Abstract
Saltwater intrusion is generally related to seawater-level rise or induced intrusion due to excessive groundwater extraction in coastal aquifers. However, the hydrogeological heterogeneity of the subsurface plays an important role in (non-)intrusion as well. Local hydrogeological conditions for recharge and saltwater intrusion are studied in a coastal groundwater system in Vietnam where geological formations exhibit highly heterogeneous lithologies. A three-dimensional (3D) hydrostratigraphical solid model of the study area is constructed by way of a recursive classification procedure. The procedure includes a cluster analysis which uses as parameters geological formation, lithological composition, distribution depth and thickness of each lithologically distinctive drilling interval of 47 boreholes, to distinguish and map well-log intervals of similar lithological properties in different geological formations. A 3D hydrostratigraphical fence diagram is then generated from the constructed solid model and is used as a tool to evaluate recharge paths and saltwater intrusion to the groundwater system. Groundwater level and chemistry, and geophysical direct current (DC) resistivity measurements, are used to support the hydrostratigraphical model. Results of this research contribute to the explanation of why the aquifer system of the study area is almost uninfluenced by saltwater intrusion, which is otherwise relatively common in coastal aquifers of Vietnam.
Résumé
L’intrusion saline est généralement liée à l’augmentation du niveau marin ou induite par un pompage excessif des eaux souterraines dans les aquifères côtiers. Cependant, l’hétérogénéité hydrogéologique du sous-sol joue également un rôle important dans l’intrusion et la non intrusion. Les conditions hydrogéologiques locales concernant la recharge et l’intrusion saline sont étudiées dans un système aquifère côtier au Vietnam où les formations géologiques présentent des lithologies fortement hétérogènes. Un modèle hydrostratigraphique tri-dimensionnel a été élaboré pour la zone d’étude par l’intermédiaire d’une procédure de classification récursive. La procédure comprend une analyse de cluster qui utilise comme paramètres la composition lithologique, la longueur de la distribution et l’épaisseur de chaque intervalle lithologique distinct de 47 forages, pour distinguer et cartographier les intervalles de logs de forage de propriétés lithologiques similaires dans des formations géologiques différentes. Un schéma hydrostratigraphique en 3D est ainsi généré à partir du modèle construit et est utilisé comme un outil pour évaluer les écoulements liés à la recharge et à l’intrusion saline dans le système aquifère. Le niveau d’eau souterraine et la chimie de l’eau, et des mesures directes géophysiques de résistivité, sont utilisés pour calibrer le modèle hydrostratigraphique. Les résultats de cette recherche contribuent à l’explication de la raison pour laquelle le système aquifère de la région d’étude n’est presque pas influencé par une intrusion saline, ce qui est par ailleurs relativement courant dans les aquifères côtiers du Vietnam.
Resumen
La intrusión de agua salada está generalmente relacionada con el ascenso del nivel del mar o la intrusión inducida debido a una extracción excesiva de agua subterránea en los acuíferos costeros. Sin embargo, la heterogeneidad hidrogeológica del subsuelo también juega un rol importante en la (no) intrusión. Se estudian condiciones hidrogeológicas locales para la recarga y la intrusión de agua salada en un sistema de agua subterránea costero en Vietnam donde las formaciones geológicas exhiben litologías altamente heterogéneas. Se construyó un sólido modelo tridimensional hidroestratigráfico del área de estudio a través de un procedimiento de clasificación recursivo. El procedimiento incluye un análisis en cluster que usa como parámetros la composición litológico, la distribución en la profundidad y espesor de cada intervalo perforado litológicamente distintivo de 47 perforaciones, para distinguir y mapear los intervalos de registros de pozos de propiedades litológicas similares en diferentes formaciones geológicas. Se generó un block diagrama hidroestratigráfico 3D a partir del modelo sólido construido y es usado como una herramienta para evaluar las trayectorias de recarga y la intrusión de agua salada en el sistema de agua subterránea. El nivel y la química del agua subterránea, y las medidas geofísicas de resistividad de corriente continua (DC), son usados para apoyar el modelo hidroestratigráfico. Los resultados de esta investigación contribuyen a la explicación de por qué el sistema acuífero del área de estudio casi nunca está influenciado por la intrusión de agua salada, lo que es por otra parte relativamente común en acuíferos costeros de Vietnam.
