Spatial Variability Of Hydrological Properties In A Catchment Of The Gully Region, The Loess Plateau

In order to rehabilitate and develop the ecological system in gully region of the Loess Plateau, we studied the spatial variability of hydrological properties in a typical catchment-Wangdongguo. The objectives of this study are: (1) collect the basis data about soil physical properties, soil moisture, infiltration and evapotranspiration in the catchment scale for developing a catchment hydrological model, based on the DTM, (2) provide the hydrological information in the catchment scale for developing agricultural production, vegetation rehabilitation, and reasonable land using in this region. The main conclusions drawn from this study are:(1) The soil physical properties, including bulk density, saturated soil moisture, field capacity, and wilting moisture, were measured at 56 plots across the catchment. It was found that the soil physical properties had significant spatial variability in the catchment scale because of the joint-influences of land use, topography, physiognomy, and other factors. The spatial variation is small for field capacity, moderate for wilting moisture and bulk density, and great for saturated soil moisture. According to physiognomy, the bulk density changed as the following order: upland>hills> hillslopes>gully slopes, the saturated soil moisture arranged as: hillslopes>hills>gully slopes>upland, while field capacity and wilting moisture are as follows: gully slopes> hills>hillslopes>upland. The soil physical properties have obvious vertical distribution characteristic in the slope. The bulk density in sunlit slope is greater than it in sunless slope, and change in the follow order in the slope: tophills>upland> hillslopes, while after rainy season, it is as follows: gully slopes>upland>hills> hillslopes. In addition, the soil moisture has obvious vertical distribution characteristic in the slope. It decreased with the increase of the gradient. The soil moisture in sunlit slope is greater than that in sunless slope, and changes as the following order in the slope: tophills>hillslopes>gully slopes. Also, the evapotranspiration has obvious vertical distribution characteristic in the slope. The evapotranspiration decreased...