Hydrochemical characterization of a coal mine plume detected by an airborne geophysical survey

A trial airborne electromagnetic (AEM) geophysical survey was carried out across a 13 × 9 km area of the northern Nottinghamshire (UK) coalfield. One of the objectives was to examine the influence of coal mines (collieries) and associated spoil heaps situated above the Triassic Sherwood Sandstone aquifer. The conductivity models obtained from the AEM survey revealed extensive zones of enhanced subsurface conductivity in the vicinity of all the collieries in the survey area. The present study provides information regarding subsequent investigations (ground geophysics and borehole) to confirm the AEM results and to investigate the geochemical nature of the conductive zone identified in the vicinity of one of the collieries.Following ground geophysical confirmation of the airborne results, three boreholes were drilled into one of the conductive zones to the east of a working colliery. Geophysical logs and analysis of pore fluid geochemistry demonstrate that there is a very strong correlation between the borehole induction logs (formation conductivity), total dissolved solids (TDS) and chloride in the pore waters. The three cored boreholes have confirmed that there is a groundwater plume with high concentrations of TDS, compared with background, moving east from the Thoresby Colliery on a hydraulic gradient of 0.023. Porewater geochemistry obtained from core has been compared with that of local aquifer waters and with samples obtained from the colliery. The results indicate that the plume chemistry could result from the mixing of a typical Sherwood Sandstone composition with colliery spoil leachate. The AEM conductivity models have been successfully correlated with ground geophysical models, borehole induction logs, TDS and chloride in the pore waters. By implication, the geophysical results obtained over a larger area indicate the wider extent of such impacts in relation to both former and current mining activities.     

Main and trace elements in KTB-VB fluid: composition and hints to its origin

The pilot hole (VB) of the German Continental Deep Drilling Program (KTB) was drilled to a depth of 4000 m, where large amounts of free fluids were met. The KTB‐VB 4000 m fluid can be related to either Mesozoic seawater or formation water from Permo‐Carboniferous sedimentary rocks of the Weiden embayment. During the Upper Cretaceous uplift of the Bohemian Massif both fluids could have passed organic‐rich Triassic to Carboniferous formations of the Weiden embayment before invading the uplifted and fractured basement rocks of Devonian amphibolites and metagabbros, where the chemical composition of the fluids was changed by albitization, adularization, and chloritization. Results of chemical mass balances for both sources are presented. In order to concentrate the formation water from the Weiden embayment significant amphibolitization has to be assumed. During a 1‐year pumping test the chemical composition of the 4000 m fluids remained constant. The accuracy of chemical analyses is critically reviewed. An improved preconcentration method of rare earth elements and yttrium in high‐Ca‐bearing saline fluids is described.     

The Role of Surface Water Drainage in Environmental Change: a Case Example of the Upper South East of South Australia; an Historical Review

The role of surface water drainage in environmental change in Australia is rarely appreciated. Drains can modify surface water hydrology, not only altering flow regimes but also rapidly dispersing contaminants and altering the natural hydrological balance of associated flora and fauna. Yet drainage continues to be considered a viable management strategy rather than as a cause of land degradation. The impact of surface water drainage in an inherently saline area of South Australia, the Upper South East, is investigated. Surface water drains were constructed by developers in an attempt to increase the area of land available and viable for agricultural land use. Drainage strategies altered the natural direction, magnitude and frequency of surface water flow. The Upper South East has experienced periods of both increased surface water and flooding, and surface water deficit, in the past one hundred years. The region now receives less surface water than under pre‐European conditions, but local runoff is channelled into and through the wetlands more rapidly than before European settlement. Future management strategies are likely to continue this trend, to the detriment of remnant natural wetlands.     

明初大运河南旺分水枢纽水工技术考

明朝初年,国脉皆仰东南,为解决南方粮财物的北运问题,宋礼和白英受命组织修建了大运河山东段南旺分水枢纽。该枢纽主要包括引汶济运、导泉补源、设立水柜和置闸节流四个组成部分。其中,引汶济运是工程之重点,包括戴村坝、小汶河、南旺分水以及配套工程等四个子系统。这些水利设施组成一个和谐的系统工程,保证了该段运河的水量稳定充足,从而实现了大运河500余年的正常通行。南旺分水枢纽代表了我国古代运河水工的最高科学技术成就,堪称世界水利史上的一大经典范例。     

King Bhumibol: The Symbolic “Father of Water Resources Management” and Hydraulic Development Discourse in Thailand

The present Thai monarch’s reputation in matters hydrological is an integral element of the mythology and symbolism that have characterised his reign. Royalists have carefully constructed the king as a semi-deified “Father of Thai Water Management”, “Royal Rainmaker”, wise inventor of hydraulic technology and planner of “royal initiatives” over a period of six decades. Yet, despite the links that are often drawn between water resources control, spiritual cosmology and political governance surrounding pre-modern Southeast Asian rulers, there has been surprisingly little critical scholarship undertaken on this contemporary aspect of kingship and state-making in Thailand. This paper examines the evolving discourse surrounding the monarchy and hydraulic development as a response to a perceived neglect regarding the central role of water in cementing the king’s power and legitimacy. It argues that King Bhumibol’s apparent hegemony in the national water resources governance paradigm has been an essential element underpinning the longevity and authority of his reign, partly facilitated through the workings of a network of allied strategic interests. Drawing from a range of sources, this paper makes a cautious start in addressing the subject and attempts to open up a space for further critical reflection and discussion regarding the significance of water resources control to Thailand’s royal statecraft.     