摘要
海水入侵通常与海平面上升或由于过度开采沿海含水层的地下水而诱发的入侵有关。然而,地表之下的水文地质非均质性在(非)入侵中发挥着重要作用。本文研究了越南一个沿海地下水系统的补给和海水入侵的水文地质条件,这个地下水系统的地层具有很高的非均质性岩性。通过递归分类程序建立了研究区三维水文地层实体模型。这个程序包括聚类分析,聚类分析结果作为47个钻孔中每个岩性上与众不同钻井间隔的岩性组成、分布深度和厚度的参数,以区分和绘制不同地地层类似岩性特性的测井间隔。根据建立的实体模型生成三维水文地层栅状剖面图,用作评价地下水系统补给通道和海水入侵的工具。地下水位、化学条件及地球物理直流电电阻率等各项测量结果用来支持水文地层模型。这项研究有助于解释为什么研究区的含水层系统几乎没有受到海水入侵的影响,而海水入侵在越南其他沿海含水层中相对很常见。
Resumo
A intrusão salina é geralmente associada a uma subida do nível do mar ou a uma intrusão induzida devida ao excesso de extração de água subterrânea em aquíferos costeiros. No entanto, a heterogeneidade hidrogeológica da subsuperfície joga também um papel importante na (não)-intrusão. São estudadas as condições hidrogeológicas locais para a recarga e para a intrusão salina num sistema hidrogeológico costeiro do Vietname, onde as formações geológicas exibem litologias altamente heterogéneas. Foi construído um modelo hidroestratigráfico tridimensional (3D) sólido da área de estudo, através de um procedimento classificativo recursivo. O procedimento inclui uma análise de agrupamento que usa como parâmetros a composição litológica, a distribuição em profundidade e a espessura de cada intervalo litológico distinto de 47 sondagens, para distinguir e mapear intervalos de perfis de sondagem com propriedades litológicas similares em diferentes formações geológicas. A partir do modelo sólido construído foi gerado um diagrama de cerca tridimensionnal da hidroestratigrafia usado como uma ferramenta para avaliar os caminhos de recarga e a intrusão salina no sistema hidrogeológico. São usadas medições do nível da água subterrânea, do quimismo e de resistividade geofísica com corrente direta (CD) para suportar o modelo hidroestratigráfico. Resultados desta pesquisa contribuem para explicar porque é que o sistema aquífero da área em estudo não é praticamente influenciado pela intrusão salina, o que é relativamente comum nos aquíferos costeiros do Vietname.
Tóm tắt
Xâm nhập mặn thường liên quan đến nước biển dâng hay khai thác nước quá mức trong các tầng chứa nước ven biển. Tuy nhiên, tính phân dị về địa chất thủy văn của môi trường chứa nước cũng đóng vai trò quan trọng ảnh hưởng đến quá trình xâm nhập mặn. Trong bài báo này, các tác giả đã nghiên cứu điều kiện địa chất thủy văn đối với bổ cập và xâm nhập mặn của một hệ thống nước ngầm ven biển ở Việt Nam gồm các thành tạo địa chất có tính phân dị cao về thành phần thạch học. Một mô hình địa tầng địa chất thủy văn ba chiều (3D) đã được các tác giả xây dựng theo một quy trình phân loại lặp. Quy trình này bao gồm việc áp dụng kỹ thuật phân tích nhóm dựa trên 4 thông số về tuổi địa tầng, thành phần, chiều sâu phân bố và chiều dày của các lớp thạch học trong cột địa tầng của 47 lỗ khoan để nhóm gộp và liên kết các khoảng chiều sâu khoan thành các lớp có cùng đặc tính giống nhau. Trên cơ sở kết quả phân tích nhóm này, mô hình và mạng lưới mặt cắt địa tầng địa chất thủy văn ba chiều đã được xây dựng và sử dụng như một công cụ để luận giải con đường bổ cập và xâm nhập mặn đến hệ thống nước dưới đất. Mực nước, thành phần hóa học của nước dưới đất và kết quả đo mặt cắt điện cũng đã được sử dụng để hỗ trợ thành lập mô hình và mặt cắt nói trên. Kết quả của nghiên cứu này đã góp phần lý giải tại sao hệ thống nước dưới đất trong vùng nghiên cứu hầu như không bị xâm nhập mặn, trong khi phần lớn các tầng chứa nước ven biển khác ở Việt Nam thường hay bị nhiễm mặn.
