1. Introduction
Waterfront public spaces are rare spaces in cities with both blue and green landscapes, which are important outdoor spaces for promoting public health and well-being [
1]. The aftermath of public health events has raised awareness of the important role of urban blue and green spaces in mental health and well-being [
2]. People then began to actively explore more opportunities for natural exposure. However, with the acceleration of urbanization, blue and green spaces are gradually being crowded out, and urban residents have fewer opportunities for natural exposure, which is detrimental to their physical and mental health [
3]. Modern urban design emphasizes the human-oriented design concept [
4]. In the refined development of public space, it is difficult for the traditional ‘top-down’ design method to fully respond to the actual demands of users [
5,
6]. In urban regeneration, the ‘human-centred’ approach prioritizes the well-being of individuals and public interest and emphasizes the active participation of the public [
7]. Only by understanding and responding to the actual users’ demands can we effectively improve the quality of the public space along the waterfront [
8]. Changes in demand may lead to contradictions between supply and demand for waterfront public space, resulting in a ‘supply–demand mismatch’, which in turn affects the effectiveness of the design. To address this problem, the concepts of adaptive urban design and seasonal urban planning are gradually gaining attention. Adaptive urban design emphasizes the flexibility and adjustability of design solutions [
9]. Seasonal urban planning focuses on planning urban spaces according to climatic conditions and seasonal changes in order to optimize resource allocation and meet public needs [
10]. Sheng Liu et al. reviewed climate-responsive design strategies to adapt to extreme heat events from an architectural and urban design perspective [
11]. Many scholars are actively using adaptive urban planning and design in urban ecosystems to proactively address climate challenges [
12,
13]. Adaptive urban design and seasonal urban planning can effectively help waterfront public spaces in winter cities cope with extreme climate challenges.
Winter cities are defined as cities with daytime maximum temperatures that do not exceed 0 °C for at least two months each winter, with high snowfall and a cold climate [
14], such as Harbin, China, and Edmonton, Canada. At least 30 countries in the world are located in the Northern Hemisphere, and approximately 600 million people live in winter climates [
15]. More than half of the territory in China is located in a cold or bitterly cold zone [
16]. Seasonal changes have a significant impact on the mental health of the population and are closely associated with symptoms such as depression and anxiety [
17]. The global prevalence of winter depression is as high as 10%, of which 70% is recurrent major depressive disorder [
18,
19]. This condition is particularly common in high northern latitudes [
20,
21]. Waterfront public spaces are particularly important in winter cities due to their unique ecological landscape and health promotion potential [
22,
23]. Waterfront public spaces contribute positively to residents’ health by enhancing opportunities for physical activity, fostering social interaction, mitigating pollution through processes such as carbon sequestration by vegetation and the natural purification of water bodies, and alleviating stress [
24].
The concept of urban waterfront public space in existing studies is broader, and it is mostly integrated with the study of green space. There is a significant difference between blue space and green space, and the presence of water elements needs to be fully considered in the study [
25]. Current research is mostly focused on coastal cities [
26,
27,
28]. Inland rivers and lakes have relatively few research results and need more attention [
29]. Design strategies are also mostly limited to landscape or planning systems without an in-depth exploration of specific spatial elements. The design of waterfront public space in winter cities often ignores regional characteristics. There are differences in the renewal design in different urban cultural backgrounds, urban functions, and development levels [
30,
31]. Therefore, the design of urban waterfronts should take into account the specific context and avoid mechanically applying existing planning models. Ideal waterfront design should be combined with pre-strategic planning [
32] and post-use evaluation [
33,
34] to ensure the rationality and locality of the design.
Under the constraints of climatic conditions, the seasonal changes in user demands for waterfront public spaces in winter cities are obvious [
35,
36]. Correctly understanding and responding to these changes in demands are the keys to optimizing the use of resources and enhancing the value of the space. Providing accurate supply services from the demand side can effectively avoid a ‘supply–demand mismatch’ and improve the efficiency of resource allocation. Insufficient supply may lead to social inequity, and residents who are unable to meet their needs will face a decline in their quality of life and well-being. Excess supply, in turn, will lead to wasted resources [
37]. Adaptive urban design to cope with climate change under extreme climate challenges is still in the stages of exploration and development. The utilization and development of waterfront public space need further attention.
