Slope surface-channel-drainage basin sediment production and transportation cooperative treatment method for midstream area of Yellow River

Abstract

The invention discloses a Yellow River midstream area slope-channel-drainage basin sediment production and transportation cooperative treatment method. The method is specifically implemented according to the following steps that a drainage basin to be treated is selected, drainage basin microtopography is divided, and the current situation of water and soil conservation measures is determined; evaluating the spatial suitability and the construction potential of the watershed microtopography and the water and soil conservation measure current situation; determining a slope measure configuration scheme; determining a channel silt dam configuration scheme; and slope gully treatment measure collaboration evaluation is carried out, and the coupling coordination degree of the target drainage basin is determined to serve as an optimal drainage basin collaboration treatment measure scheme. The slope-channel-drainage basin relation of the drainage basin is fully coordinated, drainage basin treatment quality improvement and efficiency improvement are promoted, and the problem that in the prior art, synergy is insufficient is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of ecological environment protection, and relates to a method for coordinated management of sediment production and transport in slopes, channels and basins in the middle reaches of the Yellow River. Background Art

[0002] The middle reaches of the Yellow River are one of the areas in my country with the most serious soil erosion and the most fragile ecological environment. The area is full of gullies, loose soil, concentrated rainstorms, high erosion intensity, and extremely difficult to control. It is the key area causing the Yellow River to have less water and more sand, and the unbalanced water-sediment relationship. It is also the core governance area for the ecological protection of the Yellow River Basin.

[0003] River basin management is the core driving force for promoting ecological civilization in the middle reaches of the Yellow River, and the primary task of river basin management is the scientific layout of soil and water conservation measures. In traditional river basin management planning, small watershed comprehensive management is the main model of river basin management in the middle reaches of the Yellow River, with forest and grass vegetation restoration and slope-to-terracing projects on slopes, and silt dams built in ditches to store sediment. The layout of soil and water conservation measures aims to minimize soil loss, ignoring the river's demand for sediment transport, insufficient consideration of the synergy between slope measures and ditch measures, and a lack of a goal-oriented river basin management model in the middle reaches of the Yellow River.

[0004] Therefore, it is urgent to develop a target-oriented watershed management model for the middle reaches of the Yellow River, fully coordinate the relationship between the basin slope-channel-watershed, and promote the improvement of the quality and efficiency of watershed management. Summary of the invention

[0005] The purpose of the present invention is to provide a method for coordinated management of slope-channel-basin sediment production and transport in the middle reaches of the Yellow River, so as to solve the problem of insufficient coordination in the prior art.

[0006] The technical solution adopted by the present invention is a method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River, which is specifically implemented according to the following steps: Step 1: Select the watershed to be managed, divide the watershed microtopography and determine the status of soil and water conservation measures; Step 2: Determine the spatial suitability and construction potential of watershed soil and water conservation measures based on the micro-topography and current characteristics of watershed soil and water conservation measures divided in step 1; Step 3: Determine the slope measures configuration plan based on the spatial suitability and construction potential in step 2; Step 4, determining the channel silt dam configuration plan based on the slope measures configuration plan in step 3 and the target sediment transport modulus; Step 5: Based on the ditch silt dam configuration plan in step 4, conduct a synergistic evaluation of the slope ditch control measures and determine the coupling coordination degree of the target watershed as the optimal synergistic control measure plan for the watershed.

[0007] The present invention is also characterized in that: Step 1.1, use a drone to fly at low altitude in the selected watershed to generate a digital orthophoto map and digital surface model of the watershed; Step 1.2, using the watershed digital surface model constructed in step 1.1 to reconstruct the terrain, obtain the digital elevation model of the watershed, and use the digital elevation model to divide the watershed micro-topography; Step 1.3, use the digital orthophoto generated in step 1.1 to interpret the image and obtain the land use structure and current distribution of soil and water conservation measures in the watershed.

[0008] Step 1.2.1, divide the geomorphic units; Step 1.2.1.1, extract the contour lines of the digital surface model of the watershed, remove the contour lines with shorter lengths, and interpolate the contour lines to regenerate the digital elevation model of the watershed; Step 1.2.1.2, use window analysis to determine the average value of the digital elevation model data with a window size of 11*11, perform difference calculation between the original digital elevation model data and the average digital elevation model data, and divide the entire watershed into two geomorphic units: inter-gully land and gully land; Step 1.2.2, divide the slope direction: use the digital elevation model to calculate the basin slope direction, and divide the slope direction into three categories: sunny slope, semi-sunny slope and shady slope; Step 1.2.3, classify the slope: the digital elevation model is used to calculate the slope of the watershed, and the slope is divided into four categories, including gentle slope with a slope of 0°~15°, slope with a slope of 15°~25°, steep slope with a slope of 25°~35°, and abrupt slope with a slope greater than 35°; Step 1.2.4: spatially superimpose the geomorphic units, slope aspects, and slope gradients to obtain different types of watershed microtopography.

[0009] When dividing the geomorphic units, the negative terrain with a difference value less than 0 is determined as the valley land of the basin, and the remaining positive terrain with a difference value not less than 0 is determined as the inter-valley land of the basin.

