TITLE:
Groundwater Leakage and River Runoff in a Catchment Influenced by Tectonic Movement
AUTHORS:
Md Motaleb Hossain, Kazuhisa A. Chikita, Yoshitaka Sakata, Takuto Miyamoto, Yasuhiro Ochiai
KEYWORDS:
Groundwater Leakage, Fault, Water Balance, Evapotranspiration, One-Layer Model
JOURNAL NAME:
Open Journal of Modern Hydrology,
Vol.5 No.2,
April
29,
2015
ABSTRACT: In order
to clarify how groundwater leakage and river runoff occur in a catchment under
tectonic movement, the water balance was estimated in the forested (88.3% in
area) Oikamanai River catchment (area, 62.6 km2), Hokkaido, Japan.
The catchment’s geology is early Miocene to Pliocene sedimentary bedrock of
partly high permeability, accompanied by currently active faults. Daily
evapotranspiration, E, in water
balance was calculated by applying the one-layer model to meteorological data
in the rainfall season of 2011 and 2012, with the topographic influence on heat
balance of the catchment considered. The coupling with the short-term water
balance method for river runoff events allows us to estimate groundwater leaking
to the other catchments through the faults and bedrock. As a result, the
leakage corresponded to 50% - 80% of effective rainfall (=P - E: P, rainfall) in 2011, whereas it was
lower or negative in 2012. The estimate of leakage then included variability of
ca. 80%. In 2012, shallow groundwater storage seems to retain high baseflow
during non-rainfall.