Method for quickly delineating target area of mountainous bedrock fissure water exploration

Abstract

The application discloses a method for quickly delineating a target area of mountainous bedrock fissure water exploration, and aims to solve the technical problems of low exploration efficiency, high cost, long period and unstable success rate caused by complex mountainous terrain and uneven distribution of bedrock fissure water in traditional exploration methods. The application combines quantitative analysis of surface gully with structural hydrogeological theory, directly and quantitatively determines the dominant migration direction of groundwater by preparing a regional gully distribution rose diagram, and accurately delineates the bedrock fissure water enrichment target area based on the structural gully model. The method effectively reduces more than two-thirds of the field physical workload, shortens the exploration period by more than 80%, and reduces the engineering cost by about 80%. At the same time, the target area delineated based on clear geological evidence significantly improves the success rate of drilling water, greatly reduces the safety risk of field operation in complex mountainous environment, and realizes the exploration goal of high efficiency, economy and safety.

Description

Technical Field

[0001] This invention relates to the field of geological exploration technology, specifically to a method for rapidly delineating target areas for bedrock fissure water exploration in mountainous areas. Background Technology

[0002] Bedrock fissure water, found in rock fissures, joints, and fracture zones, is an important water source for the lives and production of residents in mountainous areas. Its enrichment and migration are controlled by the development direction and combination characteristics of regional faults, joints, and other water-conducting structures, and its spatial distribution exhibits significant heterogeneity and anisotropy, leading to technical bottlenecks in traditional exploration methods, such as difficulty in target area location and low verification success rate.

[0003] Currently, traditional methods for exploring bedrock fissure water in mountainous areas generally employ a progressive workflow: data collection → large-scale hydrogeological mapping → regional geophysical survey → drilling verification. This method relies on intensive fieldwork, aiming to gradually narrow the target area through isometric coverage. However, in mountainous environments with dramatic topographic relief, widespread bedrock exposure, and limited access, this model suffers from the following prominent problems: (1) Low efficiency and high cost of field operations: Large-scale ground mapping requires traversing complex terrain, which requires a large investment of manpower and is difficult to ensure safety; geophysical exploration is constrained by terrain, making electrode placement and survey line layout difficult, resulting in low data acquisition efficiency and high equipment transportation costs.

[0004] (2) Strong ambiguity in structural interpretation and insufficient reliability of target area: The occurrence of bedrock fissure water is highly localized. Conventional geophysical methods (such as electrical and seismic methods) have limited ability to distinguish deep micro-fracture structures. The inversion results are easily affected by surface lithology and topographic relief, resulting in strong ambiguity in the identification of water-conducting structures. Based on this, the boreholes often fail to reveal effective aquifers, resulting in "blind drilling" and waste of exploration funds.

[0005] Ultimately, existing technologies lack an effective means to quickly identify and scientifically focus on potential water-rich target areas in the early stages of exploration, leading to a significant amount of subsequent physical work being done blindly and inefficiently. Therefore, there is an urgent need in this field for a new method that can directly, quickly, and accurately delineate water-finding target areas to guide subsequent exploration projects, fundamentally reduce inefficient investment, and achieve safe, economical, and efficient water-finding goals.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the background technology of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a rapid delineation method for bedrock fissure water exploration target areas in mountainous areas based on regional valley distribution rose diagrams. This method solves the technical problems of low exploration efficiency, large workload, high cost, long cycle, and unstable success rate caused by the complex terrain and uneven distribution of bedrock fissure water in mountainous areas in traditional exploration methods.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for rapidly delineating target areas for bedrock fissure water exploration in mountainous areas, comprising the following steps: Obtain geological data and digital elevation model data for the survey area; Based on a preset effective valley discrimination threshold, spatial distribution information of valleys is extracted from the digital elevation model data. The spatial distribution information includes azimuth and planar extension length. The extracted gullies were reconnoitered in the field to verify their spatial attributes and to analyze their genetic correlation with regional faults and joint structures, thus determining the development direction of dominant gullies. Based on the verified azimuth and length data of the valleys, a regional valley distribution rose diagram is compiled. The rose diagram is a polar coordinate statistical diagram, and its radial length represents the cumulative value of the valley length within the corresponding azimuth interval. By identifying the azimuth intervals in the rose diagram with the largest cumulative length value or a proportion exceeding a set ratio, the dominant tectonic direction controlling the migration of bedrock fracture water is determined. Based on the aforementioned advantageous structural orientation, regional hydrogeological conditions, spatial distribution of existing hydrogeological points, spatial combination characteristics of valleys, and scale of water demand, one or more target areas for bedrock fissure water exploration are delineated. The delineation of the target areas is conditionally based on the requirement that they coincide with the spatial distribution of known water-conducting structures.

