A Basin-Scale Framework for Identifying Hydro-Cultural Heritage Corridor Patterns and Guiding Graded Protection: Evidence from the Xiangjiang River Basin, China

Abstract

Hydro-cultural heritage is shaped by strong hydrological dependence and historical accessibility. To address insufficient identification of river-basin heritage linkages and their weak translation into graded protection, this study develops an analytical framework integrating heritage-site evaluation, cultural source identification, resistance-surface construction, potential corridor extraction, network grading, and protection guidance, and applies it to the Xiangjiang River Basin, China. Heritage sites were evaluated by protection level, historical continuity, spatial proximity, and hydro-cultural relevance. Cultural source areas were identified using weighted kernel density analysis, potential corridors were extracted using the minimum cumulative resistance model, and the graded corridor network was examined using network-structure indices. The results show river-oriented clustering, localized nucleation, and belt-like extension. Eight primary and fourteen supplementary cultural source areas were identified. Potential corridors are concentrated along the Xiangjiang main stem and major tributaries. In the resistance-surface construction, distance to the water system received the highest AHP-derived resistance weight, while GeoDetector showed that it had the highest, although modest, single-factor explanatory power among the tested variables for corridor spatial differentiation. The corridor network exhibits a primary–secondary–tertiary graded structure. This study reveals the spatial continuity and hierarchy of hydro-cultural heritage corridors and provides a methodological reference for river-basin conservation.

1. Introduction

Hydro-cultural heritage refers to a composite assemblage of cultural remains formed through long-term practices of water management, water use, and waterfront habitation [1,2,3,4,5]. It embodies both material carriers and the cultural memory associated with them. Unlike conventional point-based heritage, its formation, evolution, and dissemination are strongly shaped by natural water systems and the human–environment relational networks associated with them [3,4,6]. As a result, it often exhibits linear, belt-like, or node-clustered spatial characteristics [7,8]. Figure 1 schematically illustrates the conceptual structure of a hydro-cultural heritage corridor proposed in this study. Hydro-cultural heritage should not be understood as a simple assemblage of isolated sites, but as an integrated corridor-based system composed of heritage nodes, corridor linkages, and associated waterfront environments [9,10]. Accordingly, conservation strategies should shift from the protection of individual sites to an integrated corridor-based approach [11,12].

As heritage conservation paradigms have shifted from the rescue of individual monuments toward holistic conservation, cultural landscape protection, and linear-heritage conservation, identifying the actual spatial linkages among heritage sites at broader scales has become a central issue. The Xiangjiang River Basin has long functioned as a corridor for transportation, trade, settlement interaction, and cultural diffusion. It also preserves abundant remains, including ancient ferry crossings, historic wharves, waterfront settlements, and water conservancy facilities. However, under rapid urbanization and spatial restructuring, approaches based on administrative divisions and discrete heritage points cannot adequately reveal either the cross-regional continuity of hydro-cultural heritage or its internal hierarchical structure. The key question, therefore, is how to move beyond administrative boundaries to identify corridor linkages and their graded connectivity characteristics [13,14].

In recent years, studies on heritage-corridor identification, spatial network analysis, and cultural landscapes have provided important methodological support for the integrated conservation of regional heritage [7]. Internationally, heritage-corridor thinking has also developed through the American National Heritage Areas legislative and planning tradition and the cultural-routes framework, both of which emphasize the integration of historical, cultural, natural, and landscape resources within broader territorial systems [15,16]. These international perspectives suggest that heritage corridors should be understood not only as linear spatial forms, but also as integrated systems linking heritage resources, historical movement, cultural landscapes, and contemporary governance. Methods such as the minimum cumulative resistance model, the analytic hierarchy process, kernel density analysis, and network-structure analysis have been widely applied in studies of cultural–ecological corridors, historical routes, intangible cultural heritage tourism corridors, and traditional settlement networks [7,17,18,19]. These studies suggest that spatial linkages among heritage elements are typically uneven rather than homogeneous, and instead form hierarchical patterns composed of core nodes, important corridors, and peripheral supporting units [20,21]. Nevertheless, two major gaps remain. First, existing research has focused mainly on cultural–ecological corridors, intangible cultural heritage tourism corridors, and traditional settlement networks, whereas the continuous spatial identification of hydro-cultural heritage corridors remains limited [22,23,24]. Second, existing grading studies largely remain at the level of rank identification or functional typology and do not adequately explain how corridors of different grades differ in terms of cultural continuity, historical linkage intensity, and conservation priorities [25,26]. For hydro-cultural heritage, corridor formation and grading are shaped not only by node clustering and spatial accessibility but also by hydrological hierarchy, historical water-transport linkages, and the overall conservation needs of the basin [13,14]. An identification framework therefore needs to be developed from the perspective of the basin as an integrated unit. Without such an integrated basin-level framework, hydro-cultural heritage conservation is likely to remain fragmented across administrative units and isolated sites, making it difficult to recognize corridor continuity, distinguish corridor hierarchy, and translate spatial patterns into differentiated conservation priorities.

Building on this understanding, this study takes the Xiangjiang River Basin as an empirical case and develops an integrated framework for identifying, grading, and guiding the protection of hydro-cultural heritage corridors. The framework follows an analytical pathway from heritage-site evaluation, cultural source identification, resistance-surface construction, and MCR-based corridor extraction to network grading and protection translation. It addresses four questions: (1) How can the spatial differentiation and hierarchical characteristics of hydro-cultural heritage in the Xiangjiang River Basin be identified? (2) How do natural environments, historical linkages, and modern disturbances interact to shape corridor formation? (3) How can potential corridors be identified using the minimum cumulative resistance model, and how can their network structure be further graded and validated? (4) How can corridor-network grading be translated into protection guidance and implementation pathways? Accordingly, the main outputs include a heritage-site evaluation, primary and supplementary cultural source areas, a comprehensive resistance surface and potential corridor pattern, a graded corridor network, and a planning-oriented protection framework. This study provides a spatial basis for the integrated conservation of hydro-cultural heritage in the Xiangjiang River Basin and a methodological reference for other basin regions characterized by strong hydrological dependence and historical waterfront linkages [27].

2. Research Design

2.1. Study Area

The Xiangjiang River Basin is located in Hunan Province, central China, and constitutes one of the province’s most important river basins. The Xiangjiang River is a major tributary of the middle Yangtze River and the principal river system in Hunan Province. Its main stem runs from south to north across Hunan and ultimately discharges into Dongting Lake. With a main-stem structure supported by numerous tributaries, the basin provides a natural framework for transportation, irrigation, settlement interaction, and cultural diffusion. The location and topographic setting of the Xiangjiang River Basin are shown in Figure 2.

Historically, the Xiangjiang River has supported irrigation, water transport, commercial exchange, settlement linkage, and cultural diffusion [4,5]. Along the river, diverse heritage remains have accumulated, including ancient wharves, ferry crossings, water conservancy facilities, and waterfront settlements, all of which exhibit clear waterfront dependence and corridor-oriented characteristics. Selecting the Xiangjiang River Basin as the study area helps move beyond the constraints of administrative boundaries and enables the identification of the spatial linkages and organizational characteristics of hydro-cultural heritage from the perspective of the basin as an integrated unit, thereby laying the foundation for subsequent cultural source identification, comprehensive resistance-surface construction, and potential corridor extraction [28,29].

2.2. Data Sources and Processing

2.2.1. Data Sources

The data used in this study comprised two categories: hydro-cultural heritage site data and GIS spatial data. Hydro-cultural heritage site data were mainly derived from national- and provincial-level protected cultural heritage units, official catalogues of traditional villages, and other publicly available sources, and were used for heritage-site identification, comprehensive evaluation, and cultural source identification. GIS spatial data mainly included basin boundaries, river-system data, DEM data, land-use data, modern transportation networks, and historical routes (ancient post roads), and were primarily used for study-area delimitation, resistance-factor extraction, resistance-surface construction, and corridor analysis. All spatial datasets were standardised in ArcGIS 10.7 through coordinate unification, format conversion, and clipping to the study-area boundary. The data sources used for spatial analysis are summarized in

Table 1. Data sources and main uses.