[0010] Step 2.1, determine the potential and suitable distribution areas of terrace construction in the basin; According to the results of the basin micro-topography division and the existing terrace distribution in the basin, the inter-ditch land with a slope of less than 25° is regarded as the suitable distribution area for terraces, and the suitable distribution area for terraces but without terrace construction is regarded as the potential for terrace construction; Step 2.2, determine the suitable distribution area of ​​forest land; Step 2.2.1, calculate the normalized green-blue difference index (NGBDI) based on the digital orthophoto: (1) In the formula, G is the visible green band; B is the visible blue band; Step 2.2.2, determine the NGBDI threshold, segment the NGBDI, and extract the forest land distribution; Step 2.2.3, based on the extracted forest land distribution, calculate the proportion of forest land area in each watershed micro-topography, and determine the micro-topography with a proportion of more than 20% as the suitable distribution area of ​​forest land; Step 2.3, determine the vegetation restoration potential of the watershed; Step 2.3.1, calculate the normalized difference vegetation index (NDVI) based on the multispectral digital orthophoto map; Step 2.3.2, calculate the vegetation coverage of the watershed according to the pixel binary model, extract the 95% quantile vegetation coverage value in each watershed micro-topography as the vegetation restoration potential value, and determine the vegetation restoration potential of the watershed; Step 2.4, determine the suitable layout area and construction potential of check dams in the basin; Divide the watershed into areas not exceeding 5km 2 For multiple sub-basins, according to the sub-basin land use status map, the sub-basins without residential areas, schools, and important transportation facilities are identified as suitable areas for the layout of check dams, and the sub-basins without check dams in the suitable layout areas are identified as potential areas for the construction of check dams.

[0011] Step 3.1, determine different vegetation and terrace slope management measures configuration scenarios based on the spatial suitability and construction potential of terraces and vegetation; Step 3.2, combining different slope management measures configuration scenarios to form a scenario combination model; In step 3.3, the universal soil loss equation (RUSLE) is used to calculate the slope soil erosion modulus under different scenario combination modes.

[0012] There are 7 scenarios for slope management measures configuration, namely: Scenario I: Maintain the status quo and do not add governance measures; Scenario II: sloping cultivated land and bare land are covered by 50% grassland; Scenario III: The grassland on the shady slope of the valley is arranged as forest land, and the vegetation coverage reaches 60%; Scenario IV: The grasslands on the shady and semi-sunny slopes of the valley are arranged as forest land, with a vegetation coverage of 60%; Scenario V: The inter-ditch grassland with a slope below 15° is built into terraces; Scenario VI: For forests and grasslands with a vegetation coverage of less than 75%, the coverage is increased by 10%, not exceeding the potential value; Scenario VII: For forest land and grassland with vegetation coverage less than 75%, the coverage is increased by 20%, which does not exceed the potential value.

[0013] Step 4 is as follows: Step 4.1: Given the target sediment transport modulus of the basin, the target sediment transport modulus is 500t / (km 2 .a) 100t / (km 2 .a) 1500t / (km 2 .a) 2000t / (km 2 .a) The sediment retention capacity of the silt dam is obtained by subtracting the target sediment discharge of the watershed from the slope soil erosion of different scenario combination models in step 3.3; Step 4.2: According to the control area of ​​the silt dam, determine the number of silt dams required to achieve different sediment transport modulus targets under different scenario combination modes in step 3.2.

[0014] Step 5 is as follows: Step 5.1, calculate the coupling degree of the slope-ditch measures; (2) Where C is the coupling degree of slope-ditch measures, C∈[0,1], the larger the C value, the higher the coupling degree; U1 is the area of ​​terraces and vegetation in the slope measures, and U2 is the number of silt dams in the ditch measures; Step 5.2, calculate the comprehensive index of slope gully management; (3) In the formula, T is the comprehensive index of slope gully management, P ( x ) is the slope management degree, which is the area of ​​terraces and vegetation slope measures and the soil erosion modulus in the basin is greater than 1000t / (km 2 .a) Area ratio; G ( y ) is the channel management degree, which is the ratio of the number of silt dams to the potential value of silt dam construction; α , β are the contribution shares of the slope and the ditch respectively. α = β =0.5; Step 5.3, calculate the coupling coordination degree D, and determine the governance plan with the largest coupling coordination value as the best governance plan for the basin; (4) In the formula, D is the coupling coordination degree; C is the coupling degree of slope-ditch measures; T It is the comprehensive index of slope gully management.

[0015] In step 1.1, a multispectral small drone with a global navigation satellite system is used for aerial survey, and the heading overlap rate and lateral overlap rate during flight are not less than 70%.

[0016] The beneficial effect of the present invention is that the method for coordinated management of sediment production and transport in the slope-channel-basin area in the middle reaches of the Yellow River has a scientific process, strong operability, and fully coordinates the relationship between the slope-channel-basin area, and solves the problem of insufficient coordination in the existing coordinated management of sediment production and transport in the slope-channel-basin area in the middle reaches of the Yellow River. It is more comprehensive and accurate, has good applicability, and is an indicator for evaluating the coordination and sustainability of sediment production and transport in the slope-channel-basin area in the middle reaches of the Yellow River, and provides scientific support for the diversity, stability and sustainability of the ecosystem in the middle reaches of the Yellow River. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of the method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River according to the present invention; FIG2 (a) is a result diagram of dividing landform units in Example 6 of the present invention; FIG2( b ) is a diagram showing the slope aspect division result in Embodiment 6 of the present invention; FIG2( c ) is a diagram showing the slope division results in Example 6 of the present invention; FIG3 (a) is a diagram showing the current status of vegetation coverage in the watershed in Example 6 of the present invention; FIG3( b ) is a vegetation restoration potential map in Example 6 of the present invention; Figure 4 This is a result diagram of the sub-basin division and the current status of the silt dam construction in Example 6 of the present invention. DETAILED DESCRIPTION

[0018] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1 The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River of the present invention is specifically implemented according to the following steps: Step 1: Select the watershed to be managed, divide the watershed microtopography and determine the status of soil and water conservation measures; Step 2: Determine the spatial suitability and construction potential of watershed soil and water conservation measures based on the micro-topography and current characteristics of watershed soil and water conservation measures divided in step 1; Step 3: Determine the slope measures configuration plan based on the spatial suitability and construction potential in step 2; Step 4, determining the channel silt dam configuration plan based on the slope measures configuration plan in step 3 and the target sediment transport modulus; Step 5: Based on the ditch silt dam configuration plan in step 4, conduct a synergistic evaluation of the slope ditch control measures and determine the coupling coordination degree of the target watershed as the optimal synergistic control measure plan for the watershed.