‘Satisfaction’ is an effective measure of the relationship between users’ demands (psychological expectations) and the reality of the situation [
38]. The level of satisfaction with the urban spatial environment will not only affect people’s willingness and motivation to use the space [
39,
40] but also further affect its social and health benefits. Satisfaction was originally used in the business field mainly to measure the level of consumer satisfaction with products or services. Then, satisfaction was introduced in the fields of urban planning, citizen participation, and social sciences to measure the match between people’s demand for urban space [
41,
42,
43], public facilities [
44,
45], and community services [
46,
47] and the reality of the situation. Therefore, satisfaction evaluation can effectively guide urban renewal, planning, and design strategy designation [
48].
In previous satisfaction studies, the KANO model and the IPA model have been widely used. In 1959, Fredrick Herzberg proposed the famous ‘two-factor theory’ [
49]. Motivated by this theory, Professor Noriaki Kano in Japan proposed the theory of glamour quality and the Kano model [
50] to explain how users perceive and evaluate quality attributes. Researchers applied the KANO model to evaluate the quality of environmental services such as riverbanks [
51], green parks [
52], pedestrianized recreational areas [
53], and urban noise [
54]. The IPA model proposed by Martilla and James in 1977 is widely used for demand decision analysis [
55]. Various industries favour the model for its clarity, ease of use, and intuitive results. In recent years, IPA has been widely used in landscape and architecture to characterize user demands and experience situations [
56,
57]. Although the IPA model and KANO model are widely used, both have certain limitations. First, the KANO questionnaire design and data processing techniques are relatively basic, which may lead to bias in analyzing users’ psychological perceptions. Second, the KANO model is somewhat subjective in the classification and priority setting of demands without sufficiently considering the differences in the importance of demands. To improve the accuracy of the KANO model and IPA model, scholars have constructed integrated models by combining them with other methods, such as fuzzy theory [
58], AHP [
59], SERVQUAL [
60], etc., to match the demands of different industries better. The KANO model and IPA analyses have their focuses, which can theoretically be complementary to each other [
61,
62,
63]. This study will integrate the KANO model and IPA model to combine the advantages of both to make the classification and prioritization of spatial demand more accurate and scientific.
Based on the interaction between environment and behavioral demand, we propose a path to optimize the public space on the waterfront in winter cities from the demand side (
Figure 1). When users’ satisfaction is low, an in-depth user demand analysis is first needed, which is the basis of scientific service provision. Through a systematic survey and feedback mechanism, the demands and preferences of different age groups and communities are comprehensively collected to ensure the comprehensiveness and inclusiveness of the design. Subsequently, the areas of mismatch between supply and demand are analyzed to identify problems further. Finally, the physical environment is corrected through feedback to improve the match between demand and perceived quality, achieving resource allocation and service optimization.
Typical winter cities in Northeast China were selected as the study area for conducting field research and satisfaction questionnaire surveys. This study aims to reduce the mismatch between the actual use feelings and demand expectations among users for waterfront public space in winter cities from the demand side to optimize the allocation of resources and to improve the utilization rate of resources. The specific research objectives are as follows: (1) Construct a set of demand evaluation indexes for urban waterfront public space in winter cities to establish the basis for the optimization of waterfront public space in cold regions from the perspective of users’ demand. (2) Integrate the KANO-IPA model to classify the spatial demand indicators of urban waterfront public space in cold regions and identify the key optimization indicators. (3) Quantify the priority of the spatial indicators and propose the optimization strategy of waterfront public space in winter cities with differentiated priorities.
3. Results
3.1. Reliability Analysis and Validity Test
The reliability of the questionnaire scale was tested in this study using SPSS 27.0 software. The findings showed that the reliability coefficients of the forward, reverse, and importance questions were 0.941, 0.943, and 0.893, respectively, which were over 0.8, and two of them were over 0.9, which indicated that the KANO-IPA questionnaire designed in this study had a high degree of reliability and ensured the validity and applicability of the collected data [
75].
KMO and Bartlett’s sphericity test was used in this paper to assess the validity of the questionnaire. The results showed that the KMO values for the forward, reverse, and importance questions were 0.926, 0.935, and 0.866, respectively, which were greater than 0.8, and the p-value was less than 0.05, indicating that the questionnaire data had a high level of reliability and were suitable for further analysis.