Data Type	Main Source	Specification/Description	Main Use
Hydro-cultural heritage site data	National Cultural Heritage Administration of China, competent cultural heritage authorities of Hunan Province, official catalogues of traditional villages, and other publicly available sources	National-level protected heritage units (through the Eighth Batch, promulgated on 7 October 2019); provincial-level protected heritage units in Hunan (actual list current to 31 December 2024); sixth-batch Chinese Traditional Villages (officially announced on 16 August 2023)	Heritage-site identification, evaluation, weighted kernel density analysis, and cultural source identification
Basin boundary data	Relevant geospatial data platforms and previous studies	Basin boundary vector data	Study-area delineation and spatial clipping
River-system data	Public geospatial data platforms and related openly available sources	Main stem and tributary vector data	River-system framework extraction, distance-to-water calculation, and spatial relationship analysis
DEM data	Geospatial Data Cloud and other public elevation-data platforms	30 m DEM	Elevation extraction, slope derivation, and construction of the comprehensive resistance surface
Land-use data	Public resource and environmental data platforms	Land-use raster data	Land-use classification and construction of the comprehensive resistance surface
Modern transport network data	Public transport geospatial data platforms and map data	Road-network vector data current to December 2025	Distance-to-transport calculation and representation of modern development resistance
Historical courier-route data	Historical transport studies, local documentary sources, and manual verification	Historical routes compiled from Qing–Republican sources	Distance-to-route calculation and representation of historical linkage effects

.

Table 2. Historical references and their uses in background interpretation and corridor validation.

Reference/Source	Main Use in Interpretation and Validation
Mao Jian, Cultural Studies of the Xiangjiang River Basin; Social Sciences Academic Press: Beijing, China, 2022 [30].	Used to interpret the historical and cultural evolution, human–water relations, water–land transport, and regional cultural context of the Xiangjiang River Basin.
Hunan Provincial Local Gazetteers Compilation Committee, ed., Collated Edition of the Guangxu Hunan General Gazetteer; Hunan People’s Publishing House: Changsha, China, 2017; collated edition [31].	Used to verify Qing-period geography, river systems, administrative divisions, ferry crossings, roads, and local historical records in Hunan.
Li Daoyuan; Chen Qiaoyi, collated and verified, Shui Jing Zhu Jiaozheng (Collated and Verified Commentary on the Water Classic); Zhonghua Book Company: Beijing, China, 2007 [32].	Used to interpret ancient river systems, hydrological geography, and early historical-geographical background.
Zhang Weiran, Xiangjiang (The Xiangjiang River); Jiangsu Education Publishing House: Nanjing, China, 2010 [33].	Used to interpret the Xiangjiang main stem, river culture, regional cultural cognition, and human–land relations.
Sima Qian, Shiji (Records of the Grand Historian); Zhonghua Book Company: Beijing, China, revised edition, 2013; punctuated edition first published in 1959 [34].	Used to provide early historical background and macro-historical context for long-term human–environment interactions.
Jiang Xiangyuan, Bilu Lanlü yi Qi Shanlin: A History of Ancient Transportation in Hunan from Prehistory to the End of the Qing Dynasty; China Communications Press: Beijing, China, 2020 [35].	Used to interpret ancient transport, waterways, postal roads, and water–land transport linkages in Hunan.
Hunan Provincial Cultural Relics Bureau, ed., Illustrated Compendium of Hunan Cultural Heritage; Yuelu Press: Changsha, China, 2008 [36].	Used to verify heritage-site names, types, images, and basic information for sample verification.
Hunan Provincial Department of Water Resources and Hunan Provincial Department of Culture and Tourism, Hunan Province Water Culture Construction Plan (2021–2035); Changsha, China, 2022 [37].	Used as a contemporary policy reference for water-culture construction, heritage protection, resource investigation, and heritage utilisation.
Jiang Xi and Xu Jianhe, “Development Process and Distribution Characteristics of Water Cultural Heritage in Hunan Province”; Chinese and Overseas Architecture, 2023, Issue 7, pp. 14–20 [38].	Used to interpret the classification, development stages, and spatial distribution characteristics of water cultural heritage in Hunan Province.
Li Juan, Study on Transportation and Changes in Folk Culture in the Xiangjiang River Basin during the Tang and Song Dynasties; Master’s thesis, Jinan University: Guangzhou, China, 2010 [39].	Used to supplement the historical evolution of transportation and waterborne cultural linkages in the Xiangjiang River Basin during the Tang and Song dynasties.

lists the historical references used for background interpretation, sample verification, and historical consistency checking, including the cited editions or publication information where available.

These historical references were not only used to interpret the historical background of the Xiangjiang River Basin, but also served as documentary support for the historical consistency validation of representative graded corridors in Section 3.4.

2.2.2. Sample Selection and Preprocessing

This study selected national- and provincial-level protected cultural heritage units and nationally recognized traditional villages as the core sample set, emphasizing regional representativeness, structural significance, and cross-regional comparability. Municipal- and county-level heritage sites were not included in the core modelling sample because their publication standards, coordinate completeness, classification criteria, and hydro-cultural relevance vary considerably across local jurisdictions. Directly incorporating them may cause sample-density differences to reflect data completeness rather than actual hydro-cultural patterns. Meanwhile, the selected heritage sites represent the accumulated spatial outcomes of hydro-cultural heritage formed through long-term historical evolution, rather than remains belonging to a single historical period.

Because kernel density analysis, resistance-surface construction, and corridor identification all require explicit spatial coordinates, only tangible heritage sites with clear geographic locations were incorporated into the unified spatial-modelling framework. Intangible cultural heritage and movable remains were treated only as background references and were not included in subsequent GIS modelling. The historical attributes and water-related relevance of the samples were cross-checked using local gazetteers, historical documents, specialized studies, and publicly available materials to improve the accuracy of heritage-type identification, spatial positioning, and the interpretation of historical linkages.

2.3. Research Methodology

This study establishes a methodological framework comprising heritage-site evaluation, cultural source identification, comprehensive resistance-surface construction, potential corridor extraction, corridor grading, and network-structure validation.

2.3.1. Heritage-Site Evaluation

The analytic hierarchy process (AHP) was used to conduct a comprehensive evaluation of hydro-cultural heritage sites [40]. The evaluation indicators included protection level, historical continuity, spatial proximity, and hydro-cultural relevance. Consistency testing was conducted to ensure the reliability of the weighting results. The formulas are as follows:

$${\mathrm{S}}_{\mathrm{i}}={\displaystyle \sum _{\mathrm{j}=1}^{\mathrm{n}}}{\mathrm{w}}_{\mathrm{j}}{\mathrm{x}}_{\mathrm{ij}} ,\mathrm{CI}={\displaystyle \frac{\mathrm{C}\mathrm{I}=-\mathrm{n}}{\mathrm{n}-1}} ,\mathrm{C}\mathrm{R}={\displaystyle \frac{\mathrm{CI}}{\mathrm{RI}}}$$

(1)

where ${\mathrm{S}}_{\mathrm{i}}$ is the comprehensive evaluation score of heritage site i, ${\mathrm{w}}_{\mathrm{j}}$ is the weight of indicator $\mathrm{j}$, and ${\mathrm{x}}_{\mathrm{ij}}$ is the standardised value of indicator $\mathrm{j}$ for heritage site i. ${\mathrm{\lambda }}_{\max }$ is the maximum eigenvalue of the judgment matrix, $\mathrm{CI}$ is the consistency index, $\mathrm{RI}$ is the random consistency index, and $\mathrm{CR}$ is the consistency ratio. When $\mathrm{CR}$ < 0.10, the judgment matrix is considered to have acceptable consistency. The complete AHP pairwise comparison matrix, derived weights, and consistency-test results for the four heritage-site evaluation indicators are provided in Supplementary Tables S1 and S2.

