Evaluation of the WEPP model and digital elevation grid size, for simulation of streamflow and sediment yield in a heterogeneous catchment

Abstract

The paper presents the result of an application of the GeoWEPP model in a heterogeneous semi‐agricultural catchment located in the northern Italian Apennines mountain range. The objectives were: (a) to evaluate the GeoWEPP model in a heterogeneous catchment in a Mediterranean climate and (b) to examine the effect of digital elevation model grid size on hydrological and sediment yield simulations. The catchment is characterized by large heterogeneity in geology, soil type, vegetation cover and topography. In addition, 10% of its area is occupied by calanchi (badlands), characterized by steep, bare soil and accentuated erosion. Experimental streamflow data were compared with those simulated by GeoWEPP for a period of eight years and the results were evaluated by means of statistical indices, with the analysis of the flow duration curve. Simulated sediment yields were compared with experimental data for one year. The streamflow cumulative annual results were satisfactory with NSE oscillating between 0.40 and 0.83 and RMSE between 1.1 and 2.9 mm. Also, the performance of the model with daily streamflow data was positive (NSE = 0.68 and RMSE = 1.9 mm). The flow duration curve indicated that GeoWEPP could represent the experimental streamflow for fluxes over 1 mm d−1. The model performance for simulation of sediment yield was satisfactory with both digital elevation models of different grid sizes (NSE = 0.84 and 0.87). Indeed, the sensitivity analysis tests of the model showed that there was no statistically significant improvement in the accuracy of the digital elevation model between 10 and 2 m resolution. These results were confirmed for both streamflow as well as sediment yield. Additional sensitivity analysis of other model parameters performed on the entire catchment and badlands hillslopes showed that bedrock hydraulic conductivity primarily affected the model in both settings. Copyright © 2014 John Wiley & Sons, Ltd.

Subdividing Large Mountainous Watersheds into Smaller Hydrological Units to Predict Soil Loss and Sediment Yield Using the GeoWEPP Model

“…In respect to model evaluation, observed (O i ) and predicted (P i ) annual sediment values were compared by using the percent deviation (Dv) [24], Nash and Sutcliffe (1970) simulation coefficient (ENS), and the coefficient of determination (R 2 ) [20,23,25]. The deviation of sediment values, Dv, given by the following equation is one criterion for goodness-of-fit: 10 (1988-94, 1996, 1999, and 2000) that had all the monthly measurements done by the SHA in order to make the comparison properly with the predicted values.…”

Application of GeoWEPP for Evaluating Sediment Yield in a Mountain Area: Agatsuma Watershed, Japan

“…Dun et al [2009] and Zhang et al [2009] introduced a key restrictive layer in WEPP to reproduce runoff in forested watersheds, but the target watershed sizes were smaller than GeoWEPP recommendations. Pieri et al [2014] successfully applied GeoWEPP to a heterogeneous watershed with steep slopes and significant sediment discharge from badlands. The applicability of GeoWEPP to typical watersheds in Japan, consisting of steep, forested slopes, still needs to be assessed.…”

“…1, 2018 then needs to be removed. Limited previous research, such as Pieri et al . [2014], introduced this "spin-up process" ; however details regarding setting the depth to the non-erodible layer were not provided.…”

“…[2014], introduced this "spin-up process" ; however details regarding setting the depth to the non-erodible layer were not provided. Pieri et al [2014], applied GeoWEPP to a watershed with significant erosion, and due to this, a spin-up period may have been needed for proper redistribution of initial sediment deposition as discussed above.…”

Modeling of Phosphorus Losses by Water Erosion

“…Models such as the Water Erosion Prediction Project (WEPP) have provided good results in predicting erosion rates (Amorim et al, 2010;Mahmoodabadi & Cerdá, 2013). WEPP is widely used by researchers in temperate regions (Foltz et al, 2011;Pieri et al, 2014). For this reason, verifying the applicability of this model to the Brazilian edaphoclimatic conditions is essential.…”