基于Aquifer Test的水文地质参数计算方法研究

根据抽水试验结果,常用人工求参的方法确定水文地质参数。人工求参方法计算结果较为可靠,但计算过程繁琐,并且结果因人而异,具有人为随意性。利用AquiferTest软件求参,计算方便快捷,与人工求参方法对比,具有计算精度较高,规范性好等优点。     

A Probabilistic Multiperiod Simulation–Optimization Approach for Dynamic Coastal Aquifer Management

Combined simulation–optimization (CSO) schemes are common in the literature to solve different groundwater management problems, and CSO is particularly well-established in the coastal aquifer management literature. However, with a few exceptions, nearly all previous studies have employed the CSO approach to derive static groundwater management plans that remain unchanged during the entire management period, consequently overlooking the possible positive impacts of dynamic strategies. Dynamic strategies involve division of the planning time interval into several subintervals or periods, and adoption of revised decisions during each period based on the most recent knowledge of the groundwater system and its associated uncertainties. Problem structuring and computational challenges seem to be the main factors preventing the widespread implementation of dynamic strategies in groundwater applications. The objective of this study is to address these challenges by introducing a novel probabilistic Multiperiod CSO approach for dynamic groundwater management. This includes reformulation of the groundwater management problem so that it can be adapted to the multiperiod CSO approach, and subsequent employment of polynomial chaos expansion-based stochastic dynamic programming to obtain optimal dynamic strategies. The proposed approach is employed to provide sustainable solutions for a coastal aquifer storage and recovery facility in Oman, considering the effect of natural recharge uncertainty. It is revealed that the proposed dynamic approach results in an improved performance by taking advantage of system variations, allowing for increased groundwater abstraction, injection and hence monetary benefit compared to the commonly used static optimization approach.

     

An Aquifer Management Case Study – The Chalk of the English South Downs

The Chalk aquifer of the English South Downs is very heavily utilised. The groundwater resources have enjoyed a formal programme of management which started in the 1950s, although a number of actions had been taken earlier in order to deal with saline intrusion and potential risk to groundwater quality from urbanisation. In the late 1950s the policy of leakage/storage boreholes was first adopted, whereby the leakage boreholes along the coast were pumped in winter to intercept fresh water discharge to the sea and to maximise the recharge potential inland, and inland storage boreholes were used, as much as possible, in the summer months only. A comprehensive monitoring programme supported by aquifer modelling has enabled a gradual increase in overall abstraction to take place without increasing groundwater degradation due to saline intrusion. There have been various pollution prevention strategies over the years, and these have been effective in protecting the groundwater despite the high population density and widespread agricultural activity within the South Downs. The management of the aquifer has clearly been successful; there are many lessons from this experience that can be applied to other regions and other aquifers.     

Tourism as tragedy? Common problems with water in post-revolutionary Nicaragua

This paper examines the increased demand placed on limited water resources by a rapidly growing tourism sector in Playa Gigante, Nicaragua. Results from field campaigns suggest that recharge of the local aquifer may not meet burgeoning tourism demands for water. This paper also points to initial conflicts over water between locals and tourism operations, which are further complicated by ineffective implementation of national water policies and the common pool nature of groundwater. The conclusion discusses the need for more extensive research and better implementation of water policy through community governance and collaboration.     

Defining Groundwater Remediation Objectives with Cost-benefit Analysis: Does It Work?

The use of cost-benefit analysis (CBA) is increasingly advocated as a tool for supporting water planning decisions, in particular at the local (site) level. This paper questions whether CBA is relevant for evaluating groundwater management options at the scale of large regional aquifers. It highlights the difficulties related to estimating the cost of groundwater protection and remediation measures at the regional (water body) level. It also identifies methodological challenges in estimating the economic value of the benefits of groundwater protection. The paper is based on an original case study carried out on the upper Rhine valley aquifer in eastern France. The methodology deployed combines engineering approaches to assess the cost of remediation and economic methods (contingent valuation) to estimate the benefits associated with groundwater improvement.     

