Chenyapanich, S.

Grünberger, Olivier

Hammecker, Claude

Maeght, Jean-Luc

Montoroi, Jean-Pierre

Srisuk, K.

Sukchan, S.

Wiryakitnateekul, W.

Horizon / Pleins textes

 The 2nd WASWAC World Conference THE THREATS TO LAND AND WATER 
RESOURCES IN THE 21ST CENTURY: PREVENTION, MITIGATION AND RESTORATION  
4-7 September 2013, Le MERIDIEN Chiang Rai Resort, Chiang Rai 
 
 
GROUNDWATER DYNAMICS RELATED TO SALINIZATION AND EROSION OF SOILS (PHRA YUN 
DISTRICT, NORTHEAST THAILAND) 
 
Jean-Pierre Montoroi1*, Olivier Grünberger2, Claude Hammecker3, Jean-Luc Maeght1, Somjai Chenyapanich4, 
Somsak Sukchan4, Wanpen Wiriyakitnateekul4, Kriengsak Srisuk5 
 
1* Institute of Research for Development, UMR Bioemco, Bondy, France (Jean-Pierre.Montoroi@ird.fr) and 
corresponding author 
2 Institute of Research for Development, UMR Lisah, Montpellier, France 
3 Institute of Research for Development, UMR Eco&Sols, Montpellier, France 
4 Land Development Department, Bangkok, Thailand 5 University of Khon Kaen, Khon Kaen, Thailand 
 
Abstract: The northeast of Thailand is mainly occupied by a large sub-watershed of the Mekong River where 
two major rivers are flowing through sedimentary deposits affected by upward movement of deep saline 
groundwater. Upstream of the Chi River, two study sites were selected in the west and east of the village of 
Phra Yun (16°20’N, 102°39’), one in the lowlands cultivated with flooded rice near the village of Ban Daeng 
(16°21’N, 102°36’), the other in the uplands within a large rubber-tree plantation near the village of Ban Non 
Tun (16°20’N, 102°44’30”). In lowlands during dry season, discrete saline patches of various sizes and shapes 
cover soil surface with white efflorescences. In uplands features of soil erosion are widespread and a sudden 
soil redistribution occurs downstream during heavy rainfall events. Salinization and erosion of soils are 
enhanced by human activities, namely deforestation (wood cutting), land use changes (denudation of soils), 
water storage (dam, pond) and groundwater abstraction for salt production (pumping). The buildup and 
spread of both soil processes have resulted in major economic and environmental impacts. 
The position and the chemical composition of groundwater were monitored in the lowland site using four 
boreholes 20m deep, two inside saline patches, two outside, and in the upland site along a slope using eight 
deep piezometers (from 10 to 32m in depth). At each site, the device has been complemented by a network of 
shallow piezometers (< 3m in depth). The pedological and mineralogical characteristics of the soils and 
bedrocks were determined at laboratory and on site. In lowlands, groundwater salinity has a heterogeneous 
distribution, vertical and lateral, and is controlled by the structure and nature of sedimentary deposits. The 
hydrogeological system is similar in both sites and characterized by two aquifers. One is deep and fractured, 
the other is shallow and sandy. The two aquifers are separated by a clayey layer thicker downstream and 
weakly permeable. A conceptual model linking the groundwater dynamics of both sites is proposed. It shows 
the interdependence of the two hydrosystems in dry conditions (saline contamination in the uplands) and in 
wet conditions (water dilution and prolonged waterlogging in the lowlands). 
 


WASWAC world conference : the threats to land and water resources in the 21st century : prevention, mitigation and restoration : abstracts

WASWAC world conference : the threats to land and water resources in the 21st century : prevention, mitigation and restoration : abstracts

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