[0009] In some embodiments of this disclosure, the effective gully discrimination threshold includes: the gully plane extension length is not less than 200 meters and the cutting depth is not less than 30 meters.

[0010] In some embodiments of this disclosure, gullies with a horizontal extension length greater than 500 meters and a cutting depth greater than 100 meters are designated as high-priority exploration targets.

[0011] In some embodiments of this disclosure, when compiling the regional valley distribution rose diagram, the azimuth angle is divided into multiple tolerance intervals, each tolerance interval spanning 5° to 15°.

[0012] In some embodiments of this disclosure, the criteria for determining the dominant construction direction are any one of the following: (1) The direction corresponding to the single directional interval with the largest cumulative valley length in the rose diagram; (2) The dominant directional zone is formed by the sum of the cumulative lengths of valleys in multiple consecutive directional intervals accounting for no less than 50% of the total length of the entire map.

[0013] In some embodiments of this disclosure, the principles followed when delineating the target area for bedrock fracture water exploration include: (1) The main body of the target area extends along the direction of the dominant structure; (2) The dominant gullies are densely developed within the target area, or there is an intersection of two or more gullies in different directions; (3) The spatial range of the target area coincides with or is adjacent to the distribution of known densely connected water-conducting fractures or joints; (4) The target area covers or is adjacent to existing springs, borehole water outlets or historical water supply points; (5) The area of ​​the target zone is positively correlated with the planned water usage.

[0014] In some embodiments of this disclosure, after delineating the exploration target area, a target area priority ranking step is also included: based on at least two of the following indicators, such as valley size, tectonic control intensity, distance from existing hydrological points, and topographic water catchment conditions, multiple target areas are comprehensively scored and ranked to guide the subsequent drilling verification sequence.

[0015] In some embodiments of this disclosure, the extraction of valley spatial distribution information from digital elevation model data employs an automatic valley identification algorithm based on a combination of topographic humidity index and slope, or a deep learning semantic segmentation model to extract valleys at the pixel level.

[0016] This invention, through a technical approach of "automatic valley extraction—structural direction determination—multi-element fusion delineation," achieves the reconstruction of exploration logic and optimization of the workflow. Compared with existing technologies, this invention has at least one of the following technical effects or advantages: 1. This technology enables rapid and objective identification of structural water-controlling directions in the early stages of exploration, providing prior geological constraints for target area delineation: Based on a digital elevation model, and according to preset effective valley discrimination thresholds (e.g., length ≥200m, cutting depth ≥30m), the azimuth and length data of valleys can be automatically extracted. Through field reconnaissance, the genetic correlation with faults and joints is verified, and a valley distribution rose diagram is then compiled to quantitatively identify the azimuth intervals with the largest cumulative valley length or the dominant proportion. This allows for the scientific determination of the dominant structural direction controlling fracture water transport. This technique transforms traditional directional judgments based on subjective experience into objective analysis based on statistical diagrams, effectively solving the technical challenge of lacking prior information on structural directions in the early stages of exploration and providing reliable geological guidance for subsequent target area delineation.

[0017] 2. Constructing a target area delineation mechanism of "directional constraints + multi-factor coupling" significantly improves the scientific nature of target area positioning and drilling success rate. This invention, when delineating the target area, takes "the spatial distribution of the target area matching known water-conducting structures" as a necessary condition. It integrates and analyzes multi-source information such as the dominant structural direction, valley spatial combination (e.g., dense development or directional convergence), distribution of existing hydrogeological points, and water demand. This mechanism avoids the problem of target area deviation from water-conducting structures caused by relying solely on a single geophysical anomaly or empirical inference in traditional methods. It shifts drilling deployment from "experience-driven" to "structural evidence-driven," fundamentally reducing the risk of "blind drilling" and increasing the probability of revealing water-bearing structures.

