南水北调进京后怀柔应急水源地地下水资源涵养研究

怀柔应急水源地作为北京最大的应急地下水源地,在连续10多年的干旱期间,为保障城市供水安全做出了巨大贡献。文章在总结怀柔应急水源地10年供水历程的基础上,评价了连续干旱和应急开采条件下区域水资源的变化;结合南水北调进京的契机,从"资源人工回补"和供水系统"热备运行"两方面开展当地地下水资源涵养研究工作,以保障怀柔应急水源地可持续"应急供水"能力,为应对南水北调供水过程中的突发事件,做好水资源战备储备。     

Metropolitan food systems in developing countries: The perspective of “Urban Metabolism”

The perspective of the paper is that of urban metabolism which views cities, metaphorically, as metabolic processes which take in people, food, resources, and energy, transform these into a distinctive quality of life, and emit people, products, and wastes. The paper focuses on urban food metabolism, by using the concept of the food system which includes the sub-systems of production, supply, distribution and consumption of food. The paper seeks to review the state of knowledge for each of these sub-systems, to provide examples that illustrate the functioning and determinants of urban food systems, to identify critical gaps in knowledge, to outline central research desiderata and to examine critically the analytic value of the concept of urban food metabolism.Revised version of a paper presented to the International Symposium on Urban Metabolism, held in Kobe, Japan, September 6–11, 1993     

Mass fluxes of xenobiotics below cities: challenges in urban hydrogeology

Urban areas are the focus of major ecological, social and economical activity. They are thus also prime locations of increasing conflict with regard to water use and water protection. As a direct and/or indirect consequence of urban land use and human activity, urban water systems are frequently polluted with organic contaminants including waste water-born xenobiotics such as pharmaceuticals, personal care products (collectively known as PPCPs) and endocrine-active substances. This study reviews new integrated methodologies including flux calculations as well as chemical investigations for determining the impact of human activities on urban water systems and on processes within the urban watershed. The use of indicator substances, representing different contaminant sources and pathways, integral pumping tests and mass balance approaches are suitable alternatives within these environments. The issues are explored using contaminant mass balance examples from Halle/Saale and Leipzig, Germany.     

Socio-economic factors influencing sustainable water supply in Botswana

The paper examines the socio-economic and political issues of sustainable water supply in Botswana. It pays particular attention to the actual and potential role of economic instruments. Water consumption occurs both in a market and non-market contexts (producer = consumer). Due to rapidly increasing water demand and the fact that the "easy" solutions to increase water supply have largely elapsed, Botswana is concerned with water shortages which may hamper peoples basic needs and industrial development in the future. Other sustainability concerns relate to the environment (pollution), social factors (equity and affordability) and economic considerations (cost recovery and efficiency). Prices, costs and the value of water are instrumental in striking a compromise between these goals. Trends in pricing and their relationship with costs and resource value are presented, and the impact of prices and subsidies on water demand and supply reviewed in order to assess their contribution towards a sustainable equilibrium. There is a substantial scope to improve the performance of economic instruments such as price subsidies and tax relief. The long-term marginal costs calculated in the Botswana National Water Master Plan contribute to prices approaching the costs of water production, but it excludes the environmental considerations. Resource scarcity is partly reflected where it increases the water supply costs; the indirect use and non-use values and external impacts are not incorporated in the water charges. Higher prices would increase the economic feasibility of water recycling and water harvesting and generate investment capital needed for the expansion of the water supply systems. Government subsidies may discourage efficient resource use. It is generally concluded that there is need for greater emphasis on re-use of waste water and control of the demand by harmonizing fees or tariffs between urban and rural areas as far as non-essential use is concerned; and provide more incentives for large-scale consumers to increase water use efficiency and sustainability.     

