Modelling the impacts of spatial heterogeneity in soil hydraulic properties on hydrological process in the upper reach of the Heihe River in the Qilian Mountains, Northwest China

Abstract

Spatial heterogeneity of soil has great impacts on dynamic processes of the hydrological systems. However, it is challenging and expensive to obtain spatial distribution of soil hydraulic properties, which often requires extensive soil sampling and observations and intensive laboratory analyses, especially in high elevation, hard to access mountainous areas. This study evaluates the impacts of soil heterogeneity on hydrological process in a high elevation, topographically complex watershed in Northwest China. Two approaches were used to derive the spatial heterogeneity of soil properties in the study watershed: (1) the spatial clustering method, Full‐Order‐CLK was used to determine five soil heterogeneous clusters (configurations 97, 80, 60, 40 and 20) through large number of soil sampling and in situ observations, and (2) the average values of soil hydraulic properties for each soil type were derived from the coarse provincial soil data sets (Gansu Soil Handbook at 1 : 1 000 000 scale). Subsequently, Soil and Water Assessment Tool model was used to quantify the impact of the spatial heterogeneity of soil hydraulic properties on hydrological process in the study watershed. Results show the simulations by Soil and Water Assessment Tool with the spatially clustered soil hydraulic information from the field sampling data had much better representation of the soil heterogeneity and had more accurate performance than the model using the average soil property values for each soil type derived from the coarse soil data sets. Thus, incorporating detailed field sampling, soil heterogeneity data greatly improve performance in hydrological modelling. Copyright © 2015 John Wiley & Sons, Ltd.

Variation of soil hydraulic properties with alpine grassland degradation in the eastern Tibetan Plateau

“…The hydrological effects of large-scale alpine meadow degradation are noticeable and serious in the Tibetan Plateau (Jin et al, 2015;Wang et al, 2012). For hydrological modelling, accurate parameter acquisition is necessary for simulation accuracy (Vereecken et al, 2015).…”

“…Our results indicate that hydraulic properties will be altered significantly both vertically and spatially with degradation. Therefore, to improve the performance of hydrological modelling, differences in soil hydraulic properties under different degradation degrees should be seriously considered (Jin et al, 2015).…”

A Comparison of Markov Chain Random Field and Ordinary Kriging Methods for Calculating Soil Texture in a Mountainous Watershed, Northwest China

“…The elevation of the upstream of the Heihe River Watershed ranges from 1674 to 5584 m above sea level (m a.s.l.) [44,45].…”

“…The elevation of the upstream of the Heihe River Watershed ranges from 1674 to 5584 m above sea level (m a.s.l.) [44,45]. Soil maps available for this watershed include the global soil texture map (1:1,000,000 scale) [46] and the 1:1,000,000 soil map of China [47,48].…”

Improving soil organic carbon parameterization of land surface model for cold regions in the Northeastern Tibetan Plateau, China

“…1 shows the location and extent of the study area, which is the main runoff generation area for the Heihe River basin and covers an area of 10,009 km 2 . Most of the area is covered by alpine grassland, and the elevation varies greatly from 1674 to 5584 m ASL (Jin et al, 2015). The majority of the soil is seasonally frozen.…”