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The Coupling Relationship Between the Sediment Yield from Rainfall Erosion and the Topographic Feature of the Watershed

Author: CuiLingZhou
Tutor: LiZhanBin
School: Northwest University of Science and Technology
Course: Soil
Keywords: Watershed model test Watershed Topographic The Landforms information dimension Watershed erosion and sediment yield forecast
CLC: S157
Type: PhD thesis
Year: 2002
Downloads: 688
Quote: 17
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Abstract


The Small Watershed is the basic unit of China's ecological environment restoration and comprehensive soil erosion control, erosion and sediment yield regularity and development trend forecast has been academic research hotspot of Soil and Water Conservation. The landforms affect small watershed erosion and sediment yield of the underlying surface factor quantitative parameters generally inherit slope landform feature quantification methods (such as slope, slope length factor) and average slope, average slope length and gully density parameter these parameters is only an overview of watershed topography and single-factor expression, does not truly reflect the essence of complex watershed topographic characteristics and interrelated. In this paper, based on the watershed topographic that has the significantly with fractal characteristics, from the simulation of departure, the use of fractal theory and methods, combined with high-precision photographic measurement and GIS technology, the watershed model erosion produced sand spatial and temporal variation characteristics, geomorphology morphological development process and its corresponding the fractal characteristics of the watershed model soil erosion and sand topography coupled relationship-depth study and validation study with 11 years of rainfall sediment runoff observations Chabagou Watershed erosion and sediment yield from a single slope simulation, forecast to watershed erosion and sediment yield simulation, the the topography parameters extracted forecast conversion process provides the theory and methods, to provide scientific and practical basis for the comprehensive management of soil erosion of small watershed in the Loess Plateau. This article achieved the following results: 1. The watershed model soil erosion and sand timing variation times the rainfall average sediment transport rate performance period with basin model development process, namely the development of the initial period (first to fifth rainfall), active developmental period (sixth to 18 rainfall) and the development of the field to 19 of the twenty-fifth game of the relatively stable period (rainfall). Erosion and sediment yield in the development of the initial period, the watershed model presents a more obvious by the disorderly to the orderly development of the different rainfall intensity rainfall runoff sediment concentration and runoff sediment transport rate with rainfall lasted change presents a power relationship; in active development period, the watershed model erosion and sediment yield further showing a regulated and orderly, including development of early active period (sixth to 14th rainfall) different rainfall intensity times the rainfall runoff sediment concentration and runoff sediment transport rate diachronic change the power relationship with rainfall (the sixth and the tenth in a runoff sediment concentration with rainfall lasted changes show the exponential relationship), development (Race 15 to 18 games of the active period of the late rainfall) different rainfall strong times rainfall runoff sediment concentration and runoff sediment transport rate with rainfall duration changes exponentially; relatively stable period in the development of the different rainfall intensities times rainfall runoff sediment concentration and runoff sediment transport rate with rainfall lasted dynamic changes to secondary polynomial. 2. The watershed model erosion variation Erosion and sediment yield space to the active site of the sand gradually rendered by the lower part of the watershed model with basin model development process development characteristics of the upper watershed model under the central part of the development of the initial period and the development of an active period Erosion and Sediment Yield active site The upper part of the watershed model develops for the period of the active site of the erosion and sediment yield. The main gully soil erosion in the watershed model in a dominant position in the sand process the main ditch sediment yield accounted for watershed model total sediment yield ratio is maintained in the range of 48.7-66.6%, and total sediment deposition amount of the share of the main ditch watershed model the ratio of the amount of sedimentation is maintained at between 64.9% -99.4%. 3. Watershed model during the development of the landforms valley extended and incised mainly in the form of the topography of the watershed model development, valley extended development occurs mainly in the development of active period, the main ditch share proportion of the total area in the valley watershed model valley extended developmental process maintained at 60% above: the main tributary cut development the most dramatic in the early performance of the development in the early and the development of an active period, and its V-shaped cross section is presented in the development of early and stable during the period shallow U-shaped and relatively flat bottom of the trapezoid cross-section of development of the main ditch obvious priority in each tributary. 4. Fractal characteristics of the watershed model topography and its topography and erosion and sediment yield coupled watershed model of the relationship between different developmental periods showed good scale-free zone in their respective fractal characteristics, topography information dimension Di presented with the watershed model landform development trend watershed model first increases and then decreases soil erosion and sand and topography characteristics sediment transport rate showed strong synchronization and correlation watershed model times rainfall relative timing and space. Sr and landforms dimension Di exponentiation relations. 5. Fractal characteristics of watershed Chabagou Saudi topography Chabagou watershed and catchment times rainfall sediment transport modulus Ms modulus and peak flow Q. And runoff depth h showed a strong positive correlation and multiple regression results showed obvious spatial variability. Watershed and support Chabagou basin topography in scale-free interval showed better fractal characteristics, topography information dimension Di 0.9661 (Du Ravine fork), 0.9419 (West Village), 0.8935 (11) 0.8308 (Camel ear Lane), 0.8140 (snake Jinjiagou), 0.6368 (black alum ditch), the 0.5821 (Shuiwang groove). 6. The basin rainfall Chabagou relational model of soil erosion and sand topography coupled basin Chabagou Du Ravine bifurcated (96k. Spoon,) I of old (21kmz), camel (5.74km spoon, black alum ditch (ear Lane 0.133kmz) Shuiwang ditch (0.107km spoon of five small watershed topography information dimension Di, and 116 games of erosive rainfall water sand basin Chabagou times rainfall sediment transport modulus Ms with the flood peak the flow modulus Q Bu runoff depth h and geomorphological information dimension Di multiple regression statistical model. Xizhuang (49kin spoons and snake Jinjiagou of (the Fab 4 km spoon two sticks basin 57 rainfall water and sediment data and topography information dimension Di validation of the model to improve the accuracy and reliability of the single forecast times of the relationship between water and sediment rainfall sediment modulus, indicating that the impact on erosion and sediment yield is appropriate to reflect watershed topographic landforms information dimension Di. 7. watershed topography characteristics shaped quantified study proposed a watershed geomorphology form of information-dimensional number Di of the calculation model and the specific method, this parameter is based on the fractal theory and methods of watershed geomorphology form of general characteristics of the comprehensive quantitative, reveals the watershed topographic complexity of quantitative nature, to overcome the the existing quantitative parameters (such as slope, slope length, average slope and gully density, etc.) only takes a the landforms single factor and its linear characteristics inadequacies, landforms quantitative research from simple slope major shift for complex watershed topography?

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CLC: > Agricultural Sciences > Agriculture as the foundation of science > Soil > Soil and Water Conservation
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