HR: 10:50h
AN: H32C-03    [Abstracts]
TI: Fractal Fluctuations of Groundwater Levels: Observation, Interpretation, and Implication
AU: * Zhang, Y
EM: you-kuan-zhang@uiowa.edu
AF: Dept. of Geoscience, IIHR Hydrosciences and Engineering, 121 TH, Iowa City, IA 52242
AU: Li, Z
EM: zhongwei-li@uiowa.edu
AF: Dept. of Geoscience, Univ. of Iowa 121 TH, Iowa City, IA 52242
AB: Groundwater recharge (R) from precipitation and discharge to rivers as baseflow (BF) are two of the main processes in the basin-scale water cycle. These processes vary with time and space. Effective management of water resources requires deep understanding of these processes. Due to the lack of data or the difficulties in measuring R and BF, however, our current knowledge and understanding of these complex processes are very limited, especially about their temporal and spatial variations. Various assumptions are made about spatial variations of R in existing studies and little attention has been given to temporal variations of R and BF. While it is difficult to measure R and BF, it is relatively easy to measure the water levels in observation wells (h) and runoff in rivers. Extensive groundwater level data sampled at various time intervals over periods of years or decades are often available. Fluctuations of the water table in a groundwater system are dynamic responses of the system to its recharge and discharge, and thus contain significant amount of information about the recharge and discharge. Our spectral analyses of the observed water levels in 7 monitoring wells at the Walnut Creek watershed of Iowa and in 14 USGS long-term monitoring wells as well as the baseflow to Walnut Creek and other four streams show that both h and BF may fluctuates as temporal fractals. We will explain why scaling generally exists in these as well as other hydrological variables, provide possible physical bases for the scaling rule, and indicate some implications of the finding.
DE: 1829 Groundwater hydrology
DE: 1839 Hydrologic scaling
DE: 1869 Stochastic hydrology
DE: 1872 Time series analysis (3270, 4277, 4475)
SC: Hydrology [H]
MN: Fall Meeting 2005