Hydrogeology Journal

, Volume 20, Issue 7, pp 1355–1374 | Cite as

Conceptual and numerical models for sustainable groundwater management in the Thaphra area, Chi River Basin, Thailand

Report

Abstract

Sustainable management of groundwater resources is vital for development of areas at risk from water-resource over-exploitation. In northeast Thailand, the Phu Thok aquifer is an important water source, particularly in the Thaphra area, where increased groundwater withdrawals may result in water-level decline and saline-water upconing. Three-dimensional finite-difference flow models were developed with MODFLOW to predict the impacts of future pumping on hydraulic heads. Four scenarios of pumping and recharge were defined to evaluate the system response to future usage and climate conditions. Primary model simulations show that groundwater heads will continue to decrease by 4–12 m by the year 2040 at the center of the highly exploited area, under conditions of both increasing pumping and drought. To quantify predictive uncertainty in these estimates, in addition to the primary conceptual model, three alternative conceptual models were used in the simulation of sustainable yields. These alternative models show that, for this case study, a reasonable degree of uncertainty in hydrostratigraphic interpretation is more impactful than uncertainty in recharge distribution or boundary conditions. The uncertainty-analysis results strongly support addressing conceptual-model uncertainty in the practice of groundwater-management modeling. Doing so will better assist decision makers in selecting and implementing robust sustainable strategies.

Keywords

Conceptual models Regional hydrogeology Groundwater management Numerical modeling Thailand 

Modèles conceptuels numériques de gestion durable de la nappe dans la région de Thaphra, Bassin de la Rivière Chi, Thaïlande

Résumé

La gestion durable des ressources en eau souterraine est vitale pour le développement des zones présentant un risque de surexploitation de la ressource. Dans le Nord-Est de la Thaïlande, l’aquifère Phu Thok est une importante ressource en eau, particulièrement dans la zone de Thaphra, où les prélèvements croissants en eau souterraine peuvent provoquer un abaissement du niveau de nappe et une remontée d’eau salée. Des modèles d’écoulements tridimensionnels aux différences finies ont été développés sous MODFLOW pour prévoir l’impact de futurs pompages sur les niveaux hydrauliques. Quatre scénarios de pompage et de recharge ont été simulés pour évaluer la réponse du système à l’utilisation future et aux conditions climatiques. Les simulations du modèle de base montrent que les niveaux de la nappe continueront à décroître, jusqu’à 4 à 12 m vers l’année 2040, au centre de la zone fortement exploitée, dans des conditions simultanées de pompage et de sècheresse croissants. Pour quantifier l’incertitude prévisionnelle sur ces estimations, en plus du modèle conceptuel de base, trois autres modèles conceptuels ont été utilisés pour simuler des prélèvements durables. Ces modèles montrent que, dans le cas étudié, un degré raisonnable d’incertitude dans l’interprétation hydro-stratigraphique a plus d’incidence que l’incertitude dans la distribution de la recharge ou dans les conditions aux limites. Les résultats de l’analyse d’incertitude incitent fortement à prendre en compte l’incertitude du modèle conceptuel dans la pratique de la modélisation de gestion des aquifères. Faire ainsi aidera mieux les décideurs dans la sélection et la mise en place de stratégies durables solides.

Modelos conceptual y numérico para la gestión sustentable de agua subterránea en el área de Thaphra, cuenca del Río Chi, Tailandia

