A. Szabó, Z. Gribovszki, P. Kalicz, J. Szolgay, Bence Bolla
Abstract The decline in groundwater levels is a cause of concern in many regions of the world, including the Sand Ridge of Hungary. The causes of the regional depletion range from rising air temperatures, changes in precipitation, domestic and agricultural groundwater use and past amelioration and recent afforestation, including the effects of drilling for crude oil exploration. The relations between the decline, the soil water regime and groundwater recharge under existing aged forests remained unclear thus far. Based on our monitoring of groundwater and soil moisture we aim to clarify this interplay in a new experimental site on the hilltop of the Sand Ridge. We compared three land-uses: a 41-year-old black locust (Robinia Pseudoacacia) offshoot forest, an 83-year-old first generation black pine (Pinus nigra) forest, and a grassland control site. The observed differences in the soil moisture profiles and dynamics were connected to the use of water by the given type of vegetation. We indicated a connection between the disruption of the groundwater recharge and the loss of contact of the rooting system of the forests with the deepening of the unconfined aquifer. Even if the aged forests could locally contribute to the decline, we conclude that the decline at the hilltop site that may be more strongly driven by other regional factors.
{"title":"The soil moisture regime and groundwater recharge in aged forests in the Sand Ridge region of Hungary after a decline in the groundwater level: an experimental case study","authors":"A. Szabó, Z. Gribovszki, P. Kalicz, J. Szolgay, Bence Bolla","doi":"10.2478/johh-2022-0019","DOIUrl":"https://doi.org/10.2478/johh-2022-0019","url":null,"abstract":"Abstract The decline in groundwater levels is a cause of concern in many regions of the world, including the Sand Ridge of Hungary. The causes of the regional depletion range from rising air temperatures, changes in precipitation, domestic and agricultural groundwater use and past amelioration and recent afforestation, including the effects of drilling for crude oil exploration. The relations between the decline, the soil water regime and groundwater recharge under existing aged forests remained unclear thus far. Based on our monitoring of groundwater and soil moisture we aim to clarify this interplay in a new experimental site on the hilltop of the Sand Ridge. We compared three land-uses: a 41-year-old black locust (Robinia Pseudoacacia) offshoot forest, an 83-year-old first generation black pine (Pinus nigra) forest, and a grassland control site. The observed differences in the soil moisture profiles and dynamics were connected to the use of water by the given type of vegetation. We indicated a connection between the disruption of the groundwater recharge and the loss of contact of the rooting system of the forests with the deepening of the unconfined aquifer. Even if the aged forests could locally contribute to the decline, we conclude that the decline at the hilltop site that may be more strongly driven by other regional factors.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"308 - 320"},"PeriodicalIF":1.9,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48543844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Fér, Antonín Nikodem, Sára Trejbalová, A. Klement, L. Pavlů, R. Kodešová
Abstract An application of different mulch materials may lead to changes in soil properties. Our previous study, focused on the impact of various mulches during the 4-year period, showed that the change in some properties can be very rapid (e.g., soil pH), but in other cases such as hydraulic properties, the changes can be gradual. To find out, whether the extension of the mulching period will further affect the studied soil properties, the experiment continued for another 2 years. Differences between values of organic carbon content (Cox), soil physical quality (Sinf), gravitational water (GW) and readily available water (RAW) of soils not covered by any mulch and under various mulches (bark chips; wood chips; wheat straw; Agrotex EKO+ decomposable matting; polypropylene fabric covered bark chips; crushed stone) were much larger than those observed in our previous study. On the other hand, the opposite trend was observed for the water stable aggregates (WSA) index or soil pH. Differences between additionally measured hydraulic conductivities at the pressure head of −2 cm and repellency index (RI) were mostly insignificant. Results indicated that organic mulches can either positively (e.g., increase WSA index and Cox, and decrease GW) or negatively (e.g., decrease Sinf and RAW, and increase RI) affect soil properties.
