A potential dam-controlled accretion zone identification method based on formation process constraints

Abstract

The application discloses a potential dam-controlled siltation area identification method based on formation process constraints. The method extracts a channel confluence network and divides the channel confluence section based on a digital elevation model, demarcates a candidate siltation area and an associated slope area based on each channel confluence section, and combines to form a spatial statistical unit; the terrain undulation and flatness of the candidate siltation area are calculated, a Gaussian similarity function is constructed based on field confirmation samples, and a comprehensive terrain adaptation degree is obtained; the rainfall erosion force factor, slope length and slope gradient factor and soil erodibility factor of the associated slope area are calculated, and the erosion sediment potential is obtained; the comprehensive terrain adaptation degree and the erosion sediment potential of the same spatial statistical unit are coupled by multiplication, a dam-controlled siltation formation process identification index is formed, and a potential dam-controlled siltation area is identified through threshold screening. The application can effectively identify the candidate position and spatial range of the dam-controlled siltation area from the formation process.

Description

Technical Field

[0001] This invention relates to the fields of geospatial information processing and soil and water conservation monitoring technology, specifically to a method for identifying potential dam-controlled siltation zones based on formation process constraints. Background Technology

[0002] The dam-controlled sedimentation zone refers to the area formed by dam-like structures such as silt-retaining dams, dikes, and embankments within a gully, which intercept and control the deposition of upstream runoff and sediment. These zones are distributed along the gully's confluence path and are important spatial indicators of the scope of soil and water conservation engineering, gully sediment redistribution, and land use safety.

[0003] The dam-controlled sedimentation zone is formed by the combined effects of slope erosion and sediment production, gully water and sediment transport, channel confluence and sediment transport, interception by sediment-trapping structures, and upstream backfilling and deposition. Rainfall generates slope runoff and induces slope erosion, with the resulting sediment being transported to gullies along with the runoff. After entering the gullies, the runoff and the sediment it carries continue to undergo gully erosion, sediment entrainment, and transport along the course of the gullies under the concentrated flow of the gullies. When the runoff and sediment are intercepted and controlled by dams or other sediment-trapping structures, the flow velocity and sediment transport capacity decrease, and the sediment gradually deposits and backfills upstream of the sediment-trapping structures, forming a relatively gentle sedimentary topography.

[0004] Since dam-controlled sedimentation zones are the result of multiple processes, their spatial identification cannot rely solely on a single topographic indicator or remote sensing image feature. Existing spatial identification methods related to dam-controlled sedimentation zones typically include dam site surveys, manual image interpretation, extraction of cultivated dam land, and screening based on single topographic conditions such as slope and topographic relief. Dam site surveys can only indicate the location of the sediment-trapping structure and are insufficient to determine the upstream sedimentary range controlled by it; cultivated dam land extraction mainly identifies dam land that has been cultivated and is prone to overlooking sedimentary areas covered by water, abandoned, or not yet stably cultivated; when directly identifying based on the appearance of remote sensing images, ordinary valley plains, floodplains, terraces, roads, and other low-slope features may have similar spectral, textural, or morphological characteristics to dam-controlled sedimentation zones, easily leading to misidentification. Summary of the Invention

[0005] To address the shortcomings of existing methods for identifying dam-controlled sedimentary zones, which fail to adequately consider their formation process and thus struggle to accurately determine the candidate locations and spatial extent of these zones, this invention proposes a potential dam-controlled sedimentary zone identification method based on formation process constraints. By characterizing the formation of dam-controlled sedimentary zones as the combined effect of sedimentary topography shaping within the sedimentary zone and rainfall-erosion-sediment production processes in the associated slope areas, a spatial statistical unit is constructed, consisting of sedimentary zones delineated along gully confluence paths and slope areas with water-sediment aggregation relationships. Sedimentary topography characteristics of the sedimentary zones and erosion-sediment production characteristics of the slope areas are calculated and correlated to form an identification index for the dam-controlled sedimentary formation process, thereby achieving the goal of accurately identifying the candidate locations and spatial extent of dam-controlled sedimentary zones.

