A method for providing sand for repairing a coastal beach based on digital marine monitoring

Abstract

The application discloses a kind of based on digital ocean monitoring coastal beach repair sand supply method, it is related to marine monitoring and coastal engineering technical field, including, continuously monitor wave, tide, alongshore current and beach change, identify candidate sand supply phase when natural power drive sediment to sediment loss section migration, carry out persistency and phase jump verification to channel opening state, sediment transport direction state and sand receiving response state, eliminate short-time fluctuation false triggering, and form sand supply phase interlocking mark in combination with sand supply source release conflict;Based on sand supply phase interlocking mark, according to erosion hot spot coverage relationship, sediment transport path continuity and sand receiving response corresponding relationship, determine main sand supply source in combination with sand supply competition relationship, sand protection conflict relationship and path conflict relationship.The application verifies persistency and phase jump of candidate sand supply phase and forms sand supply phase interlocking mark, reduces sand supply false triggering caused by short-time wave, tide and alongshore current change.

Description

Technical Field

[0001] This invention relates to the field of marine monitoring and coastal engineering technology, and in particular to a method for sand supply for coastal beach restoration based on digital marine monitoring. Background Technology

[0002] With the development of digital monitoring of the marine environment and coastal ecological protection and restoration technologies, coastal beach restoration is gradually evolving from artificial sand replenishment, nearshore protection, and phased beach management to continuous marine environmental monitoring and the coordinated utilization of natural dynamics. The process of coastal beach restoration requires the acquisition of marine monitoring data from different sources, such as beach morphology, water depth and topography, historical coastline, waves, tides, coastal currents, and sediment conditions. By continuously monitoring changes at different times and locations of different shorelines, we can understand the shoreline retreat, beach shoulder changes, nearshore channel evolution, sediment depletion, and natural dynamic changes, providing dynamic monitoring basis for the identification of eroded shorelines and the regulation of sediment supply.

[0003] In the current process of coastal beach restoration, the correspondence between marine monitoring data from different sources in terms of monitoring time, shoreline location, and vertical profile location is often inconsistent, making it difficult to form unified digital monitoring data that can continuously reflect the state of the same shoreline. At the same time, the existing restoration methods usually determine the timing of sediment supply based on local and short-term hydrodynamic conditions. When the sediment source engine area, artificial sandbar area, and sandy headland area participate in the restoration together, there is a lack of continuous linkage between the dynamic monitoring status of the marine environment and different sediment supply sources. Short-term changes in waves, tides, and coastal currents can easily lead to misjudgments of the sediment supply status, resulting in sediment supply competition, sediment conservation conflicts, and sediment transport path conflicts. This leads to a mismatch between natural dynamic conditions and sediment release status, affecting the continuous replenishment of sediment to erosion hotspots and sediment-depleted sections. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a method for coastal beach restoration and sand supply based on digital ocean monitoring to solve the problems of lack of unified spatiotemporal correspondence of multi-source ocean monitoring data and mismatch of multi-source sand supply release under natural dynamic changes.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a method for sediment supply for coastal beach restoration based on digital ocean monitoring. The method includes: collecting data on shoreline morphology, water depth topography, hydrodynamics, and sediment from the target coastal beach; performing spatiotemporal registration according to monitoring time and shoreline location to form digital monitoring data; identifying erosion hotspots and sediment-deficient sections based on the digital monitoring data; delineating sediment supply control sections; locating sediment source engine areas, artificial sandbar areas, and sandy headlands; and configuring sediment supply parameters; continuously monitoring wave, tide, coastal current, and shoreline changes; identifying candidate sediment supply phases when natural forces drive sediment transport to sediment-deficient sections; and monitoring the channel opening status, sediment transport direction status, and sediment reception response status. The system performs continuity and phase jump checks to eliminate short-term fluctuations that trigger false triggers, and forms a sediment supply phase interlocking mark based on the release conflict of sediment supply sources. Based on the sediment supply phase interlocking mark, the main sediment supply source is determined according to the erosion hotspot coverage relationship, sediment transport path continuity and sediment reception response correspondence, combined with the sediment supply competition relationship, sediment conservation conflict relationship and path conflict relationship. Non-main sediment supply sources are identified as sediment storage and conservation constraints. The release of the main sediment supply source is controlled and differentiated sediment conservation is implemented for non-main sediment supply sources, generating a coordinated sediment supply regulation command. The system executes natural dynamic-driven sediment supply according to the coordinated sediment supply regulation command, and verifies the changes in shoreline morphology and sediment transport paths to form a multi-source coordinated dynamic sediment supply record.

[0007] As a preferred embodiment of the coastal beach restoration and sand supply method based on digital ocean monitoring described in this invention, the steps of identifying erosion hotspots and sediment-depleted sections, and delineating the sand supply control shoreline sections are as follows: Establish shoreline mileage benchmarks and vertical bank profile benchmarks for the target coastal beaches. Map the beach morphology, water depth topography, historical shoreline, hydrodynamic conditions and sediment particle size data to the shoreline mileage benchmarks and vertical bank profile benchmarks respectively. Register the data with the same spatiotemporal benchmarks according to the monitoring time, shoreline location and vertical bank profile location to form digital monitoring data. Based on digital monitoring data, the morphological changes corresponding to shoreline retreat, beach shoulder narrowing, foreshore slope steepening, low tide beach reduction and nearshore channel deepening are identified. The shoreline sections with continuous morphological deterioration and located in the downstream direction of the coastal current are identified as erosion hotspots, and the shoreline sections with insufficient sediment content in the profile and insufficient sediment deposition in the nearshore shallow water area are identified as sediment-depleted sections. Based on the dominant coastal sediment transport direction, sediment deficit level, and natural dynamic triggering type of each shoreline, adjacent shorelines with consistent characteristics are merged into sediment supply control shorelines. The upstream sediment supply inlet, downstream sediment receiving outlet, erosion hotspot location, and sediment deficit range are determined. The continuity of natural dynamic triggering type and sediment transport direction is verified. When natural dynamics can transport sediment from the upstream sediment supply inlet to the erosion hotspot location, the corresponding sediment supply control shoreline is determined as a triggerable shoreline.

[0008] As a preferred embodiment of the coastal beach restoration sand supply method based on digital ocean monitoring described in this invention, the steps for locating the sand source engine area, artificial sandbar area, and sandy headland area and configuring sand supply parameters are as follows: Based on the upstream sediment supply inlet, downstream sediment receiving outlet, erosion hotspot location, sediment deficit section range and dominant coastal sediment transport direction of the triggerable shoreline section, the offshore activity water depth range is determined in combination with water depth topography, and the shoreline node location is determined in combination with beach morphology, and the sediment source engine area, artificial sandbar area and sandy cape area are screened respectively. Based on the sand source engine area, artificial sand dam area and sandy cape area, respectively establish coastal sand supply channels, onshore compensation channels and nodal slow release channels, so that the coastal sand supply channels correspond to the long-term coastal sand supply function, the onshore compensation channels correspond to the underwater energy dissipation and onshore compensation function, and the nodal slow release channels correspond to the shoreline nodal slow release function. The sand source engine area is configured with sand replenishment profile, sand replenishment particle size and sand injection volume; the artificial sand dam area is configured with dam site water depth, distance from shore and dam body scale; and the sandy cape area is configured with cape direction, cape scale and tidal channel scale. Each sand supply parameter is matched with the corresponding sand supply channel and sand supply function.

[0009] As a preferred embodiment of the coastal beach restoration and sand supply method based on digital ocean monitoring described in this invention, the steps of continuously monitoring wave, tide, coastal current, and beach changes are as follows: The sand source engine area, artificial sandbar area and sandy headland area are respectively mapped to the coastal sand supply channel, the onshore compensation channel and the nodal slow release channel, and wave, tide, coastal current and beach morphology monitoring data are collected according to the scope of each sand supply channel. The monitoring data is matched with the predetermined sediment transport direction and sediment deficit section of the corresponding sediment supply channel. When the natural dynamic direction is consistent with the predetermined sediment transport direction of the corresponding sediment supply channel and the change in the bank morphology points to the sediment deficit section and forms a sediment receiving response, it is determined to be in the open window state. When the natural dynamic direction is consistent but the sediment receiving response does not appear continuously, it is determined to be in the observation window state. When at least one of the following conditions is met: the natural dynamic direction deviates from the predetermined sediment transport direction of the corresponding sediment supply channel or the change in the bank morphology does not point to the sediment deficit section, it is determined to be in the closed window state.

[0010] As a preferred embodiment of the coastal beach restoration sediment supply method based on digital ocean monitoring described in this invention, the step of identifying candidate sediment supply phases when sediment is transported to sediment-depleted sections by natural dynamics includes the following steps: Based on the window status corresponding to the coastal sand supply channels, the onshore compensation channels, and the node slow release channels, the channel opening status, sand transport direction status, and sand receiving response status of each sand supply channel are jointly identified and respectively mapped to the sand source engine area, artificial sand dam area, and sandy cape area to determine the candidate sand supply phase of each sand supply source. The candidate sediment supply phases are continuously verified, and the candidate sediment supply phases that maintain the same sediment transport direction, the same channel opening state, and the same sediment receiving response state within the continuous monitoring period are determined as valid sediment supply phases. For candidate sand supply phases that do not maintain the corresponding state continuously, phase jump verification is performed. If a phase jump exists, it is determined to be a short-term fluctuation false trigger. If there is no phase jump and a continuous stable state has not yet been formed, it is determined to be a phase to be confirmed.

[0011] As a preferred embodiment of the coastal beach restoration sand supply method based on digital ocean monitoring described in this invention, the steps for forming the sand supply phase interlock marker are as follows: The sand supply sources corresponding to the effective sand supply phases are identified as release candidate sand supply sources, the sand supply sources corresponding to the phases to be confirmed are identified as observation candidate sand supply sources, and the sand supply sources that are not identified as release candidate sand supply sources but need to be maintained as sand storage and conservation candidate sand supply sources are identified as maintenance candidate sand supply sources. The corresponding sand supply channels for releasing candidate sand supply sources are matched with the locations of erosion hotspots, the range of sediment-depleted sections, and the sand-receiving response within the same sand supply control section. The states of releasing candidate sand supply sources pointing to the same erosion hotspots, the overlapping states of sand supply channels, and the impact of sediment release on maintaining the sand storage and conservation state of candidate sand supply sources are verified respectively. If any state meets the corresponding release conflict condition, a release conflict is determined to exist. Based on the release of candidate sand supply sources, observation of candidate sand supply sources, maintenance of candidate sand supply sources and corresponding release conflict relationships, a sand supply phase interlocking mark is formed.