Finite element modeling of slug tests in an aquifer with stratigraphical and structural heterogeneities

Slug interference tests using an array of multilevel active and monitoring wells permit enhanced aquifer characterization. Analyses of these field test data rely on numerical inverse models. In order to provide synthetic data sets and to have a better understanding of the flow mechanisms, we used a three-dimensional finite element analysis (FEHM) to explore the effects of idealized, stratigraphical (strata) and structural (faults) heterogeneities with low permeability values on the transient head field that is associated with slug tests in an aquifer. Firstly, we tested our model on homogeneous aquifers and the effectiveness of our modeling strategies have been validated via the excellent agreement of our modeling results with those of the semi-analytical model of Liu & Butler (1995) . In our heterogeneity investigations, we embedded vertical and horizontal zones of lower permeability into a homogenous, isotropic, and confined aquifer to represent low-permeability faults and strata respectively. A slugged interval is located at the center of the aquifer. Effects of strata thickness and permeability contrast as well as other effects associated with the offset of low-permeability strata were explored. In particular, modeling results are represented by contour maps of peak travel time and maximum head perturbation of generated hydraulic pulses. Furthermore, various phenomena, such as real-time matrix diffusion, intermittent matrix–fracture interactions, and faster pulse arrival through a longer flow trajectory, are concretely presented in the snapshots of head perturbations in the aquifer. Our finite element modeling provides useful information for understanding the behaviors of diffusive pressure propagation in an aquifer with stratigraphical and/or structural heterogeneities, and for designing hydraulic tomography to enhance aquifer characterization.     

Heterogeneity effects on possible salinity-driven free convection in low-permeability strata

Although studies of free convection commonly focus on highly permeable strata, but numerical analyses indicate that density-driven free convection may also occur in heterogeneous low-permeability strata. Traditional Rayleigh number criteria are overly conservative in predicting thermohaline convection in these systems; so, numerical models are used to make inferences on the process. Simulations with stochastic realizations of permeability fields show that dense plumes can take preferential pathways to sink through generally low-permeability strata; patch analysis using percolation theory shows that the threshold permeability for the onset of free convection can be as low as 10⁻¹⁶ m² even with a mean permeability of 10⁻¹⁸ m². Threshold permeability for the percolation pathways decreases with increasing concentration gradient, vertical correlation length and the mean and variance of the permeability. The connectedness of relatively high-permeability zones is important in initiating and controlling plume fingers of free convection in both single-layer and sand-shale sequence models. Permeable units above and below are conducive to free convection through intervening low-permeability strata if buoyancy gradients exist. This heterogeneity is on scales that are difficult to sample by drilling and too localized to be simulated in regional models but may be significant in solute transport in these systems.     

Spatial variations in the salinity of pore waters in northern deep water Gulf of Mexico sediments: implications for pathways and mechanisms of solute transport

Spatial variations in the salinity of pore waters in sedimentary basins can provide important insight into basin-scale hydrogeologic processes. Although there have been numerous studies of brine seeps in the deep water Gulf of Mexico, much less is known about porewater salinities in the vast areas between seeps. A study has been made of spatial variation in pore water salinities in sediments in an approximately 500 km by 200 km area of the northern deep water (water depth >500 m) Gulf of Mexico sedimentary basin (GOM) to provide insight into pathways and mechanisms of solute transport in this portion of the basin. A second objective was to document salinities in the upper 500 m of the sedimentary section, the approximate depth to which methane hydrates, a potential future energy resource, may be stable. Elevated salinities would reduce the P – T stability range of hydrates. Salinities were calculated from borehole logs using a dual electrical conductivity model. Even though much of the northern GOM is underlain by allochthonous salt most of the undisturbed shallow sedimentary section has not been permeated by hypersaline waters. These waters are limited to areas near brine seeps. Hypersaline waters having salinities in excess of 100 g l⁻¹ become more common at subseafloor depths of 2 km and greater. A field study at Green Canyon 65 and published numerical simulations of fluid flow above tabular salt bodies suggest that brines produced by salt dissolution migrate laterally and pond above salt and/or within minibasins and that the dominant mechanism of vertical solute transport is a combination of compaction-driven advection and diffusion, not large-scale thermohaline overturn. Superimposed on this diffuse upward flux of dissolved salt is the more focused and localized expulsion of saline fluids up faults.     

“大跃进”期间的深耕土地运动

1957～1958年,毛泽东对山东省厉家寨村和河南省长葛县深翻土地增产经验的总结报告充分肯定,号召全国学习,通过深翻土地达到增产目的。1958年8月,中共中央发出指示,要求全国在两三年内,将一切可能深耕的土地全部深耕一尺以上。全国掀起了轰轰烈烈的深耕土地热潮。在运动中,各地积极组织学习长葛县的深翻土地方法和经验,开展群众性深翻土地大会战。科研人员也积极研制和改造深翻农机具,总结和论证深翻措施及效果,开展深翻土地创高产试验。尽管通过深耕土地达到增产在一定的科学范围内是可行的,但1958年全国性的深耕土地运动,在翻土深度、进度和数量上层层加码,出现了许多盲目蛮干的事例,未能取得预期的增产效果。