Detecting groundwater level in shallow unconfined aquifer with microwaves for use in debris flow warning
Journal
International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment, Proceedings
Start Page
613
End Page
624
ISBN (of the container)
9789059660595
Date Issued
2007
Author(s)
Abstract
This study is to examine the feasibility of measuring the groundwater level using ground-based microwave equipment. The propagation of electromagnetic waves in soil depends on the variation of dielectric constants which vary with the water content in the soil. Laboratory experiments by emitting electromagnetic waves to a sandbox with pre-measured moisture profile are performed. The reflective signals are recorded by network analyzer system. The four-component mixing model proposed by Dobson et al. (1985) is shown to be better and is used in this study. The simulated water table depth has a maximum error of 2.7% compared with measured data under several water content profiles. In the field experiments, we used the pulse generator to produce an impulse and emitted signals by a Yagi-Uda type antenna. The reflected signal is recorded by oscilloscope. Auto-correlation function is used to identify objects detected. The field experiments showed that the microwave can penetrate scattered trees and bushes. The distances measured in the field experiment has a maximum error 2%. © 2007 Millpress.
Event(s)
4th International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment
Subjects
Dielectric constant
Groundwater level
Layered-media method
Microwave
Description
4th International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment, 10 September 2007 through 13 September 2007, Chengdu
Type
conference paper