[0012] As a preferred embodiment of the coastal beach restoration and sand supply method based on digital ocean monitoring described in this invention, the steps for determining the main sand supply source and the sand storage and conservation constraints are as follows: Based on the interlocking markers of the sediment supply phase, the release candidate sediment supply sources are associated with the opening status of the coastal sediment supply channels, the onshore compensation channels, and the node slow release channels, respectively. When two or more release candidate sediment supply sources correspond to the same erosion hot spot, a sediment supply competition relationship is determined. When the release of the release candidate sediment supply source affects the sediment storage and preservation status of other sediment supply sources, a sediment preservation conflict relationship is determined. When the sediment supply channels overlap and the actual sediment transport direction deviates from the predetermined sediment transport direction of the corresponding sediment supply channel, a path conflict relationship is determined. Based on the coverage relationship of erosion hotspots, the continuity of sediment transport paths and the correspondence of sediment-receiving responses, and combined with the hit status of sediment supply competition, sediment protection conflict and path conflict, the main sediment supply judgment value of each candidate sediment supply source is determined. The candidate sand source with the highest main sand supply value is determined as the main sand supply source, and sand supply sources other than the main sand supply source are determined as the objects of sand storage and conservation constraints.

[0013] As a preferred embodiment of the coastal beach restoration and sand supply method based on digital ocean monitoring described in this invention, the steps of controlling the release of the main sand source and implementing differentiated sand conservation for non-main sand sources are as follows: The sand supply channels corresponding to the main sand supply source are defined as the target release state, and the non-main sand supply channels corresponding to the sand storage and conservation constraints are defined as the target sand storage and conservation state. When the object of sand storage and conservation is the sand source engine area, the sand source engine area is defined as the target-restricted natural diffusion state. When the object of sand storage and conservation is the artificial sand dam area, the artificial sand dam area is defined as the target basic outline preservation state. When the object of sand storage and conservation is the sandy cape area, the sandy cape area is defined as the target restricted slow release state.

[0014] As a preferred embodiment of the coastal beach restoration and sand supply method based on digital ocean monitoring described in this invention, the steps for generating coordinated sand supply control commands are as follows: Consistency verification is performed on the target release status of the main sand source, the target sand conservation status of the non-main sand source, and the channel release restriction status corresponding to the sand supply phase interlock mark. When the sand supply channel corresponding to the main sand source meets the target release state, the sand storage and conservation constraint object meets the target sand conservation state corresponding to the sand supply source type, and the non-main sand supply channel limited by the sand supply phase interlock mark is not determined to be in the target release state, it is determined that the release of the main sand source and the sand conservation of the non-main sand source meet the interlock requirements, and a coordinated sand supply control command is generated.

[0015] As a preferred embodiment of the coastal beach restoration and sand supply method based on digital ocean monitoring described in this invention, the steps for forming a multi-source collaborative dynamic sand supply record are as follows: In accordance with the instructions for coordinated sand supply regulation, the release of the main sand source and the interlocking of the non-main sand source to conserve sand are carried out. The changes in the morphology of the beach and the sediment transport path after the sand supply are reviewed to determine the transport status of sediment along the sand supply channel corresponding to the main sand source to the erosion hotspots and sediment-deficient sections. The release process of the main sand source, the interlocking and sand-preserving status of the non-main sand source, the changes in shoreline morphology, and the verification results of sediment transport paths are correlated according to the same sand supply control section to form a multi-source coordinated dynamic sand supply record.

[0016] The beneficial effects of this invention are as follows: By establishing shoreline mileage benchmarks and vertical shoreline profile benchmarks, marine monitoring data from different sources, such as shoreline morphology, water depth topography, historical shoreline, hydrodynamic conditions, and sediment particle size, are registered with the same spatiotemporal benchmark according to monitoring time, shoreline location, and vertical shoreline profile location. This enables the marine environmental conditions from different sources and at different monitoring times to form unified and corresponding digital monitoring data, providing a continuous data foundation for determining erosion hotspots, sediment-depleted sections, and sediment-supply-controlled shorelines. Furthermore, by verifying the persistence and phase jumps of candidate sediment-supply phases, sediment-supply phases are formed. Interlocking markers are used to reduce false triggering of sediment supply caused by short-term wave, tide, and coastal current changes; the main sediment supply source is determined based on the coverage relationship of erosion hotspots, the continuity of sediment transport paths, and the correspondence between sediment receiving responses, and differentiated sediment conservation measures are implemented for non-main sediment supply sources, so that coastal sediment supply, onshore compensation, and nodal release are coordinated according to natural dynamic conditions, reducing ineffective sediment release and excessive consumption of non-main sediment supply sources; by reviewing the changes in shoreline morphology and sediment transport paths after sediment supply, the continuity and adaptability of coastal beach erosion restoration, continuous sediment replenishment, and shoreline morphology restoration are improved. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only 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 flowchart of a method for sand supply to coastal beaches for restoration based on digital ocean monitoring.

[0019] Figure 2 A flowchart for configuring the sand supply control section and sand supply parameters.

[0020] Figure 3 A flowchart for forming candidate sand supply phases and sand supply phase interlocking markers.

[0021] Figure 4 The flowchart shows the process for determining the primary sand source and coordinating sand supply regulation. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0025] Reference Figures 1-4 This is one embodiment of the present invention, which provides a method for sand supply for coastal beach restoration based on digital ocean monitoring, comprising the following steps: S1. Collect data on the shoreline morphology, water depth topography, hydrodynamics, and sediment of the target coastal beach. Perform spatiotemporal registration according to the monitoring time and shoreline location to form digital monitoring data. Based on the digital monitoring data, identify erosion hotspots and sediment-depleted sections, divide the shoreline for sediment supply control, locate the sand source engine area, artificial sandbar area, and sandy cape area, and configure the sediment supply parameters.

[0026] S1.1: Establish shoreline mileage benchmarks and vertical bank profile benchmarks for the target coastal beaches. Correspond the beach morphology, water depth topography, historical shoreline, hydrodynamic conditions and sediment particle size data to the shoreline mileage benchmarks and vertical bank profile benchmarks respectively. Register the data with the same spatiotemporal benchmarks according to the monitoring time, shoreline location and vertical bank profile location to form digital monitoring data. Specifically, on-site measurements and historical data compilation are conducted on the target coastal beach. Coastline mileage benchmarks are determined along the continuous direction of the target coastal beach shoreline, and vertical shoreline profile benchmarks are laid out according to the direction perpendicular to the shoreline. The beach morphology, water depth topography, historical shoreline, hydrodynamic conditions, and sediment particle size data are respectively correlated to the corresponding shoreline mileage positions and vertical shoreline profile positions, and the monitoring time corresponding to the monitoring cycle is used as the target monitoring time. For data with inconsistent monitoring times, the monitoring time with the smallest time difference from the target monitoring time is retrieved from the corresponding data. When the time difference does not exceed the preset maximum allowable time difference, the corresponding monitoring data is mapped to the target monitoring time according to the nearest neighbor method. When the time difference exceeds the preset maximum allowable time difference, the corresponding data is marked as having no valid time match. For data with inconsistent spatial locations, the monitoring points are projected onto the shoreline mileage benchmark to determine the corresponding shoreline mileage location. According to the spatial distance between the monitoring points and each vertical bank profile benchmark, the monitoring points are mapped to the nearest vertical bank profile location that is within the preset maximum allowable spatial distance. When multiple monitoring points are mapped to the same shoreline mileage location and the same vertical bank profile location, the arithmetic mean of the same monitoring values ​​is taken as the monitoring value of the corresponding location. When the monitoring points exceed the effective coverage of the target shoreline or vertical bank profile and there are no monitoring points that meet the preset maximum allowable spatial distance, the corresponding location is marked as having no valid spatial match. Only data with valid time and spatial matching are mapped according to the same monitoring time, the same shoreline location, and the same vertical bank profile location to form digital monitoring data.

[0027] It should be noted that the shoreline morphology data is derived from on-site topographic surveys and shoreline profile measurements, used to characterize changes in the beach shoulder boundary, foreshore slope, and low-tide beach surface; the water depth topography data is derived from nearshore water depth measurements and seabed topographic surveys, used to characterize changes in nearshore water depth, seabed elevation, and nearshore trough; the historical shoreline data is derived from previous surveying data, remote sensing imagery, and shoreline monitoring data; hydrodynamic conditions include wave conditions, tidal conditions, and coastal current conditions; and sediment particle size data are derived from sediment sampling and testing at the beach surface, intertidal zone, and nearshore shallow water areas. Digital monitoring data are linked and stored according to monitoring time, shoreline mileage location, and vertical profile location, ensuring a consistent temporal and locational correspondence for monitoring data from different sources on the same shoreline section.

[0028] The preset maximum allowable time difference is determined based on the normal monitoring sampling interval of various monitoring data and the typical duration of the natural dynamic state of the target coastal beach. The example value range is 20% to 50% of the normal monitoring sampling interval of the corresponding monitoring data. The specific value is determined based on the sampling time deviation between monitoring data from different sources, the time synchronization error of monitoring equipment, and the continuous change characteristics of wave, tide and coastal current states between adjacent monitoring times. The preset maximum allowable spatial distance is determined based on the spacing between adjacent vertical bank profiles, the scale of bank section division, and the positioning error of monitoring equipment. The example value range is 20% to 50% of the spacing between adjacent vertical bank profiles. The specific value is determined based on the on-site vertical bank profile layout density, the positioning error of monitoring points, the scale of spatial changes in the beach morphology, and the effective coverage of adjacent vertical bank profiles. Data without valid temporal or spatial matching will not be included in the determination of erosion hotspots, sediment depletion sections, natural dynamic triggering types, sediment transport directions, and sediment-receiving responses for the corresponding monitoring period, and will be marked as having no valid matching.

[0029] S1.2: Based on digital monitoring data, identify the morphological changes corresponding to shoreline retreat, beach shoulder narrowing, foreshore slope steepening, low tide beach reduction and nearshore channel deepening. Identify the shoreline sections with continuous morphological deterioration and located in the downstream direction of the coastal current as erosion hotspots, and identify the shoreline sections with insufficient sediment content in the profile and insufficient sediment deposition in the nearshore shallow water area as sediment-depleted sections. Specifically, the data on shoreline morphology, water depth topography, historical shoreline, hydrodynamic conditions, and sediment particle size corresponding to the same shoreline location and the same vertical shoreline profile are read from the digital monitoring data and compared in chronological order of monitoring time. The movement of the shoreline position relative to its historical stable position toward the land is identified as shoreline retreat; the contraction of the beach shoulder boundary relative to its historical stable boundary toward the land is identified as beach shoulder narrowing; the increase of the foreshore slope relative to its historical stable slope is identified as foreshore slope steepening; the decrease of the low tide beach elevation relative to its historical stable elevation is identified as low tide beach lowering; and the decrease of the nearshore trough bottom elevation relative to its historical stable elevation is identified as nearshore trough deepening.

