ALBERT

Description: The present work investigates pollutant removal and the transformation of nitrogen from sewage wastewater using a pilot-scale multi-stage bio-vermifilter system. Over a study period of 48 weeks, the pollutant removal performance of the system was measured and the effects of hydraulic loading rate (HLR) and dry–wet ratio (D/W) were estimated. The relationship between oxygen transfer rate and load of oxygen necessity was calculated and analysed for system optimisation. The method for diluting the isotope δ 15 N-NO 3 − was applied to study nitrogen transfer. Moreover, statistical correlations were analysed to determine the crucial factors which influence nitrogen transfer efficiency. The system removes pollutants efficiently; specifically, the average removal efficiencies are 94.2 % for chemical oxygen demand (COD), 93.3 % for NH 4 + -N, and 58.2 % for total nitrogen (T-N). Lowering HLR and D/W can enhance nitrogen removal. Nitrogen speciation and transformation were examined under an optimised condition with an HLR of 0.36 m day −1 and a D/W of 3. The results of isotope δ 15 N-NO 3 − dilution showed that NO 3 − -N was mainly produced in trickling bio-filter and vermibio-filter (VBF) I. By contrast, NO 3 − -N was mainly reduced in VBF II. Under stable operating conditions and environmental factors, COD/T-N was verified as the crucial factor in nitrogen removal.

Description: This study presents a novel roughness formulation to conceptually account for microtopography and compares it to four existing roughness models from literature. The aim is to increase the grid size for computational efficiency, while capturing subgrid scale effects with the roughness formulation to prevent the loss in accuracy associated with coarse grids. All roughness approaches are implemented in the Hydroinformatics Modeling System and compared with results of a high resolution shallow water model in three test cases: rainfall-runoff on an inclined plane with sine-wave shaped microtopography, flow over an inclined plane with random microtopography and rainfall-runoff in a small natural catchment. Although the high resolution results can not be reproduced exactly by the coarse grid model, e.g. local details of flow processes can not be resolved, overall good agreement between the upscaled models and the high resolution model has been achieved. It is concluded that the accuracy increases with the number of calibration parameters available, however the calibration process becomes more difficult. Using coarser grids results in significant speedup in comparison with the high resolution simulation. In the presented test cases the speedup varies from 20 up to 2520, depending on the size and complexity of the test case and the difference in cell sizes. The proposed roughness formulation generally shows the best agreement with the reference solution, compared to the other models investigated in this study.

Description: To determine the ammonia nitrogen adsorption and release characteristics of surface sediments in Dianchi Lake, 36 surface sediment (0–10 cm) samples were collected in 2013. Results showed that compared with other lakes in China (e.g. Erhai Lake and Taihu Lake), Dianchi Lake had high levels of ammonia nitrogen (NH 4 + –N) adsorption capacity, release rate and release capacity. The ammonia nitrogen release risk of Dianchi sediments was relatively high. Comparison of the equilibrium ammonium concentration ( ENC 0 ) in surface sediments and the ammonium contents in the overlying water of Dianchi Lake indicated that ENC 0 was high for most lake sections. Therefore, the sediments of Dianchi Lake would be a pollution source, and ammonia nitrogen release risk was high because the surface sediments of Dianchi Lake were heavily contaminated with nitrogen. The total nitrogen (TN) and NH 4 + –N contents of the sediments of Dianchi Lake greatly influenced the ammonia nitrogen adsorption–release process. Aside from TN, nitrogen fractions should also be studied when assessing pollutant release risk from lake sediments. NH 4 + –N was the main fraction of nitrogen released from sediments, which was highly significant when evaluating sedimentary release capacity. The sedimentary release capacity and release potential of nitrogen provided important information to assess release risks.

Description: The variability and sensitivity of crop evapotranspiration (ET) measurements at field scale are still poorly understood in the irrigated farmland of arid region in Northwest China. The spatial and temporal dynamics and sensitivity of field ET are fundamental for the scaling up and validation of ET estimates from remote sensing data. In the study, we analysed the dynamics, impact factors and sensitivity of spring wheat ET during the growing season in Northwest China. Results indicated that there was a significant effect of first irrigation event on the spatial and temporary variability of ET. At the tillering-shooting stage (before the first irrigation event), spatial variability of ET was the lowest and gradually increased with crop growth. In some experimental plots, spring wheat ET had a significantly higher temporal stability than other plots except for the tillering-shooting stage. The sample sites with higher temporal stability could be used for long-term monitoring samples and for up scaling of ET measurements. In comparison with LAI and ET 0 , surface soil moisture change ∆ θ 0–20 cm was the most sensitive variable of ET measurements, which could be used as the auxiliary variable to improve the ET accuracy. With the soil moisture measurements, the relative error of ET was 9.4 % with only half the number of ET sampling data.

Description: Sediment contamination by heavy metals can result in significant damage to the ecological water environment. Sediment dredging is a useful way to reduce the adverse effects of heavy metal pollution in freshwater. The dredging depth is a key parameter in environmental dredging engineering. In this paper, we propose an innovative method called the critical-risk-depth method for calculating the environmental dredging depth that has been specifically designed for removal of river sediments contaminated by heavy metals. To determine the critical risk depth for dredging, the heavy metal concentrations at different sediment depths and their potential ecological risks must be tested and evaluated. The first step of the method involves analyzing sediments to determine the lateral and vertical distribution of heavy metals. In the next step, Hakanson’s potential ecological risk index is used to assess the ecological risk of heavy metals at different sediment depths. Finally, the recommended environmental dredging depths are calculated based on the potential risk for change in the vertical distribution and the given threshold level for the potential critical risk from heavy metals. We carried out a case study to determine the dredging depth for river sediment in Pinghu. The sediment analysis results show that the contents of Cd, Zn, and Pb are excessive when compared with the local soil background levels. Because of the accumulation effect of heavy metals in sediments, the heavy metal contents tend to decrease with sediment depth, but this trend may change as a result of human activities and other river dredging events. There is a high potential ecological risk level from heavy metal pollution in sediments in the study area, and the recommended environmental dredging depths of the ten rivers range from 35 to 100 cm.

Description: A multi-element geochemical soil survey was performed to assess the geochemical baseline and the environmental impacts of some potentially harmful elements in soils of the Kerman city. In doing so, a total of 175 samples, including residual (5), evaporate (6), silty–clay plain (42), urban (15), archaeological (3), road side (12), runway side (3), rail road side (7), agricultural (34), machinery battery manufacturing station (10), gasoline station (17), machinery paint working station (17) and cemetery (4) soil samples were collected on the 1:50,000 scale map of the Kerman city. The soil samples were analysed by ICP-OES for Ag, As, Bi, Cd, Co, Cr, Cu, Hg, Li, Mo, Ni, Pb, Se, Sn, V, W and Zn. The resulting elemental values in non-contaminated residual soils are similar to that of global background soil level (Salimen et al. Geochemical atlas of Europe. Part 1, Background information, methodology and maps. Finland Geological Survey, p 526, 2006 ; Lindsay Chemical equilibria in soils. Wiley, p 449, 1979 ). However, the soils close to the gasoline stations are enriched in Pb with variations up to 202 mg/kg. Soils developed around the machinery battery manufacturing stations also give a very high concentration of Pb as high as 60,445 mg/kg. The anomalous contents of Pb in soil samples close to the machinery paint working places range from 0.27 to 692 mg/kg. Some high values of Zn up to 1655 mg/kg are related to the agricultural soils in Pistachio gardens. The results highlight that the most anomalous harmful elements include Pb, Sn, Cd, Cu, Zn, Sb, As and Mo, which is supported by their high enrichment factors.

Description: Groundwater resources of karst aquifers within Circum-Mediterranean are a vital natural resource, which have been exploited since the dawn of the Mediterranean civilization. In Greece, carbonate formations are thought to be one of the most important sources for various water uses, that are vital for the country’s economy and development, that is agriculture and water supply. In most cases, they are considered as integral parts of some of the most strategic hydrosystems in Greece, containing surface water and groundwater resources that secure water supply for several anthropogenic activities. This paper provides a review of different aquifer types in Greece (granular and karstic), focusing on karst hydrosystems. It presents their spatial distribution throughout the entire Greek territory, and describes the most important environmental stresses upon them, while it analyzes their importance and role to the country’s water supply. Finally, this study analyzes the river basin of (Central Greece), used as a reference hydrosystem, to prove the ample importance of karst reservoirs in Greece.

Description: Capillary barrier cover systems (CBCSs) are useful and low-cost earthen cover systems for preventing water infiltration and controlling seepage at solid waste landfills. A possible technique to enhance the impermeable properties of CBCSs is to make water repellent grains by mixing the earthen cover material with a hydrophobic agent (HA). In this study, six different grains with different geometries and sizes were used to prepare dry hydrophobized grains by mixing with different contents of oleic acid as a HA. Wet hydrophobized grains were prepared by adjusting the water content ( θ g ; kg kg −1 ) of dry hydrophobized grains. To characterize the water repellency (WR) of dry and wet hydrophobized grains, initial solid-water contact angles ( α i ) were measured using the sessile drop method (SDM). Based on SDM results from the α i –HA content and α i – θ g curves, useful WR indices were introduced as “Area_ dry ” and “Area_ wet ” (areas under the α i –HA content and α i – θ g curves, respectively), “HA_ zica ” and “θ g_zica ” (maximum HA content and θ g at which WR disappears, respectively), and “α i,peak ” and “HA_ αi,peak ” (peak α i in the α i –HA content curve and corresponding HA content to α i,peak , respectively). Pearson correlation analysis was performed to identify correlations between proposed WR indices and basic grain properties. Results showed that WR indices correlated well to d 50 and coefficient of uniformity ( C u ) and regression equations for WR indices were obtained as functions of d 50 and C u ( r 2  〉 0.7).

Description: In the present study, minimax probability machine regression (MPMR) and extreme learning machine (ELM) have been adopted for prediction of seismic liquefaction of soil based on strain energy. Initial effective mean confining pressure ( \( \sigma_{\text{mean}}^{\prime} \) ), initial relative density after consolidation ( D r ), percentage of fines content (FC), coefficient of uniformity ( C u ), and mean grain size ( D 50 ) have been taken as inputs of MPMR and ELM models. MPMR and ELM have been used as regression techniques. The performances of MPMR and ELM have been compared with the artificial neural network. A sensitivity analysis has been carried out to determine the effect of each input. The experimental results demonstrate that proposed methods are robust models for determination seismic liquefaction potential of soil based on strain energy.

Description: Experiments were conducted to investigate the relationship between the ultrasonic pulse velocity (UPV), transmission ratio (TR), attenuation coefficient (AC) and mechanical properties of soil and rock mixture (SRM) with different rock percentage, under uniaxial compression. Cylindrical SRM specimens (50 mm diameter and 100 mm height) with rock block percentage of 20, 30, 40, and 50 % were produced to perform a series of Uniaxial Compressive Strength (UCS) test. The ultrasonic wave was transmitted and received by a P-wave piezoelectric transducer (130 kHz) and the ultrasonic travel time and amplitude were recorded by an ultrasonic detector during the whole deformation process of specimens. From the test results, the UPV decreased and AC increased with the increasing rock percentage for all specimens by ultrasonic inspection before UCS test. The failure mechanism of all specimens showed splitting-sliding mixed pattern, macro-cracks have a direction of 0–10° parallel or sub-parallel to normal stress, and UCS decreased with increasing of rock percentage. In addition, the UPV and TR have fluctuation growth trend with increasing of axial stress while the increment rate decreased gradually. The statistical correlations between UPV and TR and axial stress are presented and discussed. Moreover, the relationship between ultrasonic parameters and axial stress for soil and rock specimens were also discussed. These results confirm that the ultrasonic and mechanical properties of SRM are closely related to rock percentage. As a special geomaterial, the mechanical properties of SRM are different from rock and soil; this can be further confirmed by ultrasonic tests.