{"title":"How various mulch materials can affect the soil hydro-physical properties","authors":"M. Fér, Antonín Nikodem, Sára Trejbalová, A. Klement, L. Pavlů, R. Kodešová","doi":"10.2478/johh-2022-0016","DOIUrl":"https://doi.org/10.2478/johh-2022-0016","url":null,"abstract":"Abstract An application of different mulch materials may lead to changes in soil properties. Our previous study, focused on the impact of various mulches during the 4-year period, showed that the change in some properties can be very rapid (e.g., soil pH), but in other cases such as hydraulic properties, the changes can be gradual. To find out, whether the extension of the mulching period will further affect the studied soil properties, the experiment continued for another 2 years. Differences between values of organic carbon content (Cox), soil physical quality (Sinf), gravitational water (GW) and readily available water (RAW) of soils not covered by any mulch and under various mulches (bark chips; wood chips; wheat straw; Agrotex EKO+ decomposable matting; polypropylene fabric covered bark chips; crushed stone) were much larger than those observed in our previous study. On the other hand, the opposite trend was observed for the water stable aggregates (WSA) index or soil pH. Differences between additionally measured hydraulic conductivities at the pressure head of −2 cm and repellency index (RI) were mostly insignificant. Results indicated that organic mulches can either positively (e.g., increase WSA index and Cox, and decrease GW) or negatively (e.g., decrease Sinf and RAW, and increase RI) affect soil properties.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"269 - 275"},"PeriodicalIF":1.9,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45700466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marco Maio, G. Marini, N. Fontana, P. Gualtieri, G. Caroppi
Abstract This paper explores the impacts of reconfiguration and leaf morphology on the flow downstream of a flexible foliated plant. 3D acoustic Doppler velocimetry and particle image velocimetry were used to experimentally investigate the hydrodynamic interaction between a foliated plant and the flow, testing two plants with different leaves morphology under different bulk flow velocities. The model vegetation was representative of riparian vegetation species in terms of plants hydrodynamic behavior and leaf to stem area ratio. To explore the effects of the seasonal variability of vegetation on the flow structure, leafless conditions were tested. Reconfiguration resulted in a decrease of the frontal projected area of the plants up to the 80% relative to the undeformed value. Such changes in plant frontal area markedly affected the spatial distributions of mean velocity and turbulence intensities, altering the local exchanges of momentum. At increasing reconfiguration, the different plant morphology influenced the mean and turbulent wake width. The leafless stem exhibited a rigid behavior, with the flow in the wake being comparable to that downstream of a rigid cylinder. The study revealed that the flexibility-induced reconfiguration of plants can markedly affect the local distribution of flow properties in the wake, potentially affecting transport processes at the scale of the plant and its subparts.
{"title":"Impact of reconfiguration on the flow downstream of a flexible foliated plant","authors":"Marco Maio, G. Marini, N. Fontana, P. Gualtieri, G. Caroppi","doi":"10.2478/johh-2022-0017","DOIUrl":"https://doi.org/10.2478/johh-2022-0017","url":null,"abstract":"Abstract This paper explores the impacts of reconfiguration and leaf morphology on the flow downstream of a flexible foliated plant. 3D acoustic Doppler velocimetry and particle image velocimetry were used to experimentally investigate the hydrodynamic interaction between a foliated plant and the flow, testing two plants with different leaves morphology under different bulk flow velocities. The model vegetation was representative of riparian vegetation species in terms of plants hydrodynamic behavior and leaf to stem area ratio. To explore the effects of the seasonal variability of vegetation on the flow structure, leafless conditions were tested. Reconfiguration resulted in a decrease of the frontal projected area of the plants up to the 80% relative to the undeformed value. Such changes in plant frontal area markedly affected the spatial distributions of mean velocity and turbulence intensities, altering the local exchanges of momentum. At increasing reconfiguration, the different plant morphology influenced the mean and turbulent wake width. The leafless stem exhibited a rigid behavior, with the flow in the wake being comparable to that downstream of a rigid cylinder. The study revealed that the flexibility-induced reconfiguration of plants can markedly affect the local distribution of flow properties in the wake, potentially affecting transport processes at the scale of the plant and its subparts.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"357 - 375"},"PeriodicalIF":1.9,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43640971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The aim of the study was to evaluate the climate and geographic factors controlling the hydrological drought of the rivers located in the Upper Vistula catchment in the Polish Carpathians. Drought was identified based on the daily flow (based on water stage measered once a day at 6 UTC) series dating from between 1975 and 2019 at 49 gauging cross-sections. Four physico-geographical regions were identified in the Polish Carpathians and spatial variabilities of the basic drought characteristics were developed within these regions. Such spatial distributions were treated as maps indicating drought hazard areas in the region. In addition, an analysis was undertaken to study the seasonality of the start and end times of the drought (all in the multi-annual period), the longest duration of droughts, the droughts of the highest volume in multi-annual period, as well as the number of drought days. Multi-annual variability of the number of drought days was also analysed. The results suggest that droughts in the Polish Carpathians are events characteristic of summer and autumn, whereas in the Tatra Mountains and the Podhale region - of autumn and winter. The greatest hazard of a prolonged and high-volume drought occurs in the Podhale region and the Tatra Mountains, while the lowest hazard is observed in the Bieszczady Mountains and the eastern part of the studied area.
