{"title":"Quantification of data‐related uncertainty of spatially dense soil moisture patterns on the small catchment scale estimated using unsupervised multiple regression","authors":"H. Paasche, Ingmar Schröter","doi":"10.1002/vzj2.20258","DOIUrl":"https://doi.org/10.1002/vzj2.20258","url":null,"abstract":"Multiple regression analysis is a valuable method to reduce information gaps in a sparse soil moisture data set by fusing its information content with those of densely mapped data sets. Regression analysis utilizing uncertain data results in an indeterminate regression model and indeterminate soil moisture predictions when applying the regression model. We employ an unsupervised multiple regression approaches, taking optimally located sparse soil moisture measurements directly as coefficients in a linear regression model. We propagate data uncertainties into our probabilistic soil moisture estimation results by embedding the regression in a Monte Carlo approach. The computed uncertainty defines the quantitative limit for information retrieval from the resultant ensemble of soil moisture maps. This raises doubts on the true presence of some prominent channel‐like features of increased soil moisture that are clearly visible in a previously and deterministically derived soil moisture map ignoring the presence of data uncertainty. The approach followed in this work is computationally simple and could be applied routinely to databases of similar size. Insufficient uncertainty communication by the data provider became the biggest obstacle in our efforts and led us to the insight that the geoscientific community may need to revise their standards with regard to uncertainty communication related to measured and processed data.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49657459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jelte G. H. de Bruin, V. Bense, M. J. van der Ploeg
{"title":"Soil thermal properties during freeze–thaw dynamics as function of variable organic carbon and grain size distribution","authors":"Jelte G. H. de Bruin, V. Bense, M. J. van der Ploeg","doi":"10.1002/vzj2.20252","DOIUrl":"https://doi.org/10.1002/vzj2.20252","url":null,"abstract":"Permafrost regions are experiencing increasing air temperatures, accelerating the thawing process, and thickening the active layer in summer. This can accelerate the release of greenhouse gasses into the atmosphere from the organic carbon stored in the permafrost. The long‐term thawing rates of permafrost below the active layer are governed by the soil thermal properties, the heat capacity, and thermal conductivity, which vary due to differences in grain sizes and distribution and organic matter content. Using nine column experiments comprised of fully saturated synthetic permafrost samples exposed to freeze–thaw cycles, the relative contributions of a range of soil grain sizes and organic matter contents on the soil thermal properties were investigated. The columns were subjected to a freeze and thaw cycle while soil temperatures were recorded in profiles. To infer the thermal properties from these experimental data, a numerical heat transfer model was used. The best fit between the observations and a batch of 5544 numerical models was used to find optimum values for permafrost thermal properties. The optimized heat capacity varied between 500 and 650 (J/m3 K) and thermal conductivity between 2.45 and 3.55 (W/m K). These optimized parameters were subsequently used to model a 100‐year permafrost active layer thaw scenario under warming air temperatures. Variations in the optimized thermal properties resulted in a time difference in thawing depth of 10–15 years and thawing depths varied between 9 and 10 m between the different optimized thermal properties at the end of the 100‐year scenario.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46992854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Wolf prize awarded to Rien van Genuchten","authors":"V. Lakshmi, M. Flury","doi":"10.1002/vzj2.20253","DOIUrl":"https://doi.org/10.1002/vzj2.20253","url":null,"abstract":"Martinus Th. (“Rien”) van Genuchten has been awarded the 2023 Wolf Prize in Agriculture. The Wolf Prize is awarded to “outstanding scientists and artists from around the world for achievements in the interest of humanity and friendly relations among people.” The prize is awarded in the disciplines of medicine, agriculture, mathematics, chemistry, and physics. For agricultural sciences, the Wolf Prize is widely considered one of the world’s most prestigious recognitions. Rien van Genuchten was born in 1945 in Vught, The Netherlands. He received his early education at the Agricultural University of Wageningen, The Netherlands, and his PhD at New Mexico State University in the United States. He then spent most of his career at the US Salinity Laboratory in Riverside, CA, before moving to the University of Rio de Janeiro, Brazil, and to Utrecht University, The Netherlands. One of his most influential publications describes a closed-form equation for predicting the hydraulic conductivity of unsaturated soils, known as the van Genuchten equation (van Genuchten, 1980). He was, together with Jirka Simunek, the developer of the widely used HYDRUS software package for simulating the movement of water, heat, and solutes in variably saturated media (Šimůnek et al., 2016). Early in his career, he also published a compendium on analytical solutions of the one-dimensional convection–dispersion equation (van Genuchten & Alves, 1982), a resource widely used to analyse solute transport at the column and field scale.