Sulfur biogeochemical cycling and novel Fe-S mineralization pathways in a tidally re-flooded wetland

Sulfur biogeochemical cycling and associated Fe-S mineralization processes exert a major influence over acidity dynamics, electron flow and contaminant mobility in wetlands, benthic sediments and groundwater systems. While S biogeochemical cycling has been studied intensively in many environmental settings, relatively little direct information exists on S cycling in formerly drained wetlands that have been remediated via tidal re-flooding. This study focuses on a tidal wetland that was drained in the 1970s (causing severe soil and water acidification), and subsequently remediated by controlled re-flooding in 2002. We examine reduction rates and Fe-S mineralization at the tidal fringe, 7 years after the commencement of re-flooding. The initial drainage of the wetland examined here caused in-situ pyrite (FeS₂) oxidation, resulting in the drained soil layers being highly acidic and rich in -bearing Fe(III) minerals, including jarosite (KFe₃(SO₄)₂(OH)₆). Tidal re-flooding has neutralized much of the previous acidity, with the pore-water pH now mostly spanning pH 5-7. The fastest rates of in-situ reduction (up to ∼300 nmol cm⁻³ day⁻¹) occur within the inter-tidal zone in the near-surface soil layers (to ∼60 cm below ground surface). The reduction rates correlate with pore-water dissolved organic C concentrations, thereby suggesting that electron donor supply was the predominant rate determining factor. Elemental S was a major short-term product of reduction, comprising up to 69% of reduced inorganic S in the near-surface soil layers. This enrichment in elemental S can be partly attributed to interactions between biogenic H₂S and jarosite - a process that also contributed to enrichment in pore-water Fe²⁺ (up to 55 mM) and (up to 50 mM). The iron sulfide thiospinel, greigite (Fe₃S₄), was abundant in near-surface soil layers within the inter- to sub-tidal zone where tidal water level fluctuations created oscillatory redox conditions. There was evidence for relatively rapid pyrite re-formation within the re-flooded soil layers. However, the results indicate that pyrite re-formation has occurred mainly in the lower formerly drained soil layers, whereas the accumulation of elemental S and greigite has been confined towards the soil surface. The discovery that pyrite formation was spatially decoupled from that of elemental S and greigite challenges the concept that greigite is an essential precursor required for sedimentary pyrite formation. In fact, the results suggest that greigite and pyrite may represent distinct end-points of divergent Fe-S mineralization pathways. Overall, this study highlights novel aspects of Fe-S mineralization within tidal wetlands that have been drained and re-flooded, in contrast to normal, undisturbed tidal wetlands. As such, the long-term biogeochemical trajectory of drained and acidified wetlands that are remediated by tidal re-flooding cannot be predicted from the well-studied behaviour of normal tidal wetlands.     

Combined tectonic-sediment supply-driven cycles in a Lower Carboniferous deep-marine foreland basin,Moravice Formation,Czech Republic

The Lower Carboniferous Moravian–Silesian Culm Basin (MSCB) represents the easternmost part of the Rhenohercynian system of collision-related, deep-water foreland basins (Culm facies). The Upper Viséan Moravice Formation (MF) of the MSCB shows a distinct cyclic stratigraphic arrangement. Two major asymmetric megacycles bounded by basal sequence boundary, each about 500 to 900 m thick, have been revealed. The megacycles start with 50- to 250-m-thick, basal segments of erosive channels: overbank successions and slope apron deposits interpreted as lowstand turbidite systems. Up-section they pass into hundred metre-thick, fine-grained, low-efficiency turbidite systems. Palaeocurrent data show two prominent directions, basin axis-parallel, SSW–NNE directions, which are abundant in the whole MF, and basin axis-perpendicular to oblique, W–E to NW–SE directions, which tend to be confined to the basal parts of the megacycles or channel-lobe transition systems in their upper parts. Based on the facies characteristics, palaeocurrent data, sandstone composition data and trace-fossil distribution data, we suggest a combined tectonics–sediment supply-driven model for the MF basin fill. Periods of increased tectonic activity resulted in slope oversteepening probably combined with increased rate of lateral W–E sediment supply into the basin, producing the basal sequence boundary and the subsequent lowstand turbidite systems. During subsequent periods of tectonic quiescence, the system was filled mainly from a distant southern point source, producing the thick, low efficiency turbidite systems. Consistently with the previous models, our own sediment composition data indicate a progressively increasing sediment input from high-grade metamorphic and magmatic sources up-section, most probably related to an uplift in the source area and progressive unroofing of its structurally deeper crustal parts. The first occurrence of the Cruziana–Nereites ichnofacies in sand-rich turbidite systems in the youngest parts of the MF (Goel to Gospi Zone), supported by rapidly increasing quartz concentrations in sandstones, is thought to indicate a transition from generally underfilled to generally overfilled phase in evolution of the MSCB basin. This transition may be linked to the onset of Upper Viséan phase of northward basin-fill progradation assumed by previous authors.     

