摘要
[目的]与天然形成的热带珊瑚岛相比,新成珊瑚岛因其建成过程中水力冲填和沉积导致剖面分布有致密层。为探明珊瑚砂剖面结构水力性质和水文条件对坡面水分入渗、壤中径流等水文过程与珊瑚砂颗粒输移的影响。[方法]以新成珊瑚岛剖面致密层为研究对象,通过珊瑚岛原位剖面调查和取样,分析珊瑚砂剖面的质地类型及其水文物理性质。结合室内珊瑚砂模拟降雨试验,分析均质和致密层分布的坡面在不同水文条件下的水文与珊瑚砂流失过程特征。[结果]粗质珊瑚砂具有较强导水能力,而致密层导水能力较差,饱和导水率仅为其他质地类型珊瑚砂的8%。均质珊瑚砂坡面降水全部入渗淋溶,无地表径流。而致密层可延滞水分向深层迁移,坡面以壤中径流为主,约占总降水量的87%,导致珊瑚砂体内出现颗粒输移流失。同时,水文条件从自由入渗、水分饱和到渗流的改变可促进壤中径流量和珊瑚砂流失量,但导水能力低的致密层能削减渗流条件下珊瑚砂流失量。[结论]致密层可明显改变珊瑚砂淡水水文和砂颗粒流失,导致局部区域淡水循环浅层化、溶蚀裂隙发育等潜在效应。研究结果对理解珊瑚岛淡水循环过程和建设生态岛均具有重要意义。
[Objective]Compared with naturally formed tropical coral islands,newly formed coral islands develop dense layers within their profiles due to hydraulic filling and sedimentation during the construction process.This study aims to investigate the effects of the hydrological properties and hydrological conditions of coral sand profile structures on hydrological processes such as slope water drainage,subsurface runoff,and coral sand particle transport.[Methods]Taking the dense layers in the profile of a newly formed coral island as the research object,in-situ profile surveys and sampling were conducted to analyze the texture types and hydro-physical properties of the coral sand profile.Combined with laboratory-simulated rainfall experiments,the hydrological process and coral sand loss characteristics on slopes with homogeneous layers and dense layers under different hydrological conditions were analyzed.[Results]Coarse coral sand exhibited strong hydraulic conductivity,while the dense layer had poor hydraulic conductivity,with a saturated hydraulic conductivity only 8%of that of other coral sand texture types.On slopes with homogeneous coral sand,all rainfall infiltrated through leaching,with no surface runoff.In contrast,the dense layer retarded water migration to deeper layers,causing subsurface runoff as the main form,accounting for about 87%of total rainfall and leading to particle transport and loss within the coral sand body.At the same time,changes in hydrological conditions,from free drainage to saturation and seepage,could promote subsurface runoff and coral sand loss,but a dense layer with low hydraulic conductivity could reduce coral sand loss under seepage conditions.[Conclusion]Dense layers can significantly alter the freshwater hydrology and sand particle loss of coral sand,potentially leading to effects such as shallower freshwater circulation and the development of dissolution fissures in localized areas.These results are of great significance for understanding the circulation process of coral islands and for the construction of ecological islands.
作者
王林华
俞梦笑
王森浩
李志鹏
李旭
刘菊秀
闫俊华
WANG Linhua;YU Mengxiao;WANG Senhao;LI Zhipeng;LI Xu;LIU Juxiu;YAN Junhua(South China Botanical Garden,Chinese Academy of Sciences,Guangzhou 510650,China;South China National Botanical Garden,Guangzhou 510650,China)
出处
《水土保持学报》
北大核心
2025年第5期179-187,共9页
Journal of Soil and Water Conservation
基金
国家重点研发计划“海洋环境安全保障与岛礁可持续发展”重点专项(2022-102)
国家自然科学基金项目(4247012753)
广州市科技项目-基础与应用基础研究项目(202201010341)。
关键词
致密层
水文条件
径流过程
珊瑚砂输移
珊瑚岛
dense layer
hydrological condition
runoff process
coral sand transport
coral island