[0030] The continuous status of the above-mentioned morphological changes during the continuous monitoring period is verified. When the magnitude of the morphological change reaches the corresponding preset deterioration threshold and the preset number of monitoring times is reached, the corresponding bank section is identified as a bank section with continuous morphological deterioration. Combining the direction of the coastal current in the digital monitoring data, the bank section with continuous morphological deterioration located in the downstream direction of the coastal current is identified as an erosion hotspot. The current profile sediment volume and nearshore shallow water sediment volume of the same vertical bank profile are compared with the corresponding historical stable state. When the profile sediment volume reaches the preset profile deficit threshold and the nearshore shallow water sediment volume reaches the preset sediment deficit threshold, the corresponding bank section is identified as a sediment deficit section.

[0031] It should be noted that the preset deterioration threshold is determined based on the range of natural changes in the shoreline morphology during the stable monitoring period, the allowable deviation range of the restoration target, and the field measurement error. The example value range is 5% to 15% relative to the historical stable state. The example value range for the preset profile deficit threshold is 10% to 25% reduction in profile sediment volume relative to the historical stable state. The example value range for the preset sediment deficit threshold is 10% to 30% reduction in nearshore shallow water sediment volume relative to the historical stable state. The example value range for the preset number of monitoring sessions is 3 to 6 times, and the specific value is determined based on the monitoring sampling interval, the duration of natural changes in the shoreline, and the duration characteristics of short-term hydrodynamic disturbances.

[0032] S1.3: Based on the dominant coastal sediment transport direction, sediment deficit level, and natural dynamic triggering type of each shore section, adjacent shore sections with consistent characteristics are merged into sediment supply control shore sections. The upstream sediment supply inlet, downstream sediment receiving outlet, erosion hotspot location, and sediment deficit section range are determined. The continuity of natural dynamic triggering type and sediment transport direction is verified. When natural dynamics can transport sediment from the upstream sediment supply inlet to the erosion hotspot location, the corresponding sediment supply control shore section is determined as a triggerable shore section. Specifically, based on digital monitoring data, the direction of coastal currents, wave incidence, and changes in shoreline morphology are read from the corresponding shore sections of erosion hotspots and sediment-depleted sections. The direction of coastal currents is correlated with the spatial distribution of erosion hotspots and sediment-depleted sections. The dominant coastal sediment transport direction is determined by combining the direction of sediment movement formed by obliquely incident waves and the continuous expansion direction of morphological changes. Insufficient sediment volume in the profile, insufficient deposition in nearshore shallow waters, narrowing of the beach shoulder, lowering of the beach surface at low tide, and deepening of the nearshore channel are respectively identified as sediment depletion events. The sediment depletion level is determined based on the number of events identified in the same shore section during continuous monitoring periods. Based on the changes in wave conditions, tidal conditions, and coastal current conditions before and after morphological changes, the duration of the corresponding hydrodynamic conditions reaching the trigger state, the consistency between the corresponding sediment transport direction and the morphological change direction, and the temporal relationship between the corresponding hydrodynamic changes and morphological changes are verified. Hydrodynamic conditions that meet the corresponding trigger conditions are identified as effective triggering hydrodynamics. The natural dynamic triggering type is determined based on the type of effective triggering hydrodynamics.

[0033] Adjacent shorelines with the same dominant sediment transport direction, sediment deficit level, and natural dynamic triggering type are continuously merged to form sediment supply control shorelines. According to the dominant sediment transport direction, the upstream boundary of the sediment supply control shoreline is determined as the upstream sediment supply inlet, and the downstream boundary is determined as the downstream sediment receiving outlet. The corresponding erosion hotspot locations and sediment deficit sections are associated with the sediment supply control shorelines.

[0034] Furthermore, during the continuous monitoring period, the consistency between the actual natural dynamic triggering type and the corresponding natural dynamic triggering type of the sediment supply control section is verified, and the angle between the actual sediment transport direction and the dominant coastal sediment transport direction is verified. When the natural dynamic triggering type is consistent, the angle between the actual sediment transport direction and the dominant coastal sediment transport direction does not exceed the preset direction tolerance, and the actual sediment transport direction points from the upstream sediment supply inlet to the erosion hotspot, the corresponding sediment supply control section is determined as a triggerable section.

[0035] It should be noted that when no sediment deficit hit item appears, it is determined to be a state of no sediment deficit; when one hit item appears, it is determined to be a level of slight sediment deficit; when two hit items appear, it is determined to be a level of moderate sediment deficit; and when three or more hit items appear, it is determined to be a level of severe sediment deficit. The wave triggering state is determined based on the consistency between the sediment transport direction and the morphological change direction during the wave action and the change in wave intensity. When the wave intensity increases relative to the corresponding stable monitoring state to reach the preset wave change threshold, the corresponding state continuously reaches the preset triggering duration, and the angle between the sediment transport direction and the morphological change direction formed by the wave action does not exceed the preset direction tolerance, the wave condition is determined to have reached the triggering state. The tidal trigger state is determined based on the correspondence between the tidal rise and fall process and the timing of morphological changes. When the magnitude of the tidal change reaches a preset tidal change threshold relative to the corresponding stable monitoring state, the corresponding change occurs earlier than or covers the timing of the morphological change, and the direction of sediment transport corresponding to the tidal effect is consistent with the direction of morphological change, the tidal condition is determined to have reached the trigger state. The coastal current trigger state is determined based on the changes in coastal current velocity and direction. When the coastal current velocity increases relative to the corresponding stable monitoring state to reach a preset velocity change threshold, the corresponding state continuously reaches a preset trigger duration, and the angle between the coastal current direction and the dominant coastal sediment transport direction does not exceed the preset direction tolerance, the coastal current condition is determined to have reached the trigger state.

[0036] Example value ranges for preset wave change threshold, preset tide level change threshold, and preset flow velocity change threshold are 10% to 25%, 10% to 20%, and 10% to 25% relative to the corresponding stable monitoring state, respectively. The specific values ​​are determined based on the natural fluctuation range of the corresponding hydrodynamic conditions during the historical stable monitoring period, the measurement error of the monitoring equipment, and the magnitude of hydrodynamic changes when identifiable sediment migration occurs. Example value range for preset trigger duration is 2 to 5 consecutive monitoring sampling intervals. The specific value is determined based on the duration of short-term hydrodynamic disturbance and the duration required for continuous sediment transport. Example value range for preset direction tolerance is 10° to 25°. The specific value is determined based on the natural swing range of the sediment transport direction in the multi-year hydrodynamic monitoring data of the target coastal beach and the on-site direction monitoring error.

[0037] When only one type of hydrodynamic condition reaches the corresponding triggering state, the corresponding natural dynamic triggering type is determined as wave triggering type, tidal triggering type, or coastal current triggering type; when two or more types of hydrodynamic conditions reach the corresponding triggering state simultaneously during the same morphological change period, and the corresponding sediment transport directions do not conflict with each other beyond the preset direction tolerance, it is determined as a composite dynamic triggering type; when two or more types of hydrodynamic conditions reach the corresponding triggering state simultaneously but the corresponding sediment transport directions conflict with each other, the composite dynamic triggering type is not determined, and the determination continues according to the hydrodynamic state at the next monitoring time; when wave conditions, tidal conditions, and coastal current conditions do not reach the corresponding triggering state, the natural dynamic triggering type is not determined, and the corresponding shoreline does not enter the determination of the triggerable shoreline in this monitoring cycle.

[0038] S1.4: Based on the upstream sediment supply inlet, downstream sediment receiving outlet, erosion hotspot location, sediment deficit section range and dominant coastal sediment transport direction of the triggerable shoreline section, determine the offshore activity water depth range in combination with water depth topography, determine the shoreline node location in combination with beach morphology, and screen the sand source engine area, artificial sandbar area and sandy cape area respectively. Specifically, digital monitoring data corresponding to the triggerable shoreline sections are read, with the continuous shoreline direction from the upstream sediment supply inlet to the downstream sediment receiving outlet as the shoreline development direction, and the vertical shoreline profile direction as the offshore development direction. Based on the water depth topography, wave conditions, tidal conditions, coastal current conditions, and historical sediment migration locations corresponding to each vertical shoreline profile, the nearshore water depth range where sediment initiation and location migration can continuously occur during natural dynamic processes is determined as the offshore activity water depth range. The shoreline end position and shoreline inflection point position are determined based on the changes in the continuous shoreline direction in the beach morphology, and the corresponding positions are determined as shoreline node positions.

[0039] The beach shoulder area and intertidal zone located between the upstream sediment supply inlet and the upstream side of the erosion hotspot, which are spatially continuous with the upstream sediment supply inlet and can extend along the dominant coastal sediment transport direction to the erosion hotspot and the downstream sediment receiving outlet, are identified as the sediment source engine area; the nearshore shallow water area that can correspond to the sediment deficit section along the vertical bank profile within the offshore active water depth range is identified as the artificial sandbar area; and the shoreline node area located at the shoreline node position and which can correspond to the erosion hotspot and sediment deficit section on both sides of the shoreline is identified as the sandy cape area.

[0040] It should be noted that the offshore activity water depth range is determined jointly based on the water depth topography, wave action range, tidal range, coastal current stability range, and historical sediment migration location in the digital monitoring data. The near-shore boundary is determined by the location where sediment can maintain natural migration and has not entered the stable beach surface, while the offshore boundary is determined by the location where sediment continuously migrates and disappears under natural dynamic action. The spatial continuity requirement is met when there is no spatial interruption between the sediment source engine area and the upstream sediment supply inlet, and the corresponding continuous sediment supply range can reach the erosion hotspot and the downstream sediment receiving outlet along the dominant coastal sediment transport direction.