{"title":"The spatial and temporal variability of hydrological drought in the Polish Carpathians","authors":"K. Baran-Gurgul","doi":"10.2478/johh-2022-0007","DOIUrl":"https://doi.org/10.2478/johh-2022-0007","url":null,"abstract":"Abstract The aim of the study was to evaluate the climate and geographic factors controlling the hydrological drought of the rivers located in the Upper Vistula catchment in the Polish Carpathians. Drought was identified based on the daily flow (based on water stage measered once a day at 6 UTC) series dating from between 1975 and 2019 at 49 gauging cross-sections. Four physico-geographical regions were identified in the Polish Carpathians and spatial variabilities of the basic drought characteristics were developed within these regions. Such spatial distributions were treated as maps indicating drought hazard areas in the region. In addition, an analysis was undertaken to study the seasonality of the start and end times of the drought (all in the multi-annual period), the longest duration of droughts, the droughts of the highest volume in multi-annual period, as well as the number of drought days. Multi-annual variability of the number of drought days was also analysed. The results suggest that droughts in the Polish Carpathians are events characteristic of summer and autumn, whereas in the Tatra Mountains and the Podhale region - of autumn and winter. The greatest hazard of a prolonged and high-volume drought occurs in the Podhale region and the Tatra Mountains, while the lowest hazard is observed in the Bieszczady Mountains and the eastern part of the studied area.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"156 - 169"},"PeriodicalIF":1.9,"publicationDate":"2022-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48996938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thaís M. G. Silveira, F. Hoerlle, A. S. Rocha, M. Lima, M. G. Ramirez, E. Pontedeiro, M. V. van Genuchten, Daniel O.A. Cruz, P. Couto
Abstract CO2 injection is a well-known Enhanced Oil Recovery (EOR) technique that has been used for years to improve oil extraction from carbonate rock and other oil reservoirs. Optimal functioning of CO2 injection requires a thorough understanding of how this method affects the petrophysical properties of the rocks. We evaluated pore-scale changes in these properties, notably porosity and absolute permeability, following injection of CO2-saturated water in two coquina outcrop samples from the Morro do Chaves Formation in Brazil. The coquinas are close analogues of Pre-salt oil reservoirs off the coast of southern Brazil. The effects of carbonated water injection were evaluated using a series of experimental and numerical steps before and after coreflooding: cleaning, basic petrophysics, microtomography (microCT) imaging, nuclear magnetic resonance (NMR) analyses, and pore network modeling (PNM). Our study was motivated by an earlier experiment which did not show the development of a wormhole in the center of the sample, with a concomitant increase in permeability of the coquina as often noted in the literature. We instead observed a substantial decrease in the absolute permeability (between 71 and 77%), but with little effect on the porosity and no wormhole formation. While all tests were carried out on both samples, here we present a comprehensive analysis for one of the samples to illustrate changes at the pore network level. Different techniques were used for the pore-scale analyses, including pore network modeling using PoreStudio, and software developed by the authors to enable a statistical analysis of the pore network. Results provided much insight in how injected carbonated water affects the pore network of carbonate rocks.