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45493792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Monitoring spatiotemporal soil moisture variability in the unsaturated zone of a mixed forest using electrical resistivity tomography","authors":"Julia S. Rieder, C. Kneisel","doi":"10.1002/vzj2.20251","DOIUrl":"https://doi.org/10.1002/vzj2.20251","url":null,"abstract":"European forests are suffering considerably from the consequences of the droughts of recent years, and the exact reasons and influencing factors for this are still not fully understood. This study was conducted to characterize the changes and dynamics of soil moisture in a mixed forest in northern Bavaria within 1 year. Since electrical resistivity correlates well with soil water content, we used two‐dimensional electrical resistivity tomography (ERT) monitoring and time‐lapse analyses to supplement punctual measurements by sensors and soil analyses to show soil moisture changes throughout a whole year (2020–2021). While the topsoil dries out significantly from summer to autumn down to a depth of about 3 m, a clear increase in soil water content and a decrease in resistivity below 3 m can be observed during winter period. Anomalies in the topsoil (0–1 m) showing lower resistivities than the surrounding substrate could be related to tree positions by additional terrestrial laser scans. A significant relationship could be found between tree crown projection area and resistivity in 1–2 m depth. We found a trend that mean resistivity below pine is lower as below beech. ERT data were also used to estimate the soil water content via Archie's law and the results correlate strongly with the measured values, but the degree of correlation varies depending on the depth level. ERT as a noninvasive method, in combination with additional data, for example, on the vitality status of individual trees, could help to better understand root water uptake and water supply to trees, especially during periods of drought.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45332630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Banasiak, L. Weaver, B. Humphries, R. Dann, Martina Blaurock, M. Gosses, L. Pang, M. Close
{"title":"Microbial and solute transport through intact vadose zone cores of heterogeneous alluvial gravel under variably saturated conditions","authors":"L. Banasiak, L. Weaver, B. Humphries, R. Dann, Martina Blaurock, M. Gosses, L. Pang, M. Close","doi":"10.1002/vzj2.20250","DOIUrl":"https://doi.org/10.1002/vzj2.20250","url":null,"abstract":"The movement of bacterial and viral pathogens through soil and vadose zone and subsequently into groundwater is a major public health concern. There are relatively few studies on the transport and fate of microbes through variably saturated vadose zone media compared with their transport in the soil and saturated groundwater zones. In this study, we investigated the transport of Escherichia coli, F‐RNA bacteriophage MS2, and a conservative solute tracer bromide through three intact vadose zone cores, under saturated (discharge rate ∼100 mm h−1) and unsaturated (discharge rate 10 and 0.5 mm h−1) flow conditions. The vadose zone media were sandy gravel overlying a sand lens in core 1, a heterogeneous SG mix in core 2, and SG with an open framework gravel lens through the middle of the core in core 3. The three flow regimes resulted in different transport characteristics through each of the cores. As expected, microbial transport through all cores was higher under saturated conditions, compared with unsaturated conditions. Overall, E. coli removal was consistently greater than that of MS2 phage irrespective of core media or flow conditions. There were relatively minor removals (factors of 1–2.5) of both microbes under saturated conditions, reductions of 2–3 orders of magnitude under the high flow unsaturated conditions, and almost complete removal (4 to >5 orders of magnitude) under the low flow unsaturated conditions. The much greater removal of microbes under unsaturated conditions has significant implications and potential benefits for land management decisions.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":"22 1","pages":"20 - 3"},"PeriodicalIF":2.8,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46245131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Min Shi, Yuesuo Yang, Ying Lu, Xi Zhang, Jinyu Shi