Description: Representative agricultural soil samples from Tianjin, the third biggest city in China, were investigated for 16 PAHs in 2008 ( n  = 87) and 2012 ( n  = 60). Surface soil samples were air-dried and sieved. The total PAH (T-PAH) concentrations ranged from 29.7 to 4502.5 ng/g (mean value 619.9 ng/g) in 2008; and from 228.6 to 14,722.1 ng/g (mean value 1295.8 ng/g) in 2012. Bap concentrations exceeded the suggested standards at many sites. Bap and T-PAH spatial variations were represented with maps. The pollution status was also compared to many other cities. PAH soil pollution near the urban areas was found to be serious in both 2008 and 2012. Pollution at some sites became severer in 2012 comparing to that in 2008. Principal component analysis and two indicative ratios were employed to find the potential sources. The results in the 2 years both revealed that the major source of soil PAHs was coal combustion, which coincided well with the previous studies. The study added to the basic data of local PAH distribution, and pointed out a proper way for the government to reduce the pollution.

Description: It is presented the results of studying of small glaciers located in the Eastern Siberia along transect the Kodar mountains – Baikalskiy and Barguzinskiy ridges – the Eastern Sayan mountains. Some glaciers from this transect have not been described before. The inventorying of these glaciers is based on high-resolution satellite images and fieldworks. The most numbers of glaciers are located in the Kodar mountains and few are in the Baikalskiy and the Barguzinskiy ridges. Most likely, these glaciers remained mainly due to coldest winters and geomorphologic features. The main parameters of a glacier’s data (the dynamics, the current state, cartographic representation, remote sensing data and others) are selected by analogy of the international glaciological database.

Description: To evolve a proper management scenario for groundwater utilization, identification of groundwater potential zones is an important step. In the present study, an attempt has been made to identify possible groundwater potential zones both in terms of quantity and quality. A methodology is proposed for identification of groundwater potential index (GWPI) and a new water quality index (WQI) based on analytic hierarchy process. The proposed methodology has been applied to the shallow alluvial aquifer of central Ganga basin, Kanpur (India). Land use/land cover, soil, geology, recharge rate, drainage density, rainfall, slope, elevation, normalized difference vegetation index, groundwater depth or depth to groundwater table are used for GWPI calculation. Moreover, WQI considers alkalinity (as CaCO 3 ), magnesium (Mg 2+ ), total dissolved solids and fluoride (F − ) as influencing attributes. Final integration of attributes yield GWPI and WQI map. The resulting GWPI map has been classified into three groundwater potential zones namely: good, moderate and poor covering 26.94, 43.76, and 29.30 %, area, respectively. The WQI map has been classified into five quality zones namely: above permissible limit, poor, moderate, good, very good covering 12.39, 7.63, 15.17, 38.18, and 26.64 % area, respectively. Monitoring data from well locations along with GWPI and WQI map reveals the proper potential zones. This analysis demonstrates the potential applicability of the methodology for a general aquifer system.

Description: PM 10 samples were collected on haze days (visibility 〈10 km) within Zhengzhou City, North China. Mineralogical and chemical compositions of these PM 10 samples were determined by X-ray diffraction and X-ray fluorescence analysis, respectively. Results indicated that the crystalline phase in PM 10 was composed of crustal minerals, sulfate, and chloride. The sulfate mainly included koktaite, gypsum, anhydrite, and boussingaultite, as well as trace amounts of mascagnite. Multiple linear regression of koktaite/(gypsum + anhydrite) (K/G) and gypsum/anhydrite (G/A) with temperature ( T ) and relative humidity (RH) indicated that koktaite–gypsum–anhydrite transformation was significantly influenced by temperature and relative humidity ( P  〈 0.05). The negative and positive regression coefficients of T (RC K/G  = −0.711, RC G/A  = −0.433) and RH (RC K/G  = 0.469, RC G/A  = 0.572) indicated that temperature and humidity had positive and negative effects on the koktaite–gypsum–anhydrite transformation, respectively. The enrichment of koktaite, gypsum, and boussingaultite had a negative effect on visibility, and in the process of the koktaite–gypsum–anhydrite transformation, the effect of these sulfates on visibility was weakened. Sulfur within PM 10 mostly occurred as anions in sulfate. It was found to mainly originate from coal combustion, and enrichment was far greater in winter than during the other three seasons. Chlorine was mainly associated with coal combustion, as well as straw burning to some extent. It mainly occurred as anions in koktaite as well as chloride, and there was a far greater enrichment of chlorine during winter. Arsenic occurred mainly as anions in anhydrite, and was more enriched during summer. It had origins in both coal combustion and agricultural activities. Furthermore, it is considered possible that fluorine occurred as noncrystalline organic matter.

Description: Construction of bulkheads is a common response to erosion of estuarine shorelines. Bulkheads are usually built incrementally, resulting in wider sandy beaches remaining as enclaves between bulkhead segments. This paper measures the characteristics of bulkheads and enclaves and evaluates (1) whether horseshoe crabs ( Limulus polyphemus ) utilize enclaves for spawning when they provide partial sheltering during periods of high wave energies; and (2) whether eggs become trapped in the enclaves and are available to shorebirds when the beaches in front of bulkheads are inundated. The characteristics of bulkheads and beach enclaves were identified in five developed reaches in Delaware Bay, USA. Counts of horseshoe crabs were made in enclaves in two of these reaches during times of high wave energies and compared to counts in nearby unarmored segments. Egg tracer and trapping experiments were conducted at one of the enclaves to assess egg movement. Results indicate that the percent of bulkheads intersecting the beach below mid-foreshore varies from 10 to 50 %. Spawning densities were greater in enclaves than on longer unarmored segments on some days. Enclaves serve as a sink for eggs moving along the base of the bulkheads. Most birds feeding on horseshoe crab eggs preferred sites outside the enclaves and bulkhead segments. Any advantage of bulkheads creating enclaves and sinks for eggs moving alongshore is likely overridden by their disruption to natural process and habitats, but having unarmored enclaves between bulkhead segments may be preferable to one continuous bulkhead, based on environmental benefits.

Description: Phosphorus adsorption and release characteristics of surface sediments from Dianchi Lake were investigated through indoor simulation experiments. Kinetics and thermodynamics of adsorption and release of phosphorus in sediments were studied, and the influence of different phosphorus fractions on adsorption and release was analysed. Results show that the total phosphorus content in the sediments ranged from 843.96 to 8144.44 mg kg −1 , which was 2–8 times as much as those in other lakes in China (e.g. Erhai Lake and Taihu Lake). The average values of different phosphorus forms in the sediment samples were ranked in the order of organic P (OP), calcium-bound P (Ca-P), metal oxide-bound P (Al-P), residual P (Res-P), Fe-bound P (Fe-P) and weakly absorbed P(NH 4 Cl-P). Compared with the case of other lakes in China, the sedimentary phosphorus adsorption capacity of Dianchi Lake was at a higher level, but its maximal release rate and release capacity were low, indicating a relatively low release risk. By comparing the equilibrium phosphate concentration in the sediments and the soluble reactive phosphorus in the overlying water, the risks of phosphorus release from sediments in Caohai, Lake Central and Southern Waihai were found to be relatively low in the short term, but were high in Northern Waihai. The release behaviour of sedimentary phosphorus in Dianchi Lake was mainly determined by NH 4 Cl-P, Fe-P and Al-P, among which NH 4 Cl-P and Fe-P served a greater function. Therefore, the contents of different fractions of phosphorus and their distribution characterization should be considered when characterizing the adsorption and release status of lake sedimentary phosphorus.

Description: This paper intends to investigate the anti-seepage characteristics of Xiashu loess used as landfill cover under wetting–drying cycles. A series of tests were performed to systematically evaluate the surface cracks, pores, the hydraulic conductivity and water seepage of the soil under wetting–drying cycles. The cracking tests indicated that the cracking intensity factor (CIF) increased with the number of wetting–drying cycles. After three wetting–drying cycles, the CIF gradually reached a stable value. The influence of the compactness of the compacted clay was significant to cracking. After four drying–wetting cycles, the CIF of compacted clay with relatively low compactness ( ρ  = 1.65 g/cm 3 , W 5  = 25 %) was 0.15, and the CIF of compacted clay with higher compactness ( ρ  = 1.65 g/cm 3 , W 3  = 21 %) was only 0.06. With the increase in the number of wetting–drying cycles, the accumulated pore volume of the soil particles increased and the maximum pore size was nearly unchanged. After four drying–wetting cycles, the proportion and average diameter of macro-pore in the soil particles were both increased. However, the proportion and average diameter of the meso-pore slightly decreased. Furthermore, the proportion and average diameter of the micro-pores were unchanged. After four wetting–drying cycles, the hydraulic conductivity of the compacted soil was at 8.3 × 10 −7 –1.5 × 10 −5 cm/s, which was increased about three orders of magnitude compared with the compacted soil without cracks. The hydraulic conductivity of compacted soil increased linearly as cracks increased. The hydraulic conductivity of compacted soil also gradually increased to a stable value as the pore volume increased. After 1 month of wetting–drying cycles, the cracks of soil with low compactness had extended to a depth of 15 cm below the soil surface while the cracks of soil with higher compactness only reached a depth of 5 cm.

Description: This paper presents the imaging of contaminant plumes in Qinhuai River and its bed for the remediation strategies of the river. Qinhuai meets with Yangtze River at Nanjing area via inner and outer channels, coursing through urban districts of the city. The discharge of urban effluents has badly affected the water quality of the river. Generally, contamination assessment is carried out through traditional point-based sampling methods. However, these methods are often inadequate to estimate accurately the spatial distribution of contaminants and their extension. Therefore, electrical resistivity tomography (ERT) is applied because of its high quality imaging to investigate contamination and its extension in Qinhuai River and its bed. Eight sites were selected at outer and inner channels of the river. A 2-D inversion of the perceived data was carried out and the obtained resistivity values were converted into salinity after temperature correction. The acquired images of resistivity and salinity show that in low streaming conditions the river has large zones of low resistivity in the water body, which are extending toward underlying bed corresponding to high contamination. Conversely, in high streaming conditions, the low resistivity zone shrinks significantly at almost all the studied sites except Xishan Bridge (site E), which still showed high plume of contamination. This phenomenon reveals that in low streaming conditions the contamination level is high while in high streaming conditions salts are flushed out from the river. This study further demonstrates that ERT method can be a useful technique for the environmental studies of rivers, canals and surface water environments.