[0006] According to one aspect of the present invention, a method for identifying potential dam-controlled sedimentation zones based on formation process constraints is provided, comprising: extracting a channel confluence network based on runoff accumulation, and dividing the channel confluence network into confluence segments; based on each confluence segment, delineating candidate sedimentation zones distributed along the channels and associated slope areas that have a water-sediment aggregation relationship with the candidate sedimentation zones, and combining the candidate sedimentation zones and associated slope areas to form spatial statistical units; acquiring the sedimentary topographic features of the candidate sedimentation zones, and constructing a system based on field-confirmed dam-controlled sedimentation zone samples. A Gaussian similarity function is established for typical dam-controlled siltation topographic structures, and the comprehensive topographic fit of candidate siltation areas is calculated using the Gaussian similarity function. Furthermore, the erosion and sediment yield characteristics of the associated slope areas are obtained, and the erosion and sediment yield potential of the associated slope areas is calculated based on rainfall erosivity factor, slope length and gradient factor, and soil erodibility factor. The comprehensive topographic fit of the same spatial statistical unit is coupled with the erosion and sediment yield potential to obtain dam-controlled siltation formation process identification indicators, and potential dam-controlled siltation areas are determined based on these indicators.

[0007] As a further technical solution, the spatial statistical unit is used to associate the sedimentary topographic conditions of the candidate alluvial area with the erosion and sediment yield conditions of the associated slope area within the same spatial framework; Each gully confluence section, candidate siltation zone, associated slope area, and spatial statistical unit satisfies the following: , , , In the formula, Indicates position Accumulated flow at the confluence point; This represents the extraction threshold for the channel merging network; This indicates the number of connected channel pixels contained in a channel confluence segment; Indicates the maximum segment size; This indicates that the first [unit] is obtained from the channel merging network that satisfies the conditions of accumulative flow and continuous length. Each ditch confluence section ; The structural element used to represent spatial expansion; and These respectively represent candidate siltation areas and slope areas delineated according to their corresponding spatial expansion ranges; Indicates the first Candidate siltation areas corresponding to the confluence sections of each ditch; This indicates the associated slope area adjacent to the candidate siltation area; This represents the first [section / area] composed of the candidate siltation zone and the associated slope zone. Spatial statistical unit.

[0008] As a further technical solution, the sedimentary topographic features include topographic relief and flatness; the topographic relief is used to characterize the degree of local elevation change within the candidate sedimentary area, and the flatness is used to characterize the proportion of effective pixels within the candidate sedimentary area whose slope is not greater than a preset slope threshold, and respectively satisfy: , , In the formula, Indicates candidate siltation areas; This indicates the number of valid pixels in the candidate congestion region; p represents the number of valid pixels within the candidate congestion region. This represents the difference between the maximum and minimum elevations within the moving window containing pixel p; Indicates the slope of pixel p; This represents the slope threshold for dividing gently sloping terrain. Represents the characteristic function.

[0009] As a further technical solution, the terrain relief and flatness are transformed respectively to obtain the terrain relief transformed value. and flatness transformation value The transformation process satisfies: , , Among them, the terrain relief transformation value and the flatness transformation value This is used to estimate the typical central parameters and discrete scale parameters of the Gaussian similarity function in the transformed feature space.

[0010] As a further technical solution, the typical center and discrete scale of the Gaussian similarity function are determined based on field-confirmed samples of the dam-controlled siltation area; for erosion type e, the typical center of the topographic relief transformation value is calculated from the field-confirmed samples under the corresponding erosion type. and discrete scale and the typical center of the flatness transformation value. and discrete scale The topographic relief fit of the candidate siltation areas was calculated using the following formulas. and flatness fit : , .

[0011] As a further technical solution, the terrain undulation adaptation degree is fused using a harmonic average. and flatness fit The comprehensive terrain adaptability of the candidate siltation area is obtained. The comprehensive terrain adaptability satisfy: , in, This represents a stable term used to prevent the denominator from being zero.

[0012] As a further technical solution, the erosion and sediment production potential The soil erosivity factor is determined by multiplying the rainfall erosivity factor, slope length and gradient factor, and soil erodibility factor of each effective pixel within the associated slope area. Regional statistics are then performed by averaging the products of all effective pixels within the associated slope area, and the following conditions must be met: , In the formula, Represents the associated slope area of ​​a spatial statistical unit; This indicates the number of effective pixels within the associated slope area; p represents the number of effective pixels within the associated slope area. , and These represent the rainfall erosivity factor, slope length and gradient factor, and soil erodibility factor of pixel p, respectively.

[0013] As a further technical solution, the DamSiltation index for identifying the dam-controlled siltation formation process is obtained by using the comprehensive terrain adaptability. With the aforementioned erosion and sediment production potential It is obtained by product coupling and satisfies: , The product coupling is used to simultaneously constrain the sedimentary topographic adaptation conditions of the candidate siltation zone and the erosion and sediment supply conditions of the associated slope zone.