Similar content being viewed by others
References
Bang NH (1996) Study of borehole logging in groundwater prospection wells in the Southern Plain of Vietnam (in Vietnamese). Southern Center for Water Resources Planning and Investigation, Archives of Department of Water Resources Management of Vietnam, Hanoi, 128 pp
Barnhardt ML, Hansel AK, Stumpf AJ (2001) Developing the database for 3-D modeling: acquiring, assembling, verifying assessing, interpreting and integrating source data. In: Berg RC, Thorleifson LH (eds) Geological models for groundwater flow modeling, 35th annual meeting, north-central section GSA: Bloomington-Normal, IL. Illinois State Geological Survey, Open File Series 2000–1, 6 pp
Bayer P, Huggenberger P, Renard P, Comunian A (2011) Three-dimensional high-resolution fluvio-glacial aquifer analog, part 1: field study. J Hydrol 405:1–9
Be KV (2003) Synthesis report on drilling execution and assessment of complementary groundwater reserve for well-field in Gio Linh Town, Quang Tri Province (in Vietnamese). Groundwater Exploitation and Business Company No. 1. Archives of Department of Water Resources Management of Vietnam, Hanoi, 66 pp
Berg RC, Thorleifson LH (2001) Geological models for groundwater flow modeling. Open File Series 2000–1, Illinois State Geological Survey, Champaign, IL
Bieu N (2001) Synthetic report on “Investigation project on geology and solid mineral resources in offshore zone (0–30m) of Vietnam, scale 1:5000,000” (in Vietnamese). Marine Geology and Mineral Resources Center, Vietnam Administration for Sea and Islands (VASI), Hanoi, 221 pp
Birks HJB (2012) Analysis of stratigraphical data. In: Birks HJB, Lotter AF, Juggins S, Smol JP (eds) Tracking environmental change using lake sediments, vol 5: data handling and numerical techniques. Springer, Dordrecht, The Netherlands, pp 355–378
Bonnesen EP, Larsen F, Sonnenborg TO, Klitten K, Stemmerik L (2009) Deep saltwater in Chalk of North-West Europe: origin, interface characteristics and development over geological time. Hydrogeol J 17:1643–1663
Bridge DM, Hough E, Kessler H, Lelliott M, Price SJ, Reeves HJ (2004) Integrating modelling of geoscience information to support sustainable urban planning, Greater Manchester Area, northwest England. In: Berg RC, Russell HAJ, Thorleifson LH (eds) Three-dimensional geological mapping for groundwater applications, Open File Series 2004–8, Illinois State Geological Survey, Champaign IL, pp 16–19
Burschil T, Scheer W, Kirsch R, Wiederhold H (2012) Compiling geophysical and geological information into a 3-D model of the glacially-affected island of Föhr. Hydrol Earth Syst Sci 16:3485–3498. doi:10.5194/hess-16-3485-2012
Carrera J, Hidalgo JJ, Slooten LJ, Vazquez-Sune E (2010) Computational and conceptual issues in the calibration of seawater intrusion models. Hydrogeol J 18:131–145
Chang SW, Clement TP, Simpson MJ, Lee K (2011) Does sea-level rise have an impact on saltwater intrusion? Adv Water Resour 34:1283–1291
Duong NX (1978) Synthesis report on geological mapping, Quang Tri – Le Thuy Sheet, scale 1:200.000 (in Vietnamese). Geological Division no. 206, Archives of General Department of Geology and Minerals of Vietnam, Hanoi, 139 pp
Edmunds WM (2001) Palaeowaters in European coastal aquifers: the goals and main conclusions of the PALAEAUX project. Geol Soc Lond Spec Publ 189:1–16
Giang NT (1995) Synthesis report on groundwater exploration project in Gio Linh Area, Quang Tri Province (in Vietnamese). Hydrogeological-Engineering Geological Division no. 708, Archives of Department of Water Resources Management of Vietnam, Hanoi, 72 pp