Hydropeaking in small hydropower in Norway—Compliance with license conditions?

Hydropeaking involves rapid changes in water flow, causing negative effects on aquatic organisms. To reduce these effects, hydropower licenses contain restrictions on hydropeaking. The owners of a hydropower plant are obliged to follow the requirements in the license. This study was conducted to understand the effect of environmental policies in small hydro licenses. We studied the occurrence of hydropeaking by analysing 256 high‐head, small Norwegian hydropower plants in relation to a set of characteristics that define each plant. We selected plants that were online during 2005–2014 and chose 2015 as a year for hourly production patterns. We counted the number of starts, that is, the moment when the hydro facility starts to produce energy, as an indicator of hydropeaking. Among the analysed plants, 75.8% had restrictions to practice hydropeaking. Production typically showed daily, weekly, and annual cycles though shapes varied depending on turbine type and location. The number of starts was independent on having or not having a license to practice hydropeaking. The average duration of periods with production and the average production in these periods were higher for plants without restrictions. The number of starts varied widely among plants. The number of starts was lower for installed Pelton turbines than for Francis and Kaplan turbines, which was in agreement with the characteristics of the turbines. Overall, these results show that hydropeaking restrictions given in the licenses are rarely followed. The high number of starts may be explained by failure in the grid system, improper maintenance, and financial interests. Their relative importance should be subject to further investigation.     

Private Participation in Small Hydropower Development in China——Comparison with International Communities

In recent years, Chinese private investment in SHP (small hydropower) has been booming like mushrooms after rain. Globally,many developing countries have formulated a series of incentive policies to encourage the mobilization of private capital for SHP, but the recent enforcement is far from meeting expectation. This article overviews private enterprises investing in SHP domestically, analyzes similarities and differences between China and international communities, as well as the comparability and mutual referential values, and also explores some approaches for improvement Furthermore, this article presents several particular issues in this respect, with a hope to further promote the sound development of SHP privately financed. Attached here are 2 tables and 2 figures.     

Contaminants Associated with Suspended Sediments in Lakes Erie and Ontario, 1997–2000

Sediment traps were installed at individual index stations in the western basin of Lake Erie and the Mississauga (central) basin of Lake Ontario, and refurbished seasonally during the period 1997–2000. In Lake Ontario, sediment down flux rates and corresponding contaminant down flux rates were highest in winter and increased with depth due to the influence of resuspended bottom sediments. Sediment down flux rates in western Lake Erie (22 to 160 g m⁻² d⁻¹) were far greater than in Lake Ontario (0.19–3.0 g m⁻² d⁻¹). Suspended material in western Lake Erie was characterized as predominately resuspended bottom sediments; down flux rates were roughly 5- to 10-fold higher in spring and fall, compared to summer. Suspended sediment concentrations of PCBs and other organochlorine contaminants, represented by both annual means and individual seasonal values, were higher in Lake Ontario throughout the duration of the study, compared to Lake Erie. The mean annual concentration of PCBs in suspended sediments over the period 1997–2000 was 330 ng/g in western Lake Erie and 530 ng/g in Lake Ontario. Based on a comparison with historical data from Lake Ontario, mean contaminant concentrations over the period 1997–2000 for PCBs, hexachlorobenzene, and mirex corresponded to decreases of 38%, 74%, and 40%, respectively, since the mid-1980s. Corresponding down flux rates for PCBs, hexachlorobenzene, and mirex decreased by approximately 70%, 90%, and 80%, respectively, since the 1980s.     

Experience in using a guide vane design with a “floating” lower bearing

Conclusion The use of the floating bearing of the vanes in the lower ring of the gate apparatus makes it possible to reduce the cycle and labor expenditures of manufacture at the plant and on assembly of the gate apparatus with a substantial improvement of the quality of assembly.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 4, pp. 45–47, April, 1984.     