2.3.2. Cultural Source Identification

Based on the comprehensive evaluation, this study applies weighted kernel density analysis (KDE), using comprehensive evaluation scores as weights, to identify clusters of high-value heritage sites and their continuous concentration areas [7,41]. The KDE surface was used to identify continuous medium-to-high-density candidate patches rather than to define source areas directly [41,42]. The formula is as follows:

$${\mathrm{f}}_{\mathrm{w}}\left(\mathrm{xx}\right) ={\displaystyle \sum _{\mathrm{i}=1}^{\mathrm{n}}}{\mathrm{w}}_{\mathrm{i}}\mathrm{K}\left({\displaystyle \frac{\mathrm{x}-{\mathrm{x}}_{\mathrm{i}}}{\mathrm{h}}}\right)$$

(2)

where ${\mathrm{f}}_{\mathrm{w}}\left(\mathrm{x}\right)$ is the weighted kernel density value at the location, ${\mathrm{w}}_{\mathrm{i}}$ is the weight of the heritage point, $\mathrm{h}$ is the search radius, and $\mathrm{K}$ is the kernel function. A 250 m cell size and a 12 km search radius were used in the main analysis, while 8 km and 16 km radii were tested for sensitivity comparison. Candidate patches were then assessed using operational rules for patch continuity, heritage-site support, KDE core intensity, and network-linkage function. The bandwidth comparison and candidate-patch assessment are provided in Supplementary Tables S6 and S7a,b.

2.3.3. Comprehensive Resistance-Surface Construction and Potential Corridor Extraction

Building on cultural source identification, this study further constructs a comprehensive resistance surface for hydro-cultural heritage corridors in the Xiangjiang River Basin. The selection of resistance factors was optimized by integrating previous research, the characteristics of the study object, data availability, and the analytical requirements of basin-scale analysis. Ultimately, six factors—distance to the water system, elevation, slope, distance to historical roads, land-use type, and distance to modern major transport routes—were selected to construct a comprehensive resistance system [17,26]. These factors reflect natural environmental resistance, modern development resistance, and hydrological–historical linkage. The resistance-factor weights were also determined using AHP, and the complete pairwise comparison matrix and consistency-test results are provided in Supplementary Tables S3 and S4. Using the comprehensive resistance surface as the cost surface and the primary and supplementary cultural source areas as source locations, the minimum cumulative resistance (MCR) model was employed to extract potential low-cost linkage paths, following least-cost modelling approaches that use resistance surfaces to represent functional landscape connectivity [19,43]. The formula is as follows:

$$\mathrm{MCR}=\min \sum ({\mathrm{D}}_{\mathrm{ij}} \times {\mathrm{R}}_{\mathrm{i}})$$

(3)

where MCR is the minimum cumulative resistance between a source location and a target spatial unit, ${\mathrm{D}}_{\mathrm{ij}}$ is the spatial distance from source j to spatial unit i, and ${\mathrm{R}}_{\mathrm{i}}$ is the resistance value of spatial unit i. In this study, the MCR model is used to identify potential linkage corridors, and its output corresponds to a set of potential corridors rather than a corridor network that has already been graded.

All resistance factors were reclassified into five ordinal levels, and the breakpoint rationale is provided in Supplementary Table S8. To test the sensitivity of MCR-based corridor extraction to resistance weighting, the main AHP-derived weighting scheme was compared with two alternatives: an equal-weight scheme and a hydrological–historical reinforced scheme. Across the three weighting schemes, the source areas, resistance factors, and MCR procedure remained unchanged, and only the factor weights varied. The weighting schemes and comparison results are reported in Supplementary Tables S9 and S10 and Figure S3.

2.3.4. Corridor Grading and Network-Structure Validation

The potential corridors extracted by the MCR model primarily reflect low-cost linkages between cultural source areas, but they are insufficient to reveal structural differences among pathways within the overall connectivity system [44,45]. Therefore, this study further conducts corridor grading and network-structure validation. Corridors were classified into primary, secondary, and tertiary levels according to connected objects, path-sharing intensity, and structural function. Primary corridors connect primary source areas and maintain basin-scale axial continuity; secondary corridors connect primary and supplementary source areas or supplementary source areas with each other and support regional or tributary linkage; tertiary corridors mainly connect general heritage sites and peripheral nodes. After corridor grading, three levels of subnetworks are constructed: the primary network, the primary–secondary network, and the complete graded network. Following a graph-theoretic perspective on landscape connectivity, in which spatial systems are represented through nodes and links, network-structure indices, including $\mathrm{\alpha }$, $\mathrm{\beta }$, and $\mathrm{\gamma }$, are then used to provide supplementary validation of the grading results [46,47]. The formulas are as follows:

$$\mathrm{\alpha }={\displaystyle \frac{\mathrm{L}-\mathrm{V}+1}{2\mathrm{V}-5}} ,\mathrm{\beta }={\displaystyle \frac{\mathrm{L}}{\mathrm{V}}} ,\mathrm{\gamma }={\displaystyle \frac{\mathrm{L}}{3(\mathrm{V}-2)}}$$

(4)

where $\mathrm{V}$ is the number of nodes and $\mathrm{L}$ is the number of links in the network. The $\mathrm{\alpha }$ index reflects network closure, the $\mathrm{\beta }$ index reflects the average level of connectivity between nodes and links, and the $\mathrm{\gamma }$ index reflects the overall degree of network connectivity. These indices were used as post-grading topological indicators rather than direct criteria for generating corridor grades. They were used to examine whether the graded network followed the expected sequence of backbone formation, regional supplementation, and peripheral access.

2.3.5. GeoDetector Analysis

GeoDetector was introduced at the results-analysis stage as an ex-post explanatory tool to examine the explanatory power of resistance factors and their interactions on the spatial differentiation of potential corridors [48,49,50]. It was not used to determine AHP weights or corridor grades. The dependent variable was derived from the potential corridor distribution or corridor-density result, while the explanatory variables included distance to the water system, elevation, slope, land-use type, distance to modern major transport routes, and distance to historical roads. To maintain consistency with the resistance-surface construction, continuous variables were discretized using a five-level classification scheme, and land-use type was treated as a categorical variable.

2.4. Research Framework

Based on heritage-site evaluation, cultural source identification, comprehensive resistance-surface construction, potential corridor extraction, and network grading, this study establishes a research framework of “source identification—corridor extraction and network grading—protection conversion”, linking spatial analysis with planning-oriented protection guidance [51], as shown in Figure 3.

3. Results

3.1. Evaluation of Hydro-Cultural Heritage and Cultural Source Identification

3.1.1. Classification of Hydro-Cultural Heritage Types

Based on the available spatial sample, the 181 hydro-cultural heritage sites were classified into four categories: water conservancy heritage, water-transport heritage, settlement-landscape heritage, and belief-and-ritual heritage. Water conservancy and water-transport heritage reflect historical practices of water governance, water use, and river-based connectivity, whereas settlement-landscape and belief-and-ritual heritage embody waterfront habitation, production landscapes, and water-related cultural memory. The spatial distribution of hydro-cultural heritage sites is shown in Figure 4a, while the composition of heritage types is shown in Figure 4b and summarized in

Table 3. Composition of hydro-cultural heritage types in the Xiangjiang River Basin.