Subaerial terminoglacial fans I: a semi-quantitative sedimentological analysis of the proximal environment

Fans formed under subaerial terminoglacial (previously called ice-contact) conditions have several characteristics that differ from those formed under other conditions. Twenty-five such fans in NE Poland were investigated to model the dominant genetic processes involved. These fans show, as do other types, a proximal, a middle and a distal environment. The present study deals with the proximal environment. The fans date from the last, i.e. Weichselian or Vistulian, glacial. The proximal terminoglacial fan comprises abundant gravelly sediments, resembling the glacial deposits from which they were derived. Three facies, each subdivided into two subfacies, can be distinguished; these are dominated by mass flows, unchannelised flows, and stream (= channelised) flows, respectively. The characteristics of the facies are described and illustrated. It is concluded that the irregular supply of water by the nearby ice masses dominates the sedimentary processes.     

Aquifer contamination by chlorinated-VOCs: the case of an urban metropolis megasite overlying the Coastal Plain aquifer in Israel

The Tel Aviv metropolitan region (200 km²), located on the sandy and phreatic Mediterranean Coastal Plain aquifer in Israel, is an example of a contaminated megasite that is additionally complicated by being part of a densely populated urban environment. Despite being a major source of fresh potable water, no dedicated aquifer monitoring systems exist. The vast majority of tested water supply wells (82% of 90 wells) were found to be contaminated with one or more chlorinated volatile organic compounds (Cl-VOCs) such as trichloroethene and tetrachloroethene, originating from multiple sources, including former industrial sites. Temporal variations in Cl-VOC concentrations in water supply wells were large and unpredictable. Such aquifer contamination requires immediate action in terms of aquifer management and municipal water distribution. To cope with temporal and spatial variations in contaminant concentrations in water supply wells in an area where monitoring wells are absent, aquifer impact areas were defined based on the concentration of the Cl-VOC contaminant in pumping wells that was greatest in relation to its drinking water standard over a 3-year period. Such a map can be used to define water supply treatment and municipal well monitoring requirements, until an adequate monitoring system is established.     

Managing for sustainability in an arid climate: lessons learned from 20 years of groundwater management in Arizona,USA

Substantial progress has been made within central Arizona in moving towards a more sustainable water future, particularly in transitioning the urban demand from a primarily nonrenewable groundwater-based supply to increasing dependence on the Colorado River, Salt River and effluent. Management efforts include a wide range of regulatory and voluntary programs which have had mixed success. The Department of Water Resources has learned a number of key lessons throughout the years, and this paper attempts to establish the water management context and identify those lessons for the benefit of others who may want to evaluate alternative approaches to groundwater management. Themes to be discussed include evaluating water management approaches in a public policy context, the effectiveness of alternative management approaches and the relative merits of regulatory vs. nonregulatory efforts, and the importance of high-quality data in making management decisions.

Co-precipitation of radium in high ionic strength systems: 2. Kinetic and ionic strength effects

