Academic literature on the topic 'Water management, MODELLING, COASTAL AQUIFER'
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Journal articles on the topic "Water management, MODELLING, COASTAL AQUIFER"
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Olabode, Oluwaseun Franklin, and Jean-Christophe Comte. "Modelling of groundwater recharge in the megacity of Lagos, Nigeria: preliminary results using WetSpass-M." Advances in Geosciences 59 (December 20, 2022): 53–57. http://dx.doi.org/10.5194/adgeo-59-53-2022.
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Abstract. Lagos, Nigeria is one of the World's fastest-growing cities. The increasing water demand has led to depletion and deterioration of the groundwater resources contained in its highly productive coastal aquifers. Groundwater recharge processes and drivers, which dictate groundwater replenishment, and their changes associated with rapid urbanization, are yet to be quantified and understood. We used the spatially distributed WetSpass-M model to estimate the spatiotemporal patterns and rates of recharge between 2000 and 2020 in the 5440 km2 coastal aquifer system underlying the megacity of Lagos. The influence of expanding urban areas, from 807 km2 in 2000 to 1183 km2 in 2020, coincide with reduction in the simulated recharge by 50 % in 20 years. The study also revealed diffuse and focused recharge processes associated with, respectively, the urban centres and areas closer to water bodies signalling strong groundwater-surface water interactions. The preliminary findings from this modelling work provide directions for exploring sustainable water management options including Managed Aquifer Recharge (MAR) in Lagos and other fast-growing coastal megacities in the world.
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Timaniya, Aman, and Nayankumar Soni. "“Modeling of Saline Water Intrusion using MODFLOW in Una Coastal Aquifer of Gujarat, India.”." International Journal for Research in Applied Science and Engineering Technology 10, no. 5 (May 31, 2022): 634–40. http://dx.doi.org/10.22214/ijraset.2022.42309.
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Abstract: Groundwater is the most valuable and extensively dispersed resource on the planet, and unlike any other mineral resource, it is replenished annually by meteoric precipitation. The present study would include simulation and modelling of the problem of seawater intrusion in the Una coastal area of Gujarat. The interrelationships of two miscible fluids in porous media have been widely explored both theoretically and experimentally. Because of the extreme salinity, many agricultural wells are no longer used. This high salinity is a sign of a process known as saltwater intrusion, which occurs mostly in coastal aquifers due to excessive pumping. Modelling software has also been utilized to analyze the behavior of groundwater flow models. Numerical models may simulate diverse groundwater scenarios and link them to groundwater management. To simulate seawater intrusion, MODFLOW-2005, a grid-based variable density-dependent flow model, is used. Water balance research reveals that rainwater recharge is the aquifer's primary input. To compute the water level in the area and estimate the position of the seawater intrusion barrier, the saltwater intrusion phenomena were simulated using the MODFLOW software combined with the SWI2 package. The model was used to visualize the salinity levels of the coastal aquifer's groundwater and their fluctuation over time and space from May 2004 to October 2014. The model was developed for a 10-year stress period with 100-time steps, which included a 5-year steady state and 5 years transient state stress period using the previous 10 years of pre-monsoon and postmonsoon data. This research would assist to describe Pumping's impact on groundwater levels and seawater intrusion was studied. Keywords: MODFLOW, Saltwater Intrusion, Modelling, Numerical Model, Coastal aquifer
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Dibaj, Mahdieh, Akbar A. Javadi, Mohammad Akrami, Kai-Yuan Ke, Raziyeh Farmani, Yih-Chi Tan, and Albert S. Chen. "Modelling seawater intrusion in the Pingtung coastal aquifer in Taiwan, under the influence of sea-level rise and changing abstraction regime." Hydrogeology Journal 28, no. 6 (May 23, 2020): 2085–103. http://dx.doi.org/10.1007/s10040-020-02172-4.
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Abstract A three-dimensional variable-density finite element model was developed to study the combined effects of overabstraction and seawater intrusion in the Pingtung Plain coastal aquifer system in Taiwan. The model was generated in different layers to represent the three aquifers and two aquitards. Twenty-five multilayer pumping wells were assigned to abstract the groundwater, in addition to 95 observation wells to monitor the groundwater level. The analysis was carried out for a period of 8 years (2008–2015 inclusive). Hydraulic head, soil permeability, and precipitation were assigned as input data together with the pumping records in different layers of the aquifer. The developed numerical model was calibrated against the observed head archives and the calibrated model was used to predict the inland encroachment of seawater in different layers of the aquifer. The effects of pumping rate, sea-level rise, and relocation of wells on seawater intrusion were examined. The results show that all layers of the aquifer system are affected by seawater intrusion; however, the lengths of inland encroachment in the top and bottom aquifers are greater compared with the middle layer. This is the first large-scale finite-element model of the Pingtung Plain, which can be used by decision-makers for sustainable management of groundwater resources and cognizance of seawater intrusion in coastal aquifers.
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Grundmann, J., N. Schütze, and V. Heck. "Optimal integrated management of groundwater resources and irrigated agriculture in arid coastal regions." Proceedings of the International Association of Hydrological Sciences 364 (September 16, 2014): 216–21. http://dx.doi.org/10.5194/piahs-364-216-2014.
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Abstract. Groundwater systems in arid coastal regions are particularly at risk due to limited potential for groundwater replenishment and increasing water demand, caused by a continuously growing population. For ensuring a sustainable management of those regions, we developed a new simulation-based integrated water management system. The management system unites process modelling with artificial intelligence tools and evolutionary optimisation techniques for managing both water quality and water quantity of a strongly coupled groundwater–agriculture system. Due to the large number of decision variables, a decomposition approach is applied to separate the original large optimisation problem into smaller, independent optimisation problems which finally allow for faster and more reliable solutions. It consists of an analytical inner optimisation loop to achieve a most profitable agricultural production for a given amount of water and an outer simulation-based optimisation loop to find the optimal groundwater abstraction pattern. Thereby, the behaviour of farms is described by crop-water-production functions and the aquifer response, including the seawater interface, is simulated by an artificial neural network. The methodology is applied exemplarily for the south Batinah re-gion/Oman, which is affected by saltwater intrusion into a coastal aquifer system due to excessive groundwater withdrawal for irrigated agriculture. Due to contradicting objectives like profit-oriented agriculture vs aquifer sustainability, a multi-objective optimisation is performed which can provide sustainable solutions for water and agricultural management over long-term periods at farm and regional scales in respect of water resources, environment, and socio-economic development.