Type	Description	Typical Examples	Number of Sites	Share (%)
Water Conservancy Heritage	Engineering facilities and related remains reflecting historical water-use practices such as flood control, water diversion, irrigation, flood prevention, and water supply	Aqueducts, irrigation districts, flood-control embankments, ancient wells, springs	10	5.52
Water-Transport Heritage	Connectivity facilities formed on the basis of river systems and regional routes, including bridges, ferry crossings, wharves, ancient roads, guild halls, and transport nodes	Ancient bridges, ancient ferry crossings, wharves, docks, guild halls, ancient roads	34	18.78
Settlement-Landscape Heritage	Heritage types reflecting the construction of waterfront settlements, the development of traditional villages, the spatial organization of production and everyday life, and related historical landscapes	Traditional villages, historic building complexes, ancient city walls, kiln sites, academies, former residences	100	55.25
Belief and Ritual Heritage	Remains associated with water-related memory, water-deity beliefs, local spiritual expression, and commemorative functions	Temples, ancestral halls, stelae, stone inscriptions, pagodas, memorial monuments	37	20.44
Total	—	—	181	100.00

. Overall, hydro-cultural heritage in the Xiangjiang River Basin is dominated by settlement-landscape heritage, while also incorporating water-transport and belief-related types, indicating a distinctly composite heritage structure.

3.1.2. Construction of the Hydro-Cultural Heritage Evaluation System

To identify cultural source areas that are representative at the basin scale and capable of supporting subsequent corridor construction, this study further evaluates hydro-cultural heritage sites based on the typological classification. Hydro-cultural heritage sites in the Xiangjiang River Basin vary considerably in protection level, historical continuity, spatial proximity, and hydro-cultural relevance. These differences make it necessary to assess their relative significance before identifying cultural source areas. It is therefore necessary to quantify the comprehensive value of heritage sites through an evaluation system in order to provide a basis for subsequent cultural source identification.

Drawing on the resource characteristics of hydro-cultural heritage in the Xiangjiang River Basin and relevant previous studies, this study constructs an evaluation system based on four dimensions: representativeness, continuity, clustering, and relevance [52,53]. The corresponding indicators are protection level, historical continuity, spatial proximity, and hydro-cultural relevance, as presented in

Table 4. Evaluation indicator system for hydro-cultural heritage sites.

Criterion Dimension	Indicator	Indicator Meaning	Description
Representativeness	Protection Level (A1)	Officially recognized significance	Reflects the importance of a heritage site within the existing heritage-protection system.
Continuity	Historical Continuity (A2)	Depth of historical continuity	Reflects the time depth of heritage formation and the degree of historical accumulation.
Clustering	Spatial Proximity (A3)	Degree of surrounding heritage concentration	Reflects the potential of a heritage site to form a spatial clustering core.
Relevance	Hydro-cultural Relevance (A4)	Strength of hydro-cultural association	Reflects the degree of direct association of a heritage site with water transport, water engineering, waterfront settlements, and hydro-cultural activities.

. Hydro-cultural relevance was scored according to the strength of each site’s association with water-related functions and cultural meanings; the detailed rubric is provided in Supplementary Table S5.

Specifically, protection level reflects the authority and representativeness of each heritage site within the existing heritage-protection system; historical continuity reflects the time depth and historical accumulation of heritage; spatial proximity captures the clustering basis of heritage sites within the basin; and hydro-cultural relevance measures the degree of direct association with water governance, water use, waterfront production, and daily life, and water-related cultural memory. Together, these four indicators form the basis for identifying cultural source areas. To determine indicator weights, the analytic hierarchy process (AHP) was employed, and comprehensive evaluation scores were calculated for all heritage sites. The indicator weights are presented in

Table 5. Weights of evaluation indicators for hydro-cultural heritage sites.

Indicator	Weight
Protection Level (A1)	0.34
Historical Continuity (A2)	0.18
Spatial Proximity (A3)	0.09
Hydro-cultural Relevance (A4)	0.39

, and the spatial distribution of the evaluation results is shown in Figure 5. These results were then used as weights in the subsequent weighted kernel density analysis to identify high-value concentration areas and primary cultural source areas, thereby linking heritage-site evaluation to cultural source identification.

The AHP consistency test showed acceptable consistency for the heritage-site evaluation matrix (λmax = 4.025, CI = 0.008, RI = 0.900, CR = 0.009 < 0.10). The derived weights were consistent with those reported in Table 5. Hydro-cultural relevance and protection level received relatively high weights because this study aims to identify cultural source areas for hydro-cultural corridor construction rather than to rank general heritage sites. Hydro-cultural relevance captures direct associations with water governance, water transport, hydraulic engineering, waterfront settlement, and water-related cultural memory, while protection level reflects the legal status and representativeness of heritage sites. The detailed AHP matrix and the scoring rubric for hydro-cultural relevance are provided in Supplementary Tables S1, S2 and S5.

3.1.3. Spatial Clustering Characteristics and Cultural Source Identification

Because the formation and dissemination of hydro-cultural heritage in the Xiangjiang River Basin were strongly shaped by daily interaction, transport linkages, and cultural diffusion processes developed along water systems, the search radius used in kernel density analysis should reflect the effective sphere of influence of a cultural core over surrounding areas under historical conditions of production, travel, and everyday life. More specifically, the selected radius was intended to reflect the approximate spatial range of routine activity and local interaction under historical conditions, rather than a precise travel distance. Drawing on existing understandings of the spatial diffusion of cultural transmission, as well as the CCSPM model’s emphasis on the continuous spatial representation of cultural linkages [41,42,45], and considering this historically grounded spatial scale, this study adopted a pixel size of 250 m and a search radius of 12 km for weighted kernel density analysis. The comparison focused on the stability of high-density clusters, the continuity of candidate source patches, and the degree of merging or fragmentation among adjacent clusters. Sensitivity tests using 8 km and 16 km radii showed that the main high-density clusters along the Xiangjiang main stem and major tributaries remained generally stable. The 8 km radius produced more localized but fragmented clusters, whereas the 16 km radius strengthened regional continuity but tended to merge adjacent clusters. Therefore, the 12 km radius was retained as a balanced parameter between local clustering and basin-level continuity. The detailed comparison is provided in Supplementary Table S6 and Figures S1 and S2.

The kernel density results show that hydro-cultural heritage sites in the Xiangjiang River Basin exhibit a spatial pattern characterized by clustering along water systems, localized nucleation, and belt-like extension [41,42]. High-value areas are mainly distributed along the Xiangjiang main stem and several major tributaries, where they form strong clustering cores at key nodes. By contrast, medium- and low-value areas extend continuously along both the main stem and tributary rivers, showing localized point-like or bead-like distributions. Overall, the heritage sites show a non-homogeneous spatial pattern characterized by multi-point clustering and belt-like extension along the Xiangjiang River and its tributaries, reflecting strong waterfront dependence and corridor-oriented characteristics.

As illustrated in Figure 6, candidate cultural source areas were identified from continuous medium-to-high KDE patches and further assessed using four operational criteria: patch continuity, cluster support, core prominence, and network significance. Based on these criteria, eight primary and fourteen supplementary cultural source areas were identified, while the remaining sites were retained as general heritage sites for subsequent local access and network supplementation.

The primary/supplementary boundary was defined using measurable conditions derived from the candidate-patch attributes. Primary cultural source areas were identified from candidate patches that formed continuous medium-to-high KDE patches, contained at least five heritage sites with a total evaluation score of no less than 17, showed a prominent KDE core with a KDE maximum value of no less than 17, and occupied backbone linkage positions along the Xiangjiang main stem, major tributaries, or between core source areas. Candidate patches that did not meet all primary-source conditions but retained identifiable local clustering and supported tributary extension, transitional linkage, or local network supplementation were classified as supplementary cultural source areas. The detailed assessment of all candidate patches is provided in Supplementary Table S7a,b.

The weighted kernel density distribution and the results of cultural source identification are shown in Figure 7a,b. As shown in Figure 7b, the identified source areas are coded as P1–P8 and S1–S14. Primary source areas are mainly distributed along the Xiangjiang main stem and major tributaries, whereas supplementary source areas are located between primary sources, along tributaries, and within secondary concentration zones. This source-area system transforms discrete heritage sites into a graded spatial basis for resistance-surface construction and corridor extraction.