[0018] 3. Optimize exploration workflow, significantly reduce inefficient fieldwork, and improve overall efficiency and economy: This invention reconstructs the traditional linear workflow of "fieldwork first, analysis later" into a parallel model of "desktop quantitative analysis to identify dominant directions first, followed by targeted field verification." Through automatic valley extraction and rose diagram analysis, preliminary determination of structural directions can be completed indoors, allowing subsequent fieldwork such as hydrogeological mapping and geophysical scanning to focus on a limited area controlled by the dominant direction, avoiding large-scale ineffective coverage. This workflow optimization reduces the amount of physical fieldwork by approximately two-thirds from the outset, significantly shortening the exploration cycle and reducing engineering costs.

[0019] 4. Reduce safety risks in field operations in complex mountainous environments: As a large amount of orientation identification and preliminary delineation work is moved indoors, field operations focus on reconnaissance and verification of key valleys and target areas. The scope and duration of operations are greatly reduced, effectively avoiding the safety hazards of technicians working for long periods in steep and broken terrain, and achieving a synergistic improvement in exploration efficiency and operational safety.

[0020] 5. Supports dynamic prioritization of target areas, enhancing the engineering practicality and adaptability of the method: This invention further introduces a multi-index comprehensive scoring mechanism based on valley size, structural control intensity, distance from existing hydrological points, and topographic drainage conditions to prioritize multiple candidate target areas, providing a quantitative basis for drilling verification sequence. This extended function enables the method not only to be applicable to target area identification but also to support the optimized allocation of exploration resources, adapting to the needs of water exploration projects of different scales and urgency. Attached Figure Description

[0021] Figure 1 This is a plan view of the valley distribution in the survey area according to one embodiment of this application.

[0022] Figure 2 This is a rose diagram of the valley distribution in the survey area in one embodiment of this application.

[0023] Figure 3 This is a location map of the water target area in the survey area according to one embodiment of this application. Detailed Implementation

[0024] The following examples illustrate specific implementations of the present invention. However, these examples are merely for illustrative purposes and do not limit the scope of the invention in any way. Example

[0025] This embodiment describes a rapid delineation method for target areas in bedrock fissure water exploration in mountainous areas. The specific implementation steps of the method are detailed below: S1: Data Collection and Systematic Extraction of Valley Information 1. Collect basic data: The system acquires and organizes multi-source basic data for the survey area, mainly including: Map data: regional geological map, structural outline map, topographic map; Remote sensing and digital elevation data: high-resolution satellite imagery and digital elevation models (DEM); Literature reports: Previous geological and hydrogeological survey and research reports.

[0026] 2. Geological background analysis and prediction of water-conducting structures: Based on the collected basic data, a comprehensive analysis was conducted to form a preliminary geological understanding: Stratigraphic analysis: Clarify the lithological assemblage and spatial distribution of the main strata in the survey area.

[0027] Predictive analysis of water-conducting structures: Focus on analyzing the properties of faults and other structures in the area to predict their water-conducting or water-blocking functions.

[0028] 3. Digital extraction and screening of gullies: Using geographic information technology, we can objectively and quantitatively extract and focus information on surface valleys. Valley extraction based on DEM: On the elevation image DEM map, use professional software (such as GIS) to initially identify and draw the vector lines of the valley network in the whole area.

[0029] Setting effective gully quantification thresholds: To eliminate minor geomorphic disturbances and focus on large gullies that are significant for indicating geological structures and groundwater, the following physical size thresholds are set for screening: Length thresholds: minimum effective valley length is 200 meters; the length of the most favorable valley (indicating an important water-conducting structure) is greater than 500 meters; Depth threshold: The minimum cutting depth of an effective trench is 30 meters; the cutting depth of the most favorable trench is greater than 100 meters.

[0030] Valley element measurement: For the selected effective valleys, the azimuth and planar extension length of each valley are measured one by one using the measurement tools of the drawing system, forming a structured valley attribute database for subsequent analysis.