Gill D, Shomrony A, Fligelman H (1993) Numerical zonation of log suites by adjacency-constrained multivariate clustering. AAPG Bull 77(10):1781–1791
Grimm EC (1987) CONISS: a Fortran 77 program for stratigraphically constrained cluster analysis by the method of incremental sum of squares. Comput Geosci 13(1):13–35
Hien NT (2009) Assessment of groundwater potential in the Quang Tri Province plain to serve for sustainable environment and social-economic development planning (in Vietnamese). MSc Thesis, Vietnam National University, Vietnam, 79 pp
Hinsby K, Edmunds WM, Loosli HH, Manzano M, Condesso de Melo MT, Barbecot F (2001) The modern water interface: recognition, protection and development: advance of modern waters in European aquifer systems. Geol Soc Spec Publ 189:271–288
Hinsby K, Auken E, Oude Essink GHP, de Louw P, Siemon B, Sonnenborg TO, Wiederholdt H, Guadagnini A, Carrera J (eds) (2011) Assessing the impact of climate change for adaptive water management in coastal regions. Hydrol Earth Syst Sci 16(149), special issue
Hung DQ (2012) Application of high-resolution shallow seismic sounding method to study shallow geological formations and recent tectonic and magma activities in the Central Coast of Vietnam (in Vietnamese). PhD Thesis, National Library of Vietnam, Hanoi, 249 pp
Jones NL, Wright SG (1993) Subsurface characterization with solid models. J Geotech Eng 119(11):1823–1839
Jørgensen F, Scheer W, Thomsen S, Sonnenborg TO, Hinsby K, Wiederhold H, Schamper C, Burschil T, Roth B, Kirsch R, Auken E (2012) Transboundary geophysical mapping of geological elements and salinity distribution critical for the assessment of future sea water intrusion in response to sea level rise. Hydrol Earth Syst Sci 16:1845–1862
Kessler H, Mathers SJ (2004) Maps to models. Geoscientist 14(10):4–6
Kessler H, Mathers SJ, Sobisch H-G (2004) GSI3D: the software and methodology to build near-surface 3-D geological models. BGS Internal Report IR/04/029, BGS, Keyworth, UK, 96 pp
Liu YB, De Smedt F (2004) Documentation and user manual: WetSpa Extension, a GIS-based hydrologic model for flood prediction and watershed management. Dept. of Hydrology and Hydraulic Engineering, Vrije Universiteit Brussels, Belgium, 126 pp
Long NV (1986) Synthesis report on groundwater prospecting project in Ho Xa Area, Quang Tri (Binh Tri Thien Province) (in Vietnamese). Hydrogeological-Engineering Geological Division no. 708, Archives of Dept. of Water Resources Management of Vietnam, Hanoi, 126 pp
Manh LQ (1990) Synthesis report on groundwater prospecting project in the west of Dong Ha Area, Quang Tri Province (in Vietnamese). Hydrogeological-Engineering Geological Division no. 708, Archives of Dept. of Water Resources Management of Vietnam, Hanoi, 97 pp
Misut PE, Voss C (2007) Freshwater–saltwater transition zone movement during aquifer storage and recovery cycles in Brooklyn and Queens, New York City, USA. J Hydrol 337:87–103
Oude Essink GHP (2001) Salt water intrusion in a three-dimensional groundwater system in the Netherlands: a numerical study. Trans Porous Med 43:137–158
Phuc LT (2002) Characteristics and development history of the Quaternary sediment formations in shallow seabed zone of the North Central Coast of Vietnam (in Vietnamese). PhD Thesis, National Library of Vietnam, Hanoi, 195 pp
Post V, Abarca E (2010) Preface: saltwater and freshwater interactions in coastal aquifers. Hydrogeol J 18:1–4. doi:10.1007/s10040-009-0561-9
Post V, Groen J, Kooi H, Person M, Ge S, Edmunds WM (2013) Offshore fresh groundwater reserves as a global phenomenon. Nature 504:71–78. doi:10.1038/nature12858
Rasmussen P, Sonnenborg TO, Goncear G, Hinsby K (2013) Assessing impacts of climate change, sea level rise, and drainage canals on saltwater intrusion to coastal aquifer. Hydrol Earth Syst Sci 17:421–443