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Grundmann, Jens, Ayisha Al-Khatri, and Niels Schütze. "Managing saltwater intrusion in coastal arid regions and its societal implications for agriculture." Proceedings of the International Association of Hydrological Sciences 373 (May 12, 2016): 31–35. http://dx.doi.org/10.5194/piahs-373-31-2016.
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Abstract. Coastal aquifers in arid and semiarid regions are particularly at risk due to intrusion of salty marine water. Since groundwater is predominantly used in irrigated agriculture, its excessive pumping – above the natural rate of replenishment – strengthen the intrusion process. Using this increasingly saline water for irrigation, leads to a destruction of valuable agricultural resources and the economic basis of farmers and their communities. The limitation of resources (water and soil) in these regions requires a societal adaptation and change in behaviour as well as the development of appropriate management strategies for a transition towards stable and sustainable future hydrosystem states. Besides a description of the system dynamics and the spatial consequences of adaptation on the resources availability, the contribution combines results of an empirical survey with stakeholders and physically based modelling of the groundwater-agriculture hydrosystem interactions. This includes an analysis of stakeholders' (farmers and decision makers) behaviour and opinions regarding several management interventions aiming on water demand and water resources management as well as the thinking of decision makers how farmers will behave. In this context, the technical counter measures to manage the saltwater intrusion by simulating different groundwater pumping strategies and scenarios are evaluated from the economic and social point of view and if the spatial variability of the aquifer's hydrogeology is taken into consideration. The study is exemplarily investigated for the south Batinah region in the Sultanate of Oman, which is affected by saltwater intrusion into a coastal aquifer system due to excessive groundwater withdrawal for irrigated agriculture.
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Frollini, Eleonora, Daniele Parrone, Stefano Ghergo, Rita Masciale, Giuseppe Passarella, Maddalena Pennisi, Matteo Salvadori, and Elisabetta Preziosi. "An Integrated Approach for Investigating the Salinity Evolution in a Mediterranean Coastal Karst Aquifer." Water 14, no. 11 (May 27, 2022): 1725. http://dx.doi.org/10.3390/w14111725.
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Coastal areas are characterized by considerable demographic pressure that generally leads to groundwater overexploitation. In the Mediterranean region, this situation is exacerbated by a recharge reduction enhanced by climate change. The consequence is water table drawdown that alters the freshwater/seawater interface facilitating seawater intrusion. However, the groundwater salinity may also be affected by other natural/anthropogenic sources. In this paper, water quality data gathered at 47 private and public wells in a coastal karst aquifer in Apulia (southern Italy), were interpreted by applying disparate methods to reveal the different sources of groundwater salinity. Chemical characterization, multivariate statistical analysis, and mixing calculations supplied the groundwater salinization degree. Characteristic ion ratios, strontium isotope (87Sr/86Sr), and pure mixing modelling identified the current seawater intrusion as a main salinity source, also highlighting the contribution of water–rock interaction to groundwater composition and excluding influence from Cretaceous paleo-seawater. Only the combined approach of all the methodologies allowed a clear identification of the main sources of salinization, excluding other less probable ones (e.g., paleo-seawater). The proposed approach enables effective investigation of processes governing salinity changes in coastal aquifers, to support more informed management.
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Pavelic, Paul, Kumar A. Narayan, and Peter J. Dillon. "Groundwater flow modelling to assist dryland salinity management of a coastal plain of southern Australia." Soil Research 35, no. 4 (1997): 669. http://dx.doi.org/10.1071/s96101.
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Groundwater flow modelling has been undertaken for an area of 10 500 ha within the regional unconfined aquifer system of a coastal plain of southern Australia, in the vicinity of the town of Cooke Plains, to predict the impact of various land management options (including recharge reduction and discharge enhancement) on the extent of land salinisation caused by shallow saline watertables. The model was calibrated against field data collected over 6 years. Sensitivity analysis was performed to assess the influence of mesh size, boundary conditions, and aquifer parameters, and particularly rates of recharge and evaporative discharge, on groundwater levels. These were varied until the model was shown to be capable of simulating seasonal trends and regional and local flow patterns. The model was then used to predict the impact of the management options on groundwater levels. The results showed that continuing current annual crop–pasture rotations will result in watertable rises of approximately 0·2 m in 20 years (significant in this setting), with a further 50 ha of land salinised. A reduction in the rates of groundwater recharge through the establishment of high water-use perennial pastures (e.g. lucerne) showed the most promise for controlling groundwater levels. For example, a reduction in recharge by 90% would result in watertable declines of 0·6–1·0 m within 5–10 years, with the return to productivity of 180 ha of saline land. Small-scale (say <100 ha) efforts to reduce recharge were found to have no significant impact on groundwater levels. Enhanced groundwater discharge such as pumping from a windmill was found to be non-viable due to the relatively high aquifer transmissivity and specific yield. The modelling approach has enabled a relatively small area within a regional aquifer system to be modelled for a finite time (20 years) and has shown that extension of the boundaries of the model would not have altered the predicted outcomes. Furthermore, the analysis of sensitivity to cell size in an undulating landscape where net recharge areas can become net discharge areas with only small increases in groundwater level is novel, and has helped to build confidence in the model. Modelling has demonstrated that dryland salinisation can be controlled by reducing groundwater recharge over substantial tracts of land, and is not dependent on recharge reduction over an extensive area upgradient, at least over the next 20 years.
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Dieu, Linh Pham, Diep Cong-Thi, Tom Segers, Huu Hieu Ho, Frédéric Nguyen, and Thomas Hermans. "Groundwater Salinization and Freshening Processes in the Luy River Coastal Aquifer, Vietnam." Water 14, no. 15 (July 30, 2022): 2358. http://dx.doi.org/10.3390/w14152358.
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The Vietnamese Binh Thuan province located along the Southern Central part of the coast is one of the driest in the country. The population is relying largely on groundwater for irrigation, and the groundwater resources are threatened by climate change and saltwater intrusion in river estuaries. Recent studies, however, reveal that the extension of saltwater intrusions was larger than expected, raising some doubts on the actual origin of the intrusions. In this study, we use the geochemical characterization of groundwater samples collected in both the dry and rainy seasons in the Luy river coastal area to identify hydrochemical processes responsible for the salinization and variations taking place in the shallow aquifers. The distribution of chemical components of groundwater and the indicators presenting the freshening and salinization processes, such as cation exchange code and chloride conservative element, the ionic delta, the HFE-diagram, and geochemical modelling, were studied. The results show that 65% of the samples exceed the WHO limit for drinking water and 100% of them have a degree of restriction on use from slight–moderate to severe in potential irrigation problems according to FAO. In contrast to previous expectations, freshening is the dominant process in the aquifers, and it is more advanced in the rainy season. Due to a lack of recharge and aquifer exploitation, salinization is more severe in the deeper aquifer and during the dry season. Saltwater intrusion is not limited to the zone close to the river but extends further inland and at depth, and salinity can vary quickly over short distances. Based on these new insights, we develop a new conceptual model for the evolution of salinization in the Luy river catchment involving a natural freshening process of connate water combined with anthropic influence. The conceptual model will form the basis for the development of a groundwater model of the study area and eventually lead to sustainable management scenarios for this coastal region, preventing further deterioration of the groundwater resources.
