Abstract
This study of a water cycle was conducted in an evergreen forest located in the Mekong River Basin in central Cambodia. At the observation site, we measured the dynamics of the spatial distribution of groundwater levels. The groundwater movement was analyzed two-dimensionally using boundary conditions and parameters that had been observed in the field. The climate in the research area is dominated by two seasons, which occur annually: a rainy and a dry season. The groundwater levels are generally high during the rainy season and low during the dry season. Groundwater levels were measured along a stream, which flowed through the study site. The streambed was visible at the head of the stream in January. At the next downriver well point, the streambed appeared in March. Finally, it became visible at all well points in April, meaning that surface runoff had disappeared temporarily and instead flowed underground during the ensuing dry period. Groundwater levels of the studied lateral flow perpendicular to the stream that seeped and infiltrated into the stream were 1.2–2.5 m deep (in April), which was the lowest level recorded for the year. During that period, the depth of the groundwater of the studied lateral flow fell by as much as 56 mm per month. In addition, the lateral flow groundwater infiltrated into groundwater of the stream during that period. The groundwater level fluctuation was estimated based on a two-dimensional analysis of lateral flow perpendicular to the stream using a numerical simulation model with soil physical parameters and observed boundary conditions. The observations of ground water fluctuations were well reproduced. Deep seepage of groundwater was estimated using a uniform boundary condition that allowed efflux through the bottom, estimated as being approximately 30 mm per year. The simulated deep seepage rate was considered plausible considering other hydrological components such as soil water storage fluctuation.
Similar content being viewed by others
References
Araki M, Shimizu A, Toriyama J, Ito E, Kabeya N, Nobuhiro T, Tith B, Pol S, Lim S, Khorn S, Pith P, Det S, Ohta S, Kanzaki M (2007) Changes of vertical soil moisture conditions of a dry evergreen forest in Kampong Thom, Cambodia. In: Sawada H, et al. (eds) Forest environment in continental river basins. Springer, Tokyo, p 112–124
Hattori S, Deguchi A, Daikoku K (2004) Characteristics of transpiration in leaf-scale and forest floor evaporation in dry evergreen and dry deciduous forests in O Thom I watershed. In: Sawada H, Chann S, Shimizu A, Araki M (eds) Proceedings of the international workshop on forest watersheds. Phnom Penh, Cambodia, p 67–72
Ito E, Lim S, Pol S, Tith B, Pith P, Khorn S, Tani A, Kanzaki M, Kaneko T, Okuda Y, Araki M (2007) Use of ASTER optical indices to estimate spatial variation in tropical seasonal forests on the west bank of the Mekong River, Cambodia. In: Sawada H, et al. (eds) Forest environment in continental river basins. Springer, Tokyo, p 232–240
Nobuhiro T, Shimizu A, Kabeya N, Tsuboyama Y, Kubota T, Abe T, Araki M, Tamai K, Chann S, Keth N (2007) Year-round observation of evapotranspiration in an evergreen broadleaf forest in Cambodia. In: Sawada H et al. (eds) Forest environment in continental river basins. Springer, Tokyo, p 75–86
Ohnuki Y, Kimhean C, Shinomiya Y, Sor S, Toriyama J, Ohta S (2007) Apparent change in soil depth and soil hardness in forested areas in Kampong Thom Province, Cambodia. In: Sawada H, et al. (eds) Forest environment in continental river basins. Springer, Tokyo, p 263–272
Shimizu A, Kabeya N, Nobuhiro T, Kubota T, Tsuboyama Y, Ito E, Sano M, Chann S, Keth N (2007) Runoff characteristics and observations on evapotranspiration in forest watersheds, central Cambodia. In: Sawada H, et al. (eds) Forest environment in continental river basins. Springer, Tokyo, p 135–146
Simunek J, Sejna M, van Genuchten MTh (1999) Simulating water flow and solute transport in two-dimensional variably saturated media. U.S. Salinity Laboratory,.USDA, ARS, Riverside
Toriyama J, Ohta S, Araki M, Kanzaki M, Khorn S, Pith P, Lim S, Pol S (2007) Soils under different forest types in dry evergreen forest zone in Cambodia: morphology, physicochemical properties and classification. In: Sawada H, et al. (eds) Forest environment in continental river basins. Springer, Tokyo, p 241–253
Acknowledgments
We thank Mr. Chann Sophal and the staff of Forestry Administration for their arrangement and assistance in field surveys in the Cambodian forests. We appreciate Dr. Masahiro Kobayashi’s assistance in numerical simulation. This research was carried out as a part of a research project “Assessment of the Impact of Global-Scale Change in Water Cycles on Food Production and Alternative Policy Scenarios” funded by the Ministry of Agriculture, Forestry and Fisheries of Japan.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Araki, M., Shimizu, A., Kabeya, N. et al. Seasonal fluctuation of groundwater in an evergreen forest, central Cambodia: experiments and two-dimensional numerical analysis. Paddy Water Environ 6, 37–46 (2008). https://doi.org/10.1007/s10333-008-0114-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10333-008-0114-1