An integrated hydrological model based on improved Green-Ampt model and
HYDRUS model for semi-humid and semi-arid plain areas
Abstract
Hydrology models of humid areas have always been studied deeply with
higher model accuracy, but relatively less so for semi-humid and
semi-arid areas, especially in plain. Here an integrated hydrology model
(GA-HYDRUS model) was developed based on improved Green-Ampt model and
HYDRUS model using the dataset of 7 rainfall events in Tianjin, China.
The SCE-UA optimization algorithm was applied based on the data of soil
moisture content to calibrate GA-HYDRUS model. The calibration and
verification results demonstrated that the NSE values of the average
soil moisture content were above 0.7. Meanwhile, the NSE values of the
soil moisture content at the depths of 10, 20, and 40 cm were generally
high and the R<2> were all greater than 0.75. The
average runoff coefficient of permeable surface was 0.54. Furthermore,
the relationships between different hydrological fluxes (rainfall,
surface runoff, soil infiltration and vertical groundwater recharge)
calculated by GA-HYDRUS model were analyzed. The results showed that
rainfall characteristics such as rainfall, rainfall intensity and
duration greatly affected the runoff, indicating that high rainfall
intensity and short rainfall duration would produce more surface runoff.
On the contrary, bimodal rainfall with small rainfall intensity and long
duration made the effect of vertical groundwater recharge to supplement
groundwater more significant. Therefore, the GA-HYDRUS model is a highly
effective approach to simulate the transformation processes between
surface runoff, soil water and groundwater in semi-humid and semi-arid
plains. This study may have important applications in aiding water
resources management.