[0041] S1.5: Based on the sand source engine area, artificial sandbar area and sandy cape area, respectively establish coastal sand supply channels, onshore compensation channels and nodal slow release channels, so that the coastal sand supply channels correspond to the long-term coastal sand supply function, the onshore compensation channels correspond to the underwater energy dissipation and onshore compensation function, and the nodal slow release channels correspond to the shoreline nodal slow release function. Specifically, the sand source engine area is mapped along the dominant coastal sediment transport direction to the downstream sediment receiving outlet and erosion hotspot location to determine the coastal sediment supply channel from the sand source engine area to the sediment-deficient section; the artificial sandbar area is mapped along the vertical bank profile direction to the beach shoulder area and sediment-deficient section to determine the onshore compensation channel from the artificial sandbar area to the beach shoulder area; and the coastal node location of the sandy cape area is mapped to the sediment-deficient sections on both sides of the erosion hotspot to determine the node slow release channel extending from the sandy cape area to the sediment-deficient sections on both sides.

[0042] It should be noted that the long-term coastal sediment supply effect is used to continuously influence the downstream sediment-receiving outlet and sediment-deficient section through the sediment source engine area along the dominant coastal sediment transport direction; the underwater energy dissipation and shore compensation effect is used to reduce wave energy and compensate sediment to the beach shoulder area through the artificial sandbar area; the shoreline node slow release effect is used to control the slow release of sediment at the shoreline node to both sides of the erosion hotspot through the sandy cape area.

[0043] S1.6: Configure the sand replenishment profile, sand replenishment particle size and sand injection volume for the sand source engine area; configure the dam site water depth, distance from the shore and dam body scale for the artificial sand dam area; configure the cape direction, cape scale and tidal channel scale for the sandy cape area; and match each sand supply parameter with the corresponding sand supply channel and sand supply function.

[0044] Specifically, based on the upstream sand supply inlet, downstream sand receiving outlet, erosion hotspot location, sediment deficit range, and sediment particle size data corresponding to the coastal sand supply channel, a replenishment profile, replenishment particle size, and injection volume are configured for the sand source engine area. The sediment deficit volume is determined cumulatively along the shoreline direction of the sediment deficit section based on the cross-sectional area deficit of the current sediment deficit section relative to the historical stable profile. The product of the sediment deficit volume and the target replenishment ratio is used as the basic replenishment volume. The basic replenishment volume is then compensated for based on the expected sediment transport loss rate and replenishment construction loss rate during the coastal sand supply process to determine the injection volume. The replenishment profile is determined according to the historical stable profile morphology and the current sediment deficit location, prioritizing the placement of new sediment in the beach shoulder area, intertidal zone, and the corresponding starting position of the coastal sand supply channel where the profile deficit occurs. The replenishment particle size is determined according to the original beach sediment particle size distribution.

[0045] Based on the offshore activity depth range, vertical bank profile location, abutment area, sediment deficit section range, and corresponding wave and water depth topographic data corresponding to the onshore compensation channel, the dam site water depth, offshore distance, and dam body dimensions are configured for the artificial sandbar area. The effective wave height and corresponding water depth during wave propagation from the offshore side to the shore are statistically analyzed along the vertical bank profile. Locations where stable breaking begins but are still within the offshore activity depth range are identified as candidate dam site locations. The water depth corresponding to the candidate dam site location is determined as the dam site water depth, and the horizontal distance from the candidate dam site location to the corresponding abutment boundary is determined as the offshore distance. The dam body dimensions are defined by the dam crest elevation, dam height, and dam body dimensions. The width and slope of the dam are determined together. The dam crest elevation is determined based on the normal tide level at the candidate dam site and the allowable overtopping height under the target wave-dissipating conditions. The dam height is determined based on the difference between the dam crest elevation and the seabed elevation at the dam site. The dam width is determined based on the allowable wave overtopping conditions at the dam crest and the construction stability width. The dam slope is determined based on the particle size of the dam material, the intensity of wave action, and the underwater slope stability requirements. After configuration, the sliding stability, settlement, and slope stability of the dam body under the action of the target waves are verified. If the stability requirements are not met, the dam width is increased, the dam slope is reduced, or the candidate dam site is adjusted to the offshore side until the corresponding stability requirements are met.

[0046] Based on the shoreline node location corresponding to the node release channel, the sediment-deficient sections on both sides of the erosion hotspot, the direction of the coastal current, the tidal range, and the water exchange status at the node location, the headland orientation, headland scale, and tidal channel scale are configured for sandy headland areas. The headland orientation is determined by combining the target release direction of the sediment-deficient sections on both sides of the erosion hotspot with the downstream direction of the coastal current. The headland scale is determined based on the sediment-deficient shoreline range to be covered by the shoreline node location and the allowable sediment release range on both sides of the headland. The effective flow area of ​​the tidal channel is determined based on the target exchange flow and allowable velocity to be maintained at the node location within a tidal cycle, and the tidal channel scale is determined by combining the tidal range and the effective water depth at the corresponding location. When the tidal channel scale determined according to the target exchange flow results in the sediment retention of the sandy headland area being lower than the sediment storage and conservation requirements, the tidal channel scale is gradually reduced and the actual flow velocity is re-verified to ensure that the adjusted tidal channel simultaneously meets the minimum water exchange requirements and the allowable velocity requirements. If both requirements are still not met, the corresponding shoreline node location is not used as the current deployment location for the sandy headland area.

[0047] Furthermore, the sand replenishment profile, sand replenishment particle size, and sand injection volume are matched with the coastal sand supply channel and the long-term coastal sand supply effect; the dam site water depth, distance from the shore, and dam body scale are matched with the onshore compensation channel and underwater energy dissipation and onshore compensation effect; and the cape orientation, cape scale, and tidal channel scale are matched with the node slow release channel and shoreline node slow release effect.

[0048] It should be noted that the target replenishment ratio is determined based on the sediment deficit level and the target degree of restoration of the target coastal beach to its historical stable profile. The example value range is 80% to 120% of the sediment deficit volume, with 80% corresponding to a slight sediment deficit level, 100% to a moderate sediment deficit level, and 120% to a severe sediment deficit level. The expected sediment transport loss rate is determined based on the difference between the actual sediment arrival volume and the amount injected from the upstream sediment supply inlet to the sediment deficit section after historical sediment replenishment. The example value range is 5% to 20%. The sediment replenishment construction loss rate is determined based on the sediment loss during the loading, delivery, and initial shaping stages of historical sediment replenishment construction. The example value range is 2% to 10%. The amount of sediment injected is compensated based on the basic replenishment volume and combined with the expected sediment transport loss rate and the sediment replenishment construction loss rate, so that the effective amount of sediment expected to reach the sediment deficit section after delivery is not less than the basic replenishment volume.

[0049] The candidate dam sites for the artificial sandbar area are determined based on water depth topography and wave monitoring data, prioritizing locations where the target waves begin to break stably and are still within the offshore activity depth range. The allowable wave height for the dam crest elevation is determined based on the requirement of maintaining water exchange while avoiding complete blockage in the artificial sandbar area. The dam width and slope are determined based on stable cross-sectional data under similar dam material, water depth, and wave action conditions, and adjusted through verification of sliding stability, settlement, and dam slope stability. The target exchange flow rate of the tidal channel is determined based on the flow rate required to maintain normal water exchange on both sides of the shoreline node within one tidal cycle, and the allowable flow velocity is determined based on the stable flow velocity range before significant initiation and scouring of the corresponding sediment particle size. The tidal channel scale prioritizes meeting the water exchange requirements. When the water exchange requirements conflict with the requirements for sediment storage and conservation, the upper limit is set at not exceeding the allowable flow velocity and without causing continuous scouring of the sandy headland area, and adjustments are made by gradually reducing the tidal channel scale.

[0050] S2. Continuously monitor changes in waves, tides, coastal currents, and shorelines. When natural forces drive sediment transport to sediment-deficient sections, identify candidate sediment supply phases. Perform continuous verification and phase jump checks on the channel opening status, sediment transport direction status, and sediment receiving response status. Eliminate false triggers caused by short-term fluctuations and form sediment supply phase interlocking markers in conjunction with sediment source release conflicts.

[0051] S2.1: The sand source engine area, artificial sandbar area and sandy headland area are respectively mapped to the coastal sand supply channel, the onshore compensation channel and the nodal slow release channel, and wave, tide, coastal current and beach morphology monitoring data are collected according to the scope of each sand supply channel; Specifically, based on the sand replenishment profile, sand particle size, and sand injection volume of the sand source engine area, the water depth, distance from the shore, and scale of the artificial sand dam site in the artificial sand dam area, and the headland orientation, headland scale, and tidal channel scale of the sandy headland area, the sand source engine area is mapped to the coastal sand supply channel, the artificial sand dam area to the onshore compensation channel, and the sandy headland area to the nodal slow release channel. Monitoring locations are determined according to the sand supply range corresponding to each sand supply channel. Wave, tide, coastal current, and shoreline morphology monitoring data reflecting long-term coastal sand supply, underwater energy dissipation and onshore compensation, and shoreline nodal slow release are collected and mapped according to the same monitoring time, the same sand supply control shoreline section, and the same channel location.

[0052] S2.2: Match the monitoring data with the predetermined sediment transport direction and sediment deficit section range of the corresponding sediment supply channel. When the natural dynamic direction is consistent with the predetermined sediment transport direction of the corresponding sediment supply channel and the change in the bank morphology points to the sediment deficit section and forms a sediment receiving response, it is determined to be in the open window state. When the natural dynamic direction is consistent but the sediment receiving response does not appear continuously, it is determined to be in the observation window state. When at least one of the following conditions is met: the natural dynamic direction deviates from the predetermined sediment transport direction of the corresponding sediment supply channel or the change in the bank morphology does not point to the sediment deficit section, it is determined to be in the closed window state. Specifically, based on monitoring data of waves, tides, coastal currents, and shoreline morphology within the coastal sediment supply channels, onshore compensation channels, and nodal release channels, the natural dynamic direction, sediment initiation state, sediment transport state, shoreline morphology change direction, and sediment-receiving response are determined respectively. The dominant coastal sediment transport direction of the coastal sediment supply channels is determined as the predetermined sediment transport direction of the corresponding sediment supply channels. The vertical direction from the artificial sandbar area to the beach shoulder area and sediment-deficient section in the onshore compensation channels is determined as the predetermined sediment transport direction of the corresponding sediment supply channels. The direction from the shoreline node position to the sediment-deficient section on both sides of the erosion hotspot in the nodal release channels is determined as the predetermined sediment transport direction of the corresponding sediment supply channels.

[0053] When the direction of natural dynamics is consistent with the predetermined sediment transport direction of the corresponding sediment supply channel, the sediment initiation state reaches the corresponding sediment initiation benchmark, the actual sediment transport direction points to the corresponding sediment-deficient section, and a sediment-receiving response is formed at the current monitoring time, it is determined to be in the open window state; when the direction of natural dynamics is consistent, but the sediment initiation state, sediment transport state, and sediment-receiving response have not all met the conditions for opening the window, it is determined to be in the observation window state; when at least one of the following conditions is met—that the direction of natural dynamics deviates from the predetermined sediment transport direction of the corresponding sediment supply channel, the sediment initiation state does not reach the corresponding sediment initiation benchmark, or the actual sediment transport direction does not point to the corresponding sediment-deficient section—it is determined to be in the closed window state.