[0020] Example 2 The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River of the present invention is specifically implemented according to the following steps: Step 1: Select the watershed to be managed, divide the watershed microtopography and determine the status of soil and water conservation measures; Step 1.1, use a drone to fly at low altitude in the selected watershed to generate a digital orthophoto map and digital surface model of the watershed; Step 1.2, using the watershed digital surface model constructed in step 1.1 to reconstruct the terrain, obtain the digital elevation model of the watershed, and use the digital elevation model to divide the watershed micro-topography; Step 1.2.1, divide the geomorphic units; Step 1.2.1.1, extract the contour lines of the digital surface model of the watershed, remove the contour lines with shorter lengths, and interpolate the contour lines to regenerate the digital elevation model of the watershed.

[0021] Step 1.2.1.2, use window analysis to determine the average value of the digital elevation model data with a window size of 11*11, perform difference calculation between the original digital elevation model data and the average digital elevation model data, and divide the entire watershed into two geomorphic units: inter-gully land and gully land; Step 1.2.2, divide the slope direction: use the digital elevation model to calculate the basin slope direction, and divide the slope direction into three categories: sunny slope, semi-sunny slope and shady slope; Step 1.2.3, classify the slope: the digital elevation model is used to calculate the slope of the watershed, and the slope is divided into four categories, including gentle slope with a slope of 0°~15°, slope with a slope of 15°~25°, steep slope with a slope of 25°~35°, and abrupt slope with a slope greater than 35°; Step 1.2.4: spatially superimpose the geomorphic units, slope aspects, and slope gradients to obtain different types of watershed microtopography.

[0022] Step 1.3, use the digital orthophoto generated in step 1.1 to interpret the image and obtain the land use structure and current distribution of soil and water conservation measures in the watershed.

[0023] Step 2: Determine the spatial suitability and construction potential of watershed soil and water conservation measures based on the micro-topography and current characteristics of watershed soil and water conservation measures divided in step 1; Step 3: Determine the slope measures configuration plan based on the spatial suitability and construction potential in step 2; Step 4, determining the channel silt dam configuration plan based on the slope measures configuration plan in step 3 and the target sediment transport modulus; Step 5: Based on the ditch silt dam configuration plan in step 4, conduct a synergistic evaluation of the slope ditch control measures and determine the coupling coordination degree of the target watershed as the optimal synergistic control measure plan for the watershed.

[0024] Example 3 The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River of the present invention is specifically implemented according to the following steps: Step 1: Select the watershed to be managed, divide the watershed microtopography and determine the status of soil and water conservation measures; Step 1.1, use a drone to fly at low altitude in the selected watershed to generate a digital orthophoto map and digital surface model of the watershed; Step 1.2, using the watershed digital surface model constructed in step 1.1 to reconstruct the terrain, obtain the digital elevation model of the watershed, and use the digital elevation model to divide the watershed micro-topography; Step 1.2.1, divide the geomorphic units; Step 1.2.1.1, extract the contour lines of the digital surface model of the watershed, remove the contour lines with shorter lengths, and interpolate the contour lines to regenerate the digital elevation model of the watershed.

[0025] Step 1.2.1.2, use window analysis to determine the average value of the digital elevation model data with a window size of 11*11, calculate the difference between the original digital elevation model data and the average digital elevation model data, and divide the entire watershed into two geomorphic units: inter-gully land and valley land; when dividing the geomorphic units, the negative terrain with a difference value less than 0 is determined as the valley land of the watershed, and the remaining positive terrain with a difference value not less than 0 is determined as the inter-gully land of the watershed; Step 1.2.2, divide the slope direction: use the digital elevation model to calculate the basin slope direction, and divide the slope direction into three categories: sunny slope, semi-sunny slope and shady slope; Step 1.2.3, classify the slope: the digital elevation model is used to calculate the slope of the watershed, and the slope is divided into four categories, including gentle slope with a slope of 0°~15°, slope with a slope of 15°~25°, steep slope with a slope of 25°~35°, and abrupt slope with a slope greater than 35°; Step 1.2.4: spatially superimpose the geomorphic units, slope aspects, and slope gradients to obtain different types of watershed microtopography.

[0026] Step 1.3, use the digital orthophoto generated in step 1.1 to interpret the image and obtain the land use structure and current distribution of soil and water conservation measures in the watershed.

[0027] Step 2: Determine the spatial suitability and construction potential of watershed soil and water conservation measures based on the micro-topography and current characteristics of watershed soil and water conservation measures divided in step 1; Step 2.1, determine the potential and suitable distribution areas of terrace construction in the basin; According to the results of the basin micro-topography division and the existing terrace distribution in the basin, the inter-ditch land with a slope of less than 25° is regarded as the suitable distribution area for terraces, and the suitable distribution area for terraces but without terrace construction is regarded as the potential for terrace construction; Step 2.2, determine the suitable distribution area of ​​forest land; Step 2.2.1, calculate the normalized green-blue difference index (NGBDI) based on the digital orthophoto: (1) Where G is the green band of visible light; B is the blue band of visible light.