[0014] As a further technical solution, when the DamSiltation index for identifying the dam-controlled siltation formation process meets the following criteria, the corresponding spatial statistical unit is retained, and the candidate siltation areas therein are identified as potential dam-controlled siltation areas: , Where T represents the threshold for identifying the dam-controlled siltation formation process; when When that happens, the corresponding spatial statistical unit is excluded.

[0015] According to one aspect of the present invention, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the method for identifying potential dam-controlled siltation zones based on formation process constraints.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention constructs spatial statistical units composed of candidate siltation areas and their associated slope areas, quantifying and correlating the sedimentary topographic conditions and slope erosion and sediment yield conditions involved in the formation of dam-controlled siltation areas within a unified spatial framework. Compared to methods that rely solely on dam locations, remote sensing image appearances, or single topographic indicators for identification, this invention starts from the dam-controlled siltation formation process, jointly constraining the degree of adaptation of the candidate area's topographic structure and the associated slope erosion and sediment yield potential. This reduces misjudgments caused by similar low-slope features such as ordinary gullies, plains, floodplains, terraces, and roads, and achieves regionalized identification of the candidate locations and spatial extent of potential dam-controlled siltation areas. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall process of a method for identifying potential dam-controlled siltation zones based on formation process constraints, provided by an embodiment of the present invention. Figure 2 A schematic diagram illustrating the calculation of Gaussian similarity and terrain structure fit based on measured samples in an embodiment of the present invention. Figure 3 A diagram illustrating the characteristic relationship between undulation, flatness, and slope erosion potential provided in an embodiment of the present invention; Figure 4 This is a partial example diagram showing the distribution of potential dam-controlled siltation areas in a certain location, provided as an embodiment of the present invention. Detailed Implementation

[0019] To accurately identify the candidate locations and spatial distribution range of dam-controlled sedimentation zones, this embodiment provides a potential dam-controlled sedimentation zone identification method based on formation process constraints. This method transforms the process characteristics involved in the formation of dam-controlled sedimentation zones, such as slope erosion and sediment production, water and sediment confluence and transport, sediment trapping structure control, and upstream backfilling and deposition, into interrelated spatial identification conditions, thereby determining the candidate locations and spatial distribution range of dam-controlled sedimentation zones.

[0020] This implementation method is based on the channel confluence network and constructs a spatial statistical unit consisting of candidate sedimentation areas and associated slope areas as a unified spatial statistical and computational framework. Within each spatial statistical unit, the sedimentary topographic adaptation conditions of the candidate sedimentation area and the erosion and sediment supply conditions of the associated slope area are quantified respectively. By coupling the two, an identification index for the formation process of dam-controlled sedimentation is formed, thereby realizing the spatial identification of potential dam-controlled sedimentation areas.

[0021] Step 1: Construct spatial statistical units.

[0022] To establish the water and sediment collection relationship between potential sedimentation zones and their associated slope areas within a unified spatial unit, and to provide a spatial basis for the subsequent quantification and correlation calculation of sedimentary topography shaping processes and slope erosion sediment production processes, the channel confluence network was first extracted based on the accumulation of runoff, and channel confluence segments were then divided along the network. Based on each channel confluence segment, potential sedimentation zones distributed along the channels and slope areas connected to them by runoff were delineated, and these two were combined to form a spatial statistical unit, which serves as the basic spatial unit for the subsequent quantification and correlation calculation of the two types of formation processes.

[0023] No. Each gully confluence section, siltation zone, slope area, and spatial statistical unit is represented as follows: , In the formula, Indicates position Accumulated flow at the confluence point; The threshold value for extracting the channel confluence network is 500 in one implementation. The number of connected channel pixels contained in a channel confluence segment; The maximum segment size, in this example, is 25 pixels; This indicates that the first [unit] is obtained from the channel merging network that satisfies the conditions of accumulative flow and continuous length. Each ditch confluence section ; The structural elements used to represent spatial extension can be used when the spatial resolution is 10 m. Pixel structure elements; and These respectively represent the potential siltation zone and the slope zone delineated according to their corresponding spatial expansion range; Indicates the first Potential siltation areas corresponding to the confluence sections of each ditch; This indicates the slope area adjacent to the potential siltation area; The first part represents the area composed of the potential siltation zone and the slope zone. Spatial statistical unit.

[0024] Step 2: Quantification of the formation process.

[0025] Within each spatial statistical unit, the topographic adaptability of the sedimentation zone and the erosion and sediment yield potential of the slope zone are quantified, including the following sub-steps.

