Hydrological Evaluation of Flow Diversion Terraces Using Downhill-Slope Calculation Method for High Resolution and Accuracy DEMs

Abstract

Slope is an important topographical parameter in hydrological models. Dramatic changes in slope are produced due to micro variations of topography in flow diversion terrace (FDT) systems. Assessing the effectiveness of FDT on soil conservation yields different results using different slope calculation methods with different resolution and accuracy digital elevation models (DEMs). In this study, the ArcGIS built-in average-neighborhood-slope (ANS) method and a downhill-slope (DHS) method were used to calculate slopes for a small agricultural watershed in New Brunswick, Canada. Six DEMs were used, i.e., 1, 5 and 10 m resolution DEMs generated with conventional photogrammetric techniques, and 1, 5, and 10 m resolution DEMs derived from light detection and ranging (LiDAR) data. Calculated slopes were summarized for the whole watershed, a patch of FDT systems, and grassed flow channels in front of embankments in the patch. Results indicated that the DHS method produced smaller slopes than the ANS method with LiDAR-1m DEM along grasses flow channels. Furthermore, the mean L-factor derived from the DHS method was smaller than that derived from the ANS in terraces and grassed flow channels for the LiDAR-1m DEM. Finally, soil loss estimated from the DHS method using RUSLE was more consistent with measurement for the watershed than that from the ANS method when the LiDAR-1m DEM was used. The DHS method can provide accurate slopes along grassed flow channels and can be used to assess FDT systems using USLE-based models with high resolution and accuracy DEMs.

Evaluating Impacts of Detailed Land Use and Management Inputs on the Accuracy and Resolution of SWAT Predictions in an Experimental Watershed

“…The basic input data included the DEM, land use, and soil maps for the BBW. A high-resolution light detection and ranging (LiDAR) based DEM (1-m resolution) was used to delineate the watershed and derive topographical characteristics [33,34]. The land use types in BBW are surveyed each year by Agriculture and Agri-Food Canada (AAFC) and summarized in Table 1.…”

Modelado De La Infiltración en Suelos Volcánicos Agrícolas Por Lluvia Mensual en La Cuenca Alta Del Río Páez, Cartago, Costa Rica

“…Una razón de esto es que la ecuación de Richards que rige el movimiento del agua en el suelo tiene una fuerte no linealidad (Shiraki et al, 2006). Otros investigadores como Chari et al (2020) sugieren que debido a la variabilidad espacial y temporal en la capacidad de infiltración del suelo que pueda ocurrir, una mejor aproximación es escalar el proceso de infiltración a un nivel más regional como la cuenca hidrográfica con el fin de expresar la dinámica del agua en el suelo de acuerdo diferentes factores como los estudiados de manera individual como la variabilidad de las propiedades del suelo (Toohey et al, 2018) el uso de la tierra (Sun et al, 2018;Babaei et al, 2018) y la pendiente (Huang, 2013;Qi et al, 2018).…”