and fisheries in the Central Baltic SeaFISHERIES OCEANOGRAPHY, Issue 4-5 2003C. Möllmann Abstract Pseudocalanus elongatus is a key species in the pelagic zone of the deep basins of the Central Baltic Sea. The copepod serves as a major food organism for larval as well as for adult, pelagic planktivorous fish. Large interannual fluctuations in the standing stock of P. elongatus have been attributed to significant changes in the hydrographic environment over the last two decades. In particular, the decreasing salinity in the Baltic deep basins, a result of a change in atmospheric forcing leading to an increase in rainfall since the 1980s and of a lack of pulses of saline water intrusions from the North Sea, was found to affect reproduction and maturation of the copepod. In parallel, dramatic changes in the weight-at-age of herring, one of the most important commercial fishes of the Baltic Sea, have been observed since the late 1980s. Using time-series on herring stomach contents, as well as length and weight, we provide evidence for a chain of events relating variability in climate, salinity and P. elongatus abundance to changes in diet and condition of herring in the Central Baltic Sea. [source] Die Detektionseffizienz von Vorausbohrungen im TunnelbauGEOMECHANICS AND TUNNELLING, Issue 5 2008Hans-Jakob Ziegler Dr. phil.nat. Vor allem im Zusammenhang mit den großen Tunnelprojekten werden Vorausbohrungen zur Erkundung des Gebirges systematisch durchgeführt. Wie die Erfahrungen vom Lötschberg- und Gotthard-Basistunnel zeigen, handelt es sich dabei um ein effizientes Hilfsmittel, um "unerwünschte Ereignisse" wie Schlamm- und Wassereinbrüche oder das Anfahren von unerwarteten Störungszonen zu vermeiden. Nur in drei Fällen traten solche "unerwünschten Ereignisse" bisher auf der betrachteten, ausgebrochenen Tunnelstrecke von insgesamt etwa 100 km auf. Dies zeigt klar den großen Nutzen von Vorausbohrungen für die Arbeits- und Planungssicherheit im modernen Tunnelbau. Die vorgestellten Beispiele belegen aber auch, dass auch mit den effizientesten Vorausbohrungen die Eintretenswahrscheinlichkeit von "unerwünschten Ereignissen" nie Null sein wird. The detection efficacy of reconnaissance drilling in tunnelling Mainly in connection with major tunnel projects, reconnaissance drilling is systematically used to survey the host rock. As shows the experience from the Lötschberg- and the Gotthard basetunnels, reconnaissance drilling is an efficient tool in avoiding "unwanted hazards" like mud or water intrusions, or the penetration of unexpected fracture or failure zones. On the observed excavated tunnel distance of about 100 km, up to now, such "unwanted hazards" occurred tree times only. This clearly demonstrates the important benefit of reconnaissance drilling for work and planning security in modern tunnelling. However, the examples presented also make obvious, that even with the most efficient reconnaissance drilling the probability of an "unwanted hazard" will never become zero. [source] Osmoregulation, growth and moulting cycles of the giant freshwater prawn (Macrobrachium rosenbergii) at different salinitiesAQUACULTURE RESEARCH, Issue 9 2010Do Thi Thanh Huong Abstract The giant freshwater prawn, Macrobrachium rosenbergii, is a species with a high commercial value in aquaculture. Two experiments were performed to determine the effects of salinities on the osmoregulation, growth and molting cycles of M. rosenbergii during growout. The first experiment was designed to determine whether these animals are capable of adapting to the changes in salinity seen in salinity intrusions in tropical deltas, with an incremental increase in salinity of 3, per day from 0, to 30, Haemolymph osmolality was rapidly regulated up to salinities of 15, , whereas animals conformed at higher salinities. The second experiment determined the growth, moulting cycle, osmolality, muscle water content and mortality during a 4-month experiment at 0,, 15, or 25, salinity. The weight gains in 0, and 15, were not significantly different and were comparable to the growth rates achieved in production farms with body mass increases of 2.6 and 2.3-fold their initial body mass, respectively, after 4 months. The 25, group suffered from low growth, high mortality and a significantly lower moulting frequency. These data show that this species can be reared in brackish water up to 15,, allowing for farming in the large areas impacted by salt water intrusions in tropical deltas. [source] | |||||||||||||