[0026] Step 2.1: Topographical adaptability of the siltation area.

[0027] For any spatial statistical unit, two continuous indices, relief and flatness, are used to evaluate the fit between the topographic structure of the siltation zone and typical dam-controlled siltation topography. Relief characterizes the degree of elevation undulation within the siltation zone, while flatness characterizes the proportion of gently sloping surfaces with a gradient not exceeding a preset threshold within the siltation zone. These are expressed as follows: , In the formula, Indicates a siltation area; This indicates the number of effective pixels in the siltation area; This represents the effective pixels within the siltation area; Represents a cell Location The difference between the maximum and minimum elevations within the moving window; Represents a cell The slope; This represents the slope threshold for dividing gently sloping terrain. Representational function, when The value is 1 if the condition is met, and 0 otherwise. Therefore, This indicates the proportion of effective pixels in the statistical area adjacent to the ditch whose slope is not greater than a preset threshold.

[0028] Based on the field-confirmed samples of dam-controlled sedimentation areas, the topographic relief and flatness were statistically analyzed. Both exhibited relatively concentrated feature values ​​and a certain degree of dispersion. Based on these statistical characteristics, the central location and dispersion of the sample features characterize the typical dam-controlled sedimentation topographic structure. Gaussian similarity functions were constructed to quantify the similarity between any candidate sedimentation area and this typical topographic structure, ensuring that the topographic fit continuously decreases as the candidate area's index value deviates from the typical center. Considering that topographic relief is positive and usually exhibits a skewed distribution, and flatness is a proportional variable with a value range limited to [0,1], natural logarithmic transformation and stabilized logit transformation were performed on both. The typical center parameter and discrete scale parameter of the Gaussian similarity function were then estimated in the transformed feature space.

[0029] .

[0030] Based on the statistical distribution of the dam-controlled siltation area samples corresponding to the field-confirmed sampling points in the transformed feature space, Gaussian distribution parameters were fitted to the topographic relief transformation values ​​and flatness transformation values, respectively. The mean obtained from the fitting was used as the typical center, and the standard deviation was used as the discrete scale. Based on this, a Gaussian similarity function was constructed to calculate the topographic relief fit and flatness fit of the candidate siltation area, respectively. , In the formula, Indicates the type of erosion; and These represent the topographic relief and flatness of the candidate alluvial area after natural logarithmic transformation, respectively; and These represent the erosion types. The typical center and discrete scale of the terrain relief transformation values ​​of the samples were obtained by fitting Gaussian parameters in the field. and These represent the typical center and discrete scale obtained by fitting the flatness transformation values ​​to Gaussian parameters under the corresponding erosion types, respectively; and These represent the topographic relief and flatness fit of the candidate siltation area, respectively.

[0031] The overall topographic fit of the candidate siltation area is obtained by merging the harmonic mean of topographic relief fit and flatness fit: , In the formula, Indicates erosion type The overall topographic suitability of the next candidate siltation areas; This represents a stabilizing term used to prevent the denominator from being zero. Using a harmonic mean can strengthen the joint constraint effect of two terrain features. When the fitness of either individual feature is low, the overall terrain fitness decreases accordingly; only when both fitness values ​​are high does the overall terrain fitness achieve a high value.

[0032] Step 2.2: Erosion and sediment yield potential of the slope area.

[0033] For any spatial statistical unit, calculate the product of the rainfall erosivity factor, slope length and gradient factor, and soil erodibility factor for each effective cell within its associated slope area, and average the obtained cell values ​​to obtain the erosion and sediment yield potential of the associated slope area: , In the formula, Represents the associated slope area of ​​a spatial statistical unit; This indicates the number of valid pixels within the associated slope area; This represents the effective pixels within the associated slope area; , and Representing pixels Rainfall erosivity factor, slope length and slope factor, and soil erodibility factor; This represents the average value of the pixel-scale erosion and sediment yield potential within the associated slope area. The higher the value, the higher the average erosion and sediment yield potential of the associated slope area, which is more conducive to sediment stripping and transport.

[0034] Step 3: Identification indicators of the dam-controlled siltation formation process.

[0035] By coupling the comprehensive topographic adaptability of the spatial statistical unit siltation zone with the erosion and sediment yield potential of its associated slope area, identification indicators for dam-controlled siltation formation process are calculated. , In the formula, Indicators for identifying the formation process of dam-controlled siltation in spatial statistical units; Indicates the overall topographic suitability of the candidate siltation area; This indicates the erosion and sediment yield potential of the associated slope area within a spatial statistical unit; This indicates the threshold for determining the dam-controlled siltation formation process. When, the corresponding spatial statistical units are retained, and candidate siltation areas within them are identified as potential dam-controlled siltation areas; when When that happens, exclude that spatial statistical unit.