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Tziritis, Evangelos, Ekaterini Sachsamanoglou, and Vassilis Aschonitis. "Assessing Groundwater Evolution with a Combined Approach of Hydrogeochemical Modelling and Data Analysis: Application to the Rhodope Coastal Aquifer (NE Greece)." Water 15, no. 2 (January 5, 2023): 230. http://dx.doi.org/10.3390/w15020230.
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Assessing the hydrogeochemical evolution of groundwater is a challenging task, which is further exacerbated when considering the multiple geogenic and anthropogenic impacts that affect its quality and the hydraulic interactions between different aquifer bodies. This study combined hydrogeochemical modelling and data analysis to assess this complex hydrogeological regime. Before modelling, the groundwater samples were clustered using a multivariate statistical method (hierarchical cluster analysis (HCA)). Then, the Geochemist Workbench (GWB) software was applied to model the hydrogeochemical groundwater evolution, including the dominant ion exchange process, and to explain the changes in groundwater chemistry towards its flow. The input data consisted of five key parameters from seventy-seven sampling points collected in two periods (accounting for the start and the end of the irrigation period). A data analytical approach based on the optimal mixing ratios between the interacting groundwater systems and recharge inputs was also performed as part of the methodological approach. It revealed a progressively temporal-dependent behaviour of the aquifer system during the irrigation period, resulting in seasonal changes in the hydrodynamic conditions and depletion of the upper aquifer layers. Specifically, the aquifer system was confirmed to undergo cation exchange as the dominant geochemical process that increases calcium concentrations. The complex hydrogeological regime was further evaluated by assessing the mixing ratios of the different aquifer layers. Hence, the aquifer system (bulk samples) was mixed with the irrigation water by 71% and 97% and with the lateral recharge by 76% and 29% for the beginning and at the end of the irrigation period, respectively. Overall, the joint assessments were confirmed by the hydrogeochemical status of the end-members and the modelling approach and explained the sequential changes in groundwater chemistry due to the dominant ion-exchange process and the mixing of different water bodies. The proposed methodological approach proved that it could be used as an exploratory and preliminary method for capturing the temporal dynamics in complex groundwater systems and supporting groundwater resource management.
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Roy, Dilip Kumar, and Bithin Datta. "Modelling and management of saltwater intrusion in a coastal aquifer system: A regional-scale study." Groundwater for Sustainable Development 11 (October 2020): 100479. http://dx.doi.org/10.1016/j.gsd.2020.100479.
Full textDissertations / Theses on the topic "Water management, MODELLING, COASTAL AQUIFER"
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Shammas, Mahaad Issa. "Sustainable management of the Salalah coastal aquifer in Oman using an integrated approach." Doctoral thesis, Stockholm : Mark- och vattenteknik Land and Water Resource Engineering, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4384.
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SELMI, AMAL. "Groundwater management and modelling of the Gaza Strip." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/40833.
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Groundwater resource is critical to the future of the Gaza Strip, as it is the
only water resource available to satisfy the daily water needs. As future
population growth will place increased stress upon water supplies, the need
for effective water management is greater than ever. To plan for the
sustainable use of groundwater resources in Gaza Strip, an understanding of
the natural hydrologic system and quantitative of the natural hydrologic
budget, are required.
This thesis addresses the problems facing the groundwater management in
Gaza Strip, through development of a 3D groundwater flow model and the
natural hydrologic budget of the Gaza aquifer. By applying the groundwater
model to future scenarios, the impacts of variable pumping and recharge on
the groundwater level in order to control sea water intrusion has been
quantified and assessed. Based on the results, recommendations are made
regarding optimal solutions to control sea water intrusion in the Gaza aquifer.
In order to study the aquifer behavior and the depth and extent of
groundwater decline, the historical changes in groundwater levels were
analyzed for the 1935 and 2009 period. For this, the kriging interpolation
method was used to estimate the groundwater level based on available well
data collected for the entire study area. Results show that groundwater levelsdropped by as much as 18 meters between 1935 and 2009. This drop is very
important in the north and south due to over exploitation of groundwater.
Chemical analyses were carried out to study the salinization process and to
identify the salinity sources in the Gaza aquifer. Results show that the
groundwater in Gaza aquifer is characterized by Na-Cl-SO4 and Ca-Mg-HCO3
facies. The occurrence of salinity in different parts of the aquifer is related to
the presence of the seawater in the western side, and lateral inflow from the
eastern border due to the hydraulic connection with brackish aquifer.
This thesis discusses the vulnerability of Gaza aquifer to sea water intrusion
by applying the GALDIT index method. Different thematic maps were
prepared for seawater intrusion indicators and overlaid to develop the
vulnerability map. The vulnerability map can be used as an additional tool to
determine areas of potential saltwater intrusion and to identify the favorable
zones to artificial recharge in the management model presented in this thesis.
For the realization of the 3D numerical flow model, the MODFLOW code
(finite difference method) was selected. The used graphical interface is GMS
6.0 (Groundwater Modeling System). The groundwater flow model was
developed in order to understand and simulate the aquifer behavior and to
control sea water intrusion. A careful calibration of the model was performed,
in which the simulated piezometric levels are compared with field
measurements to determine the validity and reliability of the model.
Based on the developed transient model, 3 management scenarios were
applied in order to study the impact of pumping rates and additional water
resources on the groundwater level for the next 20 years. These scenarios
are conceived to support coastal aquifer management plan adopted by
Palestinian Water Authority for the control of the sea water intrusion. The
results of the first management scenario show that the ground water level is
strongly influenced by the over pumping. Two large depression zones are
observed in the northern and southern Gaza Strip. Results of the second
management scenario show an increasing ground water level, by several
meters above mean sea level, under the effect of decreasing abstraction
rates. Results of the third management scenario show an increasing groundwater level, by several meters above mean sea level, under the effect of
increasing the aquifer recharge. Using treated waste water to remediate the
groundwater level and control the sea water intrusion in the Gaza aquifer
appears as the most practical and suitable solution for saltwater intrusion
control, since the other solutions require the use of fresh water resources,
which are costly and unpractical in view of the Gaza Strip situation. Therefore,
using treated wastewater represents an additional renewable and reliable
water source for the management of water resources in the Gaza Strip.