摘要CO2注入是一种众所周知的提高采收率（EOR）技术，多年来一直用于改善碳酸盐岩和其他油藏的采油效果。CO2注入的最佳功能需要彻底了解这种方法如何影响岩石的岩石物理性质。在巴西Morro do Chaves组的两个coquina露头样品中注入二氧化碳饱和水后，我们评估了这些性质的孔隙尺度变化，特别是孔隙度和绝对渗透率。coquinas与巴西南部海岸的盐前油藏非常相似。在岩心驱油前后，使用一系列实验和数值步骤评估了碳酸水注入的效果：清洁、基础岩石物理、显微CT成像、核磁共振（NMR）分析和孔隙网络建模（PNM）。我们的研究动机是早期的一项实验，该实验没有显示样品中心出现虫洞，同时文献中经常提到的coquina的渗透率增加。相反，我们观察到绝对渗透率显著降低（在71%和77%之间），但对孔隙度几乎没有影响，也没有形成虫洞。虽然所有测试都是在两个样本上进行的，但在这里，我们对其中一个样本进行了全面分析，以说明孔隙网络水平的变化。孔隙尺度分析使用了不同的技术，包括使用PoreStudio的孔隙网络建模，以及作者开发的用于对孔隙网络进行统计分析的软件。研究结果为注入的碳酸水如何影响碳酸盐岩的孔隙网络提供了很多见解。
{"title":"Effects of carbonated water injection on the pore system of a carbonate rock (coquina)","authors":"Thaís M. G. Silveira, F. Hoerlle, A. S. Rocha, M. Lima, M. G. Ramirez, E. Pontedeiro, M. V. van Genuchten, Daniel O.A. Cruz, P. Couto","doi":"10.2478/johh-2022-0001","DOIUrl":"https://doi.org/10.2478/johh-2022-0001","url":null,"abstract":"Abstract CO2 injection is a well-known Enhanced Oil Recovery (EOR) technique that has been used for years to improve oil extraction from carbonate rock and other oil reservoirs. Optimal functioning of CO2 injection requires a thorough understanding of how this method affects the petrophysical properties of the rocks. We evaluated pore-scale changes in these properties, notably porosity and absolute permeability, following injection of CO2-saturated water in two coquina outcrop samples from the Morro do Chaves Formation in Brazil. The coquinas are close analogues of Pre-salt oil reservoirs off the coast of southern Brazil. The effects of carbonated water injection were evaluated using a series of experimental and numerical steps before and after coreflooding: cleaning, basic petrophysics, microtomography (microCT) imaging, nuclear magnetic resonance (NMR) analyses, and pore network modeling (PNM). Our study was motivated by an earlier experiment which did not show the development of a wormhole in the center of the sample, with a concomitant increase in permeability of the coquina as often noted in the literature. We instead observed a substantial decrease in the absolute permeability (between 71 and 77%), but with little effect on the porosity and no wormhole formation. While all tests were carried out on both samples, here we present a comprehensive analysis for one of the samples to illustrate changes at the pore network level. Different techniques were used for the pore-scale analyses, including pore network modeling using PoreStudio, and software developed by the authors to enable a statistical analysis of the pore network. Results provided much insight in how injected carbonated water affects the pore network of carbonate rocks.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"257 - 268"},"PeriodicalIF":1.9,"publicationDate":"2022-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48861288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Vegetation and biocrust play crucial roles in dune stability and mobility, and their interaction can lead to bistability, temporal oscillations, and hysteresis. We studied a two-dimensional (2D) mathematical model of vegetation and biogenic crust cover dynamics on sand dunes. Under a certain parameter range, the space-independent version of the model exhibited the bi-stability of an oscillatory state and a steady state, and we studied the 2D dynamics of the model under these parameters. The patterns developed by the 2D model showed a high degree of spatial heterogeneity and complexity depending on the initial conditions and on the state type across the front. The results suggest that spatial heterogeneity and complexity can evolve from the intrinsic dynamics between vegetation and biocrust, even without natural geodiversity and spatiotemporal climate fluctuations. In the real world, these two types of intrinsic and extrinsic heterogeneity processes interact such that it is difficult to distinguish between them.
