Groundwater Renewal in the Middle Odra River Catchment Based on Flow Model and Isotopic Data – the Lubin Głogów Copper Region,Poland

In the area of intense mining within the Lubin Głogów Copper Region the investigation of groundwater renewal was made according to two methods: a numerical flow model and isotopic analysis. The results of model simulations show that within the shallow aquifer the groundwater renewal is quick and mostly depends on infiltration within the recharge zones. An average time of groundwater flow between recharge and discharge areas in the representative part of the entire system has been obtained as 130 years. The content of isotopes was determined in samples collected as well from the mine excavations as from water intakes. The measurements were done on 17 samples. Results of isotopic studies indicate that the relationship of δD – δ18O in groundwater gathers along the established local meteoric water line (MWL) δD = 7.58 δ18O + 4.45. Deep groundwaters that create an inflow to the mines were formed by infiltration in Holocene with reference to two of total four mines and probably in Eopleistocene in another two.     

即墨市宝龙泉水文地质条件调查与分析

通过资料收集、专项地质测量、水文地质调查与测绘、水文地质物探、水文地质钻探、钻孔抽水试验、水质分析试验和综合研究等技术方法对宝龙泉区域水文地质条件进行了勘查,对泉的成因、汇水面积、补给量和流量进行了初步的分析和探索,结果显示:泉区内发育的7条近南北和近东西向的断裂异常构成了宝龙泉泉脉的构造格局,经钻探验证,3条断裂透水性好,含水丰富,其中DF1-3和DF3-4断裂为宝龙泉的主要泉脉通道;在水位标高53. 07 m时,泉水自流的流量为296. 76 m^3/d;泉水的矿化度为0. 582 g/L,水化学类型HCO3·SO4-Ca型。地下水水质主要类型分类为Ⅱ~Ⅲ类,均受不同程度的污染,主要适用于集中式生活饮用水水源及工、农业用水。按地表汇水面积和断裂形成的区域面积分别计算,可估算出宝龙泉流量平均为303. 78 m^3/d和337. 14 m^3/d。研究结果可为宝龙泉区域泉水的保护和开发利用提供依据。     

A two-phase numerical model for sediment transport prediction under oscillatory sheet flows

To predict sediment transport under oscillatory sheet flow condition, especially for fine sand, is still a challenging research subject in coastal engineering. This paper describes a newly-developed numerical model based on two-phase theory with the use of a one-equation turbulence closure, and its applications in predicting fine sediment suspension in near-prototype oscillatory sheet flow conditions. Model results were compared with comprehensive laboratory measurements of flow velocity and sediment concentration under both symmetrical and asymmetrical oscillatory sheet flows from a large-scale water tunnel. Good agreements between the model results and measurements were achieved and the results demonstrated that the model is capable of reproducing detailed characteristics of sediment entrainment process in the sheet flow regime. The comparisons also revealed the fact that the concentration peaks at flow reversal is associated with the strong vertical sediment transport flux in the pickup layer, which has been widely observed in many laboratory experiments. The effects of flow reversal events on total sediment transport were also discussed.     

Impedance analysis of hydrodynamic behaviors for a perforated-wall caisson breakwater under regular wave orthogonal attack

An impedance analytical method (IAM) is developed to study the interaction between regular waves and a perforated-wall caisson breakwater that consists of a front perforated-wall and a chamber with a rigid impermeable back wall. The boundary conditions at the perforated-wall are established in terms of the flow resistances of the fluid passing through the holes. As a result, explicit algebraic expressions are obtained for reflection coefficients and wave loads. In the formulae, all of the parameters are known a priori. The predicted reflection coefficients and the wave forces are compared with the experimental data of other authors.     