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Sara, Barghi. "Water Management Modelling in the Simulation of Water Systems in Coastal Communities." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24364.
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It is no longer a question of scientific debate that research declares our climate is changing. One of the most important and visible impacts of this phenomenon is sea level rise which has impacts on coastal cities and island communities. Sea level rise also magnifies storm surges which can have severely damaging impacts on different human made infrastructure facilities near the shorelines in coastal zones. In this research we are concerned about the proximity of water systems as one of the most vulnerable infrastructures in the coastal zones because of the impact of stormwater combining with sewage water. In Canada, the government has plans to address these issues, but to date, there needs to be further attention to stormwater management in coastal zones across the country. This research discusses the impacts of severe environmental events, e.g., hurricanes and storm surge, on the water systems of selected coastal communities in Canada. The purpose of this research is to model coastal zone water systems using the open source StormWater Management Modelling (SWMM) software in order to manage stormwater and system response to storms and storm surge on water treatment plants in these areas. Arichat on Isle Madame, Cape Breton, one of the most sensitive coastal zones in Canada, is the focal point case study for this research as part of the C-Change International Community-University Research Alliance (ICURA) 2009-2015 project.
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Wright, Alan. "The artificial recharge of urban stormwater runoff in the Atlantis coastal aquifer." Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1005491.
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The thesis covers the investigation of the storm water runoff and artificial recharge components of the Atlantis Water Resource Management Scheme in the Southwestern Cape. The objective of the study was to obtain an in-depth knowledge of the process of artificial recharge of urban storm water runoff, in order to identify the most efficient recharge management strategy for the Atlantis aquifer. To achieve the objective it was necessary to first study the existing knowledge on urban storm water hydrology and artificial recharge by spreading, and to create a conceptual model of what might be expected. The study area was then investigated to examine how closely the actual situation was reflected by the conceptual model, enabling recommendations to be made for the sound management of the system. The stormwater runoff component was found to differ from most urban hydrological studies as a result of its large baseflow component. The sandy nature of the catchment, small percentage area of effective impervious surface, and high groundwater table resulted in the baseflow constituting more than 40% of the total storm water runoff and accounting for over 60% of the pollution load. The "first flush" effect established as a major source of pollution in other studies, was found to be of minor significance in this study area. The overall stormwater quality (excluding the noxious industrial baseflow) was found acceptable for artificial recharge within the study area, although the baseflow from the industrial sub-catchments showed the potential for being a major source of pollution in the future. The treated wastewater used for artificial recharge prior to 1987 was found to be unacceptable for recharge purposes. The treated industrial effluent should under no circumstances be recharged up-gradient of the Witzand well field. The treated domestic effluent although of a poorer quality than the resident Witzand well field groundwater could be recharged in order to boost recharge volumes and form a buffer against further intrusion by the poor quality groundwater from the Brakkefontein area. This would however only be acceptable if strict water quality control is maintained and recharge does not take place west of the present basin. The recharge basin was found to be well situated with respect to influencing the Witzand wellfield and maintaining a groundwater buffer against poor quality groundwater flow from the northeast towards the central area of the wellfield. Unfortunately the surrounding low-lying topography and sandy retaining walls have resulted in return flow and raised groundwater-levels. The raised groundwater mound does not comply with the conceptual model and together with the sandy nature of the unsaturated zone resulted in less effective purification during infiltration. The practice of letting large portions of the basin floor dry-out during summer was shown to be beneficial and the periodic cleaning of the deeper portions of the basin essential. The artificially recharged water was found to have influenced the upper portion of the aquifer well beyond the West Coast Road. The study of groundwater quality being a good method for tracing artificially recharged water. The groundwater quality has improved as a result of artificial recharge since the removal of treated wastewater from the recharge basin. The groundwater was (ii) found to be very responsive to the slightest changes in recharge basin water quality or/and quantity. Management of the recharge basin therefore had to be very much of a compromise between qualitative and quantitative approaches. The present approach of recharging all the stormwater runoff throughout the year providing the most efficient compromise under the present conditions. The study revealed that the most efficient recharge management strategy would be the recharge of treated domestic sewage effluent in the present recharge basin and all residential storm water runoff plus industrial "storm flow" stormwater runoff in a new recharge basin located northwest of the present basin. Strict water quality control must be maintained on the water discharged into the basins and an annual wet/dry cycle implemented within the basins to boost infiltration. The entire system should continue being monitored to safe guard the groundwater resource from pollution and over exploitation.
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Kowlesser, Akshay. "Sustainable Aquifer Management in Small Island Developing States : A case study of Mauritius." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-227316.