High concentrations of naturally occurring radium pose environmental and health concerns in natural and industrial systems. The adsorption of Ra²⁺ in saline water is limited compared to its adsorption in fresh water, but the process of co-precipitation may be effective in decreasing its concentration. However, despite its importance, Ra co-precipitation has rarely been studied in high ionic strength environments such as those in evaporitic systems.The fate of Ra in the reject brine of a desalination plant was studied via evaporation batch experiments at ionic strengths (I) ranging from 0.7 to 7.0 mol kg⁻¹. Precipitation sequences revealed that Ra co-precipitated with barite, even though the latter was a trace mineral compared to the precipitated gypsum. The concentration-based effective partition coefficient, , for the co-precipitation reaction was 1.04 ± 0.01. This value of is significantly lower than the value for relatively diluted solutions (1.8 ± 0.1). This low value of is mainly the result of a kinetic effect but is also slightly affected by the ionic strength.Both effects are quantitatively examined in the present paper. It is suggested that a kinetic effect influences the nucleation of (Ra,Ba)SO₄, reducing the value of the partition coefficient. This kinetic effect is caused by the favorable nucleation of a more soluble phase (i.e., a phase with a higher BaSO₄ fraction). An additional decrease in the partition coefficient results from the ionic strength effect. Considering the activity of Ra²⁺ and Ba²⁺ in the solution (rather than their concentration) makes it possible to determine the activity-based partition coefficient (), which accounts for the ionic strength effect. was calculated empirically from the experiments and theoretically via a kinetic model. The two derived values are consistent with one another and indicate the combined effect of ionic strength and precipitation kinetics.Finally, the common assumption that γ_Ra²⁺/γ_Ba²⁺=1 was re-examined using a numerical model to predict the experimental results. As the ionic strength increases, this assumption becomes less appropriate for predicting the change in as calculated in the experiments. Understanding the co-precipitation of Ra in such systems is crucial for risk assessments in which both Ra concentration and ionic strength are relatively high.     

常德市地下水应急水源地应急供水可行性评价及方案研究

寻找地下水应急水源地、建立应急供水机制,是城市发生日常供水障碍时保障居民用水安全、维护社会稳定的重要措施。通过分析常德市规划区水文地质条件,圈定了5个地下水应急水源地,总结了同类型城市地下水应急水源地的选址原则,并从水量、水质、开采能力3个方面对水源地进行了可行性分析。结合现有城市供水管网及地下水开采井保留情况,分别考虑了人均用水量最低标准20 L/d和一般标准50 L/d两种状态下的应急供水方案。应急供水每人20 L/d状态下,保留井的现有供水能力可以满足应急供水需求,而应急供水每人50 L/d状态下,河洑水源地和芦荻山水源地保留井的现有供水能力不足,建议增加开采井以满足应急供水需求。     

常德市地下水应急水源地应急供水可行性评价及方案研究

寻找地下水应急水源地、建立应急供水机制,是城市发生日常供水障碍时保障居民用水安全、维护社会稳定的重要措施。通过分析常德市规划区水文地质条件,圈定了5个地下水应急水源地,总结了同类型城市地下水应急水源地的选址原则,并从水量、水质、开采能力3个方面对水源地进行了可行性分析。结合现有城市供水管网及地下水开采井保留情况,分别考虑了人均用水量最低标准20 L/d和一般标准50 L/d两种状态下的应急供水方案。应急供水每人20 L/d状态下,保留井的现有供水能力可以满足应急供水需求,而应急供水每人50 L/d状态下,河洑水源地和芦荻山水源地保留井的现有供水能力不足,建议增加开采井以满足应急供水需求。     

Urban development in Germany — perspectives for the future

The essay portrays urban development in Germany at the end of the 20th century in the transition from Industrial Modernity to the New Modernity. The city of the Industrial Modernity is described as a traditionally closed and mixed city. It corresponds to the classical European model of the compact city with a clearly defined centre and a surrounding area which is unambiguously oriented towards this centre. This urban model is disintegrating in Germany. The essay explains this lingering but fundamental process of change. The inner cities are decreasing in importance in favour of the urban fringe, traditional relationships and connections with our cities are lost, new regional activity areas are emerging in the environs of cities. Although the urban impacts of new communication technologies have not been completely clarified, they are changing previous local relationships in the cities. This is not without consequences for urban neighbourhood relationships. The increasing polarisation in German society also affects urban structure. The social mixture in cities disappears on a small scale, public spaces are losing their functions, undesirable population groups are excluded from participation in urban life in new shopping, leisure and transport facilities. The interaction between private and public agents who influence and determine urban development has changed in recent years, and the civic sense of responsibility for the city must be newly defined. Hopes are put into the debates on the Local Agenda and - in spite of its dangers - into a project-oriented planning approach.     

Why data for a political-industrial ecology of cities?