[0028] Step 2.2.2, determine the NGBDI threshold, segment the NGBDI, and extract the forest land distribution; Step 2.2.3, based on the extracted forest land distribution, calculate the proportion of forest land area in each watershed micro-topography, and determine the micro-topography with a proportion of more than 20% as the suitable distribution area of ​​forest land; Step 2.3, determine the vegetation restoration potential of the watershed; Step 2.3.1, calculate the normalized difference vegetation index (NDVI) based on the multispectral digital orthophoto map; Step 2.3.2, calculate the vegetation coverage of the watershed according to the pixel binary model, extract the 95% quantile vegetation coverage value in each watershed micro-topography as the vegetation restoration potential value, and determine the vegetation restoration potential of the watershed.

[0029] Step 2.4, determine the suitable layout area and construction potential of check dams in the basin; Divide the watershed into areas not exceeding 5km 2 For multiple sub-basins, according to the sub-basin land use status map, the sub-basins without residential areas, schools, and important transportation facilities are identified as suitable areas for the layout of check dams, and the sub-basins without check dams in the suitable layout areas are identified as potential areas for the construction of check dams.

[0030] Step 3: Determine the slope measures configuration plan based on the spatial suitability and construction potential in step 2; Step 4, determining the channel silt dam configuration plan according to the slope measures configuration plan in step 3; Step 5: Based on the ditch silt dam configuration plan in step 4, conduct a synergistic evaluation of the slope ditch control measures and determine the coupling coordination degree of the target watershed as the optimal synergistic control measure plan for the watershed.

[0031] Example 4 The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River of the present invention is specifically implemented according to the following steps: Step 1: Select the watershed to be managed, divide the watershed microtopography and determine the status of soil and water conservation measures; Step 1.1, use a drone to fly at low altitude in the selected watershed to generate a digital orthophoto map and digital surface model of the watershed; Step 1.2, using the watershed digital surface model constructed in step 1.1 to reconstruct the terrain, obtain the digital elevation model of the watershed, and use the digital elevation model to divide the watershed micro-topography; Step 1.2.1, divide the geomorphic units; Step 1.2.1.1, extract the contour lines of the digital surface model of the watershed, remove the contour lines with shorter lengths, and interpolate the contour lines to regenerate the digital elevation model of the watershed.

[0032] Step 1.2.1.2, use window analysis to determine the average value of the digital elevation model data with a window size of 11*11, calculate the difference between the original digital elevation model data and the average digital elevation model data, and divide the entire watershed into two geomorphic units: inter-gully land and valley land; when dividing the geomorphic units, the negative terrain with a difference value less than 0 is determined as the valley land of the watershed, and the remaining positive terrain with a difference value not less than 0 is determined as the inter-gully land of the watershed; Step 1.2.2, divide the slope direction: use the digital elevation model to calculate the basin slope direction, and divide the slope direction into three categories: sunny slope, semi-sunny slope and shady slope; Step 1.2.3, classify the slope: the digital elevation model is used to calculate the slope of the watershed, and the slope is divided into four categories, including gentle slope with a slope of 0°~15°, slope with a slope of 15°~25°, steep slope with a slope of 25°~35°, and abrupt slope with a slope greater than 35°; Step 1.2.4: spatially superimpose the geomorphic units, slope aspects, and slope gradients to obtain different types of watershed microtopography.

[0033] Step 1.3, use the digital orthophoto generated in step 1.1 to interpret the image and obtain the land use structure and current distribution of soil and water conservation measures in the watershed.

[0034] Step 2: Determine the spatial suitability and construction potential of watershed soil and water conservation measures based on the micro-topography and current characteristics of watershed soil and water conservation measures divided in step 1; Step 2.1, determine the potential and suitable distribution areas of terrace construction in the basin; According to the results of the basin micro-topography division and the existing terrace distribution in the basin, the inter-ditch land with a slope of less than 25° is regarded as the suitable distribution area for terraces, and the suitable distribution area for terraces but without terrace construction is regarded as the potential for terrace construction; Step 2.2, determine the suitable distribution area of ​​forest land; Step 2.2.1, calculate the normalized green-blue difference index (NGBDI) based on the digital orthophoto: (1) Where G is the green band of visible light; B is the blue band of visible light.

[0035] Step 2.2.2, determine the NGBDI threshold, segment the NGBDI, and extract the forest land distribution; Step 2.2.3, based on the extracted forest land distribution, calculate the proportion of forest land area in each watershed micro-topography, and determine the micro-topography with a proportion of more than 20% as the suitable distribution area of ​​forest land; Step 2.3, determine the vegetation restoration potential of the watershed; Step 2.3.1, calculate the normalized difference vegetation index (NDVI) based on the multispectral digital orthophoto map; Step 2.3.2, calculate the vegetation coverage of the watershed according to the pixel binary model, extract the 95% quantile vegetation coverage value in each watershed micro-topography as the vegetation restoration potential value, and determine the vegetation restoration potential of the watershed.

[0036] Step 2.4, determine the suitable layout area and construction potential of check dams in the basin; Divide the watershed into areas not exceeding 5km 2 For multiple sub-basins, according to the sub-basin land use status map, the sub-basins without residential areas, schools, and important transportation facilities are identified as suitable areas for the layout of check dams, and the sub-basins without check dams in the suitable layout areas are identified as potential areas for the construction of check dams.