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Small Island Developing States (SIDS) are amongst the most vulnerable states in the world. They are subject to a number of stresses including economical, climatic and spatial restraints. This thesis investigates the effects that certain critical ‘stresses’ will have on the groundwater reserves of SIDS. Mauritius was chosen as the case study for this project because of three main reasons, which were that 1) islands of the Indian Ocean are the least studied compared to the pacific and Caribbean islands, 2) there is no actual groundwater model for the aquifers of Mauritius and finally 3) information and background knowledge was more accessible to the author. Two critical aquifers of Mauritius were chosen according to their respective vulnerability (extraction rates of groundwater, geological features, and rainfall patterns), Aquifers II and V. The aquifers were calibrated using data that was published by the Mauritian local authorities and through an extensive literature review. Aquifer II and Aquifer V were modelled using the software ModelMUSE and a steady state model (with a time series of 100 years) was used to calibrate the models using limited data that was obtained through the literature review. Aquifer V was successfully modelled while Aquifer II gave inconsistent results. A transient model using four scenarios inspired by the IPCC scenario analysis was used to investigate the salt water intrusion as well as the piezometric levels in both aquifers. The scenarios (run for a period of 100 years, i.e. until 2100) were of varying degrees of severity and included the main drivers of change that were believed to affect the groundwater consumption of Mauritius. The attributes that were targeted in this thesis were: economy, demography, technology and climate. These were then converted into quantifies inputs that were used in the model to assess the migration of the saltwater/freshwater interface in the aquifers. Scenario 4 which involved low recharge rate of the aquifer, high sea level rise, low GDP growth and increasing population subjected the aquifer to a reduced water table, and consequential sea water intrusion of the order 1.5 km across the cross section analysed. Scenario 3, which consisted of investment in green technology, increase in recharge of the aquifers on the other hand gave the more optimistic results with the salt water - fresh water interface moving seawards. Scenario 4 rendered unusable around 50 % of the wells in the aquifer while Scenario 3 on the other had the effects of increasing the freshwater lens of the Aquifer V. Measures such as sustainable urban drainage systems, managed aquifer recharge and Seepcat (a method which involves placing a series of pipes around coastal aquifers to prevent the intrusion of salt water) were recommended to decrease the salt water intrusion risk and eventually increase the fresh water lens of the island on various spatial and time scales. It is suggested that the coarse groundwater model developed for Aquifer V of Mauritius be refined and applied to different aquifers of the island. Moreover it is also recommended for future work that discontinuities in the geology be integrated in the groundwater model. A more detailed and nuanced water balance is also recommended to get more accurate initial conditions for the model. This thesis, by providing a coarse model to tackle the impending challenges that await Mauritius, can support a more sustainable water management of the country.Small Island Developing States (SIDS), små önationer under utveckling, är bland de mest sårbara staterna i världen. De är utsatta för ett antal stressfaktorer inklusive ekonomiska, klimatrelaterade och rumsliga restriktioner. Detta examensarbete undersöker effekterna av några kritiska stressfaktorer på grundvattenreserverna i dessa önationer. Mauritius valdes som fallstudie för detta projekt på grund av tre huvudsakliga orsaker. Dessa var att öar i Indiska Oceanen är de minst studerade jämfört med atlantiska och karibiska öar, att det inte finns någon riktig grundvattenmodell för akvifererna på Mauritius och slutligen att information och bakgrundskunskap var mer lättåtkomligt för författaren. Två kritiska akviferer på Mauritius valdes utifrån deras respektive sårbarheter (uttagshastighet av grundvatten, geologiska egenskaper och nederbördsmönster). Baserat på detta valdes Akvifer II och Akvifer V. Akvifererna kalibrerades med hjälp av data publicerat av mauritiska lokala myndigheter och genom en omfattande litteraturstudie. Akvifer II och Akvifer V modellerades i programmet ModelMUSE och en steady state-modell (med en tidsserie på 100 år) användes för att kalibrera modellerna med hjälp av begränsad data som erhölls under litteraturstudien. Inmatningsvärdena erhölls från vattenresursenheten på Mauritius, från vilka genomsnittliga värden över en tidsperiod om 15 år togs fram och användes som begynnelsevillkor för steady state-modellen. Akvifer V kalibrerades med framgång medan Akvifer II gav inkonsekventa resultat. Detta hänfördes till de stora skillnaderna i topografin i Akvifer II, vilka bidrog till att fel uppstod under uträkningen. En tidsberoende modell med fyra scenarios inspirerade av FN:s klimatpanels scenarioanalys användes för att undersöka saltvatteninträngningen samt grundvattennivån i båda akvifererna. Scenarierna (körda över en period om 100 år, d.v.s. till 2100) var av varierande viktighetsgrad och inkluderade de främsta drivkrafterna som ansågs påverka Mauritius grundvattenförbrukning. De attribut som fokuserades på i denna avhandling var: ekonomi, demografi, teknik och klimat. Dessa omvandlades sedan till indata som användes i modellen för att bedöma migrationen av saltvatten/sötvattengränsen i akvifererna. Scenario 4 som innebar liten grundvattenbildning i akviferen, hög havsnivåstigning, låg BNP-tillväxt och ökande befolkning utsatte akviferen för en reducerad vattennivå, och påföljande havsvatteninträngning av ordningen 1,5 km över den analyserade tvärsektionen. Scenario 3 gav å andra sidan mer optimistiska resultat då saltvatten/sötvattengränsen rörde sig mot havet. Scenario 4 medförde att ungefär 50 % av brunnarna i akviferen blev oanvändbara. Åtgärder såsom hållbara stadsdräneringssystem, kontrollerad grundvattenbildning och Seepcat (en metod som innebär att man placerar en serie rör runt kustområden för att förhindra saltvattenintrång) rekommenderas för att minska saltvatteninträngningen och så småningom öka öns färskvattenlins på olika rumsliga och tidsrelaterade skalor. Det föreslås att den grova grundvattenmodellen som utvecklats för Akvifer V i Mauritius förfinas och appliceras på olika akviferer på ön. Därtill rekommenderas att diskontinuiteter i geologin integreras i grundvattenmodellen i framtida arbete. Genom att applicera modellen kan viktig information användas för en hållbar vattenförvaltning på Mauritius i framtiden.
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Matengu, Brian Munihango. "Groundwater assessment and sustainable management of the coastal alluvial aquifers in Namib Desert, Namibia: Omdel Aquifer as case study." University of Western Cape, 2020. http://hdl.handle.net/11394/7852.
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Philosophiae Doctor - PhDThe study addressed the groundwater assessment and sustainable management of the coastal alluvial aquifers in Namib Desert, the Omaruru River Delta Aquifer (Omdel Aquifer) was used as a case study. Sustainable utilization of groundwater in parts of hyper-arid Sub-Saharan Africa, like the Namib Desert, is always a challenge due to lack of resources and data. Understanding of hydrogeological characteristics of the Omaruru Delta Aquifer System is a pre-requisite for the management of groundwater supply in the Central Namib area (Namib Desert). For the Omdel Aquifer in the Omaruru catchment, Namibia, issues to investigate include the lack of information on the geology and hydrogeological setting, the hydraulic properties and geometry of the aquifer at the inflow and outflow sections, groundwater recharge conditions upstream of the aquifer, and the impact of artificial recharge.
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Scarfe, Bradley Edward. "Oceanographic Considerations for the Management and Protection of Surfing Breaks." The University of Waikato, 2008. http://hdl.handle.net/10289/2668.