3.2. Construction of the Comprehensive Resistance Surface

Based on cultural source identification, this study constructed a comprehensive resistance surface for hydro-cultural heritage corridors in the Xiangjiang River Basin to represent the spatial cost of cultural-linkage expansion within the basin. The selection of resistance factors was informed by previous studies on heritage corridors, cultural landscape corridors, and related MCR research, while also taking into account the waterfront dependence, historical connectedness, and basin-scale integrity of hydro-cultural heritage corridors in the Xiangjiang River Basin. In addition, data availability, temporal consistency, and inter-variable independence were considered in optimizing the candidate factors. As summarized in

Table 6. Resistance factors used in heritage corridor studies.

Factor	Representative References	Adopted in This Study	Explanation
Elevation	[44,45,54,55]	Yes	Represents the basic constraint imposed by the broader topographic setting on spatial accessibility.
Slope	[44,45,54,55]	Yes	Reflects local movement conditions and surface-relief constraints.
Distance to the Water System	[3,4,6]	Yes	Captures the dependence of hydro-cultural heritage on the river-system framework and hydrological proximity.
Historical Roads	[44,45]	Yes	Represents traditional transport routes and historical accessibility linkages.
Land-Use Type	[44,45,54,55]	Yes	Reflects the influence of development intensity and landscape background on corridor formation.
Distance to Modern Major Transport Routes	[44,45,55]	Yes	Represents the fragmentation and disturbance imposed by modern infrastructure on traditional spatial continuity.
GDP, Population Density, POI, etc.	[3,4,6]	No	Common in studies of macro-scale spatial distribution, but poorly matched to historical processes in terms of temporal scale and not conducive to unified expression at the basin scale.
Ancient Wharves, Ancient Ferry Crossings, Jin Kou-Type Nodes, etc.	[5,12,19,44]	No	Theoretically important, but not incorporated into the formal resistance-factor system because the currently available data are limited in quantity, spatially incomplete, and insufficiently representative.

, candidate resistance factors were first reviewed from previous studies and then evaluated for their applicability to the present study.

Ultimately, six resistance factors were selected and organized into three criterion groups: natural environmental resistance, modern development resistance, and hydrological–historical linkage. Elevation and slope represent topographic constraints; land-use type and distance to modern major transport routes represent modern development disturbance; distance to the water system reflects hydrological dependence; and distance to historical roads reflects inherited accessibility [56]. The assigned resistance values and grading criteria for each factor are presented in

Table 7. Resistance factors and assigned resistance values for hydro-cultural heritage corridors in the Xiangjiang River Basin.

Dimension	Resistance Factor	Description	Effect on Resistance	Level 1	Level 2	Level 3	Level 4	Level 5
Natural Environmental Resistance (B)	Slope (°)	Reflects the basic constraint of surface relief on corridor connectivity.	Positive (+)	0–8	8–15	15–25	25–45	>45
Natural Environmental Resistance (B)	Elevation (m)	Reflects the basic constraint of topographic conditions on corridor connectivity.	Positive (+)	0–50	50–150	150–300	300–600	>600
Modern Development Resistance (C)	Land-Use Type	Reflects the disturbance of different land-development intensities on the continuity of cultural space.	Categorical assignment	Water bodies	Cultivated land	Forest and grassland	Unused land	Urban, industrial, and residential land
Modern Development Resistance (C)	Distance to Modern Major Transport Routes (km)	Reflects the fragmenting disturbance of modern transport infrastructure on traditional hydro-cultural space.	Negative (–)	>10	6–10	3–6	1–3	<1
Hydrological–Historical Linkage Factor (D)	Distance to the Water System (km)	Reflects the proximity of heritage space to the river-system framework and the strength of hydrological linkage.	Positive (+)	0–0.5	0.5–2	2–5	5–10	>10
Hydrological–Historical Linkage Factor (D)	Distance to Historical Roads (km)	Reflects the strength of linkage between heritage space and the traditional overland transport network.	Positive (+)	<1	1–3	3–6	6–10	>10

Note: Breakpoints were determined based on previous MCR and landscape-suitability studies, factor-specific mechanisms, and the spatial characteristics of hydro-cultural heritage in the Xiangjiang River Basin. Values from 1 to 5 indicate increasing resistance. Distance to modern major transport routes was interpreted as a modern development-disturbance factor. Detailed explanations are provided in Supplementary Table S8.

. The factors were reclassified into five resistance levels based on previous MCR and landscape-suitability studies, factor-specific mechanisms, and the spatial characteristics of the Xiangjiang River Basin. Detailed breakpoint rationales are provided in Supplementary Table S8. The factors were then weighted using the analytic hierarchy process (AHP), and the final weights used in the weighted overlay are reported in

Table 8. Hierarchical and overall weights of resistance factors for the comprehensive resistance surface in the Xiangjiang River Basin.

Dimension	Criterion Weight	Resistance Factor	Local Weight	Overall Weight
Natural Environmental Resistance (B)	0.207	Slope	0.545	0.113
Natural Environmental Resistance (B)	0.207	Elevation	0.455	0.094
Modern Development Resistance (C)	0.331	Land-Use Type	0.583	0.193
Modern Development Resistance (C)	0.331	Distance to Modern Major Transport Routes	0.417	0.138
Hydrological–Historical Linkage Factor (D)	0.462	Distance to the Water System	0.600	0.277
Hydrological–Historical Linkage Factor (D)	0.462	Distance to Historical Roads	0.400	0.185

Note: Overall weights were calculated by multiplying criterion weights by local weights and were used in the weighted overlay. Distance to the water system and distance to historical roads were treated as two sub-components of the hydrological–historical linkage criterion group, with local weights of 0.600 and 0.400, respectively. The complete AHP matrix and consistency-test results are provided in Supplementary Tables S3 and S4.

. These factors were subsequently superimposed to generate the comprehensive resistance surface for hydro-cultural heritage corridors in the Xiangjiang River Basin.

As shown in Table 8, the AHP-derived weights are reported at both dimension and factor levels. Distance to the water system received the highest overall weight, indicating its central role in constructing the resistance surface. Land-use type and distance to historical roads also received relatively high weights, reflecting modern land-development context and historical accessibility. The resistance-factor weighting matrix showed acceptable consistency (λmax = 6.000, CI = 0.000, RI = 1.240, CR = 0.000 < 0.10), and the complete matrix is provided in Supplementary Tables S3 and S4.

Figure 8 and Figure 9 show that low-resistance zones are concentrated along the Xiangjiang main stem and major tributaries, forming the principal directions of heritage-linkage expansion. High-resistance areas mainly occur in zones with strong topographic relief, long distance from major water systems, or intensive modern construction disturbance. Overall, the resistance pattern can be summarized as main-stem low-resistance extension, local segmentation by high-resistance areas, and supplementary linkage through tributary corridors.

3.3. Extraction of Potential Corridors Based on the MCR Model

Based on the comprehensive resistance surface, the MCR model was used to extract potential hydro-cultural heritage corridors. As shown in Figure 10, the corridors generally follow the Xiangjiang main stem and major tributaries, with dense linkages in the central and north-central basin and more branch-like extensions in the southern, southwestern, and eastern areas. The result indicates a spatial pattern of central concentration and peripheral dispersion. These potential corridors represent least-cost linkage paths and require further grading to clarify their structural roles within the overall network.

3.4. Grading of Corridor Network Structure

To further clarify the structural roles of potential corridors within the overall linkage system, this study examines corridor differentiation from a network-structure perspective. Rather than deriving corridor grades directly from network-structure indices, potential corridors are classified into three categories—primary, secondary, and tertiary—by considering the importance of the connected objects, the degree of path sharing, and their structural roles within the overall linkage pattern. Network-structure indices are then used to provide supplementary validation of the grading results.