[0054] It should be noted that the sediment initiation benchmark is determined based on the hydrodynamic state corresponding to the identifiable location migration of sediment particles of the same size during the historical monitoring period of the target coastal beach. Wave state is characterized by significant wave height and wave period, tidal state by tidal level changes, and coastal current state by coastal current velocity and direction. The critical hydrodynamic state corresponding to the transition from no identifiable location migration to identifiable location migration in historical monitoring data is determined as the sediment initiation benchmark. If only one type of hydrodynamic state reaches the corresponding sediment initiation benchmark during the current monitoring period, it is determined as a single hydrodynamic initiation state; if two or more types of hydrodynamic states reach the corresponding sediment initiation benchmark during the same monitoring period, it is determined as a composite hydrodynamic initiation state. Simultaneously, the actual sediment transport direction is considered to verify whether sediment is transported to the corresponding sediment-deficient section.

[0055] S2.3: Based on the window status corresponding to the coastal sand supply channels, shore compensation channels and node slow release channels, the channel opening status, sand transport direction status and sand receiving response status of each sand supply channel are jointly identified and respectively mapped to the sand source engine area, artificial sand dam area and sandy cape area to determine the candidate sand supply phase of each sand supply source. Specifically, the state transition is performed according to the window status corresponding to the coastal sediment supply channel, the onshore compensation channel, and the nodal slow release channel at the current monitoring time. When the window status of the corresponding sediment supply channel is open, the corresponding sediment supply channel is marked as open, and the actual sediment transport direction and sediment reception response of the corresponding sediment supply channel at the current monitoring time are read. When the coastal sediment supply channel is open, the actual sediment transport direction points to the sediment deficit section, and there is a sediment reception response at the current monitoring time, the candidate sediment supply phase of the sediment source engine area is determined. When the onshore compensation channel is open, the actual sediment transport direction points along the vertical bank profile to the beach shoulder area and the sediment deficit section, and there is a sediment reception response at the current monitoring time, the candidate sediment supply phase of the artificial sandbar area is determined. When the nodal slow release channel is open, the actual sediment transport direction points from the shoreline node position to the sediment deficit sections on both sides of the erosion hotspot, and there is a sediment reception response at the current monitoring time, the candidate sediment supply phase of the sandy headland area is determined.

[0056] S2.4: Continuously verify the candidate sand supply phases, and determine the candidate sand supply phases that maintain the same sand transport direction, the same channel opening state, and the same sand receiving response state within the continuous monitoring period as the valid sand supply phases; Specifically, according to the sediment supply control section and sediment supply source, each monitoring moment after the formation of the candidate sediment supply phase is sequentially included in the continuous monitoring cycle, and the sediment transport direction status, channel opening status, and sediment receiving response status are continuously compared. When the angle change of the actual sediment transport direction relative to the predetermined sediment transport direction of the corresponding sediment supply channel does not exceed the preset direction tolerance, the duration of the channel opening status change does not exceed the preset state fluctuation allowable duration, and the sediment receiving response change does not exceed the preset response fluctuation threshold, the corresponding change is determined as a small normal fluctuation and continues to be included in the continuous state maintenance process. When the sediment transport direction status, channel opening status, and sediment receiving response status are all maintained continuously at the end of the continuous monitoring cycle, the corresponding candidate sediment supply phase is determined as the effective sediment supply phase.

[0057] It should be noted that the continuous monitoring period is determined based on the sampling interval of monitoring data, the duration of natural dynamic stabilization, and the response lag time of the corresponding sand supply channel. The example value range is 3 to 6 consecutive monitoring sampling intervals. The example value range of the preset allowable state fluctuation duration is 1 to 3 monitoring sampling intervals. The example value range of the preset response fluctuation threshold is 5% to 15% relative to the already formed sand-receiving response state. The above parameters are determined based on the historical wave, tide and coastal current stabilization period, short-term oscillation duration, actual response lag time of each sand supply channel, natural fluctuation amplitude of sand-receiving response during the stable monitoring period, and field measurement error.

[0058] S2.5: Perform phase jump verification on candidate sand supply phases that have not maintained the corresponding state continuously. If a phase jump exists, it is determined to be a short-term fluctuation false trigger. If there is no phase jump and a continuous stable state has not yet been formed, it is determined to be a phase to be confirmed.

[0059] Specifically, for candidate sand supply phases that fail to pass the continuous verification of sand transport direction status, channel opening status, and sand receiving response status, the corresponding status of adjacent monitoring times is compared in the order of monitoring time. When a candidate sand supply phase changes from satisfying the candidate status to not satisfying the candidate status, and recovers to the candidate status before the change within a preset recovery time, a phase jump is determined, and the corresponding candidate sand supply phase is judged as a short-term fluctuation false trigger. When the corresponding status does not remain continuous and has not recovered to the candidate status before the change within the preset recovery time, and has not formed a new continuous stable state, it is determined as a phase to be confirmed. When the change of the corresponding status continues for more than the preset recovery time and forms a new stable state, the new stable state is entered into the next continuous monitoring cycle to re-determine the candidate sand supply phase.

[0060] It should be noted that the preset recovery time example ranges from 2 to 5 monitoring sampling intervals. The specific value is determined based on the duration required for short-term wave oscillations, local tidal changes, and short-term deflections of coastal currents in historical monitoring data to recover to their pre-change state, and in combination with the actual lag time from natural dynamic changes to sand-receiving response changes in the corresponding sand supply channel. The lower limit of the preset recovery time is used to eliminate instantaneous changes generated at a single monitoring moment, and the upper limit is used to avoid classifying natural dynamic changes that have formed a continuous effect as short-term disturbances.

[0061] S2.6: The sand supply source corresponding to the effective sand supply phase is determined as the release candidate sand supply source, the sand supply source corresponding to the phase to be confirmed is determined as the observation candidate sand supply source, and the sand supply source that is not determined as the release candidate sand supply source and needs to be maintained as the maintenance candidate sand supply source. Specifically, the effective sand supply phases, unconfirmed phases, and short-term fluctuation false triggers corresponding to the sand source engine area, artificial sandbar area, and sandy headland area are verified separately according to the same sand supply control section. The sand supply source corresponding to the effective sand supply phase is determined as the release candidate sand supply source, the sand supply source corresponding to the unconfirmed phase is determined as the observation candidate sand supply source, and the sand supply source corresponding to the short-term fluctuation false trigger, as well as the remaining sand supply sources that have not formed an effective sand supply phase or an unconfirmed phase, are entered into the retention candidate judgment. The same sand supply source retains only one candidate state in the same monitoring cycle. For sediment sources that are considered for maintenance, the current sediment volume is compared with the lowest sediment volume of similar sediment sources during historical stable monitoring periods when they maintained a stable state. The opening status of the corresponding sediment supply channel and the current state of recovery are verified. If any of the following conditions are met: the current sediment volume is lower than the corresponding minimum sediment volume, the corresponding sediment supply channel is not in the channel opening state, or the current sediment replenishment profile, dam outline, or cape scale has not recovered to the allowable range of the corresponding sediment supply parameters, the corresponding sediment source is identified as a maintenance candidate sediment source and the corresponding maintenance reason is recorded. If none of the above conditions are met, the corresponding sediment source is still identified as a maintenance candidate sediment source, and short-term fluctuations that are falsely triggered or failure to form a stable candidate state are recorded as maintenance reasons. The candidate sediment source is observed to remain in a temporarily suspended release state before it is transformed into a release candidate sediment source, and verification continues in the next continuous monitoring cycle.

[0062] S2.7: Correspond the sand supply channels corresponding to the release candidate sand supply sources with the erosion hotspot locations, sediment deficit ranges and sand receiving responses within the same sand supply control bank section. Verify the state of the release candidate sand supply sources pointing to the same erosion hotspot, the overlapping state of sand supply channels, and the impact of sediment release on maintaining the sand storage and conservation state of the candidate sand supply sources. If any state meets the corresponding release conflict condition, it is determined that a release conflict exists. Specifically, the overlap ratio of the sand supply channels is determined for the two candidate sand supply sources, and the sand volume reduction rate and morphological deviation rate are determined for the candidate sand supply sources in adjacent monitoring periods. The path deviation angle between the actual sediment transport direction and the predetermined sand transport direction of the corresponding sand supply channel is also determined. The channel overlap ratio, sand volume reduction rate, morphological deviation rate and path deviation angle are verified against the corresponding preset conflict judgment thresholds. When any of the indicators reaches the corresponding preset conflict judgment threshold, a release conflict is determined to exist.

[0063] It should be noted that when the sand supply channel is expressed as a linear range, the channel overlap ratio is determined based on the ratio of the overlap length to the shorter channel length of the two sand supply channels; when the sand supply channel is expressed as a planar area, it is determined based on the ratio of the overlap area to the smaller area of ​​the two sand supply areas; the sand reduction rate is determined based on the change between the sand volume of the candidate sand supply source in the previous monitoring period and the sand volume in the current monitoring period; when the sand volume in the current monitoring period is less than the sand volume in the previous monitoring period, the sand reduction rate is determined based on the ratio of the difference between the sand volume in the previous monitoring period and the sand volume in the current monitoring period to the sand volume in the previous monitoring period. When the current sediment volume is not less than the sediment volume of the previous monitoring period, the sediment reduction rate is taken as 0; when the sediment volume of the previous monitoring period is 0, the corresponding ratio is not calculated; when the sediment volume of the current monitoring period is still 0, it is recorded as a state with no sediment to be released; when the sediment volume of the current monitoring period is greater than 0, the sediment reduction rate is taken as 0, and the sediment reserve status of the corresponding sediment supply source is re-verified; the morphological deviation rate is determined by the ratio of the absolute value of the difference between the corresponding morphological parameters and the corresponding sediment supply parameter configuration values ​​in the current sediment replenishment profile, dam outline, and cape scale to the corresponding configuration value; the path deviation angle is determined by the angle between the actual sediment transport direction and the predetermined sediment transport direction of the corresponding sediment supply channel.