{"title":"Design of a bioaugmented soil aquifer treatment for efficient removal of p‐nitrophenol","authors":"Min Shi, Yuesuo Yang, Ying Lu, Xi Zhang, Jinyu Shi","doi":"10.1002/vzj2.20242","DOIUrl":"https://doi.org/10.1002/vzj2.20242","url":null,"abstract":"Secondary effluent reclamation and reuse is an effective solution to the water shortage problem, and the safety of reused water is a matter of increasing concern. p‐Nitrophenol (PNP), a common secondary effluent pollutant, can be efficiently removed using the eco‐friendly bioaugmented soil aquifer treatment (SAT) system at the laboratory scale. In this study, a sewage treatment plant in Changchun was selected as a case study to apply the bioaugmented SAT system for field scenarios efficiently. The bioaugmented SAT system was simulated using HYDRUS‐1D code. Biodegradation and adsorption coefficient were conducted from the batch experiment. Based on the degradation experiments, the concentration of bacteria injected into SAT system was designed to be 6 × 1018 colony‐forming units (CFU) m−3. To enhance the efficiency of the bioaugmented SAT system, the key parameters were optimized based on the sensitivity analysis and the response surface methodology, which showed that the optimal operating conditions were an initial concentration of 86.11 mg L−1, a medium of 4.27‐m thickness, and a wet/dry ratio of 0.28. Specifically, alternated wetting–drying conditions and increasing the medium thickness reduced PNP within a specific range. This work demonstrates the performance and applicability of the bioaugmented SAT system for removal PNP in secondary sewage effluent.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44206171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cover Image, Volume 22, Issue 1","authors":"","doi":"10.1002/vzj2.20248","DOIUrl":"https://doi.org/10.1002/vzj2.20248","url":null,"abstract":"<b>On the cover</b>: Scanning electron microscope image of a clay colloid. See Shi et al., “Impact of heavy metal cations on deposition and release of clay colloids in saturated porous media,” https://doi.org/10.1002/vzj2.20179.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":"61 7","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138505130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Pouye, S. Cissé Faye, M. Diédhiou, C. Gaye, R. Taylor
{"title":"Nitrate contamination of urban groundwater and heavy rainfall: Observations from Dakar, Senegal","authors":"A. Pouye, S. Cissé Faye, M. Diédhiou, C. Gaye, R. Taylor","doi":"10.1002/vzj2.20239","DOIUrl":"https://doi.org/10.1002/vzj2.20239","url":null,"abstract":"In low‐income urban areas of major cities in Africa, sanitation provision derives primarily from onsite systems often comprising septic tanks and pit latrines. Such systems rely upon the ability of the surrounding soil and substratum to attenuate contaminants like nitrate and pathogenic microorganisms in wastewater. Here, we assess soil–water and solute dynamics in Quaternary aeolian sands underlying a densely populated suburb (Keur Massar) of Dakar (Senegal) using high‐frequency monitoring and vadose zone modeling (Hydrus‐1D). Observations of rainfall intensity, soil moisture content, and shallow groundwater‐level fluctuations and nitrate concentrations were carried out at an experimental site adjacent to a septic tank supplied by toilets used by a primary school. Rapid rises in soil moisture content and episodic recharge contributions observed in groundwater levels caused by heavy (>10 mm h−1) and extreme (>20 mm h−1) rainfall are well modeled (R2 = .79–.83; RMSE = 0.012–0.019) by pore‐matrix flow in the unsaturated zone by the Darcy–Richards equation. Spot sampling around the most intense rainfall of 2020 (45 mm h−1) reveals a fivefold rise and fall in the concentration of nitrate in soil moisture (∼500 to ∼2,500 mg L−1). These measurements provide new insight into the hydrological dynamics by which shallow groundwater is grossly contaminated (>500 mg L−1) by nitrate through episodic flushing by heavy rainfall of wastewater from a vast estimated network of over 250,000 septic tanks underlying this suburb of Dakar.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45586412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Recipients of 2022 VZJ Editor's Citation for Excellence named","authors":"Emmanuel Arthur, Josh Heitman, Steffen Schlüter","doi":"10.1002/vzj2.20255","DOIUrl":"https://doi.org/10.1002/vzj2.20255","url":null,"abstract":"The Vadose Zone Journal editorial board has selected four individuals for recognition for excellence in performing their work as associate editors. The recognition is based on their efforts in establishing a quality review process—for timely and professional manuscript editing, for fair and rigorous integration of reviewer comments, and for overall excellence in managing a professional review process. The editorial board has also chosen four individuals for the Editor’s Citation for Excellence in Review. Members of the VZJ Editorial Board want to express their deepest appreciation for these associate editors and volunteer reviewers, who have benefited our journal, our community, and our sciences through their outstanding work.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":"3 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50991060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}