As shown in Figure 11, the grading results indicate that hydro-cultural heritage corridors in the Xiangjiang River Basin form a primary–secondary–tertiary graded structure, expressed as a “2 + 8 + N” pattern. The two primary corridors constitute the basin-scale backbone, the eight secondary corridors support tributary linkage and regional supplementation, and “N” denotes a functional category of tertiary access corridors that mainly serve local access for general heritage sites and peripheral nodes. In this expression, “N” is not intended as a fixed numerical count, but as an open functional layer representing access-oriented tertiary corridors. Overall, hydro-cultural heritage corridors in the Xiangjiang River Basin have been transformed from potential linkage paths into a graded network composed of a continuous structural backbone, regional supplementary links, and local access branches.

The network-structure indices in

Table 9. Network-structure indices of the graded hydro-cultural heritage corridor network in the Xiangjiang River Basin.

Network Level	Number of Nodes (V)	Number of Links (L)	Alpha Index (α)	Beta Index (β)	Gamma Index (γ)	Structural Characteristic
Primary Network	8	7	0.000	0.875	0.389	Dendritic backbone with limited loop redundancy
Primary–Secondary Network	21	32	0.324	1.524	0.561	Enhanced local connectivity and alternative linkages
Complete Graded Network	201	212	0.030	1.055	0.355	Expanded peripheral access through dendritic terminal links

Note: The α, β, and γ indices are used to examine the topology of the graded network after corridor grading, rather than to directly generate corridor grades. In the “2 + 8 + N” expression, “N” denotes the functional category of tertiary access corridors rather than a fixed numerical count.

further support this hierarchical interpretation. As primary, secondary, and tertiary corridors are progressively incorporated, network coverage expands from primary and supplementary cultural source areas to general heritage sites. Sensitivity analysis also shows that the primary corridors and major secondary corridors remain generally stable under the three weighting scenarios, with differences mainly occurring in local access lines. Detailed comparison results are provided in Supplementary Tables S9 and S10 and Figure S3.

As shown in Table 9, the primary network has an α value of 0.000, indicating a dendritic backbone with strong axial guidance but limited loop redundancy. After secondary corridors are added, α, β, and γ increase to 0.324, 1.524, and 0.561, respectively, suggesting enhanced local connectivity and alternative linkages. In the complete network, the number of nodes increases from 21 to 201, while α decreases from 0.324 to 0.030. This does not indicate network degradation; rather, it reflects the access-oriented role of tertiary corridors, which expand peripheral coverage through dendritic terminal links without generating proportional loop redundancy.

To further examine the historical consistency of the graded corridor results, representative primary and secondary corridors were compared with historical documents, local gazetteers, historical transport studies, and records related to water transport, ferry crossings, wharves, and waterfront settlements. This validation was used as an ex-post consistency check and did not participate in MCR corridor extraction or network grading. Because the MCR model identifies potential low-cost linkage paths rather than precisely reconstructing specific historical routes, the comparison focuses on whether the graded corridors are spatially consistent with documented historical water-transport directions, waterfront settlement belts, historical nodes, and cultural transmission routes. Specifically, the comparison considered three types of historical correspondence: directional consistency with documented waterborne transport routes, spatial overlap with ferry crossings, wharves, towns, and waterfront settlement belts, and functional consistency with historically recorded water–land transition or cultural-transmission nodes. The validation results are summarized in

Table 10. Historical consistency validation of representative graded corridors.

Representative Graded Corridor	Historical Evidence Used for Validation	Consistency Judgement
Representative primary corridor along the Xiangjiang main stem and Xiaoshui direction	Consistent with documentary descriptions of the Xiangjiang main stem and the Xiaoshui River as long-term waterborne transport and trade corridors; the modelled direction also connects a series of waterfront settlement areas, ancient-city nodes, wharf-related locations, and historical-cultural cores distributed along this north–south linkage.	High
Representative primary corridor linking the Xiangjiang main stem with eastern tributary areas	Consistent with the documented distribution of historical towns, temples, ancient city sites, and water–land transition nodes along the Xiangjiang main stem and its major eastern tributaries, the corridor direction reflects the connection between the main river axis and tributary-based cultural nodes.	High
Representative secondary corridor in the Lushui–Zhuzhou section	Shows spatial agreement with documentary records and local evidence of ferry crossings, wharves, waterfront settlements, and regional transport nodes around the Lushui–Zhuzhou section, indicating a historically plausible tributary-to-main-stem linkage.	Moderate–High
Representative secondary corridor in the Qishui–middle Xiaoshui area	Shows spatial agreement with historical ferry and wharf nodes, waterfront settlement belts, and regional cultural-linkage directions in the Qishui–middle Xiaoshui area, supporting its interpretation as a secondary corridor for southwestern regional supplementation.	Moderate–High

. The historical validation therefore examines long-term consistency with documentary evidence, rather than exact correspondence with routes from a specific period.

4. Discussion

4.1. Formation Mechanisms of Corridor Patterns and the Significance of Integrated Conservation

To explain the formation mechanisms of hydro-cultural heritage corridor patterns in the Xiangjiang River Basin, this study employed GeoDetector to analyze the spatial differentiation of potential corridors. As shown in Figure 12, distance to the water system has the highest single-factor explanatory power (q = 0.135), followed by elevation (q = 0.044) and land-use type (q = 0.030). The q-values of distance to historical roads, slope, and distance to modern major transport routes are relatively low. However, the interaction detector shows that all factor-pair q-values are higher than those of individual factors, and the strongest interactions all involve distance to the water system. These results suggest that the water-system framework plays a central role in corridor differentiation, but corridor formation is not determined by a single factor. Rather, it is jointly shaped by hydrological linkage, topographic context, historical accessibility, land-use conditions, and modern development disturbance [57,58].

The relatively low q-values of slope (q = 0.012), distance to modern major transport routes (q = 0.010), and distance to historical roads (q = 0.018) indicate weak independent explanatory power for the overall corridor pattern, but do not mean that these factors are invalid in the resistance surface. Slope mainly affects local terrain-related movement costs, modern major transport routes represent development disturbance and spatial fragmentation, and historical roads reflect historical accessibility and water–land transport transitions. The interaction between distance to the water system and elevation suggests that corridors tend to form in low-elevation river valleys and waterfront terraces. The interaction between distance to the water system and distance to historical roads indicates the combined influence of river systems and historical water–land transport linkages. The interaction between distance to the water system and distance to modern major transport routes suggests that modern development disturbance mainly affects corridor continuity in urbanized waterfront sections and transport-corridor overlap zones. Therefore, the GeoDetector results should be interpreted as evidence of a composite formation mechanism rather than as confirmation of a single dominant factor [50].

Historically, the main stem of the Xiangjiang River has long functioned as a corridor for regional transportation, commercial exchange, and cultural diffusion. High-grade heritage linkages therefore tend to concentrate along the main navigation route and key waterfront nodes, forming the primary corridor framework. Tributary systems further support settlement distribution, resource diffusion, and local cultural exchange, enabling the corridor network to extend outward and form supplementary regional linkages. Meanwhile, modern construction land and transport infrastructure have reshaped some historical linkages and created local ruptures or detours in certain sections. Accordingly, the conservation of hydro-cultural heritage in the Xiangjiang River Basin should move beyond isolated site protection or administratively fragmented conservation [9,12]. It should instead treat the basin as an integrated unit and coordinate cultural heritage, water-system environments, historical routes, and contemporary spatial disturbance within a unified analytical and governance framework [28,52]. Graded protection should therefore be based on continuous conservation and hierarchical coordination.

4.2. Functional Interpretation and Protection-Oriented Translation of the Graded Corridor Network

Based on the corridor-grading results reported in Section 3.4, this section does not present additional corridor-identification results. Instead, it interprets how primary, secondary, and tertiary corridors can be translated into differentiated protection orientations and planning guidance, following an integrative landscape-planning logic that connects analytical outputs with practical conservation and management needs [51]. In this interpretive framework, primary corridors are understood as structural axes requiring continuous conservation and coordinated waterfront-space control; secondary corridors are understood as regional linkage corridors requiring node coordination and transition-zone management; and tertiary corridors are understood as local access corridors suitable for low-intensity guidance, interpretation, and gradual revitalization. Figure 13 illustrates this protection-oriented interpretation of the graded corridor system.

