Comment on “Modified expression for unsaturated hydraulic conductivity according to Mualem–van Genuchten to allow proper computations at low pressure heads” by M. Heinen
Marcia S. Batalha, Camila R. Bezerra‐Coelho, Elizabeth M. Pontedeiro, Martinus Th van Genuchten, Jian Su
{"title":"Comment on “Modified expression for unsaturated hydraulic conductivity according to Mualem–van Genuchten to allow proper computations at low pressure heads” by M. Heinen","authors":"Marcia S. Batalha, Camila R. Bezerra‐Coelho, Elizabeth M. Pontedeiro, Martinus Th van Genuchten, Jian Su","doi":"10.1002/vzj2.20332","DOIUrl":null,"url":null,"abstract":"This comment concerns evaluation of the Mualem–van Genuchten (MvG) unsaturated soil hydraulic functions at very low (negative) pressure heads as described recently in an important study by Heinen. He showed that below some critical pressure head, the unsaturated hydraulic conductivity should be approximated by a power function, even when evaluated using double precision computations. We show that a more precise approximation is possible when the approximation is formulated in terms of effective fluid saturation (<jats:italic>S<jats:sub>e</jats:sub></jats:italic>) rather than the pressure head, <jats:italic>h</jats:italic>. More general constraints are also provided when the approximated hydraulic conductivity equation should be used. The alternative formulation and constraints were implemented earlier in the SOHYP and RETC software packages.","PeriodicalId":23594,"journal":{"name":"Vadose Zone Journal","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Vadose Zone Journal","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1002/vzj2.20332","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
This comment concerns evaluation of the Mualem–van Genuchten (MvG) unsaturated soil hydraulic functions at very low (negative) pressure heads as described recently in an important study by Heinen. He showed that below some critical pressure head, the unsaturated hydraulic conductivity should be approximated by a power function, even when evaluated using double precision computations. We show that a more precise approximation is possible when the approximation is formulated in terms of effective fluid saturation (Se) rather than the pressure head, h. More general constraints are also provided when the approximated hydraulic conductivity equation should be used. The alternative formulation and constraints were implemented earlier in the SOHYP and RETC software packages.
期刊介绍：
Vadose Zone Journal is a unique publication outlet for interdisciplinary research and assessment of the vadose zone, the portion of the Critical Zone that comprises the Earth’s critical living surface down to groundwater. It is a peer-reviewed, international journal publishing reviews, original research, and special sections across a wide range of disciplines. Vadose Zone Journal reports fundamental and applied research from disciplinary and multidisciplinary investigations, including assessment and policy analyses, of the mostly unsaturated zone between the soil surface and the groundwater table. The goal is to disseminate information to facilitate science-based decision-making and sustainable management of the vadose zone. Examples of topic areas suitable for VZJ are variably saturated fluid flow, heat and solute transport in granular and fractured media, flow processes in the capillary fringe at or near the water table, water table management, regional and global climate change impacts on the vadose zone, carbon sequestration, design and performance of waste disposal facilities, long-term stewardship of contaminated sites in the vadose zone, biogeochemical transformation processes, microbial processes in shallow and deep formations, bioremediation, and the fate and transport of radionuclides, inorganic and organic chemicals, colloids, viruses, and microorganisms. Articles in VZJ also address yet-to-be-resolved issues, such as how to quantify heterogeneity of subsurface processes and properties, and how to couple physical, chemical, and biological processes across a range of spatial scales from the molecular to the global.
京公网安备 11010802042870号
京ICP备2023020795号-1
分享
求助内容：
应助结果提醒方式：
扫码关注我们