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0037] Figure 1 The overall flow of the method described in this embodiment of the invention is illustrated. The potential dam-controlled sedimentation zone, as referred to in this embodiment, is an area that meets the requirements for dam-controlled sedimentation formation in terms of gully confluence location, sedimentary topographic structure, and associated slope erosion and sediment yield conditions. This identification result is used to characterize the spatial probability of dam-controlled sedimentation formation and is not equivalent to the actual existence of a dam-like structure, nor is it equivalent to upstream backfilling and deposition having actually occurred.

[0038] This embodiment selects a plateau as the implementation area and prepares a digital elevation model covering the area, monthly rainfall data, soil sand, silt, clay, and organic carbon content data, erosion type data, and field-confirmed dam-controlled sedimentation area sampling points. The digital elevation model is used to extract the gully confluence network and calculate slope, topographic relief, and slope length factor; monthly rainfall data is used to calculate rainfall erosivity factor; soil particle composition and organic carbon data are used to calculate soil erodibility factor; erosion type data is used to distinguish between hydraulic erosion and wind-water combined erosion; and field-confirmed sampling points are used to determine the statistical parameters of typical dam-controlled sedimentation terrain structures. High-resolution remote sensing imagery is used to assist in verifying the field sampling points and identification results, but is not the sole basis for judgment in this embodiment.

[0039] The spatial data were transformed to a unified projected coordinate system and standardized to a spatial resolution of 10 m and the same spatial range. Continuous data were processed using continuous resampling, while categorical data such as erosion types were processed using nearest neighbor methods. Depression filling and outlier handling were performed on the digital elevation model to ensure the continuity of subsequent confluence paths.

[0040] Step 1: Construct spatial statistical units.

[0041] Based on the preprocessed digital elevation model, the D8 method is used to determine the flow direction and calculate the cumulative flow of each cell. Cells with a cumulative flow of not less than 500 are extracted as channel confluence networks according to equation (1). On the channel confluence network, channel cells are grouped using an 8-neighborhood connectivity search method. Starting from any unvisited channel cell, the expansion proceeds sequentially along adjacent channel cells. The expansion stops when the number of cells in the current group reaches 25, and the group is identified as a channel confluence segment. The above process is repeated for the remaining unvisited channel cells until all channel cells are segmented. Connectivity groups with fewer than 25 cells are retained, thus obtaining multiple channel confluence segments.

[0042] Based on each gully confluence segment, morphological dilation was performed using a 3×3 pixel full-neighbor square structure element according to Equation (2). At a spatial resolution of 10 m, the original gully confluence segment and the range formed by the first to third dilations were designated as candidate sedimentation zones. The range formed by the sixth dilation was subtracted from the range formed by the second dilation to obtain the annular region composed of the third to sixth dilation layers, which was designated as the associated slope area. Subsequently, the candidate sedimentation zone and the associated slope area were combined to form a spatial statistical unit according to Equation (3), and each spatial statistical unit was assigned a unique number to associate the sedimentary topographic conditions of the candidate sedimentation zone with the erosion and sediment yield conditions of the surrounding slope area within a unified spatial framework.

[0043] Step 2: Quantification of the formation process.

[0044] Step 2.1: Calculate the overall topographic fit of the potential siltation area.

[0045] For each spatial statistical unit, the topographic relief and flatness of the candidate sedimentation area are calculated according to Equations (4) and (5), respectively. The topographic relief is calculated using a 3×3 pixel moving window, with the difference between the maximum and minimum elevations within the window representing the local elevation change of the pixel, and the average value of the local elevation difference of all effective pixels in the candidate sedimentation area is taken; the slope threshold for flatness is 5°, and the proportion of effective pixels with a slope of no more than 5° in the candidate sedimentation area is statistically analyzed.

[0046] The field-confirmed sample points are associated with the corresponding candidate siltation areas to form typical dam-controlled siltation terrain samples, and statistics are compiled according to hydraulic erosion type and wind-water combined erosion type. The terrain undulation and flatness are transformed according to Equations (6) and (7). In order to avoid the inability to perform logit transformation when the flatness is 0 or 1, this embodiment first limits the flatness to the range of [0, 1].