Description: Land degradation dynamic assessment is very important to understand the effectiveness of ecological engineering and provide decision support for future restorations. Taking the Beijing–Tianjin dust and sandstorm source region (BTSSR) as the study area, the land degradation dynamic in the first decade of twenty-first century is assessed by utilizing the time series trends of net primary production (NPP) and modified rain use efficiency (RUE), respectively, and their sensitivities and performances are evaluated through the validation. The results shows that (1) a widespread degradation in the BTSSR is identified from 2000 to 2010, with a proportion of 52.7 % by using NPP, and 65.2 % when using RUE; (2) the proposed RUE is effective in eliminating high correlations between NPP and precipitation, and overcame the problem that the RUE assumption often breaks down at the pixel scale, through incorporating the land degradation assessment division; and (3) the RUE is preferred for land degradation assessment with a higher accuracy (93.5 %), compared with NPP (81 %), which can provide valuable insights into the land degradation assessment in the arid and semi-arid regions.

Description: Submerged macrophytes mainly distribute in the wind-protected littoral zones, rather than continuously distribute around the lake due to mechanical damage by strong wave. However, it is unknown how the biomechanical properties, the key targets against mechanical stress, contribute to its survival and distribution in natural aquatic ecosystem. In this study, the distribution, plant growth, and leaf biomechanical and morphological traits of different segments of Vallisneria natans were examined at 25 sites with three wind strength [sites exposed to strong ES wind (HW), sites exposed to moderate ES wind (MW) and sites sheltered by lakeshore with weak wind disturbance], in Lake Erhai, of Yunnan Province, China. Results showed that V. natans mainly distributed in the wind-protected eastern and northern littoral zones within 5 m water depth. The smallest plant growth, strongest and least flexible leaves were at MW, indicating that V. natans is prone to dominate the littoral zones exposed to strong but short wave. Additionally, the high plant growth and relatively stronger and less flexible leaves at HW suggested that the maximization of photosynthesis was at the cost of reduced biomechanical properties and increased drag forces from similar waves, which were unfavourable to complete their life cycles and ultimately reduce the survival and distribution of V. natans under strong wave disturbance. The significant associations between the biomechanical and morphological traits may trigger trade-offs between the mechanical resistance and other plant functions, such as photosynthesis, ultimately determining survival and distribution of submerged macrophytes in natural aquatic ecosystems.

Description: The spatial and temporal distributions of sediment microorganism populations as well as their role in the evolution of Erhai Lake eutrophication were addressed in this study. Our results show that the microorganisms’ distribution is linked to many factors (e.g., temperature, substrate content, depth, aquatic macrophytes, etc.). In addition, it is likely that sediment fungi numbers indicate the degree of area source pollution to a certain extent. A high proportion of sediment actinomycetes (25.1–67.0 %) may inhibit nutrient release from the sediment, leading to a high nutrient level in sediment but relatively good water quality in the lake. Furthermore, an analysis of the depth profiles of microorganisms elucidates the development of Erhai Lake eutrophication. This study is the first to link the sediment microorganism population with the evolution of Erhai Lake eutrophication and may also provide useful information for managing lake eutrophication in the near future.

Description: In Korea, few investigations from the waste incineration were conducted on greenhouse gas emitted. This research calculates and compares non-CO 2 concentrations and emission factors for the facilities of an incinerator comprising a pyrolysis melting incineration type (incinerator A) and a stoker incineration type (incinerator B). An analysis was made of daily average concentrations of the samples collected over a 24-h period, and the results show that incinerator A had a CH 4 concentration of about 1.9 ppm and a N 2 O concentration of about 1.2 ppm; incinerator B had a CH 4 concentration of about 2.1 ppm and a N 2 O concentration of about 4.5 ppm. A pyrolysis melting incineration type showed a similar value to the emission factor derived from a gasification melting furnace suggested by NIR in Japan, and there is about a 5.1 times difference between the pyrolysis melting incineration type and the stoker incineration type used in this study. This implies that, when the same default emission factor is applied without giving consideration to the characteristics of each incinerator, greenhouse gas emissions may be excessively calculated.

Description: Leaf nitrogen (N) and phosphorus (P) stoichiometry might reflect the biogeochemical features of ecosystems, yet the potential range of stoichiometric flexibility under geochemically P-enriched soils (GPES) is still unclear. Leaf N and P of 126 plant species in 70 vegetation plots in GPES were investigated in central Yunnan, southwestern China, and leaf P fractions (i.e., inorganic vs. organic P) of the dominant species were examined. Our objectives were to improve the understanding of the role of soil N and P variability in controlling leaf N and P stoichiometry of plant communities in GPES. We found that plants in GPES had higher mean leaf P (4.07 mg/g) and lower N:P ratios (4.94) than average plant values that have been recorded in other parts of the world so far. Some fast-growing plants had extremely high leaf P (〉10 mg/g). Community leaf N and P contents increased as soil N availability increased, but soil N variability was unrelated to community leaf N:P. Instead, community leaf P and N:P ratios were primarily determined by soil P; as soil P availability increased, leaf P increased and leaf N:P significantly decreased. Greater accumulation of inorganic P relative to organic P in leaf was the direct driving factor for community leaf P and N:P ratio patterns in GPES. Although soil P availability was the main controlling factor of leaf N:P patterns, community composition could be manipulated to restore the balance of N and P stoichiometry based on the different responses across species and plant types.

Description: As external nutrients inputs above a critical level may drive shallow lakes to shift from clear water to a turbid state, it is important to detect ecological changes of the lake at an early stage of the eutrophication process. In this way, it is possible to assess the stress tolerance of the system and thereby improve the possibilities for proper management. In this study, water quality parameters and the biomass of submerged macrophytes were examined monthly in two bays receiving contrast amounts of nutrient input of a large mesotrophic lake from August, 2011 to July, 2012. We found that effects of external nutrient input could not be explained by differences between the two bays in water quality parameters, such as total nitrogen, total phosphorus, chlorophyll a, light attenuation coefficient and water transparency (Secchi depth), but by the species composition and temporal variation of submerged vegetation. In the progress of eutrophication, the submerged macrophyte community changed from Potamogeton maackianus dominance to co-dominance of Ceratophyllum demersum and P. maackianus , and became more seasonally variable in biomass and coverage due to the shorter survivorship of C. demersum . We suggest that in the early stage of eutrophication, when submerged macrophytes are still abundant, water quality parameters should be coupled with monitoring of submerged vegetation to examine the effects of external nutrient loading on shallow lake ecosystems.

Description: Contamination by any substance takes place through air, water or soil and causes serious effects on flora and fauna of the regions. Air-transmitted pollutants spread in a faraway place from emission points of the pollutant source via wind (speed and direction as causing factors). Fluoride is one the pollutant generated in aluminium industries which is harmful to human and plants in excess concentration. This study focuses on the use of spatial interpolation methods for assessment of fluoride concentration around aluminium industries. The samples were collected from different test sites in the study area to investigate the fluoride concentration level. The test sites include several locations such as industrial unit, river site, residential and distant villages. Then, the collected samples were used to predict the overall fluoride concentration in the entire study area. The aim of the study was to evaluate the spatial variation and presence of fluoride concentration in the surroundings of the aluminium industries. Geostatistical interpolation modelling was applied to assess the prediction of fluoride contamination for other non-sampling points using the direction and distance method of empirical Bayesian kriging (EBK) modelling. Thus, geospatial modelling was used to predict the contamination of fluoride around the study area to create environmental awareness. In particular, this study assesses the fluoride pollutant concentration which might become dangerous with slowly increasing concentration against its standard concentration, which will severely impact the human health. In overall, EBK can provide valuable information regarding the fluoride concentration on possible level of fluoride in concern to public health.

Description: The cementing of gas wells, especially those used for underground storage, requires precise understanding of cement properties. CO 2 sequestration projects require very-long-term cement integrity, which means that the only way to test the properties of cements used in such applications is in the laboratory. It is common knowledge in the oil and gas industry that the properties of cement slurry obtained from laboratory and field mixing do not correlate very well. This is due to differences in the mixing equipment and procedures followed (API laboratory Waring blender vs. field mixer). The dissimilarity has triggered several research studies that have resulted in the mixing energy concept. This study investigates whether the mixing energy concept can be relied on to reconcile laboratory and field results. Results to date suggest that adequate reconciliation cannot be achieved using calculated mixing energies only, and the authors propose the use of shear rate instead. Additionally, this work evaluates the change in shear rates while pumping slurries through coiled tubing and pipes of different diameters, and the associated possible alteration of cement slurry properties. Two different techniques were simulated in the study, namely the API laboratory method and accepted field mixing, which highlighted the need for a review of laboratory mixing practices towards better prediction of field cement slurry properties.

Description: For describing the time-dependent mechanical property of rock during the creep, a new method of building creep model based on variable-order fractional derivatives is proposed. The order of the fractional derivative is allowed to be a function of the independent variable (time), rather than a constant of arbitrary order. Through the segmentation treatment, according to different creep stages of the experimental results, it is found that the improved creep model based on variable-order fractional derivatives agrees well with the experimental data. In addition, the fact is verified that variable order of fractional derivatives can be regarded as a step function, which is reasonable and reliable. In addition, through further piecewise fitting, the parameters in the model are determined on the basis of existing experimental results. All estimated results show that the theoretical model proposed in the paper properly depicts the creep properties, providing an excellent agreement with the experimental data.

Description: To mitigate the disasters caused by the consumption of poor quality of water, the World Health Organization (WHO) has established standards for testing the quality of drinking water that must be met. The purpose of this study is to verify the relevance of these tests in crystalline basement aquifers in equatorial areas. The global analysis of water quality was conducted by comparing the measured concentration of iron, calcium, pH change and other major ions in the 70 water samples which were collected at different sites in the Centre Cameroun area with the WHO standards. The water quality index was estimated in the entire area using the block ordinary kriging technique. The results show a high concentration of iron, a very high or very low pH, and high temperature values at certain sites, exceeding sometimes the standard values. Finally, this study shows that the control of groundwater quality following WHO standards must always be conducted.

Description: Flawless operation during injection and a long-term seal of the storage reservoir after injection are the prerequisites for successful CO 2 storage in the geological subsurface. This requires the sealing of the porous permeable horizons by a tight caprock and long-term integrity of open and abandoned wells which have penetrated these horizons. As a basic requirement for the inception of a CO 2 injection scheme in any sequestration project, the integrity of the existing wells in the field must be proven. This paper reviews the relevant items including the geology, relevant wells and their standards, well integrity, and integrity evaluation methods. At the end, a novel concept is introduced to evaluate well integrity for abandoned wells. It is concluded that the verification of technical well integrity is significantly more difficult for abandoned wells, because measurements and tests to close information gaps are no longer possible. If information is lacking for a direct assessment, the quantification of the risk of leakage is only possible indirectly. For an indirect assessment, a realistic risk assessment should consider the composite system casing-cement-rock as a whole and also include self-healing caused by CO 2 interaction with the composite system and/or the indigenous rock. The proposed new method covers both qualitative and quantitative analysis, and it is more comprehensive, sophisticated and easier to implement.