[0064] The preset conflict judgment threshold is set based on the allowable degree of spatial overlap of the sand supply channels, the requirement to maintain the stability of the candidate sand supply source, the allowable deviation range of the morphology, and the tolerance of the direction of the sediment transport path. The example values ​​for the channel overlap ratio are 10% to 25%, the example values ​​for the sand reduction rate are 5% to 15%, the example values ​​for the morphological deviation rate are 5% to 15%, and the example values ​​for the path deviation angle are 15° to 30%. The specific values ​​are determined based on historical shoreline erosion and deposition monitoring data, corresponding sand supply parameters, allowable deviations of on-site engineering, and sand storage and conservation targets.

[0065] S2.8: Based on the release of candidate sand supply sources, observation of candidate sand supply sources, maintenance of candidate sand supply sources and corresponding release conflict relationships, a sand supply phase interlock mark is formed.

[0066] Specifically, according to the same sand supply control section, the candidate sand supply sources are matched with the sand supply channels that are allowed to enter the release state. The candidate sand supply sources are kept in a temporarily suspended release state and the candidate sand supply sources are kept in a sand storage and conservation state. For candidate sand supply sources that have release conflicts, they are not directly put into the release state at the same time. The corresponding release conflict relationship is bound to the state of each candidate sand supply source, thereby forming a sand supply phase interlocking mark that can limit the release state of different sand supply sources within the same sand supply control section.

[0067] S3. Based on the interlocking marker of the sand supply phase, the main sand supply source is determined according to the erosion hotspot coverage relationship, sand transport path continuity and sand receiving response correspondence, combined with the sand supply competition relationship, sand protection conflict relationship and path conflict relationship. The non-main sand supply source is determined as the sand storage and protection constraint object, the release of the main sand supply source is controlled and the sand protection of the non-main sand supply source is differentiated, and the coordinated sand supply regulation command is generated.

[0068] S3.1: Based on the interlocking marker of the sediment supply phase, the release candidate sediment supply sources are associated with the opening status of the coastal sediment supply channels, the onshore compensation channels, and the node slow release channels respectively. When two or more release candidate sediment supply sources correspond to the same erosion hot spot, the sediment supply competition relationship is determined. When the release of the release candidate sediment supply source affects the sediment storage and preservation status of other sediment supply sources, the sediment preservation conflict relationship is determined. When the sediment supply channels overlap and the actual sediment transport direction deviates from the predetermined sediment transport direction of the corresponding sediment supply channel, the path conflict relationship is determined. Specifically, according to the same sediment supply control section, the sediment source engine area is mapped to the coastal sediment supply channel, the artificial sandbar area is mapped to the onshore compensation channel, and the sandy headland area is mapped to the node slow release channel. The location of the erosion hotspot, the range of the sediment deficit section, the sediment reception response, and the release conflict relationship are read for each candidate sediment supply source. When two or more candidate sediment supply sources cover the same erosion hotspot, the sediment supply competition relationship is determined. When the release of a candidate sediment supply source causes at least one of the sediment reduction rate and morphological deviation rate of other sediment supply sources to reach the corresponding sediment conservation control boundary, the sediment conservation conflict relationship is determined. When different sediment supply channels spatially overlap and the path deviation angle of the actual sediment transport direction relative to the predetermined sediment transport direction of the corresponding sediment supply channel reaches the preset path deviation threshold, the path conflict relationship is determined.

[0069] It should be noted that the preset path deviation threshold is determined based on the natural swing range of the actual sediment transport direction relative to the predetermined sediment transport direction of the corresponding sediment supply channel under stable sediment supply conditions, the sediment transport direction monitoring error, and the directional angle corresponding to the point where the sediment response begins to decline after the actual sediment transport deviates. The example value range is 15° to 30°. In specific value determination, the range of angle variation between the actual sediment transport direction and the predetermined sediment transport direction of the corresponding sediment supply channel is statistically analyzed based on historical stable sediment supply monitoring data of the target coastal beach. The maximum value of the natural directional swing angle and the angle corresponding to the directional monitoring error during stable sediment supply is used as the basis for determining the lower limit of the preset path deviation threshold. The minimum value of the directional angle corresponding to the point where the sediment transport path begins to deviate from the erosion hotspot and sediment loss section and the sediment response shows a continuous decline is used as the basis for determining the upper limit of the preset path deviation threshold. This ensures that the preset path deviation threshold can accommodate normal directional swing caused by natural forces, while also distinguishing abnormal directional changes that cause deviation of the sediment supply path.

[0070] S3.2: Determine the main sediment supply judgment value of each candidate sediment supply source based on the coverage relationship of erosion hotspots, the continuity of sediment transport paths and the correspondence of sediment receiving responses, and in combination with the hit status of sediment supply competition, sediment protection conflict and path conflict. Specifically, the proportion of each candidate sediment supply source covering erosion hotspots, the proportion of sediment supply channels maintaining continuity, and the proportion of sediment-receiving response covering sediment-deficient sections are determined. The normalized conflict hit value is determined based on the actual number of hits in sediment supply competition, sediment protection conflict, and path conflict, and the main sediment supply determination value is determined accordingly.

[0071] The expression for the main sand supply determination value is: ; In the formula, Indicates the first The primary sand supply determination value for each candidate sand supply source to be released; This indicates the proportion of the corresponding sand supply channel covering the erosion hotspot location; This indicates the proportion of the corresponding sand supply channel that remains continuous; This represents the proportion of the sediment-depleted section covered by the corresponding sand-receiving response. This represents the normalized hit value corresponding to the sand supply competition relationship, sand protection conflict relationship, and path conflict relationship.

[0072] It should be noted that, The release of candidate sediment sources is determined according to the type of sediment supply channel corresponding to them. The coastal sediment supply channel is determined by the ratio of the shoreline length covering the erosion hotspot to the total shoreline length of the erosion hotspot. The shoreline compensation channel is determined by the ratio of the number of vertical shoreline profiles effectively covering the sediment-deficient section to the total number of vertical shoreline profiles in the sediment-deficient section. The node slow release channel is determined by the ratio of the shoreline length of the shoreline section affected by the node on both sides of the effective erosion hotspot to the total shoreline length of the corresponding shoreline node affected section. The ratio of the number of effective monitoring locations that continuously meet the predetermined sand transport direction requirements within the corresponding sand supply channel to the total number of effective monitoring locations in the sand supply channel is used to determine whether a location is a continuous effective monitoring location. If there is no spatial interruption between adjacent effective monitoring locations and the angle between the actual sediment transport direction and the predetermined sand transport direction of the corresponding sand supply channel does not exceed the preset direction tolerance, then the location is determined as a continuous effective monitoring location. If there is no effective monitoring location, the main sand supply judgment value of the corresponding release candidate sand supply source is not calculated, and the corresponding release candidate sand supply source is converted into an observation candidate sand supply source and waits for the next continuous monitoring cycle to re-determine. The number of locations generating effective sediment-receiving responses within the sediment-depleted section is determined by the ratio of the number of locations with valid monitoring data to the number of locations with valid monitoring data; if no location with valid monitoring data exists, it is not included. Set the value to 0, do not calculate the main sand supply determination value of the corresponding candidate sand supply source, and convert the corresponding candidate sand supply source to the observation candidate sand supply source; The value ranges from 0 to 1, and is fixed based on the number of hits in the sand supply competition relationship, sand protection conflict relationship and path conflict relationship. When none of the three types of conflict relationships are hit, the value is 0; when one type is hit, the value is 1 / 3; when two types are hit, the value is 2 / 3; and when all three types are hit, the value is 1.

[0073] S3.3: The candidate sand source with the highest main sand supply judgment value is determined as the main sand supply source, and sand supply sources other than the main sand supply source are determined as the objects of sand storage and conservation constraints.

[0074] Specifically, when there are no candidate sediment supply sources within the same controlled sediment supply section, the determination of the main sediment supply source is temporarily suspended, allowing the existing sediment supply sources to maintain their current sediment storage and conservation status, and the candidate sediment supply phase is re-determined in the next continuous monitoring cycle; when there are candidate sediment supply sources, they are arranged in descending order of the main sediment supply determination value, and the candidate sediment supply source with the highest main sediment supply determination value is determined as the main sediment supply source; when the main sediment supply determination value of all candidate sediment supply sources is 0, the determination of the main sediment supply source is temporarily suspended, and the determination is re-determined in the next continuous monitoring cycle.

[0075] When the highest primary sediment supply determination value corresponds to multiple candidate sediment supply sources, the selection is based on the number of hits in sediment supply competition, sediment conservation conflict, and path conflict, ranked from lowest to highest, with priority given to candidate sediment supply sources with fewer hits. If the number of hits is the same, priority is given to candidate sediment supply sources that do not hit path conflict. If they still cannot be distinguished, they are compared from highest to lowest proportion of the sediment-receiving response covering the sediment-deficient section. If the proportions are still the same, they are compared from longest to shortest continuous holding time of the corresponding candidate sediment supply phase in the previous continuous monitoring cycle. When determining the primary sediment supply source for the first time, the continuous holding time of the previous continuous monitoring cycle is not used as a comparison condition. If the aforementioned conditions still cannot distinguish, the determination of the primary sediment supply source is temporarily suspended and the determination is carried out again in the next continuous monitoring cycle. After the primary sediment supply source is determined, the remaining sediment supply sources within the same sediment supply control section are identified as sediment storage and conservation constraints.

[0076] S3.4: Determine the sand supply channel corresponding to the main sand source as the target release state, and determine the non-main sand supply channel corresponding to the sand storage and conservation constraint object as the target sand storage and conservation state; Specifically, based on the type of sand supply source to which the main sand supply source belongs, the corresponding sand supply channels are determined. The corresponding channels among the coastal sand supply channels, shore-to-shore compensation channels, and node slow-release channels corresponding to the main sand supply source are determined as the target release state. At the same time, the non-main sand supply channels corresponding to the sand storage and conservation constraints are determined as the target sand storage and conservation state, so that only the sand supply channels corresponding to the main sand supply source can be used as subsequent release targets within the same sand supply control section, while the non-main sand supply channels maintain the sand storage and conservation constraints.

[0077] S3.5: When the sand storage and conservation constraint object is the sand source engine area, the sand source engine area is defined as the target restricted natural diffusion state; when the sand storage and conservation constraint object is the artificial sand dam area, the artificial sand dam area is defined as the target basic outline maintenance state; when the sand storage and conservation constraint object is the sandy cape area, the sandy cape area is defined as the target restricted slow release state.