[0047] In the transformed feature space, maximum likelihood estimation is used to determine the typical center and discrete scale of the Gaussian distribution. Under the hydraulic erosion type, the typical center and discrete scale of the topographic relief transformation value are 1.626338 and 0.391082, respectively, and the typical center and discrete scale of the flatness transformation value are −1.178707 and 1.112623, respectively; under the wind-water combined erosion type, the typical center and discrete scale of the topographic relief transformation value are 1.301668 and 0.473462, respectively, and the typical center and discrete scale of the flatness transformation value are −0.414367 and 1.500307, ​​respectively. Substituting the above parameters into equations (8) and (9), respectively, the topographic relief fit and flatness fit of the candidate sedimentation area are calculated. Figure 2 The process of constructing the statistical distribution, Gaussian similarity, and terrain structure fit of the field-confirmed samples is shown.

[0048] Based on the erosion type of the spatial statistical unit, two corresponding fit terms are selected, and the harmonic average is used to fuse them according to equation (10) to obtain the comprehensive topographic fit of the candidate alluvial area, where the stable term Pick The harmonic mean is more sensitive to lower values; when any single item has a low fit, the overall terrain fit decreases accordingly; only when both items have high fits does the overall terrain fit remain high.

[0049] Step 2.2: Calculate the erosion and sediment yield potential of the associated slope area.

[0050] For the associated slope area of ​​each spatial statistical unit, the erosion and sediment yield potential is calculated according to Equation (11). The rainfall erosivity factor, slope length and gradient factor and soil erodibility factor in Equation (11) are obtained in the following manner.

[0051] (1) Calculation of rainfall erosivity factor

[0052] Based on monthly rainfall data, combined with the annual rainfall and seasonal distribution characteristics of a plateau, the annual rainfall erosivity factor is calculated using the following formula: , In the formula, This represents annual precipitation, expressed in mm. This represents the rainfall in the i-th month, in mm. This represents a dimensionless factor that reflects the seasonal distribution characteristics of annual rainfall. This represents the annual rainfall erosivity factor. (This is from the local area.) It is the seasonal allocation factor for rainfall, which is different from the flatness transformation value in equation (7).

[0053] (2) Calculation of slope length and slope factor

[0054] The slope length-gradient factor is determined by both the slope length factor and the slope factor, and is calculated using the following formula: , In the formula, Indicates the slope length and slope factor; Indicates the slope length factor; Indicates the slope factor; This indicates the slope length, expressed in meters (m). Indicates the slope length index; This represents the percentage of slope calculated by the digital elevation model. This represents the slope angle. To avoid the continuous accumulation of slope length along the confluence path, which could cause an abnormal increase in the slope length factor, this embodiment uses slope length... The maximum value is limited to 305m; when the calculated slope length exceeds 305m, it is used as 305m in the calculation.

[0055] (3) Calculation of soil erodibility factor

[0056] Based on the content of soil sand, silt, clay, and organic carbon, the EPIC equation is used to calculate the soil erodibility factor: , In the formula, , and These represent the mass percentages of soil sand, silt, and clay particles, respectively. Indicates the soil organic carbon content; =1− / 100; This represents the soil erodibility parameter calculated using the EPIC equation; 0.1317 is the conversion factor used to convert to the International System of Units (SI).

[0057] Calculate at the pixel scale , and Then, the product is calculated according to formula (11), and the arithmetic mean of the calculation results of all effective pixels in the associated slope area is taken. The obtained average value is used as the erosion and sediment yield potential of the spatial statistical unit. This index is used to compare the relative erosion and sediment yield potential between spatial statistical units, and is not used to directly estimate absolute soil loss because vegetation cover management factors and soil and water conservation measures factors are not included in the calculation. Figure 3 The characteristic distribution among undulation, flatness, and slope erosion sediment yield potential is shown.

[0058] Step 3: Identification of the dam-controlled siltation formation process

[0059] According to Equation (12), the comprehensive topographic fit of the candidate sedimentation area is coupled with the erosion and sediment yield potential of the associated slope area to obtain the identification index of the dam-controlled sedimentation formation process of the spatial statistical unit. The typical topographic differences between erosion types have been characterized in the process of Gaussian parameter fitting and comprehensive topographic fit calculation. Therefore, this embodiment adopts a unified identification threshold for different erosion types.

[0060] In this embodiment, the recognition threshold in equation (13) is... The value is set to 20. When the identification index for dam-controlled siltation formation process is not less than 20, the corresponding spatial statistical unit is retained, and the candidate siltation areas within it are identified as potential dam-controlled siltation areas; when the index is less than 20, the corresponding spatial statistical unit is excluded. To reduce non-target candidate units generated due to similar terrain conditions in large areas of continuous forest, this embodiment further calculates the forest cover ratio of the spatial statistical unit and excludes spatial statistical units with a forest cover ratio not less than 0.9. This condition is an auxiliary exclusion condition in this embodiment and does not constitute part of the identification index for dam-controlled siltation formation process.