Despite our declared era of ‘Big Data,’ we lack information on the flows of energy, water, and materials that support modern societies. These data are essential to understand how ecologies and the labor of people in far flung places supply urban areas, as well as how these resource flows are used by whom, where, and for what purpose. Like other places, the state of California is struggling with issues of data privacy and access. Water scarcity and the state’s commitments to greenhouse gas emission (GHG) mandates raise the issue of consumption and the unequal burdens that derive from it. These mandates have unveiled the lack of comparable and verifiable data to understand crucial production-consumption dynamics. This paper illustrates how spatially-explicit big data can be harnessed to delineate an urban political-industrial ecology of resource flows. Based on research using address-level energy and water use consumption data for Los Angeles County, the analysis reveals how the region’s wealthy residents use a disproportionate share of the water and energy resources. The paper also identifies structural obstacles to increasing fees and taxes or altering property rights that would reduce this consumption and foster more equitable resource use. This study has implications for theory, method, and policy related to urban sustainability, which is unobtainable without first unraveling the political-industrial ecology of the material basis of urbanization processes.     

Urbanization and the groundwater budget, metropolitan Seoul area, Korea

The city of Seoul is home to more than 10 million people in an area of 605 km². Groundwater is abstracted for public water supply and industrial use, and to drain underground facilities and construction sites. Though most tap water is supplied from the Han River, the quantity and quality of groundwater is of great concern to Seoul's citizens, because the use of groundwater for drinking water is continuously increasing. This study identifies the major factors affecting the urban water budget and quality of groundwater in the Seoul area and estimates the urban water budget. These factors include leakage from the municipal water-supply system and sewer systems, precipitation infiltration, water-level fluctuations of the Han River, the subway pumping system, and domestic pumping. The balance between groundwater recharge and discharge is near equilibrium. However, the quality of groundwater and ability to control contaminant fluxes are impeded by sewage infiltration, abandoned landfills, waste dumps, and abandoned wells. Electronic Publication     

Estimation of environmental impacts on the water quality of the Tahtalıdam watershed in İzmir, Turkey

Water pollution is a widespread problem in different areas of the world. Some of these problems originated from point contamination sources and widespread contaminant outlet sources which are observed in every country. The major elements and chemical loads of surface water have been dominated by constituents derived directly or indirectly from human activities and/or industrial practices that have increased additives in the last several decades. The point sources of contamination may result from the direct wastewater discharges to the dam sites, which are considered to be the most commonly encountered water pollution problems. One of these problems is the eutrophication process which usually occurs in the static water mass of lakes and other surface water reservoirs. This process may be caused by the continuous increase of nitrogen and phosphorus contents and decrease of O₂ level in water causing an anaerobic condition which may stimulate algae-growth flow in these water bodies, consequently reducing the quality of water. Of course, there are many research methods for determining the various kinds of water pollution. In this research, the hydrochemical parameters were evaluated to estimate the types of pollution sources, the level of pollution, and its environmental impacts on the Tahtal dam reservoir.     

A rural “eye” in the Capital: Tuti Island,Khartoum, Sudan

Islands at strategic points have often become the core of a modern city, or have been developed as historic heritage sites. This has been especially true when the settlers have been strangers in the land. This paper examines why such a situation has not occurred with Tuti Island at the confluence of the White and Blue Niles in the centre of Sudan's Three Towns capital, even though the first permanent inhabitants at the confluence were strangers and chose Tuti Island for their first settlement. The paper questions whether Tuti can survive as a green eye in its present form with the increasing pressures from the urban areas surrounding it.     

Trace elements levels in sediments of the Czech part of the Elbe river

Large segments of the world's people have elected to live where water meets land, or very near to those places. Water has a multitude of attractions to people, such as transport, power, recreation, and industrial and domestic supply. Most importantly it is essential to life. Our water supply must be fresh (non-salt), safe (free of contaminants), and be available in an adequate supply. This lesson is based on the scientific article by Philip P. Micklin entitled Man and the Water Cycle: Challenges for the 21st Century in this issue of GeoJournal. These challenges include the provision of a safe and reliable water supply throughout the world. The global issue of safe water, and access to that water is the main focus of this activity.