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Although the physical characteristics of surfing breaks are well described in the literature, there is little specific research on surfing and coastal management. Such research is required because coastal engineering has had significant impacts to surfing breaks, both positive and negative. Strategic planning and environmental impact assessment methods, a central tenet of integrated coastal zone management (ICZM), are recommended by this thesis to maximise surfing amenities. The research reported here identifies key oceanographic considerations required for ICZM around surfing breaks including: surfing wave parameters; surfing break components; relationship between surfer skill, surfing manoeuvre type and wave parameters; wind effects on waves; currents; geomorphic surfing break categorisation; beach-state and morphology; and offshore wave transformations. Key coastal activities that can have impacts to surfing breaks are identified. Environmental data types to consider during coastal studies around surfing breaks are presented and geographic information systems (GIS) are used to manage and interpret such information. To monitor surfing breaks, a shallow water multibeam echo sounding system was utilised and a RTK GPS water level correction and hydrographic GIS methodology developed. Including surfing in coastal management requires coastal engineering solutions that incorporate surfing. As an example, the efficacy of the artificial surfing reef (ASR) at Mount Maunganui, New Zealand, was evaluated. GIS, multibeam echo soundings, oceanographic measurements, photography, and wave modelling were all applied to monitor sea floor morphology around the reef. Results showed that the beach-state has more cellular circulation since the reef was installed, and a groin effect on the offshore bar was caused by the structure within the monitoring period, trapping sediment updrift and eroding sediment downdrift. No identifiable shoreline salient was observed. Landward of the reef, a scour hole ~3 times the surface area of the reef has formed. The current literature on ASRs has primarily focused on reef shape and its role in creating surfing waves. However, this study suggests that impacts to the offshore bar, beach-state, scour hole and surf zone hydrodynamics should all be included in future surfing reef designs. More real world reef studies, including ongoing monitoring of existing surfing reefs are required to validate theoretical concepts in the published literature.
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Oliveira, Jefferson Nascimento de. "Ferramental de gestão de águas subterrâneas para a cidade de São José do Rio Preto, SP." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-11082009-140524/.
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Tendo em vista a crescente utilização de mananciais subterrâneos para o abastecimento público, a modelação numérica do fluxo de água subterrânea vem continuamente ganhando importância como ferramenta imprescindível de suporte a decisões inerentes ao gerenciamento desse recurso hídrico. Nesse contexto, o meio acadêmico representa o ambiente ideal para o desenvolvimento e a avaliação de ferramentas e metodologias adequadas ao gerenciamento de águas subterrâneas, sob a ótica específica de problemas com características nacionais. Neste trabalho foi desenvolvida uma metodologia de gerenciamento, visando a sua possível utilização pelos órgãos gestores dos recursos hídricos subterrâneos. O ferramental desenvolvido enfocou a descrição, a catalogação e a extrapolação dos dados necessários à representação de todas as características físicas e hidrogeológicas da área de estudo. Posteriormente foi sistematizada a disponibilização em formato adequado à sua utilização no ambiente de trabalho do pacote SICK100, desenvolvido na Faculdade de Engenharia Civil da Ruhr-Universität Bochum. Esse pacote computacional, com base no Método de Elementos Finitos, permite a construção de modelos de fluxo de alta complexidade. A área urbana da cidade de São José do Rio Preto, abastecida principalmente por poços tubulares que captam água do Aqüífero Bauru, foi selecionada para a aplicação prática da metodologia desenvolvida. A região tem mais de 600 poços produtores cadastrados e 3500 poços clandestinos, que retiram aproximadamente 5000 \'M POT.3\'/h do aqüífero livre. Com base nessas informações e dados climáticos, foi construído um modelo numérico que permitiu simular toda a complexidade hidrogeológica da área. Também foram feitos prognósticos para dois cenários: um com diminuição da precipitação e outro com o aumento da área urbanizada e conseqüente impermeabilização. Os reflexos dessas hipóteses na dinâmica atual foram avaliados, sendo possível notar um colapso do sistema de captação, na região central da cidade, caso um dos prognósticos venha a ocorrer. O ferramental desenvolvido demonstrou ser útil ao gerenciamento de recursos hídricos, tendo ampliado o conhecimento das condições do fluxo na região.Considering the growing use of groundwater sources for public supply, numerical modeling of groundwater flow becomes an indispensable tool for decision support and adequate management of this natural resource. In this context, the academic circle represents, under the specific optics of problems with national characteristics, the ideal environment for the development and evaluation of tools and methodologies adapted to groundwater management. In this work, it was developed a management methodology which aims at its possible systematization and use by the water resources management agencies. The developed tool focused the description, cataloguing and extrapolation of all hydrogeological and physical characteristics of the study area, as it is necessary for the definition of a conceptual model. Furthermore, the data were in order to be used within the package SICK100 developed by the School of Civil Engineering at the Ruhr-University Bochum. This computational package, based on the finite element method, allows the construction of highly complex flow models, and it is executed under LINUX platform. The urban area of São José do Rio Preto, mainly provisioned by deep wells which capture water from the Bauru Aquifer, was selected for the practical application of the developed methodology. The area is exploited by more than 600 registered and 3500 clandestine wells which remove approximately 5000 \'M POT.3\'/h from the free aquifer. Based on these information and regional climatic data, it was developed a numerical flow model which allowed to simulate the entire hydrogeological complexity of the area. Prognostics were made for two different sceneries: one presented decrease of the precipitation, and another the increase of the urbanized area and consequent impermeabilization. The reflexes of those hypotheses in the current dynamics were appraised, indicating a possible collapse of the aquifer in the central area of the city, if one of the prognostics occurs. The methodology demonstrated to be useful for groundwater resources management, improving the understanding of the flow conditions in the model area.
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Aunay, Bertrand. "Apport de la stratigraphie séquentielle à la gestion et à la modélisation des ressources en eau des aquifères côtiers." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2007. http://tel.archives-ouvertes.fr/tel-00275467.
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Lieu de développement économique et démographique intense, les zones littorales font l'objet de pressions importantes sur l'environnement et, en particulier, sur les ressources en eau. Bien que la gestion des eaux souterraines côtières bénéficie de nombreux résultats issus de la recherche scientifique, une des problématiques majeures reste la connaissance de la géométrie des aquifères. Des interprétations géologiques de la genèse du bassin Plio-Quaternaire du Roussillon, issues de la stratigraphie séquentielle, sont confrontées, par l'intermédiaire d'une base données, à l'hydrogéologie de cet hydrosystème complexe localisé sur la partie littorale des Pyrénées-Orientales. L'étude statistique des points de prélèvement (distribution des crépines, productivité des forages...), l'analyse fonctionnelle (traitement du signal des chroniques piézométriques), l'hydrochimie et la géophysique électrique ont été utilisées afin d'élaborer un modèle conceptuel hydrogéologique des écoulements à l'échelle du bassin et de son prolongement vers le domaine offshore. La présence de la mer, de zones à salinité résiduelle et de cours d'eaux littoraux contribue à augmenter la salinité d'un aquifère libre supérieur (Quaternaire) sus-jacent aux différents aquifères captifs (Pliocène) exploités pour l'eau potable dans la zone littorale. La vulnérabilité face aux intrusions salines de cette ressource de bonne qualité, tant sur le point de vue quantitatif que qualitatif est appréhendée par modélisation. Dans le domaine offshore, le rôle protecteur des formations géologiques à faible et moyenne perméabilité est mis en évidence vis-à-vis de la préservation de la qualité de l'eau potable.
