HR: 08:45h
AN: H51A-04    [PDF]
TI: Assessing Land Cover Change in Sumber Jaya, Indonesia, by Rainfall-Runoff Time Series Analysis
AU: * Manik, T K
AF: National University of Singapore, Department of Geography, Singapore, 117570 Singapore
AU: Sidle, R C
EM: sidle@slope.dpri.kyoto-u.ac.jp
AF: Kyoto University, Disaster Prevention Research Institute, Gokasho, Kyoto, Uji, 611-0011 Japan
AB: Sumber Jaya catchment in South Sumatra, Indonesia, has experienced rapid land use change in the past 20 years. To investigate the impact of land cover change on catchment function for large spatial and temporal scales, a frequency distribution and time series analysis of daily rainfall and water discharge (1974-1998) were used. Rainfall from three gages distributed along the main river conformed to Gamma distributions. Most of the water discharge also followed Gamma distributions, but with different scale and shape parameters; for some years these data better fit a normal distribution. The autocorrelation coefficients showed that rainfall means were non-stationary and exhibited no seasonal pattern (i.e., random). Water discharge was also non-stationary, but exhibited some trends and a strong seasonal pattern. Because no differences were detected for either spatial or temporal patterns of rainfall in the area and the large scale topography was assumed to be similar, the differences in frequency distribution and time series pattern between rainfall and water discharge is inferred as effects of land cover change. Results from both analyses imply that the land functions as a buffer for infiltrated rainfall and discharges more water to the river as subsurface flow rather than surface runoff. This finding was consistent for $>$ 20 yr of annual records and for every 5 yr period. However, sub-catchment and hillslope studies currently underway may indicate differences in hydrologic response that cannot be elucidated by such rainfall-runoff statistical analyses.
DE: 1803 Anthropogenic effects
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2003 Fall Meeting