Modeling soil erosion between 1985 and 2014 in three watersheds on the carbonate-rock dominated Guizhou Plateau, SW China, using WaTEM/SEDEM

Abstract

The Guizhou Plateau, SW China is largely underlain by carbonate rocks. Because soils are thin, soil loss remains a serious problem despite low erosion rates. Further understanding the impacts of changes in rainfall, land use and differences in topography on sediment yield and delivery may assist in the development of suitable policies to reduce soil erosion on the plateau. A spatially distributed soil erosion and sediment delivery model (WaTEM/SEDEM) was applied to investigate temporal–spatial changes in soil erosion between 1985 and 2014 in three watersheds (Dadukou (DDK), Caopingtou (CPT) and Gaoche (GC)) located in the southwest Guizhou Plateau. The WaTEM/SEDEM model was calibrated and validated using data on sediment yields measured at the watershed scale. The total sediment yield (SY) and soil erosion modulus (SEM) firstly decreased followed by an increase, whereas the sediment delivery ratio (SDR) remained almost unchanged over the 30-year period. The major sediment source was dry farmlands. SY was the highest in the largest DDK watershed. The highest SEM occurred in the CPT watershed due to steep terrain and high ratio of dry farmland areas on steeper slopes. SEM was the lowest in the GC watershed where slope gradient and ratio of dry farmland on steeper slopes are low. SDR was the highest in the GC watershed because of its topographic characteristics. SEM was sensitive to precipitation fluctuations in the GC, DDK and particularly in the steep and intensively eroded CPT watershed, while changes in dry farmland ratio influenced the SEM in the CPT and DDK watersheds but not in the gentle and mildly eroded GC watershed. Changes in forest ratio had significant impacts on SEM only in the GC watershed. Since responses of soil erosion to variations or differences in the main impact factors differ in the different watersheds, soil conservation strategies should be watershed specific.

Pre/Post-Fire Soil Erosion and Evaluation of Check-Dams Effectiveness in Mediterranean Suburban Catchments Based on Field Measurements and Modeling

“…The optimal values were 4 for ktc-high and 1.2 for ktc-low, attributing a model efficiency of 0.72 for the NSE statistic index. Previous WaTEM/SEDEM model applications reported a model efficiency (NSE) range between 0.14 and 0.89 [10,47,[101][102][103][104][105]. According to previous researches, NSE values of 0.55 and higher indicate good model performance, and the simulated values are generally acceptable [106][107][108].…”

Assessing the source and delivery processes of organic carbon within a mixed land use catchment using a combined n-alkane and carbon loss modelling approach

“…The ambiguity in OC origin can be reduced if the spatial distribution of erosion prone areas and their likely connection to the streams can be identified. Net catchment erosion can be modelled using sediment delivery models (e.g., WaTEM/SEDEM (Van Oost et al 2000;Van Rompaey et al 2001;Verstraeten et al 2002)); however, accurate predictions for these models require calibration, commonly carried out using outlet sediment yield data (Krasa et al 2019;Luo et al 2021). However, sediment yield data are not available for many catchments, and are usually only available at the catchment outlet.…”

Determinants of ecosystem processes and services in the karst critical zone in south-west China

“…The key regulation service is soil conservation, which is considered by another two contributions to this special issue. Luo et al (2021) identify the effect of topography on soil erosion. Because of the specific lithology in the karst region, the topography is characterized by steep slopes, and dry farmland on steep slopes was studied from the point of view of soil erosion.…”