3.2. Calculation of Significant Indexes
The results of calculating the importance index
and satisfaction index
based on the data are shown in
Figure 12.
According to the feedback from the research on the sample reaches, most of the spatial demand indicators have small differences in the importance index. Still, the configuration of landscape ornaments (C4) and characteristic cultural symbol setting (G4) have been given high importance. In contrast, vertical waterfront corridor (A3), quality of water bodies (C2), commercial facilities (C8), tactility of materials (D3), and intelligent service facilities (F5) are considered relatively unimportant. In the waterfront public spaces of cold regions, users’ demands are more focused on safety, water-friendly facilities, recreational facilities, etc. Vertical river corridors do not directly enhance accessibility and the visual experience, and commercial amenities experience reduced winter demand and shift to indoor or enclosed spaces, likely contributing to their lower importance. In cold climates, surface materials such as metal and stone tend to freeze or become uncomfortable to touch, affecting the user experience [
76]. Therefore, although certain facilities are designed to have a good material feel, such details are often overlooked in cold climates, which may also explain the low importance of material tactility.
In terms of satisfaction, there are some differences in the satisfaction indexes of the indicators within the categories of demand, except for demand for pleasure and demand for social interaction. Among them, public toilets (C5), adequacy of activity sites (C3), and entrance and exit recognition (A2) are the indicators with the highest level of satisfaction. On the contrary, safety anti-skid facilities (B3), green landscape quality (C1), and shared service facilities (C7) had lower satisfaction levels. During the field research, it was found that there were few safety warning signs in the sample of the research river section, some roads were dimly lit or not illuminated, and the road surface was not smooth enough, which would significantly increase the risk of users’ activities in the waterfront concerning meeting the actual demands. The vegetation level of the sample space was not rich enough. Plaza space and other nodes were relatively lacking in green embellishment. Only the Yitong River sample C2 waterfront green space had a relatively high green space rate and was richer in species. However, there was a general lack of vegetation species adapted to the cold winter climate in the sample reaches, leading to the loss of natural vitality in the waterfront area in winter. As society progresses and people’s lifestyles change, there may be new points of demand for shared service facilities on the waterfront that are overlooked and may not have been adequately met in the current waterfront.
3.3. Attribute Classification Based on the KANO Model
Based on the improved KANO model, the spatial demand metrics were divided into four demand categories (
Figure 13), with two must-be requirements (M), twenty-four one-dimensional requirements (O), twelve attractive requirements (A), and three indifference requirements (I).
Safety anti-skid facilities (B3) and green landscape quality (C1) are two essential spatial requirements that are currently ‘pain points’ in the design of the waterfront public space in winter cities. If not improved and changed, they may greatly affect the overall satisfaction of the users of waterfront public spaces in winter cities. These two demands are key indicators for improving overall satisfaction.
Users have high expectations for one-dimensional requirements, which are called ‘itch points’. Enhancement of these aspects will have a positive relationship with satisfaction and should be given priority attention. The basic security needs include vertical waterfront corridor (A3), internal path accessibility (A4), night lighting (B2), first aid facilities (B4), activity space adequacy (C4), leisure seating (C6), shared service facilities (C7), recreation and fitness facilities (C10), car parks (C11), and recreation and entertainment facilities (C12). These indicators are directly related to the accessibility of the site and the availability of site resources and are key to ensuring the proper functioning of the public space. Although these are basic indicators, there are still many problems requiring solutions at this stage.
Most spatial indicators of elevated demand are attractive requirements (A). They are intended to optimize the spatial experience of users, and their classification as attractive requirement is in line with the expectations of the survey. It also indicates the users’ demands for improving the quality of waterfront public spaces in winter cities. Twelve attractive requirements (A) have shown a high level of satisfaction and have not expressed more expectations. In the situation of budgetary constraints or resource limitations, improvements to these spatial demands are not necessary. Rather, maintaining the status quo is sufficient. On the other hand, this suggests that these space demands are ‘points of preference’ for users. With adequate resources, user satisfaction and spatial attractiveness can be further enhanced by providing innovative designs for waterfront public spaces in winter cities.