{"title":"Sand dune vegetation-biocrust interaction as a source of spatial heterogeneity","authors":"H. Yizhaq, Y. Ashkenazy","doi":"10.2478/johh-2022-0008","DOIUrl":"https://doi.org/10.2478/johh-2022-0008","url":null,"abstract":"Abstract Vegetation and biocrust play crucial roles in dune stability and mobility, and their interaction can lead to bistability, temporal oscillations, and hysteresis. We studied a two-dimensional (2D) mathematical model of vegetation and biogenic crust cover dynamics on sand dunes. Under a certain parameter range, the space-independent version of the model exhibited the bi-stability of an oscillatory state and a steady state, and we studied the 2D dynamics of the model under these parameters. The patterns developed by the 2D model showed a high degree of spatial heterogeneity and complexity depending on the initial conditions and on the state type across the front. The results suggest that spatial heterogeneity and complexity can evolve from the intrinsic dynamics between vegetation and biocrust, even without natural geodiversity and spatiotemporal climate fluctuations. In the real world, these two types of intrinsic and extrinsic heterogeneity processes interact such that it is difficult to distinguish between them.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"145 - 155"},"PeriodicalIF":1.9,"publicationDate":"2022-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46903214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The design and evaluation of algorithms for adaptive stochastic control of the reservoir function of a water reservoir using an artificial intelligence method (learned fuzzy model) are described in this article. This procedure was tested on the Vranov reservoir (Czech Republic). Stochastic model results were compared with the results of deterministic management obtained using the method of classical optimisation (differential evolution). The models used for controlling of reservoir outflow used single quantile from flow duration curve values or combinations of quantile values from flow duration curve for determination of controlled outflow. Both methods were also tested on forecast data from real series (100% forecast). Finally, the results of the dispatcher graph, adaptive deterministic control and adaptive stochastic control were compared. Achieved results of adaptive stochastic management were better than results provided by dispatcher graph and provide inspiration for continuing research in the field.
{"title":"Adaptive stochastic management of the storage function for a large, open reservoir using learned fuzzy models","authors":"T. Kozel, M. Starý","doi":"10.2478/johh-2022-0010","DOIUrl":"https://doi.org/10.2478/johh-2022-0010","url":null,"abstract":"Abstract The design and evaluation of algorithms for adaptive stochastic control of the reservoir function of a water reservoir using an artificial intelligence method (learned fuzzy model) are described in this article. This procedure was tested on the Vranov reservoir (Czech Republic). Stochastic model results were compared with the results of deterministic management obtained using the method of classical optimisation (differential evolution). The models used for controlling of reservoir outflow used single quantile from flow duration curve values or combinations of quantile values from flow duration curve for determination of controlled outflow. Both methods were also tested on forecast data from real series (100% forecast). Finally, the results of the dispatcher graph, adaptive deterministic control and adaptive stochastic control were compared. Achieved results of adaptive stochastic management were better than results provided by dispatcher graph and provide inspiration for continuing research in the field.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"213 - 221"},"PeriodicalIF":1.9,"publicationDate":"2022-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43904180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ruan G. S. Gomes, G. Gomes, E. Vargas, M. V. van Genuchten, J. Pinto, Felipe A. Rosa
Abstract Field tests were carried out to estimate effective unsaturated soil hydraulic properties of layered residual soils in Rio de Janeiro, southeastern Brazil. Data of this type are important for understanding the initiation of rainstorm-induced soil landslides, which often occur in the state of Rio de Janeiro as well as other areas having similar geologic settings and climate conditions. Tests were carried out using a simplified field approach, referred to as the Monitored Infiltration Test, which requires only a tensiometer to measure pressure heads below the wetting front, triggered by flow from a Mariotte bottle which maintains a constant pressure at the top edge of the soil profile. The data can then be analyzed by numerical inversion using the HYDRUS-2D software package. The test is relatively fast since no steady-state flow conditions are needed, and versatile since the test can be carried out quickly on steep slopes with the help of a manual auger. Soil water retention and the unsaturated hydraulic conductivity functions were obtained for a range of young, mature and saprolitic residual soils. The effective hydraulic properties of the distinct residual soil layers can be quite large, reflecting a need to provide a careful analysis of field-scale hydraulic heterogeneity in geotechnical analyses.