Description: Magnetic anion exchange resin treatment (MIEX ® ), as well as ozonation, was applied as pretreatment for soil aquifer treatment (SAT). The removal of dissolved organic matter (DOM) derived from municipal effluent was characterized during these treatments. The DOM removal ratio increased with the increasing of MIEX ® resin dosage (5–20 mL/L), and a dosage of 5–10 mL/L was suggested for the SAT pretreatment. Under this dosage, 30 % DOC was removed from secondary effluent, which was much lower than those found with drinking water resources. The aromatic DOM with apparent molecular weight (AMW) ranging 2–5 kDa was preferentially removed by MIEX ® , especially for aromatic proteins. Differently, ozonation preferentially destroyed larger AMW (〉10 kDa) DOM, especially for fulvic and humic acid-like materials. Better purifucation was achieved by combining the two technologies. With pretreatments (MIEX ® , ozonation, and combined MIEX ® /ozonation), the DOM removals by SAT were significantly improved. The DOC and UV 254 values were reduced by 40–77 % in SAT combined with pretreatments, compared with 20–30 % reduction by only SAT. Around 50% of the fluorescent DOM was reduced in SAT and MIEX/SAT systems, while higher reductions (76-84%) were achieved in ozonation/SAT and MIEX/Ozonation/SAT systems. Different modes were identified: ozonation improved SAT on removing DOM of 1.7–5.3 kDa, whereas MIEX ® treatment attributed to the removal of small AMW (0.5–1.7 kDa) DOM responsible for the absorbance peak at 300 nm. Based on the results, DOM removed by MIEX ® treatment is complementary with those removed by SAT and ozonation, and the best DOM purification was found in combined MIEX ® /ozonation/SAT.

Description: The purpose of this study was to investigate the effects of the anisotropic ratio on the stability of slopes using the reliability index approach. A numerical analysis of the relationship between the three rainfall patterns, advanced, normal and delayed, and the anisotropic ratios was designed. This study also considered three different soil properties (sand, silt, and clay) to simulate rain infiltration. In this study, probability analysis was used to evaluate the stability of unsaturated soil slopes. The finite element computer program Geo-Studio was used to simulate the process of rainwater infiltrating a slope. The pore-water pressure results evaluated from seepage analysis (SEEP/W) were imported into the slope stability program (SLOPE/W). Results for the anisotropic ratio of hydraulic conductivity indicate that when the anisotropic ratios become higher, the reduction in the reliability index is insignificant. In addition, the simulation results indicated that when saturated hydraulic conductivity ( k s ) was less than rainfall intensities ( I ), the percentage probability of the occurrence of a landslide was larger than when k s was greater than I. Finally, in the cases of anisotropic k s , stability of the high ratio soil slopes was not found to be sensitive to the reliability index variation during the simulation period. Moreover, when k s was greater than I , slope stability decreased earlier than was the case in the opposite situation.

Description: The major ions and Sr concentrations and the Sr isotopic compositions of rainwater from four weather stations in the Ordos desert, Northwest China, were measured in this study. In the studied rainwater, Ca 2+ was the most abundant cation with a volume-weighted mean (VWM) value of 387 µmol/L, and SO 4 2− was the dominant anion, with a VWM value of 229 µmol/L. The Sr concentrations varied from 0.1 to 72 µmol/L, and the strontium isotopic ratios ( 87 Sr/ 86 Sr) range from 0.7098 to 0.7110, with an average of 0.7106, which are higher than that of seawater. The 87 Sr/ 86 Sr ratios showed the potential to trace sources of rainwater solutes when combined with other chemical composition data. The covariation between Mg/Ca vs. Ca/Na and Sr isotopic ratios vs. Ca/Sr in the rainwater suggested the mixture of at least three sources: soil dust derived from the local area and/or desert and loess areas in northwest China ( 87 Sr/ 86 Sr values of 0.7114), seawater ( 87 Sr/ 86 Sr value of 0.70917), and anthropogenic inputs ( 87 Sr/ 86 Sr value of 0.7110 and high Ca/Sr, due to coal combustion or automobile exhausts). The human activity inputs are likely the major sources of atmospheric contaminants in the Ordos rainwater. From back-trajectory analysis, principal component analysis and a comparison between the major ion compositions of other selected sites in China, we conclude that the Ordos rainwater ion composition is more significantly influenced by desert and soil dust and anthropogenic sources (primarily industrial and traffic emissions from the surrounding cities) than by marine sources.

Description: The pH, EC (electric conductivity), δ 18 O and major ions in melt water, precipitation, runoff and groundwater samples which were collected in Baishui basin were analyzed. Based on chemical analysis, the characteristic variations are analyzed in this paper. The melt water, precipitation, runoff and groundwater were Ca 2+ /Mg 2+ /HCO 3− type with similar ion compositions but showed different ion concentrations. Normally the content is high in groundwater and runoff water but low in melt water and precipitation. From the upper basin glacier downward, there was a general increasing trend for the total ion concentrations in basin. HCO 3 − and Ca 2+ accounted for more than 80 % of total ions in samples, indicating that ions mainly came from limestone and water typical of carbonate solution water. Water–rock interaction is the significant contributor to water geochemistry. The concentration of inorganic ion in melt water had an obvious diurnal variation with temperature change. The δ 18 O values increases with the altitude decrease; the similarity of δ 18 O in runoff and groundwater samples was due to their frequent transformation in karst regions.

Description: New findings have shown that the contribution of carbonate weathering to the atmospheric CO 2 sink is far greater than previous estimates, through the combined action of carbonate dissolution, the global water cycle, and photosynthetic uptake of dissolved inorganic carbon (DIC). However, in order for calculations to be accurate, any carbon source effect should be deducted from the overall carbon sink. In this study, we carried out high temporal resolution monitoring of flow and hydrochemistry within the Xiaolongbei (XLB) silicate catchment and Beidiping (BDP) carbonate catchment for 1 year. We found the dissolved inorganic carbon concentrations to be higher in BDP than in XLB, and the annual inorganic carbon fluxes in BDP are roughly 23.8 times higher than those in XLB. Similarly, the rate of carbonate rock dissolution is much higher than the rate of silicate rock dissolution. We find carbonate rock dissolution to respond rapidly to rainfall events, and it is sensitive to rainfall changes on hourly, diurnal, and seasonal scales. The high rate of carbonate rock dissolution gives rise to the high concentrations of DIC, Ca, Mg, and to the high inorganic carbon flux in this basin. Differences between the theoretical and calculated contributions of atmospheric and soil CO 2 to the DIC are possibly due to CO 2 outgassing.

Description: Global carbon estimates have identified abiotic CO 2 as a potentially significant source of atmospheric CO 2 , albeit little is known about its origin. The aim of this study was to identify the origin of soil CO 2 using carbon isotopes and 222 Rn data. The study involved collecting data from seven Slovenian forest soils developed over bedrock with contrasting geology where different origin of soil CO 2 was expected; two sampling sites were located on soils formed above carbonate bedrock, one above metamorphic bedrock and the remainder above clastic sedimentary rocks. Analysis of soil gas including the levels of CO 2 , carbon isotope measurements ( 12 C, 13 C and 14 C) and 222 Rn activity was recorded at a soil depth of 80 cm. Isotopic analysis revealed that the CO 2 was young and there was no difference in the age of soil CO 2 above either carbonate or non-carbonate bedrock. The data also suggest that the 13 C-enrichment in soil CO 2 , above carbonate bedrock was a consequence of the mixing of soil CO 2 with atmospheric CO 2 and/or the ventilation of subterranean CO 2 from pores, fissures and cavities. The latter effect was supported by the high 222 Rn concentrations observed at these sites. Based on the \(\delta^{13} {\text{C}}_{{{\text{CO}}_{2} }}\) data, photosynthesis prevailed over microbial respiration accounting for the majority (〉70 %) of total soil CO 2 over non-carbonate bedrock—at least at the time of sampling. Overall, results from this study could represent useful information for global carbon cycle models used to predict the impacts of climate changes.

Description: For the purpose of analyzing and managing Urban Water Pollution Discharge Systems (UWPDS) comprehensively, a systematic approach of tracking and tracing analyses was developed based on environmental systems analysis theory, in which the directed graph, the nodal flow balance and the network analysis of Geographic Information System (GIS) were used. Based on the digitalized UWPDS of GIS which was established by collecting and processing a large amount of topographic, sewage discharge and drainage data, this scientific approach can be applied to make the tracking and tracing analyses on wastewater treatment plants, pumping stations, illicit sewage outlets, pollution sources and drainage pipelines systematically. The upstream and downstream information about sources, discharging paths, flow quantities and final destinations of pollutants was obtained, and potential problems in the UWPDS analysis such as illicit connections between different drainage pipelines were identified, with the spatial analysis. This developed approach was tested using the UWPDS of Chaohu City (Anhui Province, China). The study results are important for the implementation of sewage interception engineering, the determination of load reduction, and the optimization of drainage pipelines and pumping stations in future.

Description: Subsurface fluid flow of reservoirs in active tectonic regions is mainly controlled by permeability of fault zones. Therefore, the characterization of fault zones is an important step toward performance assessment of a reservoir. The fluid flow is controlled also by pressure and temperature conditions. In this context, we simulated pressure and temperature fields to elaborate on the influence of permeability on subsurface fluid flow in the Lahendong geothermal reservoir. Thermal–hydraulic simulation is performed using a finite element approach. Adjusting the permeability through 370 different cases, modeling results converged to the observed data within a misfit range of 0–7 %. The best fitting models identified a deep-seated fault that has previously not been traced at the surface. Simulated temperature distribution suggests a prominent convective heat flow, driven by an upward migrating and SW–NE oriented fluid flow. This hydraulic gradient causes a pressure drop along the reservoir. High-pressure patterns are used to constrain recharge areas, in addition to infiltration measurements. Discharge flow occurs from SW to NE migrating also upward toward the hot springs. In that frame, thermal–hydraulic simulations identified previously unresolved subsurface faults, which now allow a better understanding of the subsurface permeability and its influence on fluid flow.

Description: Prediction of hydrogeochemical effects of geological CO 2 sequestration is crucial for planning an industrial or even experimental scale injection of carbon dioxide gas into geological formations. This paper presents a preliminary study of the suitability of saline aquifer associated with a depleted oil field in Czech Part of Vienna Basin, as potential greenhouse gas repository. Two steps of modeling enabled prediction of immediate changes in the aquifer and caprocks impacted by the first stage of CO 2 injection and the assessment of long-term effects of sequestration. Hydrochemical modeling and experimental tests of rock–water–gas interactions allowed for evaluation of trapping mechanisms and assessment of CO 2 storage capacity of the formations. In the analyzed aquifer, CO 2 gas may be locked in mineral form in dolomite and dawsonite, and the calculated trapping capacity reaches 13.22 kgCO 2 /m 3 . For the caprock, the only mineral able to trap CO 2 is dolomite, and trapping capacity equals to 5.07 kgCO 2 /m 3 .

