Із листування Олександра і Осипа Барвінських (1869 рік)

Брати Олександр і Осип Барвінські свого часу були активними діячами українського громадського руху Галичини. У публікації листування братів за 1869 рік відображені їхні тогочасні зацікавлення, взаємини з багатьма діячами політики, освіти, культури, обговорювалися питання роботи ряду громадських організацій («Громади», «Просвіти»), видання журналу «Правда» та ін.Oleksandr and Osyp Barvinsky brothers were active figures of ukrainian public movement of their time. The published correspondence of brothers from 1869 shows their interests, relations with many persons of politics, education, culture. A range of questions concerning work of some public organizations («Hromada», «Prosvita»), editing periodical «Pravda» etc. were discussed in letters.Братья Александр и Осип Барвинские в свое время были активными деятелями украинского общественого движения Галичины. В публикации переписки братьев за 1869 год отразились их интересы, взаимосвязи со многими деятелями политики, просвещения, культуры, обсуждались вопросы работы ряда общественных организаций («Громада». «Просвита»), издания журнала «Правда» и др

Uncertainty estimation of end-member mixing using generalized likelihood uncertainty estimation (GLUE), applied in a lowland catchment

End-member mixing models have been widely used to separate the different components of a hydrograph, but their effectiveness suffers from uncertainty in both the identification of end-members and spatiotemporal variation in end-member concentrations. In this paper, we outline a procedure, based on the generalized likelihood uncertainty estimation (GLUE) framework, to more inclusively evaluate uncertainty in mixing models than existing approaches. We apply this procedure, referred to as G-EMMA, to a yearlong chemical data set from the heavily impacted agricultural Lissertocht catchment, Netherlands, and compare its results to the traditional end-member mixing analysis (EMMA). While the traditional approach appears unable to adequately deal with the large spatial variation in one of the end-members, the G-EMMA procedure successfully identified, with varying uncertainty, contributions of five different end-members to the stream. Our results suggest that the concentration distribution of effective end-members, that is, the flux-weighted input of an end-member to the stream, can differ markedly from that inferred from sampling of water stored in the catchment. Results also show that the uncertainty arising from identifying the correct end-members may alter calculated end-member contributions by up to 30%, stressing the importance of including the identification of end-members in the uncertainty assessment

Joint estimation of groundwater salinity and hydrogeological parameters using variable-density groundwater flow, salt transport modelling and airborne electromagnetic surveys

Freshwater aquifers in low elevation coastal zones are known to be threatened by saltwater intrusion (SWI). As these areas host a significant share of the world's population, an excellent understanding of this phenomenon is required to effectively manage the availability of freshwater. SWI is a dynamic process, therefore saline groundwater distributions can change quickly over time – particularly in stressed areas with anthropogenic drivers. To model these changes, regional 3D variable-density groundwater (3D-VDG) flow and coupled salt transport models are often used to estimate the current (and future distributions) of saline groundwater. Unfortunately, parameterising 3D-VDG models is a challenging task with many uncertainties. Generally, uncertainty is reduced through the addition of observational data – such as Airborne Electromagnetic (AEM) surveys or ground-based information – that offer information about parameters such as salinity and hydraulic head. Recent research has shown the ability of AEM surveys to provide accurate 3D groundwater salinity models across regional scales, as well as highlighting the potential for good survey repeatability. To this end we investigated the novel approach of using repeat AEM surveys (flown over the same area at different points in time) and 3D-VDG models to jointly improve the parameterisation of 3D-VDG models - while simultaneously providing a detailed 3D map of groundwater salinity distributions. Using detailed 3D synthetic models, the results of this study quantitatively highlight the usefulness of this approach, while offering practical information on implementation and further research

Measuring Groundwater Flow Velocities near Drinking Water Extraction Wells in Unconsolidated Sediments

Groundwater is an important source of drinking water in coastal regions with predominantly unconsolidated sediments. To protect and manage drinking water extraction wells in these regions, reliable estimates of groundwater flow velocities around well fields are of paramount importance. Such measurements help to identify the dynamics of the groundwater flow and its response to stresses, to optimize water resources management, and to calibrate groundwater flow models. In this article, we review approaches for measuring the relatively high groundwater flow velocity measurements near these wells. We discuss and review their potential and limitations for use in this environment. Environmental tracer measurements are found to be useful for regional scale estimates of groundwater flow velocities and directions, but their use is limited near drinking water extraction wells. Surface-based hydrogeophysical measurements can potentially provide insight into groundwater flow velocity patterns, although the depth is limited in large-scale measurement setups. Active-heating distributed temperature sensing (AH-DTS) provides direct measurements of in situ groundwater flow velocities and can monitor fluctuations in the high groundwater flow velocities near drinking water extraction wells. Combining geoelectrical measurements with AH-DTS shows the potential to estimate a 3D groundwater flow velocity distribution to fully identify groundwater flow towards drinking water extraction wells

Drone-Borne Electromagnetic (DR-EM) Surveying in The Netherlands: Lab and Field Validation Results

