Use Of Hydro-Geophysics Streaming Potential (Sp) Signals In Evaluating Environmental Friendly Bio-Ecological Drainage System (Bioecodstm) Effectiveness
Loading...
Date
2010
Authors
Nik Adik, Nik Nur Azza
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
The Self-Potential (SP) technique is one of the non-invasive hydrogeophysical
methods used in subsurface water investigation to provide information concerning
near surface water flow. This study was carried out to evaluate and analyze the flow
characteristics such as the direction and magnitude of water flows associated with the
BIOECODSTM drainage system within the Engineering Campus of Universiti Sains
Malaysia (USM), Nibong Tebal. The SP values are obtained based on the
measurement of naturally occurring potential differences generated mainly via
electrochemical, electrokinetic and thermoelectric mechanisms, and the hydraulic
currents that generate underground electrical currents (tens of mV) through
electrokinetic process. The natures of streaming potential at three selected areas
were measured using a pair of non-polarized Cu/CuSO4 electrodes over the entire
array. The SP anomalies were then cross-checked with electrical resistivity and
seismic refraction supplementary survey and borehole data to analyze the upper soil
characterization as well as to calculate the rate and direction of movement of
groundwater through aquifers and confining units of the subsurface. Initial results
show that general trends of positive anomalies represent the significance of
subsurface water flow. The SP results show that the positive polarity anomalies in
order of 4 mV to 35 mV represent the significance of subsurface water flow and were
directly related to the BIOECODSTM component, swale. Any depression landscapes
over slightly elevated ground often show moderate SP voltages (value and polarity),
whilst the dry spots were typified by the lower and occasionally negative polarity
signatures in many places. These measured SP values at any particular points show
an inconsistency and strongly depend on the landscape, porosity, permeability and
moisture of soil formation, water saturation and the climatic daily variation of the
studied area. The investigations were supported by auxiliary 2-D resistivity and
seismic refraction imaging surveys to confirm the geology and condition of the
subsurface of the study area.
Description
Keywords
Hydro-Geophysics Streaming Potential (Sp) , Bio-Ecological Drainage System (Bioecodstm)