{"title":"Field-scale assessment of the unsaturated hydraulic properties of residual soils in southeastern Brazil","authors":"Ruan G. S. Gomes, G. Gomes, E. Vargas, M. V. van Genuchten, J. Pinto, Felipe A. Rosa","doi":"10.2478/johh-2022-0013","DOIUrl":"https://doi.org/10.2478/johh-2022-0013","url":null,"abstract":"Abstract Field tests were carried out to estimate effective unsaturated soil hydraulic properties of layered residual soils in Rio de Janeiro, southeastern Brazil. Data of this type are important for understanding the initiation of rainstorm-induced soil landslides, which often occur in the state of Rio de Janeiro as well as other areas having similar geologic settings and climate conditions. Tests were carried out using a simplified field approach, referred to as the Monitored Infiltration Test, which requires only a tensiometer to measure pressure heads below the wetting front, triggered by flow from a Mariotte bottle which maintains a constant pressure at the top edge of the soil profile. The data can then be analyzed by numerical inversion using the HYDRUS-2D software package. The test is relatively fast since no steady-state flow conditions are needed, and versatile since the test can be carried out quickly on steep slopes with the help of a manual auger. Soil water retention and the unsaturated hydraulic conductivity functions were obtained for a range of young, mature and saprolitic residual soils. The effective hydraulic properties of the distinct residual soil layers can be quite large, reflecting a need to provide a careful analysis of field-scale hydraulic heterogeneity in geotechnical analyses.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"244 - 256"},"PeriodicalIF":1.9,"publicationDate":"2022-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43924856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In recent years, due to the occurrence of water shortage and drought problems, particularly in arid and semi-arid regions of the world, new methods to reduce evaporation from the surface of dam reservoirs, lakes, and other water-free surfaces are investigated. This study aimed to use hydrophobic bentonite to reduce water evaporation from water surfaces, on a laboratory scale, and field conditions for the first time. Bentonite initially became hydrophobic by stearic acid (SA). Under such conditions, hydrophobic bentonite floats on the surface of water and forms a thin coating layer. The produced hydrophobic bentonite had a contact angle of 150°, indicating its superhydrophobicity. Evaporation reduction was measured under laboratory and field conditions and it was compared to hexadecanol as the reference material. The results demonstrated that the hydrophobic bentonite efficiency under laboratory conditions was similar to that of hexadecanol and prevented water evaporation by 36%. However, under field conditions, hydrophobic bentonite and hexadecanol efficiencies were 40% and 23% to reduce evaporation for 30 days, respectively. In terms of stability, hexadecanol needed to be re-injected after three days, while hydrophobic bentonite was stable and remained on the surface for more than 100 days under laboratory conditions and for more than 15 days under field conditions without needing re-injection. This coverage with method can be used to reduce evaporation from lakes, tanks, and reservoirs of small dams.