Books on the topic "Water management, MODELLING, COASTAL AQUIFER"
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Wilson, Ewan E. M. The application of digital modelling to aquifer management: (groundwater surface water interaction). Birmingham: University of Birmingham, 1989.
Find full textBook chapters on the topic "Water management, MODELLING, COASTAL AQUIFER"
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Halder, Subrata. "Development and Management of Coastal Aquifer System Through Seawater Intrusion Modelling." In Groundwater Development and Management, 209–25. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-75115-3_8.
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Hernández, R., R. Ramírez, M. López-Portilla, P. González, I. Antigüedad, and S. Díaz. "Seawater Intrusion in the Coastal Aquifer of Guanahacabibes, Pinar del Río, Cuba." In Management of Water Resources in Protected Areas, 301–8. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-16330-2_35.
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Fahrentholz, B., U. Hentschke, and P. Koske. "Acoustic detection of suspended matter in coastal waters." In Estuarine Water Quality Management Monitoring, Modelling and Research, 221–24. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/ce036p0221.
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Falcao, M., and C. Vale. "Nutrient variability in a shallow coastal lagoon (Ria Formosa, Portugal)." In Estuarine Water Quality Management Monitoring, Modelling and Research, 321–26. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/ce036p0321.
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Puls, Walter, Manfred Lobmeyr, Agmar Müller, Matthias Schünemann, and Herbert Kühl. "Investigations on suspended matter transport processes in estuaries and coastal waters." In Estuarine Water Quality Management Monitoring, Modelling and Research, 165–71. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/ce036p0165.
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Chidichimo, Francesco, Michele De Biase, and Salvatore Straface. "Modelling a Polluted Aquifer with Reconstructed Heterogeneity Using the Composite Medium Indicator Kriging." In Instrumentation and Measurement Technologies for Water Cycle Management, 581–99. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08262-7_24.
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Castillo, J. R. Fagundo, J. Pajón Morejón, P. González Hernández, M. Suárez Muñoz, and C. Melián Rodríguez. "Human Effect Over the Chemical Denudation Development in the Coastal Limestone Aquifer, Havana Southern Plane, Cuba." In Management of Water Resources in Protected Areas, 47–55. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-16330-2_6.
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Castillo, J. R. Fagundo, P. González Hernández, M. Suárez Muñoz, R. Hernández Díaz, and C. Melián Rodríguez. "Hydrogeochemical Processes Effect Over the Water Quality in the Coastal Limestone Aquifer of Güira-Quivicán, Havana Southern Plane, Cuba." In Management of Water Resources in Protected Areas, 57–65. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-16330-2_7.
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Dey, Subhajit, and Om Prakash. "Pumping Optimization for Saltwater Intrusion Management in a Coastal Aquifer with Combined Use of Sharp Interface and Density Dependent Models." In Groundwater and Water Quality, 287–301. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-09551-1_22.
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Reincke, Heinrich. "The sensitivity-survey — A useful decision-aid for the protection of the mud-flats in the German North Sea Coastal Region —." In Estuarine Water Quality Management Monitoring, Modelling and Research, 121–24. Washington, D. C.: American Geophysical Union, 1990. http://dx.doi.org/10.1029/ce036p0121.
Full textConference papers on the topic "Water management, MODELLING, COASTAL AQUIFER"
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MORANTE, FERNANDO, F. JAVIER MONTALVÁN, PAÚL CARRIÓN, GRICELDA HERRERA, JAVIER HEREDIA, F. JAVIER ELORZA, DAYANNA PILCO, and JOSELYNE SOLÓRZANO. "HYDROCHEMICAL AND GEOLOGICAL CORRELATION TO ESTABLISH THE GROUNDWATER SALINITY OF THE COASTAL AQUIFER OF THE MANGLARALTO RIVER BASIN, ECUADOR." In WATER RESOURCES MANAGEMENT 2019. Southampton UK: WIT Press, 2019. http://dx.doi.org/10.2495/wrm190141.
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Widyastuti, Indri, and Suntoyo. "Modelling Water Quality in Welang River Estuary, Pasuruan." In The 7th International Seminar on Ocean and Coastal Engineering, Environmental and Natural Disaster Management. SCITEPRESS - Science and Technology Publications, 2019. http://dx.doi.org/10.5220/0010218702750280.
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Widyastuti, Indri, and Suntoyo. "Modelling Water Quality in Welang River Estuary, Pasuruan." In The 7th International Seminar on Ocean and Coastal Engineering, Environmental and Natural Disaster Management. SCITEPRESS - Science and Technology Publications, 2019. http://dx.doi.org/10.5220/0010218702510256.
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Luoma, Samrit, and Birgitta Backman. "A hydrogeological model for groundwater management of a shallow low-lying coastal aquifer in southern Finland under climate change ." In The 1st International Electronic Conference on Water Sciences. Basel, Switzerland: MDPI, 2016. http://dx.doi.org/10.3390/ecws-1-a003.
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HERRERA-FRANCO, GRICELDA, LADY BRAVO-MONTERO, PAÚL CARRIÓN-MERO, FERNANDO MORANTE-CARBALLO, and BORIS APOLO-MASACHE. "COMMUNITY MANAGEMENT OF THE OLÓN COASTAL AQUIFER, ECUADOR, AND ITS IMPACT ON THE SUPPLY OF WATER SUITABLE FOR HUMAN CONSUMPTION." In SDP 2020. Southampton UK: WIT Press, 2020. http://dx.doi.org/10.2495/sdp200141.
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Winter, G., B. Galván, J. P. Ramos, H. Carmona, B. González, J. I. Jiménez, A. Cacereño, and S. Alonso. "An integrated system for a real time fight against maritime and coastal pollution with environmental data acquisition, pollutant spillages modelling and risk management." In WATER POLLUTION 2008. Southampton, UK: WIT Press, 2008. http://dx.doi.org/10.2495/wp080381.
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Nomura, Yukito, Mariam Sultan Almarzooqi, Ken Makishima, and Jon Tuck. "Water Compatibility and Scale Risk Evaluation by Integrating Scale Prediction of Fluid Modelling, Reservoir Simulation and Laboratory Coreflood Experiment for a Giant Oil Field in Offshore Abu Dhabi." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207319-ms.
