Erosion-Deposition Characteristics and Fencing Life of Straw Checkerboard in Alpine Sandy Lands

摘要

In the alpine sandy lands of China, there are great peculiarities and regional differences in the erosion and deposition characteristics of straw checkerboards. Fencing life of straw checkerboards is primarily affected by the erosion depth change of each intrinsic part over several years and takes great importance in optimizing the structures of straw checkerboard barrier. By way of seasonal measurement of steel chisels in straw checkerboards with three sizes and each in three slope positions, yearly and seasonal sand depth and intensity were obtained to describe the erosion and deposition characteristics in each type of straw checkerboard from the year of 2012 to 2015. Simulated three dimensional concaves revealed that serious erosion always occurred in the center- and south-oriented parts of the large straw checkerboards in higher slope positions. In contrast, deposition obviously appeared in the north- and west-oriented parts of those smaller sizes and lower slope positions. Similarly, a large deposition intensity with a range of 80–120 kg/[m~(2)·a] mainly exists in small-size and low-slope checkerboards and increased to two to three times compared with the erosive checkerboards in large sizes or higher slope. Winter and yearly erosion and deposition rates showed that the 1.5-m interval checkerboard on the middle slope would have the longest fencing life with ∼5 years, while the 1 m interval ones on the toe and the 2 m interval ones on the top had problems of overaccumulation and over-erosion, respectively, which restricted their lifetimes to 2 years. Thus, straw checkerboard should be allocated optimally according to the erosion and deposition characteristic. Generally, the medium size could be applied to all slope positions, while the small one and the large one were most suited to the top and the toe slope positions, respectively.