[0031] S2: On-site inspection and verification of elements 1. Field reconnaissance: Organize professional and technical personnel to conduct on-site inspections, mainly performing the following verification tasks: Verify the spatial attributes of the gullies: verify the direction, length and distribution of the gullies extracted in the survey area, and correct errors caused by image resolution or vegetation occlusion.

[0032] Investigate the relationship between valleys and geological structures: Focus on investigating the relationship between valley development and geological structures such as faults and joints, and confirm whether the valleys develop strictly along the weak zones of tectonics, so as to clarify their attribute as "tectonic valleys".

[0033] Verify the surface features of the fault: By observing the changes in the steepness of the terrain on both sides of the valley, the linear characteristics of the landform, and the degree of rock fragmentation, we can help verify the nature of the underlying fault (water-conducting or water-blocking).

[0034] Confirming directional consistency: Finally, verify whether the development direction of the dominant gullies is spatially highly consistent with the dominant orientation of the regional geological structure (faults, joints).

[0035] 2. Verification of key elements: During the site survey, key information from the interpretation was simultaneously verified on-site. Verification of effectiveness: Based on the set effective gully threshold (length ≥ 200 meters, cutting depth ≥ 30 meters), the scale of the main gullies is assessed on site, and the most favorable indicative gullies (such as gullies with length > 500 meters and significant cutting depth) are identified.

[0036] Record hydrological evidence: Systematically observe and record hydrogeological phenomena such as springs and wetlands exposed in and along the valley, and verify their indicative role in groundwater runoff or discharge.

[0037] S3: Compile a "Regional Valley Distribution Rose Map" and determine the dominant direction. 1. Compile a rose diagram of the regional valley distribution: After synthesizing and organizing the final data of all valid gullies obtained in steps S1 and S2, the following mapping process is executed: Establish a drawing coordinate system: Based on geological data and surface reconnaissance results, a unified plane rectangular coordinate system is established for the study area using professional drawing software such as CAD and GIS.

[0038] Drawing Valley Elements: Represent each effective valley as a directed line segment in a coordinate system. The specific rules are as follows: Starting from the origin of the coordinate system (or a unified reference point), the direction of the line segment strictly corresponds to the azimuth angle of the valley's direction, and the length of the line segment accurately represents the actual length of the valley according to a predetermined scale. After all valley line segments are drawn, line segments with the same or similar directions (within a certain azimuth tolerance range, such as ±10°) are superimposed in the same direction, i.e., their length values ​​are accumulated.

[0039] Generate the rose diagram: Finally, by connecting the endpoints of the cumulative length of the line segments in each direction, a closed polar coordinate system graph is formed, namely the regional valley distribution rose diagram.

[0040] 2. Determining the dominant direction of groundwater based on rose diagrams: Based on the geological principle that "tectonic valleys are the main channels for groundwater transport," the generated rose diagram is interpreted hydrogeologically: Determining the dominant migration direction: The direction that is most developed on the rose diagram (i.e., the direction with the most line segments and the longest superposition length) directly indicates the dominant tectonic direction controlling groundwater, that is, the dominant runoff direction of bedrock fissure groundwater.

[0041] Identify favorable runoff locations: In the rose diagram, the densely intersecting areas of valley lines in different directions correspond to the intersection points of underground water-conducting structures in different directions. These locations are favorable areas for groundwater collection and runoff.

[0042] S4: Comprehensive Analysis and Preliminary Delineation of Water Target Area Based on the determination of the dominant direction of the valley, and taking into account the following factors, the target area for water exploration is initially delineated on the map: Hydrogeological conditions: Taking into account the basic pattern of regional groundwater recharge, runoff, and discharge.

[0043] Existing hydrogeological points: Known springs, wells, etc. in the survey area are used as direct evidence of groundwater activity, and their location and elevation provide constraints for determining runoff paths and water level depth.

[0044] Spatial characteristics of gullies: Focus on areas with densely developed gullies in the dominant direction, as well as the intersection of gullies in different directions (especially the dominant and secondary directions). These areas often become confluence and enrichment zones for groundwater due to the interweaving of tectonic fissures.

[0045] Surface water distribution: Analyze the distribution of surface water bodies such as rivers and streams and their potential recharge and discharge relationship with groundwater.

