Научный журнал Российского НИИ проблем мелиорации (May 2020)
GULLY MODELING FOR FOREST RECLAMATION PURPOSES
Abstract
Purpose: modeling of gullying processes in easily soaked and erodable rocks to justify forest reclamation practices. Methods: physical modeling in laboratory conditions, with consideration of the requirements of dynamic similarity of natural and model water flows while ensuring the similarity of rock lithology cut by gullies. Results. An analysis of the quantitative characteristics of gullying showed that the average regressive growth is 3.5 m per year, the deep erosion regime is characterized by a change in the intervals of downcutting and its suppression by accumulation, the average area growth between the rims is 72.4 m² per year, and the gully growth by volume is 335,6 m³ per year. By the 10th year of its development the gully tends to a club-like shape in plan, subsequently stretching in length. The qualitative characteristics consisted of a stepped cutting, its regressive development with the activation of slope processes on the sides and the output of the peak to the channel slope. The splashes from splitting a water fluent falling through the gully overfall to the bottom contributed to the soaking and slump of the cut material. Canopies overhanging above sump gully and along the rims, imitating the humus (sod) soil layer sporadically appear and collapse. It changes the stresses in the rock mass with the opening of cracks on the slope, which causes suffusion and spasmodic regression growth. The gully bottom is constantly changing the longitudinal profile with the activation of accumulation or deep erosion. Conclusions. It is not recommended to build hydraulic structures on gullies cutting through easily soaked and eroded rocks, due to the high probability of emergency situations. It is necessary to contribute to the overgrowing of such gullies with grassy and woody vegetation by creating gully forest belts made of sprouting tree species. They are placed along the rims taking into account the average annual regressive erosion and the average annual area growth between the rims. The slope locations between the forest belt and gully rim are occupied by the perennial grasses sod.
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