Resumen

La gestión sustentable de los recursos de agua subterránea es vital para el desarrollo de áreas en riesgo debido a sobre explotación del recurso agua. En el noreste de Tailandia, el acuífero Phu Thok es una fuente de agua importante, particularmente en el área Thaphra, donde las crecientes extracciones de agua subterránea pueden resultar en una depresión de los niveles de agua y en la formación de un cono de agua salada. Se desarrollaron modelos de flujo 3D de diferencias finitas con MODFLOW para predecir los impactos de bombeos futuros sobre las cargas hidráulicas. Se definieron cuatro escenarios de bombeo y recarga para evaluar la respuesta del sistema a condiciones de uso y climáticas futuras. Las primeras simulaciones del modelo muestran que las cargas del agua subterránea continuarán decreciendo a 4–12 m hacia el año 2040 en el centro de un área altamente explotada, bajo condiciones de un incremento en el bombeo y sequía. Para cuantificar la incertidumbre predictiva en estas estimaciones, además del modelo primario conceptual, se usaron tres alternativas de modelos conceptuales en la simulación de rendimientos sustentables. Estos modelos alternativos muestran que, para este caso de estudio, un grado razonable de incertidumbre en la interpretación hidroestratigráfica es más impactante que la incertidumbre en la distribución de la recarga o en las condiciones de borde. Los resultados del análisis de la incertidumbre apoyan fuertemente el abordaje de la incertidumbre del modelo conceptual en la práctica del modelado de la gestión de agua subterránea. Al hacerlo ayudará a los tomadores de decisión para seleccionar e implementar estrategias sustentables robustas.

泰国 Chi River 流域 Thaphra 地区的地下水可持续管理的概念和数值模型

摘要

对于地下水超采地区的发展,地下水资源的可持续管理是非常重要的。在泰国东北部, Phu Thok 含水层是一个非常重要的水源,尤其是在 Thaphra 地区,持续的地下水开采会导致水位下降和咸水上升。在 MODFLOW 中开发的三维有限差分水流模型可以预测未来抽水对水头的影响。定义了四种抽水和补给的情景评估系统对未来使用和气候条件的响应。主模型模拟显示,在持续开采和干旱的条件下,强开采地区中心的地下水水头到 2040 年将下降 4-12 m。为了量化评估的不确定性,除了主概念模型,三个替代的概念模型也用于可持续开采量的模拟。这些替代模型显示,对于此次研究的案例,水文地层学合理解释中的不确定性比补给分布或边界条件的影响更大。不确定分析的结果大力支持解决地下水管理模型实践中概念模型的不确定性。这样会更好的帮助决策者选择和实施稳健的可持续发展战略。

Modelos conceptuais e numéricos destinados à gestão sustentável da água subterrânea na área de Thaphra, Bacia do Rio Chi, Tailândia

Resumo

A gestão sustentável da água subterrânea é vital para o desenvolvimento de áreas em risco de sobre-exploração dos recursos hídricos. No nordeste da Tailândia, o aquífero Phu Thok é uma importante origem da água, em particular na área de Thaphra, onde a crescente extração de água subterrânea pode resultar na descida dos níveis e na ascensão de água salina. Empregando o MODFLOW, foram desenvolvidos modelos tridimensionais de diferenças finitas para predição dos impactes de futuras bombagens na piezometria. Foram definidos quatro cenários de bombagem e recarga para avaliar a resposta do sistema às futuras condições climáticas e de utilização. As primeiras simulações dos modelos mostram que os níveis da água subterrânea continuarão a descer no centro da área mais explorada até 4–12 m por volta do ano 2040, em condições simultâneas de incremento de exploração e de seca. Para quantificar a incerteza na predição destas estimativas, para além do primeiro modelo conceptual foram usados três modelos conceptuais alternativos, para a simulação das produções sustentáveis. Estes modelos alternativos mostram que, para este estudo de caso, uma razoável incerteza na interpretação hidrostratigráfica tem mais impacte do que a incerteza na distribuição da recarga ou nas condições de fronteira. Os resultados da análise de incerteza chamam a atenção sobre a importância de considerar a incerteza dos modelos conceptuais na prática da modelação para gestão da água subterrânea. Se esta realidade for atendida, apoiar-se-ão melhor os decisores na seleção e implementação de estratégias de sustentabilidade robustas.

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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  1. 1.Department of Civil and Environmental EngineeringUniversity of WaterlooWaterlooCanada

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