Given that hydro-cultural heritage in the Xiangjiang River Basin is organized along the skeletal structure of the river system, corridors at different grades can be interpreted as performing different conservation and linkage functions within the overall linkage system. Primary corridors can therefore be interpreted as the principal axes for maintaining basin-wide continuity; secondary corridors as linkage corridors that support tributary extension, regional supplementation, and transitions between network levels; and tertiary corridors as local access corridors that connect general heritage sites and peripheral nodes. The spatial grading results have been reported in Section 3.4. On this basis,

Table 11. Protection-oriented functional guidance for graded hydro-cultural heritage corridors in the Xiangjiang River Basin.

Corridor Grade	Corridor Name	Start–End Section/Core Nodes	Supporting Water System	Main Function
Primary Corridor	Xiangjiang–Xiaoshui North–South Through Corridor	Changsha Yuelu Core Area—Xiangtan Yaowan Core Area—Hengyang Shigu Core Area—Lingling Ancient City Core Area—Daozhou Historical-Cultural Area—Jianghua Waterfront Settlement Area	Xiangjiang main stem; Xiaoshui main stem	Connects the core source areas of the basin and constitutes the north–south structural backbone of the entire basin
Primary Corridor	Liuyang River–Xiangjiang–Leishui Eastern-Linkage Primary Corridor	Liuyang Historical-Cultural Area—Changsha Yuelu Core Area—Xiangtan Yaowan Core Area—Hengyang Shigu Core Area—Caihou Shrine Historical-Cultural Area	Liuyang River; Xiangjiang main stem; Leishui	Connects high-value source areas in the eastern wing and strengthens the linkage between the principal axis and eastern tributary systems
Secondary Corridor	Upper Liuyang River Linkage Secondary Corridor	Gugang Ancient City Area—Liuyang Historical-Cultural Area	Liuyang River	Supplements the connection between upstream Liuyang River nodes and the main network
Secondary Corridor	Lianshui Western-Wing Linkage Secondary Corridor	Historical-Cultural Areas along the Lianshui River—Xiangtan Yaowan Core Area	Lianshui	Promotes linkage between western-wing tributary areas and the principal axis
Secondary Corridor	Lushui–Xiangjiang Zhuzhou Section Linkage Secondary Corridor	Historical-Cultural Areas along the Lushui River—Zhuting Ancient Wharf Historical-Cultural Area—Xiangtan Yaowan Core Area	Lushui; Xiangjiang main stem	Strengthens the connection between northeastern-wing areas and the main network of the middle–lower Xiangjiang River
Secondary Corridor	Middle Xiangjiang–Xietaishui Linkage Secondary Corridor	Hengshan Kiln Historical-Cultural Area—Former Residence of Luo Ronghuan Historical-Cultural Area—Hengyang Shigu Core Area	Xiangjiang main stem; Xietaishui	Supports supplementary linkage and extension between the middle Xiangjiang River and tributary areas
Secondary Corridor	Upper Leishui Linkage Secondary Corridor	Chaling Ancient City Historical-Cultural Area—Caihou Shrine Historical-Cultural Area	Upper tributaries of the Leishui River	Promotes the connection of southeastern upstream areas to the main network
Secondary Corridor	Southern Leishui Linkage Secondary Corridor	Banliang Waterfront Settlement Area—Xiang—Yue Ancient Route Historical-Cultural Area—Caihou Shrine Historical-Cultural Area	Leishui (Dongjiang and Oushui branches)	Strengthens the continuity between southeastern areas and the Leishui linkage belt
Secondary Corridor	Qishui–Luhongjiang–Middle Xiaoshui Linkage Secondary Corridor	Wuxi Cliff-Inscriptions Historical-Cultural Area—Xiabajing—Wu Family Mansion Historical-Cultural Area—Lingling Ancient City Core Area	Qishui; Luhongjiang; Xiaoshui	Improves internal supplementation in the southwestern area and enhances network support in the middle Xiaoshui section
Secondary Corridor	Yongming River–Southern Xiaoshui Linkage Secondary Corridor	Shangjiangxu Waterfront Settlement Area—Jianghua Waterfront Settlement Area	Yongming River; Xiaoshui	Maintains the connection between southern marginal areas and the main network
Tertiary Corridor	Tertiary Corridors of Node-Connection, Tributary-Extension, and Local-Linkage Types	General heritage sites and peripheral nodes	Nearby tributaries or waterfront paths	Realizes the connection of general heritage sites and the local extension of the network

Note: The spatial corridor-grading results are reported in Section 3.4. This table provides an interpretive translation of those results into protection-oriented functional guidance; it should not be read as an additional corridor-identification or grading result.

summarizes the protection-oriented functional interpretation of each corridor grade, including representative spatial bases, functional roles, protection priorities, and planning guidance.

4.3. Planning-Oriented Graded Protection Units and Guidance for Revitalization and Utilization

Based on the graded corridor system described above, the conservation of hydro-cultural heritage in the Xiangjiang River Basin should not remain limited to the identification of linear corridors. Instead, primary, secondary, and tertiary corridors need to be further translated into planning-oriented protection guidance units suitable for planning implementation [28], thereby enabling a transition from the identification of linkage paths to the formulation of differentiated conservation and revitalization guidance. Given the marked differences among corridors of different grades in terms of structural role, linkage range, and node-support capacity within the overall network, this study establishes a framework for graded protection and revitalization guidance along two dimensions: the construction of horizontal protection belts and the organization of longitudinal functional segments.

Horizontally, protection units are proposed as indicative guidance belts according to the linkage range, node-support capacity, and intervention intensity associated with corridors of different grades, thereby transforming the corridor system into differentiated planning guidance for conservation and revitalization [25]. The primary protection belt is defined with reference to primary corridors and the contiguous concentration areas of the primary cultural source areas they connect. It serves as the core spatial framework for integrated hydro-cultural heritage conservation in the Xiangjiang River Basin and functions to maintain the continuity of the basin-wide structural axis, preserve linkages among core source areas, and ensure continuous protection of the main water system. The coordinated linkage belt is suggested on the basis of secondary corridors together with tributary areas, transition zones, and the spaces surrounding the supplementary cultural source areas they connect. It functions to strengthen regional linkages, support coordinated articulation among subareas, and facilitate transitions between primary and secondary corridors. The peripheral guidance belt is suggested on the basis of tertiary corridors and low-intervention linkage spaces surrounding general heritage sites. It primarily supports peripheral node access, local network supplementation, and gradual revitalization and utilization. In this way, a horizontally differentiated pattern of graded protection corresponding to the basin-wide linkage structure is proposed as planning-oriented guidance rather than as a fixed statutory boundary. The spatial basis, suggested delineation rules, and planning implications of the three protection belts are summarized in

Table 12. Spatial bases, indicative guidance, and planning implications of graded protection belts in the Xiangjiang River Basin.

Protection Belt Type	Spatial Basis	Indicative Spatial Guidance	Planning Implication
Primary Protection Belt	Primary corridors + primary cultural source areas + continuous waterfront heritage clusters	Integrate primary corridor axes, primary source-area patches, and a wider cultural–ecological transition zone; calibrate boundaries with existing statutory protection boundaries and territorial planning units.	Maintain basin-scale axial continuity, protect core source areas, and control high-intensity construction in key linkage spaces.
Coordinated Linkage Belt	Secondary corridors + supplementary cultural source areas + tributary linkage spaces	Integrate secondary corridor axes, supplementary source areas, tributary transition zones, and medium-intensity linkage zones.	Strengthen regional coordination, tributary linkage, restoration of fragmented sections, and transition between network levels.
Peripheral Guidance Belt	Terminal corridors + general heritage sites + peripheral nodes	Integrate terminal linkages, general heritage sites, and low-intervention local guidance spaces.	Support peripheral access, slow-mobility interpretation, local revitalization, and gradual use.