[0061] The final selected candidate sedimentation areas are output as spatial vector data, and the following parameters are recorded: spatial statistical unit number, topographic relief, flatness, topographic relief fit, flatness fit, comprehensive topographic fit, erosion and sediment yield potential, identification indicators for dam-controlled sedimentation formation process, and final identification results. The distribution and local examples of potential dam-controlled sedimentation areas on a plateau obtained through the above steps are shown below. Figure 4 As shown.

[0062] Figure 4 Local examples show that the identification results are distributed across different geomorphic backgrounds, including loess ridges, eroded plains, loess plateaus, hills and mountains, and alluvial-diluvial deposits. Some potential areas show relatively obvious gentle sedimentary topography in remote sensing images, while others show no obvious signs of siltation. The latter still meet the requirements for formation process identification in terms of topographic structure and associated slope erosion and sediment yield conditions, indicating that the present invention outputs candidate areas with the potential for dam-controlled siltation formation, rather than a direct confirmation of the existence of dam-like structures or actual siltation.

[0063] In this embodiment, the spatial resolution, confluence accumulation threshold, continuous length threshold, spatial extension range, slope threshold, Gaussian fitting parameters, stability term, upper limit of slope length, identification threshold, and auxiliary exclusion threshold are all specific values ​​for a certain plateau region. For other implementation areas, the Gaussian parameters and corresponding thresholds can be re-determined according to the same process based on data resolution, topographical conditions, and field-confirmed samples.

[0064] In summary, this invention discloses a method for identifying potential dam-controlled sedimentation zones based on formation process constraints, relating to the fields of geospatial information processing and soil and water conservation monitoring. This method extracts the gully confluence network based on a digital elevation model and divides the gully confluence segments. Based on each gully confluence segment, it constructs a spatial statistical unit consisting of candidate sedimentation zones and their associated slope areas. It calculates the topographic relief and flatness of the candidate sedimentation zones and constructs a Gaussian similarity function based on field-confirmed samples to obtain a comprehensive topographic fit. It calculates the rainfall erosivity, slope length and gradient, and soil erodibility factor of the associated slope areas to obtain erosion and sediment yield potential. The comprehensive topographic fit is coupled with the erosion and sediment yield potential to form an identification index, and potential dam-controlled sedimentation zones are obtained through threshold screening. This invention can be used for regional identification of candidate locations and spatial extent of dam-controlled sedimentation zones.

[0065] The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that includes a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; any equivalent substitutions or adjustments made by those skilled in the art to the data source, parameter values, spatial statistical methods, or threshold determination methods without departing from the technical concept of the present invention should fall within the protection scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for identifying potential dam-controlled sedimentation zones based on formation process constraints, characterized in that, include: Based on the cumulative flow, the gully confluence network is extracted, and the gully confluence segments are divided along the gully confluence network. Based on each gully confluence segment, candidate sedimentation areas distributed along the gully and associated slope areas that have a water and sediment collection relationship with the candidate sedimentation areas are delineated respectively, and the candidate sedimentation areas and associated slope areas are combined to form spatial statistical units. The sedimentary topographic features of the candidate siltation areas are obtained, and a Gaussian similarity function of typical dam-controlled siltation topographic structures is established based on field-confirmed dam-controlled siltation area samples. The comprehensive topographic fit of the candidate siltation areas is calculated using the Gaussian similarity function. In addition, the erosion and sediment yield characteristics of the associated slope areas are obtained, and the erosion and sediment yield potential of the associated slope areas is calculated based on rainfall erosivity factor, slope length and gradient factor, and soil erodibility factor. The comprehensive topographic adaptability of the same spatial statistical unit is coupled with the erosion and sediment yield potential to obtain the identification index of dam-controlled sedimentation formation process, and potential dam-controlled sedimentation areas are determined based on the identification index of dam-controlled sedimentation formation process.