Description: An assessment of fluoride distribution in groundwater of an industrialized area (Talchir), Odisha, India, was carried out to understand the potential sources and processes. This study is significant as the water resources are being endangered by the mining and other industrial activities in this region. High concentration of fluoride (4.4 mg/L) was observed in groundwater of this area, which was attributed mainly to mining activities. Additional source for high fluoride is the basement granitic rock containing fluoride bearing minerals like amphibole, biotite and fluorite. The dominant chemical types are found to be Na–Ca–HCO 3 , Na–Mg–HCO 3 , Ca–Mg–HCO 3 and Ca–Na–HCO 3 . The groundwater facies variation was found in accordance with the local lithology. There was no marked difference in the fluoride concentration of groundwaters between near and far off mining zone. Geochemical modeling indicated precipitation of calcite and dolomite as the driving force for the release of fluoride from the formation. In addition to the precipitation of calcite and dolomite, evapotranspiration also contributes to high fluoride in groundwater. Environmental stable isotopes inferred that there was no clear isotopic distinction between high and low fluoride groundwater and the groundwater was found to be evaporated. Environmental tritium data suggested that the groundwater was modern and fluoride enrichment was facilitated by long residence time of groundwater. Statistical methods also corroborate the geochemical and isotopic inferences. The study highlights that natural geogenic source is the main cause for high fluoride in groundwater refuting earlier theories that attribute mining activities as the only source for high fluoride in this region.

Description: During in situ mining processes, high concentrations of ammonium sulfate solution are directly injected into the mountain to replace the rare earth. However, the residual ammonia nitrogen (AN) in the vadose zone from this injected solution is a serious pollutant of groundwater and soil. Unfortunately, in situ leaching methods using clean water are not effective at removing the AN. In this work, we developed a novel leaching method and examined its efficiency, as well as studied the mechanisms behind the adsorption and desorption of AN. It was found that the majority of the ammonium adsorbed in the soil was in soluble and exchangeable forms. The saturated adsorption capacity under mining conditions was 810 mg kg −1 , where only 36 % of the adsorbed AN was able to be leached out by water. However, the amount of AN leached out increased to 85 % when a KCl solution was used as the leaching agent at an optimized concentration of 2.8 mM. Furthermore, this improved leaching agent worked well at a wide range of solution pHs. Therefore, this method is an efficient means by which to remediate AN contamination after mining processes of RE ores.

Description: A hydraulic gradient model, which can be used to compute the hydraulic gradient of paste-like crude tailings backfill slurry (PTBS) transported by a pipeline system in a mine, was constructed based on rheological model derivation, numerical simulation, and regression analysis. It was proven, by a Bingham rheological model analysis of the PTBS, that the hydraulic gradient of the PTBS is inversely proportional to the pipe diameter and proportional to the average flow velocity. It was also clarified that the hydraulic gradient value depends primarily on the rheological parameters of the PTBS if the pipe diameter and flow velocity are adjustable. Consequently, rheological parameters of the PTBS in different slurry mass fractions were obtained through 3D simulation with FLUENT. The slurry pipeline transportation process and the relationship between rheological parameters and slurry mass fraction were regressed by MATLAB mathematical software. Finally, a hydraulic gradient model describing a variation rule of the hydraulic gradient of the PTBS to pipe diameter, flow velocity, and slurry mass fraction was constructed. A comparable study between the calculation result and site date indicates that the model has enough accuracy to satisfy the requirement of backfill system design with an average deviation of 8 %.

Description: Rock falls are frequent along the steep slopes of highway cuts in mountainous areas like Nepal. Araniko Highway is a major highway connecting Nepal and China that has suffered from several instability problems. Recent earthquake activity in Nepal has generated many landslides, including rock falls along the highway, mostly between Lamosangu and Liping. These landslides have deposited huge piles of debris along the highway, as well as in the hill slope above, which has increased future risk of rock fall. Here, we have tried to analyze the distribution of rock falls along the highway, their mode of failure, and the associated hazard and risk. The analysis shows that most of the rock falls are concentrated along steep rock cliffs and are mostly rock topples, with some wedge and plane failure type. For the rock fall hazard and risk assessment of the highway, we have slightly modified the original rock fall hazard and risk assessment method to fit the condition of the Araniko Highway. The developed hazard and risk map effectively indicates various levels of rock fall hazard and risk along the highway. Based on the level of hazard and risk, the maintenance and inspection work can be carried out. In addition, the study reveals that this system can be effectively used to prioritize the severity of potential rock falls along other highways with similar geological and morphological settings.

Description: Mud diapir and mud volcano have the same formation mechanism and similar development and evolution characteristics, but different geological features and forms. In this study, the development and characteristics of a mud diapir in Yinggehai Basin (northwestern South China Sea) and a mud volcano in Southwest Taiwan Basin (northeastern South China Sea) were investigated. The geochemical characteristics of their associated natural gases were also analyzed. The results indicated that the Yinggehai Basin mud diapir is mainly distributed in the deep and large depression of the central basin and presents five lines in echelon arrangement along a northwest direction. Its development and evolution characteristics are low density and speed, and abnormally high temperature and overpressure. In contrast, the Southwest Taiwan Basin mud volcano is mainly distributed in a deep water slope area of the south sag and Tainan-Kaohsiung. Onshore mud volcanoes are mainly distributed along the deep and large fault zone, and their morphological characteristics are similar to venting volcanoes. The seabed morphology of offshore mud volcano seems similar, but current research is still insufficient. There are many types of associated hydrocarbon gases in mud diapir and mud volcano, but the high maturity coal-type hydrocarbon gas is the main one. The associated non-hydrocarbon gas is rich in CO 2 and N 2 , which is mainly derived from a CO 2 source from inorganic crust. The source of both diapir and volcano is thick marine Miocene and Pliocene age mud with hydrocarbon-generating potential. The mature hydrocarbon generation, mud diapir/mud volcano migration and deposition into an appropriate reservoir, as well as diapir-associated structures, constitute a unique oil/gas migration and accumulation system, which thus adds to our understanding of the distribution of such “mud diapir/volcano-type oil/gas reservoir.”

Description: A multivariate statistical technique was used to determine the major hydrochemical processes that control the groundwater quality variations during “aquifer storage and recovery” (ASR) operations. Principal component analysis (PCA) was applied on chemical and isotopic data of 83 groundwater samples. It has allowed the reduction of the 14 variables to four significant PCs (factors F ) that explain 82.2 % of the total variance. F1 (54.1 %) represents the mineralization and groundwater nitrates pollution, whereas F2 (13.2 %) exhibits the isotopic enrichment by evaporation of waters components. Factor score of F1–F2 contains four groups: Injected freshwater (II) distinguished by low mineralization. Native groundwater characterized by relatively high mineralization. Mixing groundwater has intermediate mineralization. The shifting of native groundwater to injected water is related to the mixing ratio between these two components. Thus, the quality of groundwater samples situated close to the injected water is enhanced. Surface water (QF) is enriched by δ 18 O and δ 2 H compared to the other components due to evaporation. The spatial pattern of iso-factor scores maps is generally similar to the pattern of EC, Cl − , NO 3 − , and mixing ratio maps performed for the same experiment dates. Consequently, under the applied conditions of ASR process, the effective diameter is 250 m and 3 months of recovery time after complete injection. The results of this study clearly demonstrate the usefulness of multivariate statistical analysis as (PCA) in the ASR process investigation.

Description: Based on the hydro-meteorological data over the past 50 years (1961–2010), the runoff change of the Kaidu River was predicted for the future 30 years (2011–2040). Two statistical downscaling models, the Statistical DownScaling Model (SDSM) and the Statistical Analog Resampling Scheme (STARS), were used to downscale the HadCM3 outputs for projecting the future climate scenarios of the basin. The Soil and Water Assessment Tool (SWAT) hydrological model was driven by the projected climate scenarios to generate the future runoff. Modeling results suggested that the SWAT model can well duplicate the recorded runoff changes in the basin and thus can be applied to simulation of future runoff changes. Both the SDSM and the STARS models performed well in simulating the temperature but relatively poorly in simulating the precipitation. Under the A2 and B2 scenarios the basin will experience a significant increasing trend in temperature and an indistinctive change trend in precipitation during the entire forecast period. Under the S1–S3 scenarios, both temperature and precipitation do not exhibit distinctive changes. In terms of river runoff, the predicted average annual runoff will be relatively abundant during the period from 2010s to 2020s but obviously short after 2020s under A2 scenario and will be kept relatively steady under B2 scenario. The predicted runoff will fluctuate drastically with no any significant trend under S1–S3 scenarios. The relatively high runoffs under S2–S3 scenarios seem to indicate the importance of temperature increasing in generating runoff. The scenario-based predictions suggest that moderate emission (e.g., B2) or moderate warming (e.g., S2) is beneficial to maintaining the expected level of runoff in the future.

Description: Surface soil moisture constitutes a major component in the Earth’s water cycle. In many cases, modelling and predicting soil moisture represent a serious problem in water resources field due to the problematic measurements or lack of measurements, etc. Data-driven models such as artificial neural networks (ANN) have been characterized as a robust tool to overcome these shortcomings. This study aims to identify the optimum ANNs to model the root zone soil moisture (up to 2 m depth) in the upper reach of the Spree River using the synthetic soil moisture data from SWAT model. Thus, three different approaches were developed and compared to determine the highest performing method. These networks can be broadly categorized into dynamic, static, and statistical neural networks, which are layer recurrent network (LRN), feedforward (FF), and radial basis networks, respectively. Data sets of precipitation and antecedent soil moisture were selected based on quantification of cross-, auto-, and partial autocorrelation coefficients to represent the best behaviour of root soil moisture. The time series data were subdivided into two subsets: one for network training and the second for network testing. The determination coefficient ( R 2 ), root-mean-square error, and Nash–Sutcliffe efficiency were employed to test the goodness of fit between the actual and modelled data. Results show that, among the used methods, the LRN and FF networks have the top performance criteria, showing a reliable ability to be used as estimator for the soil moisture in this catchment.

Description: This paper assesses the harm that human-induced land degradation poses on terrestrial ecosystems. We propose and define a hazardous impact (HI) indicator and a method to quantify this degradation and promote sustainable land use under the pressure resulting from population growth. Taking human appropriation of the net primary productivity owing to land-use conversion (HANPP luc ) as a proxy, the quantification of HI was developed with support from remotely sensed net primary productivity (NPP) data and using the co-kriging method. A case study in the karst area of south China showed that HI in the study area decreased from southwest to northeast. Areas with the highest level of HI occupied 4.77 % of the total area and were distributed in northwest Sichuan Province, southwest Yunnan Province, and southern Guangxi Autonomous Region. Lower HI areas were mainly located in Hunan Province and Hubei Province. This indicates that land use has a strong impact on karst rocky desertification. To maintain a decreasing trend in HI, a land-use policy must guide human activity. In the karst areas of south China, HI and rocky desertification have similar spatial distribution and intensity. This suggests that HI can effectively reveal adverse effects on the ecosystem due to human-induced land degradation, and that it can potentially be applied to other related issues. We also argue that NPP reduction and HI level do not follow a simple 1:1 relationship, so revisions may be needed when applying the proposed indicator and approach to other regions. This approach also needs to be improved in its accuracy in terms of natural vegetation extraction.