, and the horizontal graded protection framework is illustrated in Figure 14.

Vertically, functional segmentation of the main corridor axis takes comprehensive account of heritage concentration, urban development intensity, waterfront environmental continuity, and linkage-function types. Where these indicators show clear combined changes, such locations are identified as segment-transition nodes, and the corridor is further divided into the upstream section (Section A), the midstream section (Section B), the urban-intensive section (Section C), and the downstream linkage section (Section D). Specifically, the upstream section prioritizes ecological conservation and strict protection, with an emphasis on ecological restoration and waterfront-space control. The midstream section is characterized by a relatively high concentration of heritage and should focus on heritage conservation, display and utilization, village maintenance, and node linkage. The urban-intensive section is subject to strong construction activity and development pressure and therefore requires integrated coordination, character control, and development constraints. The downstream linkage section mainly undertakes node access and inter-area linkage functions and should focus on revitalization guidance, display and utilization, and the introduction of slow-mobility networks so as to enhance the capacity of peripheral nodes to connect with the main network. The longitudinal functional segmentation of the main corridor axis is illustrated in Figure 15.

Overall, the proposed protection structure combines horizontal graded protection belts with longitudinal functional segments. It is intended as a planning-oriented guidance framework derived from the graded corridor network rather than as a statutory regulatory boundary. In practical implementation, it should be coordinated with existing heritage-protection and spatial-planning instruments in China, including cultural relic protection scopes, construction-control zones [59], historic cultural conservation areas, ecological conservation redlines, riverfront management zones, and territorial spatial-planning control units, and its indicative boundaries should be calibrated case by case rather than applied as fixed-width buffer zones.

4.4. Method Applicability, Limitations, and Transferability

This study establishes a framework for identifying hydro-cultural heritage corridors and guiding conservation in river-basin heritage regions. It is particularly suitable for areas with a clear river-system structure, strong historical waterfront linkages, and dispersed heritage sites, and can be adapted for corridor identification, network grading, and protection translation. The resistance-weighting sensitivity analysis further indicates that the primary and major secondary corridors remain generally stable under alternative weighting scenarios, suggesting that the source-based primary–secondary corridor structure is not an artifact of a single AHP-weighting scheme.

At the same time, this study has several limitations. First, the sample mainly includes national- and provincial-level protected heritage sites and traditional villages, while municipal- and county-level heritage sites, intangible cultural heritage, and movable remains were not incorporated into the unified spatial-modelling framework. This may underrepresent local hydro-cultural nodes, micro-scale tributary linkages, vernacular waterfront activity spaces, and other fine-grained cultural networks. Future research could integrate local heritage catalogues, field surveys, and public perception data to refine local-scale corridor identification. Second, cultural source identification is based on weighted kernel density results and further depends on an integrated assessment of continuity, cluster support, core prominence, and network significance; it therefore still involves a certain degree of judgment. In addition, because this study adopts a synchronic and integrative approach, the identified corridors should be understood as a comprehensive hydro-cultural linkage pattern shaped by long-term historical accumulation, rather than as a precise reconstruction of the corridor network of any single historical period. GeoDetector results may be affected by the discretization of explanatory variables and spatial autocorrelation. In this study, continuous variables were discretized using the same five-level resistance classification as in Table 7 to maintain consistency with the resistance-surface construction, and spatial autocorrelation correction or spatial regression was not systematically incorporated. Therefore, the GeoDetector results are interpreted as explanatory evidence of relative factor effects and interactions rather than strict causal inference. Third, historical waterfront nodes such as ancient wharves, ferry crossings, and other historic river-crossing nodes were not formally incorporated into the resistance-factor system because of incomplete data and insufficient spatial coverage. Some socioeconomic variables were also excluded because of temporal inconsistency and the difficulty of unified basin-scale representation. Finally, the graded protection belts and longitudinal functional segments proposed in this study are intended to express a planning-oriented spatial structure and should not be regarded as statutory regulatory boundaries.

Overall, the transferability of this framework lies primarily in its analytical logic rather than in the direct replication of specific parameters. For other basin regions characterized by strong hydrological dependence and historical linkages, the framework proposed here can be adapted by adjusting evaluation indicators, resistance factors, and protection-grading methods in accordance with local conditions [41].

Based on the results and limitations of this study, future research can be advanced in four directions. First, finer-grained local heritage data could be gradually integrated once their classification standards and spatial coordinates are sufficiently standardised, including municipal- and county-level heritage sites, historical ferry crossings, ancient wharves, and other water–land transition nodes. This would improve local-scale corridor identification and the representation of micro-scale hydro-cultural linkages. Intangible cultural heritage and public perception data could also be used as supplementary interpretive evidence to strengthen the cultural explanation of identified corridors. Second, diachronic corridor modelling could be conducted to compare hydro-cultural linkage patterns across different historical periods, such as pre-Qing, Qing–Republican, and modern stages. Third, modelled corridors could be further validated through field surveys, local gazetteers, historical transport records, archaeological evidence, and participatory mapping. Fourth, comparative studies across different river basins are needed to test the transferability of the proposed framework and to adjust evaluation indicators, resistance factors, and protection-grading methods to different hydrological, historical, and planning contexts.

5. Conclusions

Taking the Xiangjiang River Basin as the study area, this study examined the spatial continuity, hierarchical organization, and graded protection of hydro-cultural heritage corridors from an integrated river-basin perspective. By combining AHP, weighted KDE, MCR modelling, network-structure indices, and GeoDetector analysis, the study established a framework of “spatial identification–network grading–protection conversion.” The main conclusions are as follows.

First, hydro-cultural heritage in the Xiangjiang River Basin exhibits a spatial pattern characterized by clustering along water systems, localized nucleation, and belt-like extension, reflecting clear waterfront dependence and corridor-oriented features. Based on heritage-site evaluation and weighted KDE, eight primary cultural source areas and fourteen supplementary cultural source areas were identified, forming a graded source-area system in which primary source areas serve as structural cores and supplementary source areas support regional extension.

Second, the comprehensive resistance surface shows that the main stem and major tributaries provide the fundamental low-resistance framework for heritage spatial linkages, with distance to the water system playing a central role in the construction of the resistance surface and in the spatial differentiation of potential corridors. Potential corridors extracted by the MCR model are mainly distributed along the Xiangjiang main stem and major tributaries. In this pattern, the primary source areas form the north–south structural backbone, whereas supplementary source areas provide localized linkage zones. Overall, hydrological linkage, topographic context, historical accessibility, land-use conditions, and modern disturbance jointly shape the spatial conditions of corridor formation.

Third, hydro-cultural heritage corridors in the Xiangjiang River Basin exhibit a clear dendritic primary–secondary–tertiary graded structure, expressed as a “2 + 8 + N” pattern. Within this structure, primary corridors constitute the structural backbone of the basin, secondary corridors serve regional supplementation and linkage strengthening, and tertiary corridors extend toward general heritage sites and peripheral nodes. Network-structure indices further indicate that corridor grading clarifies the differentiated structural roles of corridor types and supports the transition from network identification to graded protection.

Fourth, hydro-cultural heritage corridors in the Xiangjiang River Basin are not determined by any single natural condition or historical factor. Rather, they form a basin-scale composite low-resistance corridor system structured by the river-system framework and jointly shaped by topographic context, historical linkages, and modern spatial disturbance. Based on this graded corridor network, the study further proposes a planning-oriented protection framework composed of horizontal graded protection belts and longitudinal functional segments. This framework supports a shift from isolated-site protection and administratively fragmented conservation toward basin-wide corridor governance, with continuous conservation, regional coordination, and node guidance corresponding to corridor grades. It also provides a methodological reference for other river-basin regions characterized by strong hydrological dependence and historical waterfront linkages [60].