[0037] Step 3: Determine the slope measures configuration plan based on the spatial suitability and construction potential in step 2; Step 3.1: According to the spatial suitability and construction potential of terraces and vegetation, determine the configuration scenarios of different vegetation and terrace slope management measures; there are 7 configuration scenarios of slope management measures, namely: Scenario I: Maintain the status quo and do not add governance measures; Scenario II: sloping cultivated land and bare land are covered by 50% grassland; Scenario III: The grassland on the shady slope of the valley is arranged as forest land, and the vegetation coverage reaches 60%; Scenario IV: The grasslands on the shady and semi-sunny slopes of the valley are arranged as forest land, with a vegetation coverage of 60%; Scenario V: The inter-ditch grassland with a slope below 15° is built into terraces; Scenario VI: For forests and grasslands with a vegetation coverage of less than 75%, the coverage is increased by 10%, not exceeding the potential value; Scenario VII: For forest land and grassland with vegetation coverage less than 75%, the coverage is increased by 20%, which does not exceed the potential value.

[0038] Step 3.2, combining different slope management measures configuration scenarios to form a scenario combination model; In step 3.3, the universal soil loss equation (RUSLE) is used to calculate the slope soil erosion modulus under different scenario combination modes.

[0039] Step 4, determining the channel silt dam configuration plan according to the slope measures configuration plan in step 3; Step 4.1: Given the target sediment transport modulus of the basin, the target sediment transport modulus is 500t / (km 2 .a) 100t / (km 2 .a) 1500t / (km 2 .a) 2000t / (km 2 .a) The sediment retention capacity of the silt dam is obtained by subtracting the target sediment discharge of the watershed from the slope soil erosion of different scenario combination models in step 3.3; Step 4.2: According to the control area of ​​the silt dam, determine the number of silt dams required to achieve different sediment transport modulus targets under different scenario combination modes in step 3.2.

[0040] Step 5: Based on the ditch silt dam configuration plan in step 4, conduct a synergistic evaluation of the slope ditch control measures and determine the coupling coordination degree of the target watershed as the optimal synergistic control measure plan for the watershed.

[0041] Example 5 The present invention provides a method for coordinated management of the sediment production and transport in the slope-channel-basin of the middle reaches of the Yellow River, as shown in the flow chart. Figure 1 As shown, the implementation is carried out according to the following steps: Step 1: Select the watershed to be managed, divide the watershed microtopography and determine the status of soil and water conservation measures; Step 1.1, use UAV to fly at low altitude in the selected watershed to be treated to generate digital orthophoto map and digital surface model of the watershed; in step 1.1, a multispectral small UAV with global navigation satellite system is used for aerial survey, and the heading overlap rate and lateral overlap rate during flight are not less than 70%.

[0042] Step 1.2, using the watershed digital surface model constructed in step 1.1 to reconstruct the terrain, obtain the digital elevation model of the watershed, and use the digital elevation model to divide the watershed micro-topography; Step 1.2.1, divide the geomorphic units; Step 1.2.1.1, extract the contour lines of the digital surface model of the watershed, remove the contour lines with shorter lengths, and interpolate the contour lines to regenerate the digital elevation model of the watershed.

[0043] Step 1.2.1.2, use window analysis to determine the average value of the digital elevation model data with a window size of 11*11, calculate the difference between the original digital elevation model data and the average digital elevation model data, and divide the entire watershed into two geomorphic units: inter-gully land and valley land.

[0044] When dividing the geomorphic units, the negative terrain with a difference value less than 0 is determined as the valley land of the basin, and the remaining positive terrain with a difference value not less than 0 is determined as the inter-valley land of the basin.

[0045] Step 1.2.2, divide the slope direction; The digital elevation model is used to calculate the basin slope, which is divided into three categories: sunny slope, semi-sunny slope and shady slope. Step 1.2.3, divide the slope; The digital elevation model is used to calculate the basin slope, and the slope is divided into four categories, including gentle slope with a slope of 0°~15°, slope with a slope of 15°~25°, steep slope with a slope of 25°~35°, and abrupt slope with a slope greater than 35°.

[0046] Step 1.2.4: spatially superimpose the geomorphic units, slope aspects, and slope gradients to obtain different types of watershed microtopography.

[0047] Step 1.3, use the digital orthophoto generated in step 1.1 to interpret the image and obtain the land use structure and current distribution of soil and water conservation measures in the watershed.

[0048] Step 2: Determine the spatial suitability and construction potential of watershed soil and water conservation measures based on the micro-topography and current characteristics of watershed soil and water conservation measures divided in step 1; Step 2.1, determine the potential and suitable distribution areas of terrace construction in the basin; According to the results of the basin microtopography division and the existing distribution of terraces in the basin, the inter-ditch land with a slope less than 25° is regarded as the suitable distribution area for terraces, and the area suitable for terraces but without terraces is regarded as the potential for terrace construction.

[0049] Step 2.2, determine the suitable distribution area of ​​forest land; Step 2.2.1, calculate the normalized green-blue difference index (NGBDI) based on the digital orthophoto: (1) Where G is the green band of visible light; B is the blue band of visible light.

[0050] Step 2.2.2, determine the NGBDI threshold, segment the NGBDI, and extract the forest land distribution; Step 2.2.3, based on the extracted forest land distribution, calculate the proportion of forest land area in each watershed micro-topography, and identify the micro-topography with a proportion of more than 20% as the suitable distribution area of ​​forest land.

[0051] Step 2.3, determine the vegetation restoration potential of the watershed; Step 2.3.1, calculate the normalized difference vegetation index (NDVI) based on the multispectral digital orthophoto map; Step 2.3.2, calculate the vegetation coverage of the watershed according to the pixel binary model, extract the 95% quantile vegetation coverage value in each watershed micro-topography as the vegetation restoration potential value, and determine the vegetation restoration potential of the watershed.