Seasonal and depth-related dynamics of prokaryotes and viruses in surface and deep waters of the northwestern Mediterranean Sea

The study site located in the northwestern Mediterranean Sea was visited nine times in 2005–2006 to collect water samples from the epi- (5 m), meso- (200, 600 m), and bathypelagic (1000, 2000 m) zone. Total abundance of prokaryotes and viruses was determined by flow cytometry (FCM). Prokaryotic abundance in the epi-, meso-, and bathypelagic varied between 0.9 and 15.9×10⁵, 0.6 and 2.1×10⁵, and 0.3 and 1.3×10⁵ ml⁻¹, respectively. Variation of viral abundance in the epi-, meso-, and bathypelagic was between 1.2 and 57.5×10⁶, 0.5 and 3.5×10⁶, and 0.4 and 1.3×10⁶ ml⁻¹, respectively. The fraction of low (LNA) and high (HNA) nucleic acid prokaryotes averaged 42.9% and 57.1% throughout the water column and did not differ between depth layers. Throughout the water column the fraction of low, medium, and high fluorescent viruses (Vir-LF, Vir-MF, Vir-HF) averaged 66.3%, 30.2%, and 3.5%. Vir-LF and Vir-MF did not differ between depth layers; however, Vir-HF showed a preference for surface waters. The fraction of LNA cells decreased in the epi- and increased in the bathypelagic with decreasing stratification. The fraction of Vir-LF viruses increased in the epipelagic and decreased in the bathypelagic with increasing prokaryotic abundance. Also, the relationship between viral abundance and the bacterial community was different in surface and deep waters. The data suggest that different mechanisms of interaction between viruses and their prokaryotic hosts prevail at the surface and in deep waters.     

Multi-hazard susceptibility mapping based on Convolutional Neural Networks

Multi-hazard susceptibility prediction is an important component of disasters risk management plan. An effective multi-hazard risk mitigation strategy includes assessing individual hazards as well as their interactions. However, with the rapid development of artificial intelligence technology, multi-hazard susceptibility prediction techniques based on machine learning has encountered a huge bottleneck. In order to effectively solve this problem, this study proposes a multi-hazard susceptibility mapping framework using the classical deep learning algorithm of Convolutional Neural Networks (CNN). First, we use historical flash flood, debris flow and landslide locations based on Google Earth images, extensive field surveys, topography, hydrology, and environmental data sets to train and validate the proposed CNN method. Next, the proposed CNN method is assessed in comparison to conventional logistic regression and k-nearest neighbor methods using several objective criteria, i.e., coefficient of determination, overall accuracy, mean absolute error and the root mean square error. Experimental results show that the CNN method outperforms the conventional machine learning algorithms in predicting probability of flash floods, debris flows and landslides. Finally, the susceptibility maps of the three hazards based on CNN are combined to create a multi-hazard susceptibility map. It can be observed from the map that 62.43% of the study area are prone to hazards, while 37.57% of the study area are harmless. In hazard-prone areas, 16.14%, 4.94% and 30.66% of the study area are susceptible to flash floods, debris flows and landslides, respectively. In terms of concurrent hazards, 0.28%, 7.11% and 3.13% of the study area are susceptible to the joint occurrence of flash floods and debris flow, debris flow and landslides, and flash floods and landslides, respectively, whereas, 0.18% of the study area is subject to all the three hazards. The results of this study can benefit engineers, disaster managers and local government officials involved in sustainable land management and disaster risk mitigation.     

Contrasting sediment gravity flow processes in the late Llandovery,Rhuddnant Grits turbidite system,Welsh Basin

The Rhuddnant Grits turbidite system was deposited within an elongate, fault-bounded trough in the late Llandovery (Telychian) Welsh Basin. Two groups of sandstones are identified within the system: high-matrix sandstones and laminated sandstones. The high-matrix sandstones are medium to very thick bedded, fine to very coarse-grained muddy sandstones. The high-matrix sandstone beds are almost entirely structureless and have several features indicative of deposition from high density turbidity currents, probably undergoing late stage debris flow behaviour (e.g. grain size discontinuities, inverse grading, floating clasts). The laminated sandstones are thin to very thin bedded, fine-grained and have a distinctive mud/silt lamination. Tractional structures and convolution are common in these beds. They were probably deposited by slow moving, dilute turbidity currents. Dissimilar palaeocurrent vectors and estimates of flow properties from the two types of sandstone support the contrasting nature of the depositing flows. A coarsening and thickening upwards trend is identified in the laminated sandstones of the Rhuddnant Grits Formation. This trend is not reflected in the high-matrix sandstone beds. Although the high-matrix sandstones appear in packets or groups within the laminated sandstone background, they were otherwise deposited in an entirely random manner throughout the exposed system. This may suggest that the two types of sandstone are the result of different triggering mechanisms at source, or of contrasting flow properties developed early in the flow histories.