AGU_Publication
- 1. Sign on SAO/NASA ADS Physics Abstract Service · Find Similar Abstracts (with default settings below) Toggle Highlighting · Reads History · · Translate This Page Title: Ground Water Modeling Of Arsenic Contaminated Sandy Aquifer With Response To Transient River Levels, Mek ong Delta,Cambodia. Authors: Ganguly, S.; Polizzotto, M.; Sampson, M.; Fendor, S.; Benner, S. Affiliation: AA(Boise State University, Department of Geology, Boise State University., Boise, ID 83705 United StatesSomenathGanguly@mail.boisestate.edu), AB(Stanford University, Department of Geological and Environmental Sciences, Stanford University., Stanford, CA 94305 United States ;), AC(Resource Development International, Resource Development International., Kien Svay, Kan 12204 Cambodia ;), AD(Stanford University, Department of Geological and Environmental Sciences, Stanford University., Stanford, CA 94305 United States ;), AE(Boise State University, Department of Geology, Boise State University., Boise, ID 83705 United States ;) Publication: American Geophysical Union, Fall Meeting 2006, abstract #H41B-0394 Publication Date: 12/2006 Origin: AGU Keywords: 1847 Modeling Bibliographic Code: 2006AGUFM.H41B0394G Abstract The sandy aquifer of Mekong River Delta in Cambodia is a primary drinking water source and contains elevated concentrations of dissolved arsenic (15-1300μg/L), a common problem of Southeast Asia. Both hydraulic heads and
- 2. dissolved arsenic concentrations vary temporally with respect to transienthydraulic head of the Mekong River, suggesting that groundwater flow plays a potentially important role in arsenic mobilization/transportation. The riverfluctuates annually 5 to 8 m, with the highest levels in mid-September due to upstream monsoonal rains and Himalayan snowmelt and the lowest levels in mid-May to early June. The hydraulic gradient between the river and adjacent aquifer changes direction biannually; when the river is rising the gradient is from the river to the aquifer, when the river is falling the gradient is from the aquifer towards the river. In contrast, wetlands overlying the aquifer exhibit time varying head change of 2.5 to 3m annually due to local rain from late September to early October and an apparent limited hydraulic connection toaquifer. Numerical modeling (using MODFLOW) is able to reproduce the aquifer head distribution by transiently altering the river boundary condition, supporting the hypothesis that the temporal variations in observed hydraulic head are primarily driven by the seasonal river fluctuations. The modelingalso supports the conclusion that the observed dampening of water level fluctuations in the distal part of the study area is due to increasing distance from the Mekong River.