[0052] Step 2.4, determine the suitable layout area and construction potential of check dams in the basin; Divide the watershed into areas not exceeding 5km 2 For multiple sub-basins, according to the sub-basin land use status map, the sub-basins without residential areas, schools, and important transportation facilities are identified as suitable areas for the layout of check dams, and the sub-basins without check dams in the suitable layout areas are identified as potential areas for the construction of check dams.

[0053] Step 3: Determine the slope measures configuration plan based on the spatial suitability and construction potential in step 2; Step 3.1, determine different vegetation and terrace slope management measures configuration scenarios based on the spatial suitability and construction potential of terraces and vegetation; There are 7 scenarios for slope management measures configuration, namely: Scenario I: Maintain the status quo and do not add governance measures; Scenario II: sloping cultivated land and bare land are covered by 50% grassland; Scenario III: The grassland on the shady slope of the valley is arranged as forest land, and the vegetation coverage reaches 60%; Scenario IV: The grasslands on the shady and semi-sunny slopes of the valley are arranged as forest land, with a vegetation coverage of 60%; Scenario V: The inter-ditch grassland with a slope below 15° is built into terraces; Scenario VI: For forests and grasslands with a vegetation coverage of less than 75%, the coverage is increased by 10%, not exceeding the potential value; Scenario VII: For forest land and grassland with vegetation coverage less than 75%, the coverage is increased by 20%, which does not exceed the potential value.

[0054] Step 3.2, combining different slope management measures configuration scenarios to form a scenario combination model; There are 24 scenario combination modes as follows: Scenario I, Scenario II, Scenario III, Scenario IV, Scenario V, Scenario VI, Scenario VII; Scenario II-Scenario III, Scenario II-Scenario IV, Scenario II-Scenario V, Scenario II-Scenario VI, Scenario II-Scenario VII; Scenario II-Scenario III-Scenario V, Scenario II-Scenario III-Scenario VI, Scenario II-Scenario III-Scenario VII, Scenario II-Scenario IV-Scenario V, Scenario II-Scenario IV-Scenario VI, Scenario II-Scenario IV-Scenario VII, Scenario II-Scenario V-Scenario VI, Scenario II-Scenario V-Scenario VII; Scenario II-Scenario III-Scenario V-Scenario VI, Scenario II-Scenario III-Scenario V-Scenario VII, Scenario II-Scenario IV-Scenario V-Scenario VI, Scenario II-Scenario IV-Scenario V-Scenario VII.

[0055] In step 3.3, the universal soil loss equation (RUSLE) is used to calculate the slope soil erosion modulus under different scenario combination modes.

[0056] Step 4, determining the channel silt dam configuration plan according to the slope measures configuration plan in step 3; Step 4.1: Given the target sediment transport modulus of the basin, the target sediment transport modulus is 500t / (km 2 .a) 100t / (km 2 .a) 1500t / (km 2 .a) 2000t / (km 2 .a) The sediment retention capacity of the silt dam is obtained by subtracting the target sediment discharge of the watershed from the slope soil erosion of different scenario combination models in step 3.3; Step 4.2: According to the control area of ​​the silt dam, determine the number of silt dams required to achieve different sediment transport modulus targets under different scenario combination modes in step 3.2.

[0057] Step 5: Based on the ditch silt dam configuration plan in step 4, conduct a synergistic evaluation of the slope ditch control measures and determine the coupling coordination degree of the target watershed as the optimal synergistic control measure plan for the watershed.

[0058] Step 5.1, calculate the coupling degree of the slope-ditch measures; (2) Where C is the coupling degree of slope-ditch measures, C∈[0,1], the larger the C value, the higher the coupling degree; U1 is the area of ​​terraces and vegetation in the slope measures, and U2 is the number of silt dams in the ditch measures; Step 5.2, calculate the comprehensive index of slope gully management; (3) In the formula, T is the comprehensive index of slope gully management, P ( x) is the slope management degree, which is the area of ​​terraces and vegetation slope measures and the soil erosion modulus in the basin is greater than 1000t / (km 2 .a) Area ratio; G ( y ) is the channel management degree, which is the ratio of the number of silt dams to the potential value of silt dam construction; α , β are the contribution shares of the slope and the ditch respectively. α = β =0.5.

[0059] Step 5.3, calculate the coupling coordination degree D, and determine the governance plan with the largest coupling coordination value as the best governance plan for the basin; (4) In the formula, D is the coupling coordination degree; C is the coupling degree of slope-ditch measures; T It is the comprehensive index of slope gully management.

[0060] Example 6 The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River of the present invention is specifically implemented according to the following steps: Step 1: Select the watershed to be managed, divide the watershed microtopography and determine the status of soil and water conservation measures; Step 1.1, use a drone to fly at low altitude in the selected watershed to generate a digital orthophoto map and digital surface model of the watershed; Step 1.2, the digital surface model of the watershed constructed in step 1.1 is used to reconstruct the terrain, obtain the digital elevation model of the watershed, and use the digital elevation model to divide the watershed microtopography; the area ratio of the inter-gully land in the entire watershed is 47%, and the area ratio of the gully land is 53%, as shown in Figure 2 (a). The digital elevation model is used to calculate the watershed slope, as shown in Figure 2 (b), the area ratios of sunny slope, semi-sunny slope and shady slope are 24%, 0.56% and 20% respectively, and the area ratios of gentle slope (0°~15°), slope (15°~25°), steep slope (25°~35°) and steep slope (greater than 35°) are 18%, 21%, 22% and 39% respectively, as shown in Figure 2 (c).

[0061] By spatially superimposing the geomorphic units, slope aspects and slope gradients, 24 different types of watershed microtopography were obtained. The larger watershed microtopography included gully-semi-sunny-steep slope, inter-gully-semi-sunny-slope, gully-shady-steep slope and gully-sunny-steep slope.