Russell HAJ, Thorleifson LH, Berg RC (2005) Three-dimensional geological mapping for groundwater applications: recent activities. Digital Mapping Techniques ‘05–Workshop proceedings. US Geol Surv Open-File Rep 2005–1428
Scharling P, Rasmussen ES, Sonnenborg TO, Engesgaard P, Hinsby K (2009) 3D regional scale hydrostratigraphical modeling based on sequence stratigraphical methods. Hydrogeol J 17:1913–1933
Seifert D, Sonnenborg TO, Scharling P, Hinsby K (2008) Use of alternative conceptual models to assess the impact of a buried valley on groundwater vulnerability. Hydrogeol J 16:659–674
Seifert D, Sonnenborg TO, Refsgaard JC, Højberg AL, Troldborg L (2012) Assessment of hydrological model predictive ability given multiple conceptual geological models. Water Resour Res 48, W06503. doi:10.1029/2011WR011149
Son NT, Anh TN, Giang NT, Tuan NC, Hanh ND, Hieu N, Bao DV (2009) Groundwater in Quang Tri province: the status of exploitation, utilization and management for sustainable development (in Vietnamese). Vietnam Natl Univ (VNU) Bull 1S:95–102
Sulzbacher H, Wiederhold H, Siemon B, Grinat M, Igel J, Burschil T, Günther T, Hinsby K (2012) Numerical modelling of climate change impacts on freshwater lenses on the North Sea Island of Borkum using hydrological and geophysical methods. Hydrol Earth Syst Sci 16:3621–3643
The NV (1984) Synthesis report on groundwater prospecting project in Dong Ha – Quang Tri Area (Binh Tri Thien Province) (in Vietnamese). Hydrogeological-engineering geological division no. 708, Archives of Department of Water Resources Management of Vietnam, Hanoi, 104 pp
Tien ND, Do NHT (2007) Applying the MODFLOW software in the assessment of potential extraction reserves of groundwater in the coastal sand strip of Thua Thien Hue province (from Thuan An to Vinh Hien). Proceedings of the International Symposium on Hanoi Geoengineering 2007, Theme: New Challenges in Geosystem Engineering and Exploration, 22–23 November 2007 Hanoi
Tran LT, Larsen F, Pham NQ, Christiansen AV, Tran N, Vu HV, Tran LV, Hoang HV, Hinsby K (2012) Origin and extent of fresh groundwater, salty paleowaters and recent saltwater intrusions in Red River flood plain aquifers, Vietnam. Hydrogeol J 20:1295–1313
Troldborg L, Refsgaard JC, Jensen KH, Engesgaard P (2007) The importance of alternative conceptual models for simulation of concentrations in multi-aquifer system. Hydrogeol J 15:843–860
Ward JH (1963) Hierarchical grouping to optimize an objective function. J Am Stat Assoc 38(301):236–244
Acknowledgements
This study has been carried out within the cooperative research project FWO.2011.38 “Study to build a toolset for assessment of impact of global climate change and seawater level rise on groundwater resources and ability to meet water use demand of local residents in coastal areas of Vietnam”, which is funded by the National Foundation for Science and Technology Development of Vietnam (NAFOSTED) and the National Fund for Scientific Research of Belgium (FWO). The authors are grateful to all the project staff for their contributions. Special thanks go to Mr. Vu Van Thanh from NAWAPI for his enthusiastic support in the interpretation of available geophysical data in this study.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Tam, V.T., Batelaan, O., Le, T.T. et al. Three-dimensional hydrostratigraphical modelling to support evaluation of recharge and saltwater intrusion in a coastal groundwater system in Vietnam. Hydrogeol J 22, 1749–1762 (2014). https://doi.org/10.1007/s10040-014-1185-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10040-014-1185-2