In the past decade, drones have become available and affordable for civil applications, including mapping and monitoring the Earth with geophysical sensors. In 2017 and 2019, the feasibility of executing frequency domain electromagnetic (FDEM) surveys using an off-the-shelf drone was investigated at Deltares Institute. This paper reports firstly the preparatory tests executed to determine the optimal instrumental configuration, flight path, data processing and inversion schemes and secondly the three field validation tests executed to demonstrate the feasibility of the drone-borne electromagnetic survey in real-scale applications. At several test sites, the optimal configuration of the drone and electromagnetic instruments, such as the mounting device and distance of the electromagnetic (EM) sensor with respect to the drone, the flight altitude, the coil separation and frequency of the EM source, efficiency and safety, and the assemblage of instrument and drone data were investigated. This has resulted in a robust method to acquire accurate and repeatable in-phase, quadrature and apparent resistivity data, and a workflow for data correction, processing and inversion scheme was developed. During those tests, three EM instruments were tested. The drone-borne electromagnetic (DR-EM) system has the ability and efficacy to fly over inaccessible areas and surface water. Compared to helicopter-borne electromagnetic surveys, the spatial resolution is much higher, which allows very detailed 3D mapping of subsurface targets, and the survey costs are relatively low. Repeated drone-borne electromagnetic (DR-EM) surveys allow low-cost monitoring of local changes in water saturation and salinity

Nonlinear model predictive control of salinity and water level in polder networks: Case study of Lissertocht catchment

A significant increase in surface water salinization in low-lying deltas is expected globally due to saline groundwater exfiltration driven by rising sea levels and decreasing freshwater availability. Sustaining fresh water-dependent agriculture in such areas will entail an increased demand for fresh water flushing. Unfortunately, the flushing of surface water is not operationally optimised and results in excessive use of scarce freshwater. To meet the increased demand for flushing, while minimizing the need for diverted freshwater, new operational designs are required. This paper presents a novel network model based approach that uses De Saint Venant (SV) and Advection Dispersion (AD) equations to optimize multiple objectives on water level and salinity control using a Nonlinear Model Predictive Control (NMPC). The resulting NMPC problem is solved with a receding horizon implementation, where the nonlinear program (NLP) at each iteration is solved using state-of-the-art large scale interior point solver (IPOPT). We evaluate the performance of the proposed approach and compare it to the traditional fixed flushing for a representative Dutch polder. Firstly, the approach is shown to be capable of controlling the water level and salinity level in the polder. Secondly, the results highlight that the network of canals, which were originally made for drainage, could not be made sufficiently fresh with current intake capacity. A simple design approach was used to identify appropriate new capacities for two of the gates that allow optimal flushing to guarantee the required water level and salinity constraints

Offshore fresh groundwater in coastal unconsolidated sediment systems as a potential fresh water source in the 21st century

Coastal areas worldwide are often densely populated and host regional agricultural and industrial hubs. Strict water quality requirements for agricultural, industrial and domestic use are regularly not satisfied by surface waters in coastal areas and consequently lead to over-exploitation of local fresh groundwater resources. Additional pressure by both climate change and population growth further intensifies the upcoming water stress and raise the urgency to search for new fresh water sources. In recent years, offshore fresh groundwater (OFG) reserves have been identified as such a potential water source. In this study, we quantify, for the first time, the global volume of OFG in unconsolidated coastal aquifers using numerical groundwater models. Our results confirm previously reported widespread presence of OFG along the global coastline. Furthermore, we find that these reserves are likely non-renewable resources mostly deposited during glacial periods when sea levels were substantially lower compared to current sea level. We estimate the total OFG volume in unconsolidated coastal aquifers to be approximately 1.06 0.2 million km3, which is roughly three times more than estimated previously and about 10% of all terrestrial fresh groundwater. With extensive active and inactive offshore oil pumping present in areas of large OFG reserves, they could be considered for temporary fresh groundwater exploration as part of a transition to sustainable water use in coastal areas on the long run

Fluid flow in the northern Broad Fourteens Basin during Late Cretaceous inversion

A basin-scale hydrogeological study of the inverted northern Broad Fourteens Basin, Netherlands offshore, has resulted in a reconstruction of geological evolution, an estimate of Late Cretaceous topography and model scenarios of syn-inversion meteoric water infiltration. This study was performed in the scope of a basin-scale analysis of the hydrogeological setting and hydrodynamic evolution of the Broad Fourteens Basin.This analysis is aimed at obtaining quantitative knowledge of depositional history and hydrogeological parameters, and qualitative knowledge of hydrodynamic evolution of the Broad Fourteens Basin from Carboniferous to present-day.We present an overview of the tectonic and depositional history, the most likely hydrogeological setting and model scenarios of Late Cretaceous meteoric water infiltration in the northern Broad Fourteens area. We constructed a detailed south-west north-east geological cross-section of the present-day northern Broad Fourteens Basin, and reconstructed Late Cretaceous basin geometry and topography. Using this geometry in a numerical model of density-dependent topography-driven fluid flow, we modelled several scenarios of meteoric water infiltration with estimated ranges of basin-scale permeabilities and water table head. Results indicate that a deep freshwater lens was developed during Late Cretaceous inversion, if the basin-scale hydraulic conductivity of the Rijnland and Altena Groups was at least 1·10–9 to 1·10–10 m/s, which is in general the highest value for claystones