{"title":"Experimental investigation of hydrophobic bentonite effects on reducing evaporation from water surfaces","authors":"Roza Ghahramani Jajin, A. Feizi, M. Ghorbanpour","doi":"10.2478/johh-2022-0006","DOIUrl":"https://doi.org/10.2478/johh-2022-0006","url":null,"abstract":"Abstract In recent years, due to the occurrence of water shortage and drought problems, particularly in arid and semi-arid regions of the world, new methods to reduce evaporation from the surface of dam reservoirs, lakes, and other water-free surfaces are investigated. This study aimed to use hydrophobic bentonite to reduce water evaporation from water surfaces, on a laboratory scale, and field conditions for the first time. Bentonite initially became hydrophobic by stearic acid (SA). Under such conditions, hydrophobic bentonite floats on the surface of water and forms a thin coating layer. The produced hydrophobic bentonite had a contact angle of 150°, indicating its superhydrophobicity. Evaporation reduction was measured under laboratory and field conditions and it was compared to hexadecanol as the reference material. The results demonstrated that the hydrophobic bentonite efficiency under laboratory conditions was similar to that of hexadecanol and prevented water evaporation by 36%. However, under field conditions, hydrophobic bentonite and hexadecanol efficiencies were 40% and 23% to reduce evaporation for 30 days, respectively. In terms of stability, hexadecanol needed to be re-injected after three days, while hydrophobic bentonite was stable and remained on the surface for more than 100 days under laboratory conditions and for more than 15 days under field conditions without needing re-injection. This coverage with method can be used to reduce evaporation from lakes, tanks, and reservoirs of small dams.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"170 - 177"},"PeriodicalIF":1.9,"publicationDate":"2022-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44494609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Beerkan infiltration runs could provide an incomplete description of infiltration with reference to either the near steady-state or the transient stages. In particular, the process could still be in the transient stage at the end of the run or some transient infiltration data might be loss. The Wu1 method and the BEST-steady algorithm can be applied to derive soil hydrodynamic parameters even under these circumstances. Therefore, a soil dataset could be developed using two different data analysis methods. The hypothesis that the Wu1 method and BEST-steady yield similar predictions of the soil parameters when they are applied to the same infiltration curve was tested in this investigation. For a sandy-loam soil, BEST-steady yielded higher saturated soil hydraulic conductivity, Ks, microscopic pore radius, λm, and depth of the wetting front at the end of the run, dwf, and lower macroscopic capillary length, λc, as compared with the Wu1 method. Two corresponding means differed by 1.2–1.4 times, depending on the variable, and the differences appeared overall from moderate to relatively appreciable, that is neither too high nor negligible in any circumstance, according to some literature suggestions. Two estimates of Ks were similar (difference by < 25%) when the gravity-driven vertical flow and the lateral capillary components represented the 71–89% of total infiltration. In conclusion, the two methods of data analysis do not generally yield the same predictions of soil hydrodynamic parameters when they are applied to the same infiltration curve. However, it seems possible to establish what are the conditions making the two methods similar.
{"title":"Estimation of hydrodynamic properties of a sandy-loam soil by two analysis methods of single-ring infiltration data","authors":"V. Bagarello, G. Caltabellotta, M. Iovino","doi":"10.2478/johh-2022-0005","DOIUrl":"https://doi.org/10.2478/johh-2022-0005","url":null,"abstract":"Abstract Beerkan infiltration runs could provide an incomplete description of infiltration with reference to either the near steady-state or the transient stages. In particular, the process could still be in the transient stage at the end of the run or some transient infiltration data might be loss. The Wu1 method and the BEST-steady algorithm can be applied to derive soil hydrodynamic parameters even under these circumstances. Therefore, a soil dataset could be developed using two different data analysis methods. The hypothesis that the Wu1 method and BEST-steady yield similar predictions of the soil parameters when they are applied to the same infiltration curve was tested in this investigation. For a sandy-loam soil, BEST-steady yielded higher saturated soil hydraulic conductivity, Ks, microscopic pore radius, λm, and depth of the wetting front at the end of the run, dwf, and lower macroscopic capillary length, λc, as compared with the Wu1 method. Two corresponding means differed by 1.2–1.4 times, depending on the variable, and the differences appeared overall from moderate to relatively appreciable, that is neither too high nor negligible in any circumstance, according to some literature suggestions. Two estimates of Ks were similar (difference by < 25%) when the gravity-driven vertical flow and the lateral capillary components represented the 71–89% of total infiltration. In conclusion, the two methods of data analysis do not generally yield the same predictions of soil hydrodynamic parameters when they are applied to the same infiltration curve. However, it seems possible to establish what are the conditions making the two methods similar.","PeriodicalId":50183,"journal":{"name":"Journal Of Hydrology And Hydromechanics","volume":"70 1","pages":"234 - 243"},"PeriodicalIF":1.9,"publicationDate":"2022-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49611294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：