Description: Rockfall hazard is a main threat for mountainous and hilly areas that can cause loss of life, damage to infrastructures, and traffic interruption. Rockfall frequency and magnitude vary both spatially and temporally; therefore, multi-scenarios related to rockfall characteristics (trajectories, frequency and kinetic energy) can provide early warnings by identifying the areas at risk for mitigation purposes. The aim of this study is to predict the areas at risk from future rockfall incidents and suggest suitable mitigation measures to prevent them. The most significant elements in rockfall analysis are slope topography interpretation or the digital elevation model (DEM) and the rockfall modeling approach. Light detection and ranging (LiDAR) techniques have been widely used in rockfall studies because of their capability to provide high-resolution information regarding slope surfaces. In the current study, airborne laser scanning (ALS) is used to obtain a high-density point cloud (4 pts./m 2 ) of the study area for the construction of an accurate DEM via a geographic information system. Rockfall source areas were identified based on multi-criteria method including DEM derivatives (e.g., slope, aspect, curvature and topographic contrast) in addition to terrain type and aerial photos. A 3D rockfall model has been established to determine rockfall multi-scenarios based on their characteristics according to a range of restitution coefficient (normal and tangential) and friction angle values; these parameters are particularly crucial in rockfall simulation to delineate the spatial prediction of rockfall hazard areas along the Jelapang corridor of the North–South Expressway in Malaysia. In addition, a barrier location was suggested based on limited rockfall height and kinetic energy to mitigate rockfall hazards. Results show that rockfall trajectories (stopping distance) and, subsequently, their frequency and energy are increased; moreover, barrier efficiency is reduced when the values of the mechanical parameters (Rn, Rt, and friction angle) are increased. Nonetheless, the suggested barrier location is an efficient and mitigative measure to eliminate the rockfall effect.

Description: Microbes participate in a series of complex biogeochemical processes including nitrogen and sulfur circulation. Microbial species active in the nitrogen and sulfur cycles can be used for nitrogen and sulfur pollution remediation, preserving and keeping the ecosystem in balance. Hypolentic zones in brine lakes contain stable, elevated pH and total dissolved solids and provide a unique habitat for a rich diversity of haloalkaliphilic bacteria and archaea. Few studies have investigated the diversity and microbial community structure in the sedimentary environment of hypolentic zones in brine lakebeds located on desert plateaus. In this study, sedimentary environmental characteristics, species abundance and diversity were investigated, as well as the relationships between them. Analyses revealed important roles of different bacterial species in the microbially mediated nitrogen and sulfur biogeochemical cycles in the brine lakebed. Further, the study revealed details of the ecosystem dynamics of these extreme environments, under the action of microorganisms. The biogeochemical dynamic response of different hydraulic and hydrochemical characteristics was illuminated. It showed that the amount of deoxyribonucleic acid in the sediment was interrelated with the components of brine water and depth of the hypolentic zone and was higher in brine and reduction conditions, with the stronger hydraulic forces. In the hypolentic zone of the brine lake, microbial species composition was remarkably correlated with environmental factors, spatial environmental factors and hydrogeological conditions, such as hydraulic and hydrochemical characteristics.

Description: Groundwater is one of the most important freshwater resources worldwide. However, long-term over-abstraction of groundwater has resulted in deteriorating groundwater functions, including gradually decreasing resources function and geo-environmental function and subsequent adverse geo-environmental issues. In this study, the concept of critical control levels of groundwater including blue line levels and red line levels, which play an important role in groundwater resource management, is presented for the first time. In addition, the theory of critical control levels of groundwater is established based on the groundwater geo-environmental function and resources function. A coupled numerical model of groundwater flow field and land subsidence is then established for Tianjin based on the conceptual model and analysis of the hydrological conditions of the study area. Finally, the critical control levels of groundwater for the subarea are presented based on results obtained from a numerical model by the model space division and time discretization, hydrogeological parameters processing, model calibration and validation. The results presented herein will be useful for groundwater resource management.

Description: Local site conditions may significantly affect the amplitude and frequency of ground motion during earthquakes. Recordings of recent major earthquakes have demonstrated that soil conditions can generate prominent amplification of ground shaking and can be compared with the amplification predicted by numerical simulation. This study analyzes the ground motion data from the December 2007 and March 2008 moderate Bala earthquake series considering the effect of soil conditions on ground shaking in the southern part of Ankara, the capital city of Turkey. Initially, shear wave velocity profiles of the strong ground motion stations were evaluated to define site classifications for each station in Ankara and its surroundings. Strong motion data collected during the Bala earthquake series ( M w range 5.6–4.8) were used to develop event-specific attenuation relationships for peak ground acceleration and spectral acceleration at various periods and different site conditions. Site amplification factors were derived from the regression results from the event-specific attenuation relationships for the Bala earthquake series. The implications of these ground motion amplification factors were also discussed and compared using the current seismic design codes. Finally, the response spectra from the recording stations were used to determine site amplification factors for different site conditions to evaluate the variability of the site response in localized regions in Ankara.

Description: In the Lunnan area of the Tarim Basin, the fracture cave system of the Ordovician carbonate paleokarst, with strongly heterogeneous well-developed corrosion pores, caves, fissures, and a large underground water system, is buried at depths of 5068.51–5709.74 m. There has been little research on the carbon and oxygen isotopic characteristics of the cave fills of the middle–lower Ordovician karst within this area, and little is known about the regional karst developmental stages and their filling environments. In this work, systematic geochemical studies were conducted on the carbon and oxygen isotopes of 47 karst fill samples, based on which the developmental stages of the paleokarst and their characteristic filling environments were determined. Four different karstification stages were identified together with their filling environments. The results revealed δ 13 C (PDB) values within the range of 6.06 to −8.69 ‰ with an average of −1.40 ‰ and δ 18 O values within the range of −5.78 to −17.28 ‰ with an average of −10.74 ‰. The calculated deposition temperatures of the karst fracture caves were between 2.24 and 55.84 °C with an average of 22.06 °C. The Z values of the characteristic medium salinity were between 104.33 and 133.47 with an average of 119.06. Both the δ 13 C and the δ 18 O values exhibited broad ranges, resulting in a large span of calculated temperature differences that drift to opposite ends, revealing the complex and multiphase nature of the carbonate karstification process and the respective filling environments within this area.

Description: Residual sludge coming from dimension stone working activities represents a serious environmental and economic problem for both stone industry and community. Indeed, most of the time, residual sludge is landfilled because of the difficulties to recover it; such difficulties are mainly connected to local legislation and to a lack of proper protocols. In general, two different categories of sludge can be identified: residual sludge coming from carbonate rocks (CS) and those coming from silicate rocks (SS). Both of them are characterised by a very fine size distribution. CS is mainly made up of the same compounds of the processed stones (i.e. marble, limestone, travertine). On the contrary, SS is characterised by high heavy metal content, due to the composition of the tools employed during processing activities and to the original rock characteristics. Furthermore, total petroleum hydrocarbon content can often be recognised in residual sludge. In general, residual sludge, management of which in Italy is administered in accordance with ILD 152/06, can be used as waste for environmental restoration or for cement plants. Several researches investigate possible reuses of residual sludge, after a proper processing phase, as new products. Such “new products” should be certified not only on the basis of their technical and physical characteristics but also by means of appropriate chemical analyses to guarantee that the products are not polluted. The aim of this research was to evidence that, on the basis of a correct sludge characterisation, treatment and management, it is possible to produce secondary raw materials (filler, etc.) or new products (artificial soil, etc.), in order not to waste “sludge resources”. Some examples from Italian experimentations are here reported, focusing on the treatment and recovery of SS and CS.

Description: Spatially distributed snow cover information is important for the assessment of climate-related variability of water resources and for calibration and validation of hydrological models in snow-dominated regions. Near-real-time snow cover data can be valuable for short term to seasonal streamflow prediction. Such information can be extracted using remote sensing techniques with good accuracy. Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover data, meanwhile available for more than 15 years, have been shown to be useful for monitoring snow cover extent in remote areas. This data can be processed and used with only 2-day delay, which is sufficient for many water resources management purposes. However, processing remote sensing data require knowledge and computational skills to handle large amounts of data. Moreover, cloud obscuration in optical remote sensing such as MODIS may lead to data gaps. These limitations impede the use of the freely available MODIS data for water resources management in developing countries, particularly in snow-dominated mountainous regions. To overcome this, we present the all-in-one software package MODSNOW-Tool. It processes raw MODIS data and eliminates cloud cover using advanced cloud removal algorithms. The ready-to-use output of the MODSNOW-Tool is a cloud-free snow cover map and a daily report, which includes spatiotemporal snow statistics for pre-defined river basins. The accuracy of cloud-eliminated MODSNOW snow cover maps was validated for 84 almost cloud-free days in the Karadarya river basin in Central Asia, and an average accuracy of 94 % was achieved. The MODSNOW-Tool can be used in operational and non-operational mode. In the operational mode, the tool is set up as a scheduled task on a local computer allowing automatic execution without user interaction and delivers snow cover maps on a daily basis. In the non-operational mode, the tool can be used to process historical time series of snow cover maps from MODIS.

Description: Artisanal gold mining activities continue to degrade water resources in the tropical watersheds. In this study, we examined the spatial distribution of artisanal gold mining activities and their impact on sediment and mercury concentration in the Okame River catchment, Eastern Uganda. The spatial distributions of mining activities were assessed using both a TerraSAR-X radar satellite image of 2008 and Landsat image of 2013. Water samples and river bed deposits were collected on a monthly basis for a period of 1 year to assess the impact of mining activities on the streamflow variations and sediment concentration. Our results showed that the distribution of gold mining activities increased from 4.5 km 2 in 2008 to 19.9 km 2 in 2013. Human-induced sediment loading due to gold stone washing in the sampled tributaries of Okame River was responsible for the high concentration of suspended sediments (CSS), mercury and low water levels than prior to gold stone washing. River Omanyi (0.0191 mg l −1 ) was the most highly contaminated stream with mercury followed by Nankuke River (0.0163 mg l −1 ) and Nabewo River (0.0158 mg 1 −1 ) in the Okame. There was also a significant concentration and trend of soluble mercury contamination from the sampled rivers ( R 2  = 0.8). The average concentration of mercury was found to be 0.004 ± 0.0009 mg l. This paper notes that artisanal mining activities have led to the reduction in streamflow rates, change of streamflow course and colonization of stream banks by riparian vegetation.

Description: A long-term hydrogeochemical data set is used in this study to evaluate the water quality and hydrogeochemical evolution of shallow groundwater in a Quaternary deposit. A multivariate statistical method, hierarchical cluster analysis (HCA), is applied to overcome the problem of a large number of data points in the integration, interpretation and representation of the results. HCA is applied to a subgroup of the hydrogeochemical data set to evaluate their usefulness to classify the groundwater bodies. This subgroup consists of 27 groundwater wells and 15 variables [pH, total dissolved solids, electrical conductivity (EC), Na + , Ca 2+ , Mg 2+ , K, HCO 3 − , Cl − , SO 4 2− , Fe, Mn, NH 4 , NO 3 − and SiO 2 ]. Only 12 chemical variables were used for the analysis. Four clusters have been identified: C1–C4, with two main prevalent facies, Na–HCO 3 and Ca–HCO 3 . The hydrogeochemical evolution of shallow groundwater is governed by the processes of precipitation, weathering, dissolution and ion exchange.

