Effects of Spatial Information of Soil Physical Properties on Hydrologi- cal Modeling Based on a Distributed Hydrological Model

• Published in: 中国地理科学：英文版 2013 (2), p.182-193
• Main Author: LIXianghu ZHANG Qi YE Xuchun
• Format: Article
• Language: English
• Subjects: 分布式水文模型; 土壤物理性质; 土壤蒸发; 地下水补给; 建模; 水文过程; 空间信息; 空间分布格局
• ISSN: 1002-0063; 1993-064X

The spatial distribution of soil physical properties is essential for modeling and understanding hydrological processes. In this study, the different spatial information （the conventional soil types map-based spatial information （STMB） versus refined spatial infor- mation map （RSIM）） of soil physical properties, including field capacity, soil porosity and saturated hydraulic conductivity are used respectively as input data for Water Flow Model for Lake Catchment （WATLAC） to determine their effectiveness in simulating hydro- logical processes and to expound the effects on model performance in terms of estimating groundwater recharge, soil evaporation, runoff generation as well as partitioning of surface and subsurface water flow. The results show that： 1） the simulated stream flow hydrographs based on the STMB and RSIM soil data reproduce the observed hydrographs well. There is no significant increase in model accuracy as more precise soil physical properties information being used, but WATLAC model using the RSIM soil data could predict more runoff volume and reduce the relative runoff depth errors; 2） the groundwater recharges have a consistent trend for both cases, while the STMB soil data tend to produce higher groundwater recharges than the RSIM soil data. In addition, the spatial distribution of annual ground- water recharge is significantly affected by the spatial distribution of soil physical properties; 3） the soil evaporation simulated using the STMB and RSIM soil data are similar to each other, and the spatial distribution patterns are also insensitive to the spatial information of soil physical properties; and 4） although the different spatial information of soil physical properties does not cause apparent difference in overall stream flow, the partitioning of surface and subsurface water flow is distinct. The implications of this study are that the refined spatial information of soil physical properties does not necessarily contribute to a more accurate prediction of stream flow, and the se- lection of appropriate soil physical property data needs to consider the scale of watersheds and the level of accuracy required.