Extinction in Multiple Species Fisheries Harvested with the Same Gear—The Great Lakes Ciscoes

Extinction of four deepwater ciscoe species (Coregonus spp.) in the Great Lakes occurred during a period of heavy exploitation, but during the same period there were several introduced and invading species and there also was widespread deterioration in the quality of the environment. The cause of the extinctions is uncertain, but extinction is a threat in multiple species fisheries harvested with a common gear. The possibility that the ciscoe extinctions resulted from harvesting was investigated using a general form of the surplus production model and computer simulation. In the simulations extinctions occurred even with a moderate fishing effort when a large number of different species were caught with the same gear. In the Great Lakes 4 out of 8 ciscoe species caught with the same gear apparently went extinct. In the simulations 4 extinctions out of 8 species was a common event, and the fishery alone was all that was necessary to cause the extinctions.     

Operating experiences with a molten carbonate fuel cell at Stuttgart-M?hringen wastewater treatment plant

Fuel cells on wastewater treatment plants are a relatively new technology to convert biogas from anaerobic digestion into thermal and electrical energy. Since the end of 2007, a type of MCFC fuel cell (>250 kW(el), 180 kW(th)) has been installed at Stuttgart-M?hringen wastewater treatment plant. The goals of this research project are to raise the power self-sufficiency in Stuttgart-M?hringen, to further optimise high temperature fuel cells using biogas and to gain practical experience. After approximately 9,000 h of operation, a mean electrical 'gross'-efficiency of 44% was achieved. To fully exploit this high electrical efficiency, it is essential to keep the energy consumption of peripheral devices (gas pressure unit, gas cleaning unit, etc.) of the fuel cell as low as possible.     

Kelvin-Helmholtz instability.with mass transfer through porous media： Effect of irrotational viscous pressure

This paper studies the effect of the irrotational viscous pressure on Kelvin-Helmholtz instability of the plane interface of two viscous and incompressible fluids in a fully saturated porous media with mass and heat transfers across the interface. In the earlier work, the instability of the plane interface of two viscous and streaming miscible fluids through porous media was studied by assuming that the motion and the pressure are irrotational and the viscosity enters the normal stress balance. This theory is called the viscous potential flow theory. Here, we use another irrotational theory in which the discontinuities in the irrotational tangential velocity and shear stress are eliminated in the global energy balance by considering viscous contributions of the irrotational pressure. The Darcy-Brinkman model is used in the investigation and the stability criterion is formulated in terms of a critical value of the relative velocity. It is observed that the heat and mass transfer has a destabilizing effect on the stability of the system while the irrotational shearing stresses stabilize the system.     

Effect of Well Radius on Drawdown Solutions Obtained with Laplace Transform and Green’s Function

We have developed a drawdown solution for a partially penetrating well under constant flux pumping in a confined aquifer with finite thickness. The predictions of our solution diverge from the predictions of Hantush’s solution (1961), particularly for problems with low ratios of well screen length to aquifer thickness. Furthermore, the predicted drawdown from Hantush’s solution (1961) differs from that of Yang et al.’s solution Water Resour Res 42:W0552, (2006) only near the well and at small time values as indicated in Yang et al. Water Resour Res 42:W0552, (2006). Our solution is based on Green’s function with a columnar source (sink) that represents pumping from a finite-radius well. Hantush’s solution (1961) and Yang et al.’s solution Water Resour Res 42:W0552, (2006), however, were derived from Laplace transform techniques for pumping in a well with an infinitesimal and a finite radius, respectively.     

Optimization of the water chemistry of the primary coolant at nuclear power plants with VVÉR

Results of the use of automatic hydrogen-content meter for controlling the parameter of hydrogen in the primary coolant circuit of the Kola nuclear power plant are presented. It is shown that the correlation between the hydrogen parameter in the coolant and the hydrazine parameter in the makeup water can be used for controlling the water chemistry of the primary coolant system, which should make it possible to optimize the water chemistry at different power levelsTranslated from Élektricheskie Stantsii, No. 12, December 2004, pp. 31 – 33.     