[0078] Specifically, the target sediment conservation state is determined according to the type of sediment source to which the sediment storage and conservation constraint object belongs; for the sediment source engine area, the preset diffusion control thresholds corresponding to the sediment reduction rate and the sediment replenishment profile deviation rate are used as the control boundary of the target restricted natural diffusion state; for the artificial sand dam area, the preset contour maintenance thresholds corresponding to the dam body contour loss rate, the dam site water depth deviation rate, and the offshore distance deviation rate are used as the control boundary of the target basic contour maintenance state; for the sandy cape area, the preset slow release control thresholds corresponding to the cape scale reduction rate, the tidal channel opening deviation rate, and the sediment loss rate are used as the control boundary of the target restricted slow release state, and the corresponding target sediment conservation state and control boundary are used for consistency verification before the coordinated sediment supply regulation command is generated.

[0079] It should be noted that the preset diffusion control threshold is determined based on the sand injection volume configured in the sand source engine area, the allowable deviation range of the sand replenishment profile, and the sand storage and conservation target. The example value range for the sand volume reduction rate is 5% to 15%, and the example value range for the sand replenishment profile deviation rate is 5% to 10%. The preset profile maintenance threshold is determined based on the dam body scale, dam site water depth, distance from the shore, and allowable error of on-site dam body shaping configured in the artificial sand dam area. The example value range for the dam body profile loss rate is 5% to 15%, and the example values ​​for the dam site water depth deviation rate and distance from the shore deviation rate are 5% to 10%. The preset slow release control threshold is determined based on the cape scale, tidal channel scale, and sand storage and conservation target configured in the sandy cape area. The example values ​​for the cape scale reduction rate and sand volume loss rate are 5% to 15%, and the example value range for the tidal channel opening deviation rate is 5% to 10%. The specific values ​​of each threshold are determined based on the corresponding sand supply parameters, the natural variation range during the historical stable monitoring period, the allowable error of on-site construction, and the sand conservation requirements during the non-main sand supply stage.

[0080] S3.6: Perform consistency verification on the target release status of the main sand source, the target sand conservation status of the non-main sand source, and the channel release restriction status corresponding to the sand supply phase interlock mark; Specifically, the target release status of the sand supply channel corresponding to the main sand supply source is verified against the release restriction status of the corresponding sand supply channel in the sand supply phase interlock mark. The target sand conservation status of each sand storage and conservation constraint object is verified against the target restricted natural diffusion status, target basic outline maintenance status, and target restricted slow release status of the corresponding sand supply source type. It is also verified that the control boundary corresponding to each target sand conservation status has been associated with the corresponding sand storage and conservation constraint object and that each non-main sand supply channel has not been identified as a target release status. When the sand supply channel corresponding to the main sand supply source is not subject to release restrictions, the target sand conservation status of each sand storage and conservation constraint object is consistent with the corresponding sand supply source type, the corresponding control boundary is completely associated, and each non-main sand supply channel maintains the target sand storage and conservation status, the consistency verification is determined to be passed. If any verification result is inconsistent, the consistency verification is determined to be failed, and the coordinated sand supply control command is not generated.

[0081] S3.7: When the sand supply channel corresponding to the main sand supply source meets the target release state, the sand storage and conservation constraint object meets the target sand conservation state corresponding to the sand supply source type, and the non-main sand supply channel limited by the sand supply phase interlock mark is not determined to be in the target release state, it is determined that the release of the main sand supply source and the sand conservation of the non-main sand supply source meet the interlock requirements, and a coordinated sand supply control command is generated.

[0082] Specifically, after the consistency verification is passed, the sand supply source type and corresponding sand supply channel of the main sand supply source are read, and the main sand supply source, corresponding sand supply channel, and target release status are associated. The sand supply source type of each sand storage and conservation constraint object is also read, and the sand storage and conservation constraint object is associated with the target sand conservation status in the target restricted natural diffusion state, target basic outline maintenance state, and target restricted slow release state, respectively. The corresponding control boundaries are read according to the target sand conservation status, and the allowable release of the sand supply channel corresponding to the main sand supply source is determined by combining the sand supply phase interlock marker. The constraint relationship between non-primary sand supply channels maintaining the target sand storage and conservation state and non-primary sand supply channels not being allowed to switch to the target release state is established. The primary sand supply source, corresponding sand supply channel, target release state, sand storage and conservation constraint object, corresponding target sand conservation state, control boundary, and sand supply phase interlock mark are associated according to the same sand supply control section, so that the release requirements of the primary sand supply source and the sand conservation requirements of the non-primary sand supply source form a corresponding relationship. The corresponding relationship is written into the coordinated sand supply regulation command, which serves as the execution basis for the release of the primary sand supply source and the interlocking sand conservation of the non-primary sand supply source when the sand supply is driven by natural power.

[0083] S4. Execute natural dynamic-driven sediment supply according to the coordinated sediment supply regulation instructions, and verify the changes in shoreline morphology and sediment transport paths to form a multi-source coordinated dynamic sediment supply record.

[0084] S4.1: In accordance with the coordinated sediment supply regulation instructions, the release of the main sediment source and the interlocking of the non-main sediment source to conserve sediment are carried out, and the changes in the shoreline morphology and sediment transport path after the sediment supply are reviewed to determine the transport status of sediment along the corresponding sediment supply channel of the main sediment source to the erosion hotspot and sediment-deficient section. Specifically, the engineering actions corresponding to the main sand supply source are executed according to the coordinated sand supply regulation instructions: when the main sand supply source is the sand source engine area, sand replenishment is carried out according to the replenishment profile, replenishment particle size and sand injection volume, and the sediment is controlled to enter the natural dynamic sand supply state along the dominant coastal sand transport direction according to the coastal sand supply channel; when the main sand supply source is the artificial sand dam area, the underwater morphology of the artificial sand dam area is adjusted according to the water depth at the dam site, the distance from the shore and the dam body scale, so that the sediment enters the natural dynamic sand supply state along the shore compensation channel; when the main sand supply source is the sandy cape area, the shoreline node morphology and water exchange state of the sandy cape area are adjusted according to the cape direction, cape scale and tidal channel scale, so that the sediment enters the natural dynamic sand supply state along the node slow release channel, while maintaining the interlocking sand conservation of non-main sand supply sources.

[0085] After the sediment supply operation, the shoreline morphology and sediment transport paths were re-measured. Changes in shoreline position, abutment width, foreshore slope, nearshore shallow water sedimentation, and actual sediment transport paths were matched with erosion hotspot locations, sediment-deficient sections, and the predetermined sediment transport directions of the corresponding sediment supply channels. When the angle between the actual sediment transport direction and the predetermined sediment transport direction of the corresponding sediment supply channel did not exceed the preset directional tolerance, the erosion hotspots and sediment-deficient sections formed an effective sediment-receiving response, and the changes in sediment quantity and morphology corresponding to non-primary sediment sources did not exceed the corresponding sediment conservation control limits. When setting thresholds, the verification requirements for natural dynamic sand supply to reach the corresponding sand supply control section are determined. If any condition is not met, the corresponding verification result is determined to be an abnormal verification state, the sand supply channel corresponding to the main sand supply source is suspended from continuing to release sand, and the interlocking sand protection state of the non-main sand supply source is maintained. The actual sediment transport direction, sand receiving response and abnormal sources in the non-main sand supply source sand protection state are recorded. The sand supply phase and main sand supply source are re-determined in the next continuous monitoring cycle. After a new coordinated sand supply control command that meets the interlocking requirements is formed, the release of the corresponding sand supply channel is resumed.

[0086] It should be noted that the effective sand-receiving response adopts the sand-receiving response judgment conditions determined during candidate sand supply phase identification, and the preset direction tolerance adopts the preset direction tolerance corresponding to the sediment transport direction continuity verification; the sand source engine area, artificial sand dam area and sandy cape area respectively adopt the corresponding preset diffusion control threshold, preset contour preservation threshold and preset slow release control threshold to verify the sand preservation status of non-main sand source, so that the judgment criteria before and after sand supply execution remain consistent.

[0087] S4.2: The release process of the main sand source, the interlocking and sand-preserving status of the non-main sand source, the changes in shoreline morphology and the verification results of sediment transport paths are linked according to the same sand supply control section to form a multi-source coordinated dynamic sand supply record.

[0088] Specifically, according to the same sediment supply control section, the identification results of erosion hotspots and sediment-depleted sections, the sediment supply parameters of triggerable sections, sediment source engine areas, artificial sandbar areas and sandy headlands, the monitoring status of each sediment supply channel, candidate sediment supply phases, sediment supply phase interlocking markers, main sediment supply sources, sediment storage and conservation constraints, coordinated sediment supply control instructions, and the verification results of changes in beach morphology and sediment transport paths after sediment supply are matched according to the sediment supply control section, monitoring time, name of sediment supply source and name of sediment supply channel. The correspondence between the release status of the main sediment supply source, the interlocking sediment conservation status of non-main sediment supply sources and the verification results of beach morphology and sediment transport paths is verified and organized into a multi-source coordinated dynamic sediment supply record in chronological order.

[0089] In summary, this invention establishes shoreline mileage and vertical profile benchmarks, and registers marine monitoring data from different sources, such as shoreline morphology, water depth topography, historical shoreline, hydrodynamic conditions, and sediment particle size, according to monitoring time, shoreline location, and vertical profile location, using the same spatiotemporal benchmark. This allows marine environmental conditions from different sources and at different monitoring times to form unified and corresponding digital monitoring data, providing a continuous data foundation for determining erosion hotspots, sediment-depleted sections, and sediment-supply-controlled shorelines. Furthermore, it verifies the persistence and phase jumps of candidate sediment-supply phases to form sediment-supply phases. Interlocking markers reduce false triggering of sediment supply caused by short-term wave, tide, and coastal current changes; the main sediment supply source is determined based on the coverage relationship of erosion hotspots, the continuity of sediment transport paths, and the correspondence between sediment receiving responses, and differentiated sediment conservation measures are implemented for non-main sediment supply sources, so that coastal sediment supply, onshore compensation, and nodal release are coordinated according to natural dynamic conditions, reducing ineffective sediment release and excessive consumption of non-main sediment supply sources; by reviewing the changes in shoreline morphology and sediment transport paths after sediment supply, the continuity and adaptability of coastal beach erosion restoration, continuous sediment replenishment, and shoreline morphology restoration are improved.