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Abstract An offshore field is producing oil from multiple reservoirs with peripheral water injection scheme. Seawater is injected through a subsea network and wellhead towers located along the original reservoir edge. However, because its OWC has moved upward, wells from wellhead towers are too remote to inject seawater effectively, with some portion going to the aquifer rather than oil pool. Therefore, it is planned to migrate injection strategy from peripheral to mid-dip pattern. An expected risk is scaling by mixing incompatible seawater and formation water. Such risk and mitigation measures were evaluated. To achieve the objective, the following methodology was applied: 1. Scale modelling based on water chemical analysis. 2. Define scale risk envelope with three risk categories 3. Tracer dynamic reservoir simulation to track formation water, connate water, dump flood water, injection seawater and treated seawater. 4. Review the past field scale history data 5. Coreflood experiment to observe actual phenomena inside the reservoir with various parameters such as water mixing ratio, sulphate concentration, temperature and chemical inhibitor 6. Consolidate all study results, conclude field scale risk and impact of mitigation measures. Scale prediction modelling, verified by coreflood tests, found that mixing reservoir formation water and injection seawater causes a sulphate scale risk, with risk severity depending on mixing ratio and sulphate concentration. Reservoir temperature was also found to correlate strongly with scale risk. Therefore, each reservoir should have different water management strategy. Scale impact is limited in the shallower wide reservoir with cooler reservoir temperature. Such reservoir should therefore have mid-dip pattern water injection to avoid low water injection efficiency with possible scale inhibitor squeezing as a contingency option. On the other hand, deeper reservoir has higher risk of scaling due to its higher temperature, causing scale plugging easily in reservoir pores and production wells. For such reservoir, peripheral aquifer water injection, treated low-sulphate seawater with sulphate-removal system, or no water injection development concept should be selected. By using modelling and experiment to quantify the scale risk over a range of conditions, the field operator has identified opportunities to optimize the water injection strategy. The temperature dependence of the scale risk means, in principal, that different injection strategy for each reservoir can minimize flow assurance challenges and maximize return on investment in scale mitigation measures.
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Sánchez-Murillo, Ricardo. "Hydrogeological responses in tropical mountainous springs." In I Congreso Internacional de Ciencias Exactas y Naturales. Universidad Nacional, 2019. http://dx.doi.org/10.15359/cicen.1.37.
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This study presents a hydrogeochemical analysis of spring responses (2013-2017) in the tropical mountainous region of the Central Valley of Costa Rica. The isotopic distribution of δ18O and δ2H in rainfall resulted in a highly significant meteoric water line: δ2H = 7.93×δ18O + 10.37 (r2=0.97). Rainfall isotope composition exhibited a strong dependent seasonality. The isotopic variation (δ18O) of two springs within the Barva aquifer was simulated using the FlowPC program to determine mean transit times (MTTs). Exponential-piston and dispersion distribution functions provided the best-fit to the observed isotopic composition at Flores and Sacramento springs, respectively. MTTs corresponded to 1.23±0.03 (Sacramento) and 1.42±0.04 (Flores) years. The greater MTT was represented by a homogeneous geochemical composition at Flores, whereas the smaller MTT at Sacramento is reflected in a more variable geochemical response. The results may be used to enhance modelling efforts in central Costa Rica, whereby scarcity of long-term data limits water resources management plans.
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Khanifar, Ahmad, Ibrahim Bin Subari, Mohd Razib Bin Abd Raub, Raj Deo Tewari, and Mohd Faizal Bin Sedaralit. "The World's First Offshore GASWAG EOR Full Field Implementation." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/208127-ms.
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Abstract A major matured Malaysian offshore oilfield with more than 40 years of production history under a combination of moderate to strong aquifer support and moderate-size gas cap will be subjected to a unique enhanced oil recovery (EOR) scheme, the first of its kind offshore, called Gravity Assisted Simultaneous Water Alternating Gas (GASWAG) injection process. It is essentially a scheme which involves simultaneously injection of gas and water which involves injecting water up-dip and gas down-dip structurally in a depleted oil reservoir. This method takes the advantage of gravity drainage mechanism to maximize recovery from un-swept oil zones down-dip by aquifer influx and up-dip by gas cap expansion processes and it could be different than the conventional water alternating gas (WAG) method. This paper mostly presents the dynamic modelling and simulation work which has been established during this case study to obtain the GASWAG base case model and to conduct the optimization and sensitivity assessments on the major reservoir parameters. It also describes the main subsurface uncertainties and operational risks and their impact on incremental oil reserve and the results were used to design mitigation plans to help minimize impact on oil recovery volumes. Implementing the full field scale of this EOR scheme involves a detailed reservoir management plan (RMP) with many reactivations of idle wells, well workover plans, behind casing opportunities and adding perforation interval together with identified new infill wells to maximize the flood-front movement of the injected fluids. Obviously, good communication with field operational personnel is paramount to ensure these RMP are adhered to clear targets to successfully achieve the desired incremental recovery and will be elaborated in this paper. This paper describes the strategy and workflow to monitor and measure the two key success factors of this project which are production attainability and reserve attainability. The success of this project depends on continuous evaluation to check the actual performance against the anticipated behavior. As soon as new information obtains along implementation, it will be assessed against targets to steer the way to the main goal of additional reserve by the end of field life. Thus, it requires a comprehensive monitoring plan with detailed surveillance and data collection and, well testing to revisit and update the dynamic model accordingly. The results of this study show that GASWAG has emerged to be one of the most promising techniques with the highest incremental reserve for this field among various EOR techniques evaluated such as continuous gas injection, continuous water injection, conventional WAG, aquifer-assisted WAG, and double displacement.
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Kitazawa, Daisuke, and Shuhei Fujimoto. "Modelling and Investigation of Competition for Space and Food Among Blue Mussels in Tokyo Bay." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29668.
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A mathematical model is developed to describe the competition for space and food among blue mussels, which adhere on cylindrical substrata. In order to develop and validate the model, field investigation is carried out for mussels growing on ropes installed around the mouth of Sumida River in Tokyo Bay. In addition to monitoring of environmental factors such as water temperature, salinity, and the concentration of dissolved oxygen, the relationship between the position of each mussel and its size in the mussel bed is examined precisely. The position of each mussel in the bed is specified by how much the gape of the shells comes out from the bed. As a result, the growth of the mussels in the inner layer is obviously slow and they are considered to continue living by consuming the reserved materials accumulated in their bodies. On the contrary, mussels can grow faster if only a part of the gape of their shells comes out from the mussel bed. These observed features are taken into account in the mathematical model. The model can predict well the size structure of mussels in the bed; the faster growth of the surface mussels and the slower growth of the inner mussels, which corresponds to observations. In the future the model will be also applied to mussels on the cylindrical substrata such as cultivation ropes, piers, and piles for aquaculture management and environmental impact assessment of the coastal structures.