The Numerical modelling of Two－dimensional Unsteady Flow in Open Channel with Double－line Bridge

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Monitoring the health of large rivers with macroinvertebrates: Do dominant taxa help or hinder the assessment?

Macroinvertebrate communities in the Mississippi River are often dominated by a few taxa (e.g. oligochaetes in the fine sediments and hydropsychid caddisflies on rocks) that exploit the natural abundance of fine organic particles. These taxa are moderately to highly tolerant of pollution, and the combination of high abundance and high pollution tolerance could result in the river being assessed as highly polluted. We examined how the presence or absence of dominant oligochaetes or hydropsychid caddisflies affected biometric values and responses used to monitor environmental stress in large rivers. Responsiveness was assessed across five simulated impairments created by removing different subsets of sensitive taxa from the original data for macroinvertebrates in the Upper Mississippi River near Cape Girardeau, MO. For many metrics, removal of the dominant taxa changed values, and increased the difference between existing conditions and simulated impairments. For macroinvertebrate data from fine‐sediment habitat, 8–9 of 12 metrics responded to the two most severe impairments simulated with or without dominant oligochaetes, but none changed for less severe impairments. For rock habitat, more metrics responded to moderate or severe impairments simulated when dominant hydropsychids were excluded. Few metrics performed better with dominant taxa. Overall, removal of dominant macroinvertebrate taxa improved both the accuracy and interpretability of several metrics commonly used to monitor effects of water pollution on large‐river faunas dominated by a few taxa. Removing them also makes observed responses more comparable to those frequently quantified for wadeable streams and rivers. Copyright © 2009 John Wiley & Sons, Ltd.     

Water flooding optimization with adjoint model under control constraints简

The oil recovery enhancement is a major technical issue in the development of oil and gas fields. The smart oil field is an effective way to deal with the issue. It can achieve the maximum profits in the oil production at a minimum cost, and represents the future direction of oil fields. This paper discusses the core of the smart field theory, mainly the real-time optimization method of the injection-production rate of water-oil wells in a complex oil-gas filtration system. Computing speed is considered as the primary prerequisite because this research depends very much on reservoir numerical simulations and each simulation may take several hours or even days. An adjoint gradient method of the maximum theory is chosen for the solution of the optimal control variables. Conven-tional solving method of the maximum principle requires two solutions of time series： the forward reservoir simulation and the backward adjoint gradient calculation. In this paper, the two processes are combined together and a fully implicit reservoir simulator is developed. The matrixes of the adjoint equation are directly obtained from the fully implicit reservoir simulation, which accelera-tes the optimization solution and enhances the efficiency of the solving model. Meanwhile, a gradient projection algorithm combined with the maximum theory is used to constrain the parameters in the oil field development, which make it possible for the method to be applied to the water flooding optimization in a real oil field. The above theory is tested in several reservoir cases and it is shown that a better development effect of the oil field can be achieved.     

Systemic Input-Output Computation of Green and Blue Virtual Water ‘Flows’ with an Illustration for the Mediterranean Region

The term virtual water refers to the volume of water used in the production of a commodity or service. Accordingly, virtual water ??trade?? is the amount of water ??embedded?? in commodities being transferred from one place to another as a consequence of trade. This paper argues that the conventional methods so far adopted for the computation of virtual water ??flows?? (based on Hoekstra and Hung 2002) have considered only direct water usage and not sufficiently distinguished between blue and green water resources. This has brought about flawed estimates of virtual water ??flows??, thereby limiting the usefulness of the virtual water concept as a tool for informing water policy. A novel approach for computing virtual water ??flows?? which applies the Input?Coutput (IO) methodology to account for both direct and indirect water consumption, and simultaneously distinguishes between the different typologies of water, is presented. The study upholds that the integration of these two methods can not only provide a more robust framework for quantifying virtual water ??flows??, but also enhance the relevance of the concept as a tool for water resource management policy. The implications of these alternative estimation methods are here illustrated using data referring to 11 Mediterranean economies and 7 internationally traded agricultural commodities.