2. The method for identifying potential dam-controlled siltation zones based on formation process constraints according to claim 1, characterized in that, The spatial statistical unit is used to associate the sedimentary topographic conditions of the candidate alluvial area with the erosion and sediment yield conditions of the associated slope area within the same spatial framework; Each gully confluence section, candidate siltation zone, associated slope area, and spatial statistical unit satisfies the following: ， ， ， In the formula, Indicates position Accumulated flow at the confluence point; This represents the extraction threshold for the channel confluence network; This indicates the number of connected channel pixels contained in a channel confluence segment; Indicates the maximum segment size; This indicates that the first [unit] is obtained from the channel merging network that satisfies the conditions of merging accumulation and continuous length. Each ditch confluence section ; The structural element used to represent spatial expansion; and These respectively represent candidate siltation areas and slope areas delineated according to their corresponding spatial expansion ranges; Indicates the first Candidate siltation areas corresponding to the confluence sections of each ditch; This indicates the associated slope area adjacent to the candidate siltation area; The first part represents the combination of the candidate siltation zone and the associated slope zone. Spatial statistical unit.

3. The method for identifying potential dam-controlled siltation zones based on formation process constraints according to claim 1, characterized in that, The sedimentary topographic features include topographic relief and flatness; the topographic relief is used to characterize the degree of local elevation change within the candidate sedimentary area, and the flatness is used to characterize the proportion of effective pixels within the candidate sedimentary area whose slope is not greater than a preset slope threshold, and respectively satisfy: ， ， In the formula, Indicates candidate siltation areas; This indicates the number of valid pixels in the candidate congestion region; p represents the number of valid pixels within the candidate congestion region. This represents the difference between the maximum and minimum elevations within the moving window containing pixel p; Indicates the slope of pixel p; This represents the slope threshold for dividing gently sloping terrain. Represents the characteristic function.

4. The method for identifying potential dam-controlled siltation zones based on formation process constraints according to claim 3, characterized in that, The terrain relief and flatness are transformed to obtain the terrain relief transformed value. and flatness transformation value The transformation process satisfies: ， ， Among them, the terrain relief transformation value and the flatness transformation value This is used to estimate the typical central parameters and discrete scale parameters of the Gaussian similarity function in the transformed feature space.

5. The method for identifying potential dam-controlled siltation zones based on formation process constraints according to claim 4, characterized in that, The typical center and discrete scale of the Gaussian similarity function are determined based on field-confirmed samples of the dam-controlled siltation area; for erosion type e, the typical center of the topographic relief transformation value is calculated from the field-confirmed samples under the corresponding erosion type. and discrete scale and the typical center of the flatness transformation value. and discrete scale ; The topographic relief fit of the candidate siltation areas was calculated according to the following formulas. and flatness fit : ， 。 6. The method for identifying potential dam-controlled siltation zones based on formation process constraints according to claim 5, characterized in that, The terrain undulation adaptation is fused using a harmonic average. and flatness fit The comprehensive terrain adaptability of the candidate siltation area is obtained. The comprehensive terrain adaptability satisfy: ， in, This represents a stable term used to prevent the denominator from being zero.

7. The method for identifying potential dam-controlled siltation zones based on formation process constraints according to claim 1, characterized in that, The erosion and sediment production potential The soil erosivity factor is determined by multiplying the rainfall erosivity factor, slope length and gradient factor, and soil erodibility factor of each effective pixel within the associated slope area. Regional statistics are then performed by averaging the products of all effective pixels within the associated slope area, and the following conditions must be met: ， In the formula, Represents the associated slope area of ​​a spatial statistical unit; This indicates the number of effective pixels within the associated slope area; p represents the number of effective pixels within the associated slope area. , and These represent the rainfall erosivity factor, slope length and gradient factor, and soil erodibility factor of pixel p, respectively.

8. The method for identifying potential dam-controlled sedimentation zones based on formation process constraints according to any one of claims 1 to 7, characterized in that, The DamSiltation index, used to identify the dam-controlled siltation formation process, is based on the comprehensive terrain adaptability. With the aforementioned erosion and sediment production potential It is obtained by product coupling and satisfies: ， The product coupling is used to simultaneously constrain the sedimentary topographic adaptation conditions of the candidate siltation zone and the erosion and sediment supply conditions of the associated slope zone.

9. The method for identifying potential dam-controlled sedimentation zones based on formation process constraints according to claim 8, characterized in that, When the DamSiltation index for identifying the dam-controlled siltation formation process meets the following criteria, the corresponding spatial statistical unit is retained, and the candidate siltation areas within it are identified as potential dam-controlled siltation areas: ， Where T represents the threshold for identifying the dam-controlled siltation formation process; when When that happens, the corresponding spatial statistical unit is excluded.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for identifying potential dam-controlled siltation zones based on formation process constraints as described in any one of claims 1 to 9.

Images