Use of terraces to mitigate the impacts of overland flow and erosion on a catchment

Abstract

The paper presents the impact of a historical system of terraces constructed centuries ago to mitigate the effect of a steep slope on overland flow. Systems of this type were constructed in past centuries by land owners, who then ploughed the land and grew crops on it. They used stones collected from the local agricultural fields as their terracing material. The influence of terraces on overland flow was simulated using the KINFIL. The overland flow is therefore reduced by greater infiltration of extreme rainfall excess flows on the terraces, and the KINFIL model shows to what extent the system of terraces can mitigate the resultant flood and soil erosion. The Knínice locality in North-Western Bohemia, with seven terraces and six field belts between them, was selected as the experimental catchment area. The results compare hydrographs with N-year recurrence of rainfall-runoff time, where N = 10, 20, 50, and 100 years, and the hydraulic variables, e.g. overland flow discharges of a design rainfall, hydraulic depths, flowing water velocity, and shear stress. The comparison provides hydraulic results with terraces and without terraces. The contrast between the results with and without terraces shows the positive role of the system of terraces in protecting the field belts.

Surface storm flow prediction on hillslopes based on topography and hydrologic connectivity

“…These results are in line with observations in many other parts of the world (Di Lazzaro et al, 2015;Wei et al, 2016). For example, Kovář et al (2016) found similar effects of agricultural terraces on storm runoff on a similar-sized hillslope in Bohemia (Czech Republic); however, they used the kinematic wave approximation to route storm flow because of lower rainfall intensities and a possibly greater relative contribution from subsurface flow compared to Mediterranean and semi-arid watersheds. Fig.…”

Geomorphological and sedimentological indicators of land degradation (Meghalaya Plateau, NE India)

“…The preference for large stones can explain the low occurrence of large boulders in the deforested catchment compared with the forested catchment. Selective removal of boulders is also a common stone‐clearing technique used for cultivation in other regions with karst relief or affected by freeze action (Andriani & Walsh, ; Gams, Nicod, Julian, Anthony, & Sauro, ; Kovář, Bačinová, Loula, & Fedorova, ). Rock extraction decreased the boulder areas to only 8.1% of catchment area in the deforested catchment compared with 30% of the forested catchment and gained new land for agriculture.…”

Use of terraces to reduce overland flow and soil erosion, comparison of the HEC-HMS model and the KINFIL model application

“…(6) expresses the Green-Ampt theory (Rawls & Brakensiek 1983), the left side describes the Darcy concept for the process of infiltration v f (t). K s is the hydraulic conductivity (m/s), H f is the capillary suction on the infiltration front (m), is the difference between the saturated soil moisture content and actual content (-), z f is the depth of the infiltration front (m), and z is the vertical ordinate (m) (Kovář et al 2016).…”