Description: Integrated river basin management (IRBM) is recently fostered in the European Union mainly by two framework directives which were established in order to realise sustainable and effective river basin management and aiming for integrated approaches on a river basin scale. One is the water framework directive which objective is to assess water quality and achieve a good status for all water bodies. The other one is the flood risk management directive on the assessment and management of flood risks. This paper discusses the potential synergies of the two directives against IRBM in general and describes European experts’ views which were formulated as recommendations. The status of the water bodies and water governance system in Germany are described and critically reflected against the experts’ recommendations. Potential methodological approaches which were developed and tested in German case studies are presented and discussed in the light of IRBM with focus on identifying and using cross-sectoral synergies. The analysis reveals shortcomings in IRBM approaches in Germany and potentials for identification and use of synergies if certain framework, concept approaches and methodological approaches would be used.

Description: Based on elastic wave theory, the time–frequency analysis method of acceleration amplification along the hillslope is derived by using Hilbert–Huang transform combined with modal analysis method and orthogonal theory. Its reasonability is verified by the results of shaking table test and numerical simulation. This method can not only analyse the effect of peak ground acceleration, frequency and duration of seismic waves on acceleration amplification along hillslope, but also illustrate whiplash effect of hill theoretically.

Description: Plant nitrogen (N)–phosphorus (P) stoichiometry is associated with important ecological processes. However, N–P stoichiometry in soil and plants and adaptive mechanisms of plants to infertile soils in the soil erosion areas remain unclear. We selected 15 plots with Masson pine forest of varying stand ages in typical subtropical soil erosion areas of Southern China. The total nitrogen (TN) and total phosphorus (TP) concentrations in green leaves of Masson pine forest (9.2 and 0.61 g/kg) were significantly lower than the national averages in China (18.6 and 1.21 g/kg). The N:P ratio (TN:TP) of green leaves (15.1:1) was higher than the national (14.4:1) and the global levels (11.8:1 or 11.0:1). Forest soil TN, TP concentrations (0.41 and 0.14 g/kg) were lower than the national averages. The high N:P ratio of green leaves and low soil TP, AP concentrations indicated that P was important in limiting Masson pine forest growth, especially for forests with stand age less than 10 years. Leaf TN, TP resorption efficiencies of Masson pine forests were 26.5 and 64.9 %, and TP in senesced leaves of Masson pine with different stand ages was completely resorbed, suggesting that Masson pine was effective at adapting to nutrient-poor soils. Differences in leaf N–P stoichiometry among different stand ages indicated that nutrient demand varied with Masson pine forest growth stages. Changes in forest soil N–P stoichiometry suggested that Masson pine forest afforestation could greatly improve the soil quality in the eroded lands. However, the significant improvement would take at least a 30-year-long period.

Description: This paper presents state-of-the-art modeling of complex hydraulic fracture network evolution in a naturally fractured formation with pre-existing bedding and cross joints, in the Silurian Longmaxi formation, southeast of Sichuan Basin, China. A flow-stress-damage coupling approach has been used in an initial attempt toward how reservoir responds to perforation angle, injection rate, in situ stress, cohesive and frictional strength of natural fractures. A detailed sensitivity study reveals a number of interesting observations resulting from these parameters on the fracturing network evolution in naturally fractured system. When the perforation angle is 60°, it gets to the maximum stimulated reservoir area (SRA). Injection rate as an operator parameter, it strongly impacts the interaction between hydraulic fractures and natural fractures, and associated SRA. In addition, in isotropic in situ stress field, fracturing effectiveness is not the best, complexity of SRA is enhanced when pre-existing fractures are oriented at an angle to the maximum stress. Moreover, the morphology of fracturing network and SRA is closely related to the frictional and cohesive strength of natural fractures. This work strongly links the production technology, geomechanical evaluation and aids in the understanding and optimization of hydraulic fracturing simulations in naturally fractured reservoirs.

Description: Drainage systems in China are currently being transformed from combined sewer systems into separate sewer systems; newly built areas generally use the latter for sewage and stormwater treatment. Polluted stormwater runoff is discharged directly into rivers through pipelines, thereby deteriorating the water quality of rivers. In this work, an urban stormwater system model was built with Infoworks Integrated Catchment Modeling and validated by measured data. The loads at the pipe outlets during rainstorms were analyzed as well. Stormwater system was transformed by using mathematical models under the conditions of meeting river water quality standards and preventing damage to water environmental capacity. The relative errors of volume and peak runoff of model calibration were from −2.33 to +12.06 % and −13.43 to +8.7 %, respectively. The study indicates that the stormwater system model can be used in scenario analysis, and the stormwater system can accommodate floods over a recurring interval of 10 years. Moreover, stormwater can be directly discharged into water bodies without exceeding the carrying capacity of the water environment with the transformation of the stormwater system.

Description: Underground injection (UI) is an effective and efficient means of disposing of wastewater from shale gas production. However, the influence of UI on groundwater systems should be examined carefully to protect drinking groundwater sources. A regional hydrogeological model based on TOUGH2-MP/EOS7R of part of the Sichuan Basin is established to simulate pressure changes and solute transport in response to wastewater injection into deep aquifers. Wastewater is assumed to be injected through a well at a rate of 5.45 kg s −1 for 5 years and a post-injection period of 45 years. The simulation results indicate that UI will cause significant pressure buildup during the injection period, after which pressure will dissipate during the post-injection period. The mass fraction of solute increased over the entire simulation period. The draft regulation under the Safe Drinking Water Act and the level III groundwater quality standards regulated by the Chinese government is referenced as the criteria for evaluating the influence of UI on groundwater systems. It is found that maximum pressure levels caused by UI may exceed safe levels. Uncertainties with respect to permeability are analyzed from previous studies and injection test results. Lower levels of permeability incur higher degrees of pressure buildup when UI is implemented. Different injection schemes are discussed, and we verify that pressure buildup from time-variant injection schemes is less than that from constant injection schemes for the same total injection volume. Injection schemes should be carefully evaluated before implementing UI in a shale gas reservoir.

Description: The carbonate Dammam Formation of Eocene age and the unconformably overlying clastic Kuwait Group of rocks of Mio-Pliocene age are the two aquifers that provide useable groundwater (salinity 5000 mg/l or less) in Kuwait. These aquifers extend beyond the political limits of the country to Saudi Arabia and Iraq. A detailed environmental isotopic ( 2/1 H, 18/16 O, 13/12 C, 3 H, 14 C) characterization of the groundwater system of southern Kuwait (a regional aquifer extending beyond the political limits of the country to Saudi Arabia and Iraq) has been carried out to understand its hydrodynamics so as to evolve a better conceptual flow model of the aquifer system. From the study, it was observed that the groundwater salinity of the Kuwait Group aquifer increases generally from south-west to north-east, although locally a few of them show low values. Groundwater samples from the Dammam Formation aquifer are characterized by a relatively low mineralization, compared with those of Kuwait Group aquifer. The water in the Kuwait Group aquifer in the south-western part of the country is Na–Cl type and in the Dammam Formation aquifer is Na–Cl to SO 4 –Na (Cl 〉 SO 4 ) type. A wide range of d -excess of the groundwater samples was seen (Kuwait Group aquifer +16.0 to −20.6 ‰; Dammam Formation aquifer: +22.8 to −19.6 ‰), indicating that the groundwater system contains more than one type of water with different origin (recharge area) and history (time, evaporation, climate). In both the aquifers, the groundwater samples from south and central parts and along the coast showed negative d -excess values with heavier 18 O and 2 H, indicating older recharge and greater degree of evaporation prior to recharge. The δ 18 O and δ 2 H of the initial recharge waters, respectively, are −8.8 and −40 ‰ for the Kuwait Group aquifer and −7.2 and −32 ‰ for the Dammam Formation aquifer. The corrected 14 C ages (Tamer’s model) of groundwater samples of Kuwait Group aquifer ranged from ~5000 to 24,000 a, B.P, and that of Dammam Formation aquifer ranged from ~6000 to 20,000 a, B.P. The intermediate groundwater in the south-west and central parts of Kuwait Group aquifer is recharged during humid period (~5000 to 10,000 a, B.P), whereas deeper groundwater in the south is recharged during arid period (~9000–16,000 a, B.P). The recharge to the Dammam Formation aquifer mostly occurred during a cooler (humid) phase in the past. The Dammam Formation aquifer water is hydraulically well mixed below 350 m depth. Interconnection between the two aquifers established near the coast and south-west border of the country. The results of the study were used to refine the existing conceptual groundwater flow model for the aquifer system.

Description: Management processes play an important role in helping to achieve the European Water Framework Directive (WFD)’s water quality goals. As a result, researchers have suggested numerous indicators to evaluate the relevant management processes, including indicators that are both generally applicable and highly context-specific. However, these indicators have not until now been summarized and systematized within one comprehensive framework. Consequently, researchers have experienced difficulties in evaluating the relative influence of different indicators on the WFD implementation process. This paper aims to contribute to combatting this problem by developing and applying an open framework of management indicators to evaluate the WFD’s management processes in Germany. On a conceptual level, this paper develops the basic design principles of the framework and collects around 40 management indicators in a structured way, based on an analysis of the literature related to water management. On an empirical level, this paper provides guidelines on, and specific examples of the ways in which this framework can be applied in practice, based on reports on the implementation process and data from the German reporting system WasserBLIcK. Results show that the framework is useful for systematically analysing the implementation processes of the WFD in Germany. To increase the value of the framework, the authors invite further research to facilitate the framework’s continual update and its application in the ongoing implementation processes of the WFD in Germany.

Description: Irrigated agriculture is an important economic factor in the rural parts of the metropolitan area of Hamburg. It is commonly expected that climate change will reduce the groundwater quantities available for field irrigation. Against this background, the ratio of irrigation need and groundwater recharge (IGR-ratio) is suggested as an indicator to assess climate change impacts on the vulnerability of groundwater resources towards overexploitation by agricultural irrigation. The IGR-ratio has been assessed based on the distributed water balance model mGROWA, i.e. under consideration of the simulated groundwater recharge levels and the field crop-specific irrigation need of the commonly cultivated field crops. The spatial IGR-ratio distribution determined for the observed reference period 1971–2000 has shown that the delineated vulnerable areas coincide with the regions for which high irrigation quantities have been documented at present. Additionally, the IGR-ratio depicts the areas in which irrigation is currently still negligible, but in which the introduction of irrigation into agricultural practice would lead to an immediate overexploitation of the sustainably available groundwater budget. The possible impact of future climate on IGR-ratios was determined by using a model chain of mGROWA and the regional climate models REMO and WETTREG2010. The related ensemble simulations did not provide a uniform tendency of possible future IGR-ratio changes. Whereas the mGROWA–WETTREG2010 realisations projected a very high increase in the IGR-ratios, the mGROWA–REMO realisations did not show a pronounced trend of increasing IGR-ratios. Therefore, considerable uncertainties remain regarding the future bandwidth of IGR-ratio changes.