[0090] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for sand supply for coastal beach restoration based on digital ocean monitoring, characterized in that, include: Collect data on the shoreline morphology, water depth topography, hydrodynamics and sediment of the target coastal beach, perform spatiotemporal registration according to the monitoring time and shoreline location to form digital monitoring data, identify erosion hotspots and sediment-depleted sections based on the digital monitoring data, divide the shoreline for sediment supply control, locate the sand source engine area, artificial sandbar area and sandy headland area and configure the sediment supply parameters. Continuously monitor changes in waves, tides, coastal currents, and beaches. When sediment is transported to sediment-deficient sections by natural forces, candidate sediment supply phases are identified. The channel opening status, sediment transport direction status, and sediment receiving response status are continuously verified and phase jumps are checked. Short-term fluctuations that trigger false triggers are eliminated. Sediment supply phase interlocking markers are formed in combination with sediment supply source release conflicts. Based on the interlocking markers of the sand supply phase, the main sand supply source is determined according to the erosion hotspot coverage relationship, sand transport path continuity and sand receiving response correspondence, combined with the sand supply competition relationship, sand protection conflict relationship and path conflict relationship. The non-main sand supply source is identified as the sand storage and protection constraint object, the release of the main sand supply source is controlled and the sand protection of the non-main sand supply source is differentiated, and the coordinated sand supply regulation command is generated. The natural dynamics-driven sediment supply is executed in accordance with the coordinated sediment supply regulation instructions, and the changes in shoreline morphology and sediment transport paths are reviewed to form a multi-source coordinated dynamic sediment supply record.

2. The coastal beach restoration and sand supply method based on digital ocean monitoring as described in claim 1, characterized in that, The steps for identifying erosion hotspots and sediment-depleted sections, and delineating sediment-supply-controlled bank sections, are as follows: Establish shoreline mileage benchmarks and vertical bank profile benchmarks for the target coastal beaches. Map the beach morphology, water depth topography, historical shoreline, hydrodynamic conditions and sediment particle size data to the shoreline mileage benchmarks and vertical bank profile benchmarks respectively. Register the data with the same spatiotemporal benchmarks according to the monitoring time, shoreline location and vertical bank profile location to form digital monitoring data. Based on digital monitoring data, the morphological changes corresponding to shoreline retreat, beach shoulder narrowing, foreshore slope steepening, low tide beach reduction and nearshore channel deepening are identified. The shoreline sections with continuous morphological deterioration and located in the downstream direction of the coastal current are identified as erosion hotspots, and the shoreline sections with insufficient sediment content in the profile and insufficient sediment deposition in the nearshore shallow water area are identified as sediment-depleted sections. Based on the dominant coastal sediment transport direction, sediment deficit level, and natural dynamic triggering type of each shoreline, adjacent shorelines with consistent characteristics are merged into sediment supply control shorelines. The upstream sediment supply inlet, downstream sediment receiving outlet, erosion hotspot location, and sediment deficit range are determined. The continuity of natural dynamic triggering type and sediment transport direction is verified. When natural dynamics can transport sediment from the upstream sediment supply inlet to the erosion hotspot location, the corresponding sediment supply control shoreline is determined as a triggerable shoreline.

3. The coastal beach restoration and sand supply method based on digital ocean monitoring as described in claim 2, characterized in that, The steps for locating the sand source engine area, artificial sandbar area, and sandy headland area, and configuring sand supply parameters, are as follows: Based on the upstream sediment supply inlet, downstream sediment receiving outlet, erosion hotspot location, sediment deficit section range and dominant coastal sediment transport direction of the triggerable shoreline section, the offshore activity water depth range is determined in combination with water depth topography, and the shoreline node location is determined in combination with beach morphology, and the sediment source engine area, artificial sandbar area and sandy cape area are screened respectively. Based on the sand source engine area, artificial sand dam area and sandy cape area, respectively establish coastal sand supply channels, onshore compensation channels and nodal slow release channels, so that the coastal sand supply channels correspond to the long-term coastal sand supply function, the onshore compensation channels correspond to the underwater energy dissipation and onshore compensation function, and the nodal slow release channels correspond to the shoreline nodal slow release function. The sand source engine area is configured with sand replenishment profile, sand replenishment particle size and sand injection volume; the artificial sand dam area is configured with dam site water depth, distance from shore and dam body scale; and the sandy cape area is configured with cape direction, cape scale and tidal channel scale. Each sand supply parameter is matched with the corresponding sand supply channel and sand supply function.

4. The coastal beach restoration and sand supply method based on digital ocean monitoring as described in claim 3, characterized in that, The steps for continuously monitoring wave, tide, coastal current, and shoreline changes are as follows: The sand source engine area, artificial sandbar area and sandy headland area are respectively mapped to the coastal sand supply channel, the onshore compensation channel and the nodal slow release channel, and wave, tide, coastal current and beach morphology monitoring data are collected according to the scope of each sand supply channel. The monitoring data is matched with the predetermined sediment transport direction and sediment deficit section of the corresponding sediment supply channel. When the natural dynamic direction is consistent with the predetermined sediment transport direction of the corresponding sediment supply channel and the change in the bank morphology points to the sediment deficit section and forms a sediment receiving response, it is determined to be in the open window state. When the natural dynamic direction is consistent but the sediment receiving response does not appear continuously, it is determined to be in the observation window state. When at least one of the following conditions is met: the natural dynamic direction deviates from the predetermined sediment transport direction of the corresponding sediment supply channel or the change in the bank morphology does not point to the sediment deficit section, it is determined to be in the closed window state.

5. The coastal beach restoration and sand supply method based on digital ocean monitoring as described in claim 4, characterized in that, The steps for identifying candidate sediment supply phases when sediment is transported to sediment-depleted sections driven by natural dynamics are as follows: Based on the window status corresponding to the coastal sand supply channels, the onshore compensation channels, and the node slow release channels, the channel opening status, sand transport direction status, and sand receiving response status of each sand supply channel are jointly identified and respectively mapped to the sand source engine area, artificial sand dam area, and sandy cape area to determine the candidate sand supply phase of each sand supply source. The candidate sediment supply phases are continuously verified, and the candidate sediment supply phases that maintain the same sediment transport direction, the same channel opening state, and the same sediment receiving response state within the continuous monitoring period are determined as valid sediment supply phases. For candidate sand supply phases that do not maintain the corresponding state continuously, phase jump verification is performed. If a phase jump exists, it is determined to be a short-term fluctuation false trigger. If there is no phase jump and a continuous stable state has not yet been formed, it is determined to be a phase to be confirmed.

6. The coastal beach restoration and sand supply method based on digital ocean monitoring as described in claim 1 or 5, characterized in that, The steps for forming the sand supply phase interlock mark are as follows: The sand supply sources corresponding to the effective sand supply phases are identified as release candidate sand supply sources, the sand supply sources corresponding to the phases to be confirmed are identified as observation candidate sand supply sources, and the sand supply sources that are not identified as release candidate sand supply sources but need to be maintained as sand storage and conservation candidate sand supply sources are identified as maintenance candidate sand supply sources. The corresponding sand supply channels for releasing candidate sand supply sources are matched with the locations of erosion hotspots, the range of sediment-depleted sections, and the sand-receiving response within the same sand supply control section. The states of releasing candidate sand supply sources pointing to the same erosion hotspots, the overlapping states of sand supply channels, and the impact of sediment release on maintaining the sand storage and conservation state of candidate sand supply sources are verified respectively. If any state meets the corresponding release conflict condition, a release conflict is determined to exist. Based on the release of candidate sand supply sources, observation of candidate sand supply sources, maintenance of candidate sand supply sources and corresponding release conflict relationships, a sand supply phase interlocking mark is formed.

7. The coastal beach restoration and sand supply method based on digital ocean monitoring as described in claim 6, characterized in that, The steps for determining the main sand source and the constraints for sand storage and conservation are as follows: Based on the interlocking markers of the sediment supply phase, the release candidate sediment supply sources are associated with the opening status of the coastal sediment supply channels, the onshore compensation channels, and the node slow release channels, respectively. When two or more release candidate sediment supply sources correspond to the same erosion hot spot, a sediment supply competition relationship is determined. When the release of the release candidate sediment supply source affects the sediment storage and preservation status of other sediment supply sources, a sediment preservation conflict relationship is determined. When the sediment supply channels overlap and the actual sediment transport direction deviates from the predetermined sediment transport direction of the corresponding sediment supply channel, a path conflict relationship is determined. Based on the coverage relationship of erosion hotspots, the continuity of sediment transport paths and the correspondence of sediment-receiving responses, and combined with the hit status of sediment supply competition, sediment protection conflict and path conflict, the main sediment supply judgment value of each candidate sediment supply source is determined. The candidate sand source with the highest main sand supply value is determined as the main sand supply source, and sand supply sources other than the main sand supply source are determined as the objects of sand storage and conservation constraints.

8. The coastal beach restoration and sand supply method based on digital ocean monitoring as described in claim 7, characterized in that, The steps for controlling the release of sand from the primary sand source and implementing differentiated sand conservation measures for non-primary sand sources are as follows: The sand supply channels corresponding to the main sand supply source are defined as the target release state, and the non-main sand supply channels corresponding to the sand storage and conservation constraints are defined as the target sand storage and conservation state. When the object of sand storage and conservation is the sand source engine area, the sand source engine area is defined as the target-restricted natural diffusion state. When the object of sand storage and conservation is the artificial sand dam area, the artificial sand dam area is defined as the target basic outline preservation state. When the object of sand storage and conservation is the sandy cape area, the sandy cape area is defined as the target restricted slow release state.

9. The coastal beach restoration and sand supply method based on digital ocean monitoring as described in claim 8, characterized in that, The steps for generating the coordinated sand supply regulation command are as follows: Consistency verification is performed on the target release status of the main sand source, the target sand conservation status of the non-main sand source, and the channel release restriction status corresponding to the sand supply phase interlock mark. When the sand supply channel corresponding to the main sand source meets the target release state, the sand storage and conservation constraint object meets the target sand conservation state corresponding to the sand supply source type, and the non-main sand supply channel limited by the sand supply phase interlock mark is not determined to be in the target release state, it is determined that the release of the main sand source and the sand conservation of the non-main sand source meet the interlock requirements, and a coordinated sand supply control command is generated.

10. The coastal beach restoration and sand supply method based on digital ocean monitoring as described in claim 9, characterized in that, The steps for forming a multi-source coordinated dynamic sand supply record are as follows: In accordance with the instructions for coordinated sand supply regulation, the release of the main sand source and the interlocking of the non-main sand source to conserve sand are carried out. The changes in the morphology of the beach and the sediment transport path after the sand supply are reviewed to determine the transport status of sediment along the sand supply channel corresponding to the main sand source to the erosion hotspots and sediment-deficient sections. The release process of the main sand source, the interlocking and sand-preserving status of the non-main sand source, the changes in shoreline morphology, and the verification results of sediment transport paths are correlated according to the same sand supply control section to form a multi-source coordinated dynamic sand supply record.

Images