Temporal and spatial variation characteristics of groundwater recharge
in a small watershed in the Loess hilly region
Abstract
Groundwater is an important water resource for the ecological
restoration and the life and production of the inhabitants of the Loess
hilly region. A quantitative exploration of groundwater recharge
mechanism and the spatial-temporal variation pattern is the key for an
effective evaluation of groundwater resources in this region. Based on a
Bayesian model and a Sinusoidal model, the spatial-temporal distribution
pattern of the water transmission time and the groundwater recharge
ratio were investigated. The results showed that the transmission time
of groundwater by precipitation and surface water were 443.16 d and
64.58 d, respectively, which yielded a recharge ratio of 29.22% and
70.78%, respectively. Surface water was the main recharge source of
groundwater in this region. The values of the groundwater recharge ratio
by precipitation in the rainy season and dry season were 32.83% and
25.60%, respectively. Groundwater recharge mainly occurred during the
rainy season. From upstream to downstream of the small watershed, the
groundwater recharge ratio by precipitation increased gradually, while
the groundwater recharge ratio by surface water decreased. The spatial
characteristics of groundwater recharge ratio were all nonetheless not
obvious. Groundwater recharge mainly took place in the upstream region
of the watershed, while the discharge took place in the downstream area.
Groundwater recharge occurred mostly through a combination of piston
flow and preferential flow. The findings of this study could provide a
reference for the development, the utilisation and the protection of
groundwater resources in small watershed in the Loess Hilly region.