•Two methods are combined to increase confidence in recharge estimation.•Natural fluctuations of groundwater table are reproduced in 1D numerical models.•Modified bottom boundary condition represents ...a relationship between head and flux.•Large variations of annual recharge follow the differences in annual precipitation.
Quantification of groundwater recharge is one of the most important issues in hydrogeology, especially in view of the ongoing changes in climate and land use. In this study, we use numerical models of 1D vertical flow in the vadose zone and the water table fluctuation (WTF) analysis to investigate local-scale recharge of a shallow sandy aquifer in the Brda outwash plain in northern Poland. We show that these two methods can be jointly used to improve confidence in recharge estimation. A set of preliminary numerical simulations based on soil water content measurements from 4 grassland and pine forest profiles provided a wide range of recharge estimates (263 mm to 839 mm for a 3-year period). Additional simulations were performed with the lower boundary condition specified as a functional relationship between the groundwater table elevation and the rate of groundwater outflow from the vertical profile (horizontal drains boundary condition). In this way, we could reproduce the water table fluctuations resulting from recharge and lateral discharge to nearby lakes. The agreement between simulated and observed groundwater levels differed depending on the specific set of parameters characterizing vadose zone flow, which allowed us to find the most representative parameter sets and refine the range of plausible recharge estimates (501 mm to 573 mm per 3 years). The recharge rates from WTF (410 mm to 606 mm per 3 years) were in good agreement with numerical simulations, providing that the effect of the natural recession of groundwater table due to lateral outflow was considered (master recession curve method). Our results show that: (i) the proposed approach combining 1D vadose zone modeling and WTF improves recharge estimation, (ii) multiple types of observations, including groundwater table positions, are needed to calibrate and validate vadose zone flow models, and (iii) extended periods of observations and simulations are necessary to capture year-to-year variability in the recharge rates.
Bauxite residue has been continuously produced since the inception of the alumina/aluminium industry in the late nineteenth century. The global inventory of bauxite residue reached an estimated 2.7
...billion
tonnes in 2007 increasing at 120
million
tonnes per annum. This growth highlights the urgency to develop and implement improved means of storage and remediation, and to pursue large-volume utilization options of residue as an industrial by-product. This review looks at current management practices for disposal and amendment, and how each unit process influences residue properties. Since 1980 the trend has been away from lagoon-type impoundments towards “dry” stacking; this reduces the potential for leakage, reduces the physical footprint and improves recoveries of soda and alumina. Associated technical developments in residue neutralization are considered with possible future practices in residue disposal and how that might best integrate with future utilization. For example, hyperbaric steam filtration is an emerging technology that could discharge residue as a dry, granular material of low soda content. Such properties are beneficial to long term storage and remediation, but importantly also to future utilization. Although residue has a number of characteristics of environmental concern, the most immediate and apparent barrier to remediation and utilization (improved sustainability) is its high alkalinity and sodicity. The sustained alkalinity is the result of complex solid-state and solution phase interactions while its sodicity arises from the use of caustic soda (NaOH) for digestion. This is the first in a series of four related reviews examining bauxite residue issues in detail.
► Review of bauxite residue (disposal and storage) management. ► Global inventory of stored residue 2.7
billion
tonnes. ► Only incremental improvement in residue management after 120
years. ► Barriers to utilization or remediation of high alkalinity and sodicity.
Next-generation (NG) sequencing in a natural population of Populus nigra revealed a mutant with a premature stop codon in the gene encoding hydroxycinnamoyl-CoA: shikimate hydroxycinnamoyl ...transferase1 (HCT1), an essential enzyme in lignin biosynthesis.
The lignin composition of P. nigra trees homozygous for the defective allele was compared with that of heterozygous trees and trees without the defective allele. The lignin was characterized by phenolic profiling, lignin oligomer sequencing, thioacidolysis and NMR. In addition, HCT1 was heterologously expressed for activity assays and crosses were made to introduce the mutation in different genetic backgrounds.
HCT1 converts p-coumaroyl-CoA into p-coumaroyl shikimate. The mutant allele, PnHCT1-Δ73, encodes a truncated protein, and trees homozygous for this recessive allele have a modified lignin composition characterized by a 17-fold increase in p-hydroxyphenyl units.
Using the lignin pathway as proof of concept, we illustrated that the capture of rare defective alleles is a straightforward approach to initiate reverse genetics and accelerate tree breeding. The proposed breeding strategy, called ‘breeding with rare defective alleles’ (BRDA), should be widely applicable, independent of the target gene or the species.
The main aim of this work is focused on water quality classification of the Brda river (Poland) and evaluation of pollution data obtained by the monitoring measurement during the period 1994–2002. ...The study presents the application of selected chemometric techniques to the pollution monitoring dataset, namely, cluster analysis, principal component analysis, discriminant analysis and factor analysis. The obtained results allowed to determine natural clusters and groups of monitoring locations with similar pollution character and identify important discriminant variables. Chemometric analysis confirmed the classification of water purity of the Brda river made by the Inspection of Environmental Protection but the results showed more differentiation between monitored locations. This enables better evaluation of the water quality in a monitored region. On the basis of the chemometric approach, it was also found that some locations were under the high influence of municipal contamination, and some others under the influence of agriculture (discharges from fields) within the observed time period.
It is commonly believed that changes in the use of the catchment area have a direct impact on the quality of the water environment. Rivers with dams and reservoirs are characterized by a disturbed ...outflow of sediments and nutrients from the catchment area. The research was based on indicating the variation in time and space of loads of selected parameters of the water quality of the Brda River (Northern Poland) against the land cover changes based on the CORINE Land Cover (CLC) data for the 1990–2018 period. In the lower part of the Brda catchment area, there are three hydropower dams with reservoirs in the form of a cascade, whose work clearly affects the hydrological regime of the river. The analysis of the dependence of the dynamics of water quality changes on the usage of CLC was based on indicators such as sediments (suspended sediment load) and nutrients (total phosphorus load and total nitrogen load). The use of hydrological data on the Brda discharge above and below the reservoirs made it possible to calculate sediment and nutrient trapping efficiency. Linking the CLC data with the indices responsible for the mechanical denudation of the catchment area made it possible to show the strength of changes taking place in the catchment area. The results of the research do not indicate any direct correlation between land cover changes and the dynamics of the denudation process and matter transport in the Brda catchment area. As our research shows, the strong influence on the hydrological regime of the catchment points out the necessity to search for still other research methods supporting the decision-making cycle in the field of water management in the face of climate change.
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