[0046] Structural fit: Ensure that the initially delineated target area closely matches the orientation and distribution of identified water-conducting structures such as faults, joints, and fracture zones, thus guaranteeing the reliability of the geological foundation of the target area.

[0047] Demand Scale Matching: The target area search range should be reasonably determined based on the project's planned water consumption. The greater the water demand, the larger the target area can be, and multiple target areas can also be defined.

[0048] S5: Precise Validation and Parameter Acquisition within the Target Area Within the delineated target area, a focused and detailed exploration was conducted to pinpoint the exact location. Through a series of methods, including detailed hydrogeological mapping, high-resolution geophysical exploration, control geological drilling, and standardized pumping tests, the water-bearing capacity of the target area was directly verified. Key hydrogeological parameters such as aquifer depth, permeability coefficient, and single-well yield were precisely obtained, providing a reliable basis for water resource assessment and development engineering design.

[0049] Implementation 1: Water Exploration Project in Bedrock Area, Wulongkou Town, Jiyuan City, Henan Province To illustrate the implementation methods and technical effects of the present invention, a bedrock fissure water exploration project in the mountainous area of ​​Wulongkou Town, Jiyuan City, Henan Province, is used as an example for detailed explanation.

[0050] (I) Overview of the Project Area Wulongkou Town, Jiyuan City, Henan Province, is located on the southern slope of the Taihang Mountains. It is a typical bedrock mountain area with a significant difference in elevation (the highest point in the north is 1060m above sea level, and the lowest point in the southeast is 132.6m above sea level). The terrain is complex, with numerous gullies. Groundwater from bedrock fissures is the main water source for the area, but the water table is deep, making exploration difficult.

[0051] (II) Implementation process and results of this case 1. Data Analysis and Geological Prediction: Analysis was conducted based on collected regional geological data. The main exposed strata in the project area were identified as Paleogene (conglomerate, sandstone, mudstone, and sandstone), Triassic (sandstone, mudstone, shale, and marl), and Jurassic (sandstone, limestone, mudstone, and sandstone). Preliminary analysis suggests that the water-conducting fault structures in the area mainly extend in a northeast-southwest (NE-SW) direction, and the linear valleys developed along this direction are mostly tectonic valleys (i.e., formed by water erosion of weak tectonic zones such as faults, joints, and fracture zones).

[0052] 2. Core Steps Implementation and Judgment: Extracting data based on DEM data that meets the thresholds (length ≥ 500m, cutting depth ≥ 100m, see [link]). Figure 1 Effective gully information was collected, and its spatial attributes and correlation with the geological structure were verified through on-site reconnaissance. Using all verified gully data, a regional gully distribution rose diagram was compiled (see [reference]). Figure 2The statistical results of this map show that the northeast-southwest (NE-SW) oriented gully segments are absolutely dominant in both number and total length (more than 2 / 3 of the total). Based on the principle that "tectonic gullies control groundwater migration," the dominant migration direction of bedrock fissure water in the survey area was directly determined to be northeast-southwest, providing a clear basis for subsequent target area delineation.

[0053] 3. Target Area Delineation Results: Based on the aforementioned dominant migration direction as the core constraint, and considering the spatial combination characteristics of the gullies (selecting areas with dense NE-SW gullies and confluences of gullies in different directions), existing hydrogeological points (including key springs discovered during field reconnaissance), and the planned water use scale (500 m³ / d), a water-finding target area of ​​approximately 3.8 km² was successfully delineated within the survey area (see...). Figure 3 ).

[0054] (III) Comparison with traditional methods To objectively evaluate the effectiveness of this invention, a 10km radius was taken from Wulongkou Town. 2 Taking regional groundwater exploration as an example for comparison: Traditional exploration methods require a series of steps, including large-scale hydrogeological mapping (approximately 15 people working for 30 days), large-scale engineering geophysical exploration (approximately 10 people operating 2 instruments working for 30 days), and drilling and testing at least 3 boreholes (total footage approximately 1500 meters). The preliminary estimate is that the total project cost is 3 million yuan, with a total implementation period of 180 days.