Description: The main objective of this study is to propose and verify a novel ensemble methodology that could improve prediction performances of landslide susceptibility models. The proposed methodology is based on the functional tree classifier and three current state-of-the art machine learning ensemble frameworks, Bagging, AdaBoost, and MultiBoost. According to current literature, these methods have been rarely used for the modeling of rainfall-induced landslides. The corridor of the National Road 32 (Vietnam) was selected as a case study. In the first stage, the landslide inventory map with 262 landslide polygons that occurred during the last 20 years was constructed and then was randomly partitioned into a ratio of 70/30 for training and validating the models. Second, ten landslide conditioning factors were prepared such as slope, aspect, relief amplitude, topographic wetness index, topographic shape, distance to roads, distance to rivers, distance to faults, lithology, and rainfall. The model performance was assessed and compared using the receiver operating characteristic and statistical evaluation measures. Overall, the FT with Bagging model has the highest prediction capability (AUC = 0.917), followed by the FT with MultiBoost model (AUC = 0.910), the FT model (AUC = 0.898), and the FT with AdaBoost model (AUC = 0.882). Compared with those derived from popular methods such as J48 decision trees and artificial neural networks, the performance of the FT with Bagging model is better. Therefore, it can be concluded that the FT with Bagging is promising and could be used as an alternative in landslide susceptibility assessment. The result in this study is useful for land use planning and decision making in landslide prone areas.

Description: Several famous beach bathing places and aquiculture areas locate in the Yanghe River coast of the Bohai Sea, which are very sensitive to the quality of water and sediment from river discharges. To assess heavy metal contamination, heavy metal in water body and riverbed sediments was investigated in the flood and dry seasons in 2013 at 8 sites along the Yanghe River. All heavy metal concentrations in water body were very low and less than the threshold value of drinking water quality standard of China. There was no significant correlation between heavy metal pollution in water body and riverbed sediments. Sediment pollution was assessed by five approaches including pollution load index (PLI), geo-accumulation index ( I geo ), potential ecological risk index (RI), cluster analysis (CA) and principal component analysis (PCA). The results of heavy metal contamination in riverbed sediments showed that: (1) the mean PLI in the range of 1.0–1.1 indicated a progressive deterioration, and the I geo revealed the pollution in the order of Cd 〉 Cu 〉 Zn 〉 Pb 〉 Cr; (2) the RI presented that the pollution in the downstream was much higher than that in the upstream; (3) the contamination decreased in the upstream due to decreased domestic wastewater where far from the development zone Funing Town, while it increased in the downstream because of dense population and tourists in the coastal zone; and (4) the PCA and FA demonstrate that domestic sewage was a major source of heavy metal contamination.

Description: Understanding the reasons of the disappearance of oasis civilizations along the ancient Silk Road will provide useful references for human’s adaptation to environmental changes in the extreme arid regions in the nowadays and future. Although some studies have associated the demise of complex societies with deteriorating climate in the world, the demise of the civilizations along the ancient Silk Road has remained unresolved. Here, this paper used the nearly 2000 years of climate characteristics revealed by Guliya ice cores, combined with the reconstruction of temperature from tree rings located in the west Kunlun Mountains around the Tarim Basin to examine the climate variations in the Northwestern China in the historical periods. Then this paper compared the demise time of the ancient oases civilizations along the ancient Silk Road from the relevant annals of states and counties. The results showed that climate change may be responsible for the rise and demise of past oasis civilizations in the ancient Silk Road. The periods of fourth to fifth centuries and the seventh to eighth centuries were characterized by long-term drought accompanied by cold climate; five ancient oases and seven ancient oases were demised, respectively, during these periods. Cold–dry climate could cause a deficiency in water resources for irrigation; thus, agricultural production fell and the society was destabilized. Recently, creation of a new “Silk Road economic belt” is realized. Modern oases will face more serious threat under the climate change. The region’s irrigation area increased 67.2 % over the past 30 years. The agricultural sector consumes 93 % of regional renewable water resources. Once the drought occurred, many modern oases—like their ancient counterparts—may well trigger more civil uprising and violent conflict in the already water-stressed regions.

Description: The study presented herein evaluates effects of alkaline activator (sodium hydroxide) concentration, solution (sodium hydroxide solution)-to-binder ratio (S/B), and curing condition on properties of alkali-activated natural Pozzolan mortars (geopolymers). To this end, several mixtures were made having natural Pozzolan as their binder with different concentrations of alkaline activator solution including 2.5, 5, 7.5, 10, and 12.5 molar (M) at various S/B of 0.50, 0.54, and 0.58. The produced mortars were cured at 80 °C under three different conditions of exposed (dry), sealed (wrapped), and moist until testing at ages of 1, 3, and 7 days. Multiple tests were conducted on the alkali-activated natural Pozzolan mortars including flow spread, compressive strength, flexural strength, PH measurement, absorption, and rapid chloride migration. Test results showed the sealed curing condition to be most conducive to strength gain, whereas the exposed curing condition caused dehydration and/or carbonation within the samples and the moist curing condition did not allow for full removal of excess water resulting in reduced bond formations. The moist oven-cured mortars produced higher strength than the exposed cured mortars when alkaline activator with lower molarities was used. The opposite trend was observed for the higher molarities mortars. The compressive and flexural strengths, absorption, and depth of penetrated chloride improved when NaOH concentration increased and S/B decreased.

Description: The effects of climate and land use changes on the hydrological cycle are important factors affecting the evolution of aquatic ecosystems. In this study, the streamflow response to future climate change and land use change and their relative effect is investigated using a Coupled Model Intercomparison Project Phase 5 multi-model ensemble, in conjunction with a raster-based Xin’anjiang model to simulate future streamflows under three climate change scenarios (RCP 2.6, RCP 4.5, and RCP 8.5) and three land use change scenarios (“constant,” “current rate,” and “double rate”) in the Xinjiang basin, China. The results show that the monthly streamflows in the period of 2020–2055 increase substantially at rates ranging from 5.9 to 35.5 % in the autumn and early winter months, but those decrease at rates ranging from −5.5 to −48.1 % in the other months. Annual streamflow also significantly decreases by 148–279 mm under different climate and land use change scenarios. The relative effect of climate change on annual and most monthly streamflows is significantly higher than that of land use change. However, the land use change effect becomes increasingly evident over time and can mitigate the climate change effect from January to August and enhance it in the other months. Moreover, the relative effect of land use change on streamflow is relatively greater in the dry period than that in wet period.

Description: Barite deposits of the Lasbela District, Balochistan, hosted in the Ferozabad Group (FG) of Jurassic are relatively pure and have BaO value ranging from 40.18 to 60.91 % with minor amounts of Sr, Fe and Ca. The measured average density of the studied samples (4.21 g/cm 3 ) is compatible with the API-13A specification. The quantity of water-soluble alkaline earth metals found is very low (av. 50.76 mg/kg) and safe to be used in the drilling mud. The scanning electron microscope study of some of the selected samples revealed nearly 10 % particles are fine (〈6 µm) and have equant, subrounded to rounded shape; however, larger particles (〉10 µm) are tabular and low in quantity. The average content of Pb (3418 mg/kg) in the barite samples is relatively high as designated by the API specification (1000 mg/kg), while Hg, As and Cd contents are very low, except in a few samples. The average content of Sr is 1.19 %, indicating hydrothermal origin of the barite deposits of the study area and to some extent it is toxic in biological functions. Some of the samples have elevated amount of SiO 2 (1.83–8.88 %) which may cause risk of silicosis in the persons either involved in milling industry or at well site. The positive loadings of first factor of principal component analysis for Ba and S, and density revealed genetic alliance with MVT/SEDEX mineralization, and negative loadings of Ca, Mg and Fe demonstrate hydrothermal alteration of host rock.

Description: Positive effects of biochar on nitrate (NO 3 − –N) leaching have recently been demonstrated in many studies, which mainly focused on biochar mixed into soil samples in the laboratory. However, to our knowledge, studies on nitrate leaching from soil samples were directly taken from the field where biochar was added many years ago are relatively scarce. Therefore, a laboratory soil column method was used to study the influence of biochar on the process of vertical transport of nitrate. Breakthrough curves (BTCs) were obtained separately from each biochar treatment. The results were as follows: Biochar has a significant influence on the BTCs of NO 3 − –N. The initial time and total time increased incrementally with biochar application rate, whereas the cumulative amount of leached NO 3 − –N, peak concentration and water flux of the BTCs decreased at the same time. The C6 treatment (40 t/ha) significantly decreased the amount of leached NO 3 − –N. The measured values and simulated values obtained by CXTFIT 2.0 were highly significantly related, as shown by high correlation coefficients ( r  〉 0.85**). A highly significant positive correlation ( p  〈 0.01) was found between the initial time, total time and the application rate of biochar, while cumulative mass of leached NO 3 − –N, peak concentration and water flux showed a significant negative correlation ( p  〈 0.01) with increasing biochar application rate. The results showed that the biochar added to soil could be an effective means of reducing nutrient leaching in soil column experiment in laboratory. CXTFIT 2.0 model was suitable in fitting the observed nitrate transport in upland red soils.

Description: Monitoring the land use/cover change (LUCC) is a vital part of the ecological planning in fast-changing regions. Fast industrial developments, local social dynamics like internal security problems and hard life conditions in rural places can impact LUCC directly. The purpose of this paper was to detect LUCC and its effects on landscape ecology using landscape metrics (LMs) in the Tatvan region of Turkey located in eastern Anatolia. Landscape of the Tatvan region has been transformed due to two main reasons: fast-developing industries in Turkey and security problems in the eastern Anatolian regions since 1985. Landsat 5 TM 1989 and Landsat 8 OLI 2013 satellite images were used to detect LUCC for 24 years. Additionally, landscape changes were evaluated based on LMs to observe the habitat quality change. As a result of the study, settlement areas were increased almost 100 % in 24 years because of immigration from rural to urban areas. At the same time, grasslands were transformed into agricultural lands, settlement and forestlands. Therefore, agricultural activities increased by 45 %. Animal production was the main income in the 1980s, but while the rural population decreased, agricultural activities and industrial income increased around the cities thus animal production lost importance after 2010. From the results of the edge density, mean core area, total core area, mean patch area, Shannon’s diversity index and shape index values, it was observed that overall habitat quality decreased in 24 years.

Description: Passive microwave remotely sensed soil moisture products, such as Advanced Microwave Scanning Radiometer on the Earth Observing System (AMSR-E) data, have been routinely used to monitor global soil moisture patterns. However, they are often limited in their ability to provide reliable spatial distribution data for soil moisture due to their coarse spatial resolutions. In this study, three machine learning approaches—random forest, boosted regression trees, and Cubist—were examined for the downscaling of AMSR-E soil moisture (25 × 25 km) data over two regions (South Korea and Australia) with different climatic characteristics using moderate resolution imaging spectroradiometer products (1 km), including surface albedo, land surface temperature (LST), Normalized Difference Vegetation Index, Enhanced Vegetation Index, Leaf Area Index, and evapotranspiration (ET). Results showed that the random forest approach was superior to the other machine learning models for downscaling AMSR-E soil moisture data in terms of the correlation coefficient [ r  = 0.71/0.84 (South Korea/Australia) for random forest, 0.75/0.77 for boosted regression trees, and 0.70/0.61 for Cubist] and root-mean-square error (RMSE = 0.049/0.057, 0.052/0.078, and 0.051/0.063, respectively) through cross-validation. The ET and LST were identified as the most influential among the six input parameters when estimating AMSR-E soil moisture for South Korea, while ET, albedo, and LST were very useful for Australia. In overall, the downscaled soil moisture with 1 km resolution yielded a higher correlation with in situ observations than the original AMSR-E soil moisture data. The latter appeared higher than the downscaled data in forested areas, possibly due to the overestimation of soil moisture by passive microwave sensors over forests, which implies that downscaling can mitigate such overestimation of soil moisture.