[0062] Step 1.3: Use the digital orthophoto image generated in step 1.1 to interpret the image and obtain the land use structure and current status of soil and water conservation measures in Yangjiagou. The land use is mainly natural grassland, accounting for 42.13% of the area; the area of ​​terraced fields is 238.90hm2. 2 There are 12 silt dams in total.

[0063] Step 2: According to the micro-topography and current characteristics of soil and water conservation measures divided in step 1, determine the spatial suitability and construction potential of soil and water conservation measures in the basin. The area of ​​inter-ditch land with a slope below 15° in the basin is 138.50hm 2 The area of ​​inter-ditch land with a slope between 15° and 25° is 172.50hm 2 The construction potential of terraces is 311hm 2 .

[0064] The current vegetation coverage in the basin is 63%, and the potential vegetation coverage is 80%. As shown in Figure 3 (a) and Figure 3 (b), the basin is divided into two areas with an area of ​​no more than 5 km 2 There are 15 sub-basins in the basin, among which the potential sub-basins for silt dam construction are sub-basins 2, 9, and 13 in Figure 3. Figure 4 As shown, the numerator is the number and the denominator is the area in km 2 .

[0065] Step 3: Based on the spatial suitability and construction potential in step 2, a synergistic model of basin slope-channel-basin sediment transport is constructed; The scenario models for different vegetation and terrace slope management measures were determined, and the universal soil loss equation was used to calculate the slope soil erosion modulus under different scenarios, as shown in Table 1; Table 1 shows the soil erosion modulus of different slope measures scenario models

[0066] The target sediment transport modulus of a given basin is 500t / (km 2 .a) 100t / (km 2 .a) 1500t / (km 2 .a) 2000t / (km 2 .a) The sediment interception capacity of the silt dam is obtained by subtracting the target sediment transport capacity of the basin from the soil erosion capacity of different scenario combination modes; according to the control area of ​​the silt dam, the number of silt dams required to achieve different sediment transport modulus targets under different scenario combination modes is determined, as shown in Table 2; Table 2 shows the number of silt dams to be built based on the target sediment transport modulus.

[0067] 1000t / (km2 .a) is the target sediment transport modulus, which is used to evaluate the synergy of slope gully control measures, as shown in Table 3; Table 3 shows the synergy evaluation of slope ditch measures

[0068] According to the calculation results in Table 3, under the VI slope management, the slope-ditch synergy of the management scenario with 9 silt dams is the highest.

[0069] The method for coordinated management of sediment production and transport in the slope-channel-basin of the middle reaches of the Yellow River of the present invention combines methods of different scales, reveals the changing laws of sediment and sediment concentration in the sandy and coarse sand areas of the Loess Plateau, clarifies the influencing factors of sediment concentration, and provides ideas for related research on regulating and managing water and sand disasters in the Yellow River. It is guided by the sustainable development mode, focuses on the coordinated development of ecological protection and economic construction in typical ecologically fragile areas, and further provides a scientific basis for water and soil erosion control and ecological protection in the basin.

Claims

1. A method for coordinated management of sediment production and transport in the slope-channel-basin area of ​​the middle reaches of the Yellow River, characterized in that: Follow the steps below to implement it: Step 1: Select the watershed to be managed, divide the watershed microtopography and determine the status of soil and water conservation measures; Step 2: Determine the spatial suitability and construction potential of watershed soil and water conservation measures based on the micro-topography and current characteristics of watershed soil and water conservation measures divided in step 1; Step 3: Determine the slope measures configuration plan based on the spatial suitability and construction potential in step 2; Step 4, determining the channel silt dam configuration plan based on the slope measures configuration plan in step 3 and the target sediment transport modulus; Step 5: Based on the ditch silt dam configuration plan in step 4, conduct a synergistic evaluation of the slope ditch control measures and determine the coupling coordination degree of the target watershed as the optimal synergistic control measure plan for the watershed.

2. The method for coordinated management of sediment production and transport in the slope-channel-basin of the middle reaches of the Yellow River according to claim 1 is characterized in that: Step 1 is as follows: Step 1.1, use a drone to fly at low altitude in the selected watershed to generate a digital orthophoto map and digital surface model of the watershed; Step 1.2, using the watershed digital surface model constructed in step 1.1 to reconstruct the terrain, obtain the digital elevation model of the watershed, and use the digital elevation model to divide the watershed micro-topography; Step 1.3, use the digital orthophoto generated in step 1.1 to interpret the image and obtain the land use structure and current distribution of soil and water conservation measures in the watershed.

3. The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River according to claim 2 is characterized in that: Step 1.2 is as follows: Step 1.2.1, divide the geomorphic units; Step 1.2.1.1, extract the contour lines of the digital surface model of the watershed, remove the contour lines with shorter lengths, and interpolate the contour lines to regenerate the digital elevation model of the watershed; Step 1.2.1.2, use window analysis to determine the average value of the digital elevation model data with a window size of 11*11, perform difference calculation between the original digital elevation model data and the average digital elevation model data, and divide the entire watershed into two geomorphic units: inter-gully land and gully land; Step 1.2.2, divide the slope direction: use the digital elevation model to calculate the basin slope direction, and divide the slope direction into three categories: sunny slope, semi-sunny slope and shady slope; Step 1.2.3, classify the slope: the digital elevation model is used to calculate the slope of the watershed, and the slope is divided into four categories, including gentle slope with a slope of 0°~15°, slope with a slope of 15°~25°, steep slope with a slope of 25°~35°, and abrupt slope with a slope greater than 35°; Step 1.2.4: spatially superimpose the geomorphic units, slope aspects, and slope gradients to obtain different types of watershed microtopography.