[0055] Using the method of this invention, after rapidly analyzing and accurately delineating a target area of ​​3.8 km² through steps S1 to S4, only one detection and extraction borehole was drilled within this target area for verification and parameter acquisition (S5), thus successfully achieving the goal of water discovery. The actual total project cost was 600,000 yuan, and the total implementation period was 30 days.

[0056] As can be seen from the comparison, the method of this invention can save about four-fifths of the engineering cost and shorten the construction period by more than half. This is mainly due to its use of tools such as the "regional valley distribution rose map" in the early stages of exploration to achieve rapid and accurate target area focusing, thereby avoiding more than two-thirds of the inefficient and costly fieldwork required by traditional methods. At the same time, the significant reduction in the scope and time of field operations also significantly reduces the safety risks for personnel working in complex and dangerous mountainous areas.

[0057] Although some preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0058] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of its inventive concept. Therefore, if these modifications and variations of the invention fall within the scope of the claims of this application and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A method for rapidly delineating target areas for bedrock fissure water exploration in mountainous areas, characterized in that, Includes the following steps: Obtain geological data and digital elevation model data for the survey area; Based on a preset effective valley discrimination threshold, spatial distribution information of valleys is extracted from the digital elevation model data. The spatial distribution information includes azimuth and planar extension length. The extracted gullies were reconnoitered in the field to verify their spatial attributes and to analyze their genetic correlation with regional faults and joint structures, thus determining the development direction of dominant gullies. Based on the verified azimuth and length data of the valleys, a regional valley distribution rose diagram is compiled. The rose diagram is a polar coordinate statistical diagram, and its radial length represents the cumulative value of the valley length within the corresponding azimuth interval. By identifying the azimuth intervals in the rose diagram with the largest cumulative length value or a proportion exceeding a set ratio, the dominant tectonic direction controlling the migration of bedrock fracture water is determined. Based on the aforementioned advantageous structural orientation, regional hydrogeological conditions, spatial distribution of existing hydrogeological points, spatial combination characteristics of valleys, and scale of water demand, one or more target areas for bedrock fissure water exploration are delineated. The delineation of the target areas is conditionally based on the requirement that they coincide with the spatial distribution of known water-conducting structures.

2. The rapid delineation method according to claim 1, characterized in that, The effective gully discrimination thresholds include: the gully's horizontal extension length is not less than 200 meters, and its cutting depth is not less than 30 meters.

3. The rapid delineation method according to claim 2, characterized in that, Valleys with a horizontal extension length greater than 500 meters and a cutting depth greater than 100 meters are designated as high-priority exploration targets.

4. The rapid delineation method according to claim 1 or 3, characterized in that, When compiling the valley distribution rose diagram of the region, the azimuth angle is divided into multiple tolerance intervals, with each tolerance interval spanning 5° to 15°.

5. The rapid delineation method according to claim 1, characterized in that, The criterion for determining the dominant structural direction is any one of the following: (1) The direction corresponding to the single directional interval with the largest cumulative valley length in the rose diagram; (2) The dominant directional zone is formed by the sum of the cumulative lengths of valleys in multiple consecutive directional intervals accounting for no less than 50% of the total length of the entire map.

6. The rapid delineation method according to claim 1, characterized in that, The principles followed when delineating the target area for bedrock fracture water exploration include: (1) The main body of the target area extends along the direction of the dominant structure; (2) The dominant gullies are densely developed within the target area, or there is an intersection of two or more gullies in different directions; (3) The spatial range of the target area coincides with or is adjacent to the distribution of known densely connected water-conducting fractures or joints; (4) The target area covers or is adjacent to existing springs, borehole water outlets or historical water supply points; (5) The area of ​​the target zone is positively correlated with the planned water usage.

7. The rapid delineation method according to claim 1, characterized in that, After delineating the target areas, the process also includes a target area priority ranking step: based on at least two of the following indicators, such as valley size, tectonic control intensity, distance from existing hydrological points, and topographic water catchment conditions, multiple target areas are comprehensively scored and ranked to guide the subsequent drilling verification sequence.

8. The rapid delineation method according to claim 1, characterized in that, The extraction of valley spatial distribution information from digital elevation model data employs an automatic valley identification algorithm based on a combination of topographic humidity index and slope, or a deep learning semantic segmentation model for pixel-level extraction of valleys.

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