4. The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River according to claim 3 is characterized in that: When dividing the geomorphic units, the negative terrain with a difference value less than 0 is determined as the valley land of the basin, and the remaining positive terrain with a difference value not less than 0 is determined as the inter-valley land of the basin.

5. The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River according to claim 4 is characterized in that: Step 2 is as follows: Step 2.1, determine the potential and suitable distribution areas of terrace construction in the basin; According to the results of the basin micro-topography division and the existing terrace distribution in the basin, the inter-ditch land with a slope of less than 25° is regarded as the suitable distribution area for terraces, and the suitable distribution area for terraces but without terrace construction is regarded as the potential for terrace construction; Step 2.2, determine the suitable distribution area of ​​forest land; Step 2.2.1, calculate the normalized green-blue difference index (NGBDI) based on the digital orthophoto: （1） In the formula, G is the visible green band; B is the visible blue band; Step 2.2.2, determine the NGBDI threshold, segment the NGBDI, and extract the forest land distribution; Step 2.2.3, based on the extracted forest land distribution, calculate the proportion of forest land area in each watershed micro-topography, and determine the micro-topography with a proportion of more than 20% as the suitable distribution area of ​​forest land; Step 2.3, determine the vegetation restoration potential of the watershed; Step 2.3.1, calculate the normalized difference vegetation index (NDVI) based on the multispectral digital orthophoto map; Step 2.3.2, calculate the vegetation coverage of the watershed according to the pixel binary model, extract the 95% quantile vegetation coverage value in each watershed micro-topography as the vegetation restoration potential value, and determine the vegetation restoration potential of the watershed; Step 2.4, determine the suitable layout area and construction potential of check dams in the basin; Divide the watershed into areas not exceeding 5km 2 For multiple sub-basins, according to the sub-basin land use status map, the sub-basins without residential areas, schools, and important transportation facilities are identified as suitable areas for the layout of check dams, and the sub-basins without check dams in the suitable layout areas are identified as potential areas for the construction of check dams.

6. The method for coordinated management of sediment production and transport in the slope-channel-basin of the middle reaches of the Yellow River according to claim 5, characterized in that: Step 3 is as follows: Step 3.1, determine different vegetation and terrace slope management measures configuration scenarios based on the spatial suitability and construction potential of terraces and vegetation; Step 3.2, combining different slope management measures configuration scenarios to form a scenario combination model; In step 3.3, the universal soil loss equation is used to calculate the slope soil erosion modulus under different scenario combination modes.

7. The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River according to claim 6, characterized in that: There are 7 scenarios for slope management measures configuration, namely: Scenario I: Maintain the status quo and do not add governance measures; Scenario II: sloping cultivated land and bare land are covered by 50% grassland; Scenario III: The grassland on the shady slope of the valley is arranged as forest land, and the vegetation coverage reaches 60%; Scenario IV: The grasslands on the shady and semi-sunny slopes of the valley are arranged as forest land, with a vegetation coverage of 60%; Scenario V: The inter-ditch grassland with a slope below 15° is built into terraces; Scenario VI: For forests and grasslands with a vegetation coverage of less than 75%, the coverage is increased by 10%, not exceeding the potential value; Scenario VII: For forest land and grassland with vegetation coverage less than 75%, the coverage is increased by 20%, which does not exceed the potential value.

8. The method for coordinated management of the slope-channel-basin sediment production and transport in the middle reaches of the Yellow River according to claim 7, characterized in that: Step 4 is as follows: Step 4.1: Given the target sediment transport modulus of the basin, the target sediment transport modulus is 500t / (km 2 .a) 100t / (km 2 .a) 1500t / (km 2 .a) 2000t / (km 2 .a) The sediment retention capacity of the silt dam is obtained by subtracting the target sediment discharge of the watershed from the slope soil erosion of different scenario combination models in step 3.3; Step 4.2: According to the control area of ​​the silt dam, determine the number of silt dams required to achieve different sediment transport modulus targets under different scenario combination modes in step 3.

2.

9. The method for coordinated management of sediment production and transport in the slope-channel-basin of the middle reaches of the Yellow River according to claim 8, characterized in that: Step 5 is as follows: Step 5.1, calculate the coupling degree of the slope-ditch measures; （2） Where C is the coupling degree of slope-ditch measures, C∈[0,1], the larger the C value, the higher the coupling degree; U1 is the area of ​​terraces and vegetation in the slope measures, and U2 is the number of silt dams in the ditch measures; Step 5.2, calculate the comprehensive index of slope gully management; （3） In the formula, T is the comprehensive index of slope gully management, P ( x ) is the slope management degree, which is the area of ​​terraces and vegetation slope measures and the soil erosion modulus in the basin is greater than 1000t / (km 2 .a) Area ratio; G ( y ) is the channel management degree, which is the ratio of the number of silt dams to the potential value of silt dam construction; α , β are the contribution shares of the slope and the channel respectively. α = β =0.5; Step 5.3, calculate the coupling coordination degree D, and determine the governance plan with the largest coupling coordination value as the best governance plan for the basin; （4） In the formula, D is the coupling coordination degree; C is the coupling degree of slope-ditch measures; T It is the comprehensive index of slope gully management.

10. The method for coordinated management of sediment production and transport in the slope-channel-basin of the middle reaches of the Yellow River according to claim 9, characterized in that: In step 1.1, a multispectral small drone with a global navigation satellite system is used for aerial survey, and the heading overlap rate and lateral overlap rate during flight are not less than 70%.

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