The quality of water bodies (C2), commercial facilities (C8), and intelligent service facilities (F5) are indifference requirements (I). Current users pay less attention to these demands, so too much investment may not significantly improve satisfaction. In this case, resources should be prioritized in the most impactful areas. This demand type is not involved in the discussion in the subsequent analytical decisions of the IPA model. However, this is not to say that these ‘pain points’ should be completely ignored in practice. The spatial demands of users are dynamic and may change to become more important spatial demand indicators in the future.
3.4. Evaluation of Decision-Making on the IPA Model
The respective distributions of the must-be requirement (M), one-dimensional requirement (O), attractive requirement (A), and indifference requirement (I) in the four quadrants are shown in
Figure 14. The mean value of the importance index is 0.665, and the mean value of the satisfaction index is 54.380.
In the IPA quadrant diagram, the decision outcome for the spatial demand indicators in quadrants I and II is a continuation, with quadrant I having a higher priority than quadrant II, collectively referred to as the ‘keeping on’ spatial demand indicators. Quadrant III and IV spatial demand indicators result in an optimization decision, where quadrant IV has priority over quadrant III. Those in quadrant IV are ‘priority upgrading’ spatial demand indicators, while those in quadrant III are ‘partial refinement’ spatial demand indicators. It is worth noting that both attractive requirements and indifferent requirements are located in the holding strategy area, indicating that the IPA model matches the results of the Kano model. Since indifferent demand (I) is not involved in decision-making, 18 spatial demand indicators were finally identified for priority enhancement, namely B3, C1, A4, B2, B4, C4, C6, G2, D1, D2, D6, F1, F3, F4, D7, G4, E1, and E3. In addition, seven spatial demand indicators need partial refinement, namely A3, C11, C12, C7, F2, E2, and D4. The importance and performance gaps of these demands are relatively small, indicating that progressive refinement is still needed, although not a priority for improvement. Finally, the 14 spatial demand indicators that need to be contained are C10, D3, A5, D5, G1, G3, A2, C3, C5, A6, B1, C9, A1, and C13. These demands have reached a high level, and they are sufficient to maintain the status quo.
3.5. Prioritization of Spatial Demand Indicators
Prioritizing can help supply entities select the most important spatial demand indicators that can maximize user satisfaction in the context of limited resources. Calculate the priority index of each demand indicator to achieve the quantitative results of the priority ranking of ‘priority upgrading’ spatial demand indicators (
Table 5), ‘partial refinement’ spatial demand indicators (
Table 6), and ‘keeping on’ spatial demand indicators (
Table 7).
The average priority index values for the three categories of demands, ‘priority updating’, ‘partial refinement’, and ‘keeping on’, are gradually decreasing, indicating that the impact or urgency of demands from ‘priority updating’ to ‘keeping on’ on waterfront public spaces is diminishing in order. This result aligns with decision-making logic and validates the accuracy of the spatial demand priority ranking. At the same time, the priority index of spatial demand indicators within each category shows significant differentiation, indicating that there are clear differences in the importance of these demands. Therefore, during the optimization process, attention should be focused on the most critical needs. In the type “priority updating”, the priority of the configuration of landscape ornaments (C4) is significantly higher than that of other indicators, indicating that this demand should be prioritized in the optimization of waterfront public spaces in winter cities. In the type ‘partial refinement’, there is a clear gap between the vertical waterfront corridor (A3) and the rest of the indicators in this category, with very low satisfaction and importance indices. In the type ‘priority updating’, attractive nodal space (F1), leisure seating (C6), heating facilities (D2), and openness of view to opposite shore (D6), along with the type ‘keeping on’, accessible facilities (A5), external accessibility (A1), and sanitation facilities (C9) have similar priority indices, which indicates that the urgency for optimizing these spatial demand indicators can be regarded as approximately the same.
4. Discussion
This study organized a set of spatial demand indicators that encompass seven dimensions of demand and 42 specific spatial demand indicators—an evaluation of the satisfaction with spatial demand in 12 samples from three winter cities in Northeast China. Using the KANO model to classify spatial demand indicators, we identified two must-be requirements (M), twenty-four one-dimensional requirements (O), twelve attractive requirements (A), and three indifference requirements (I). Through IPA decision analysis, we further obtained eighteen spatial demand indicators for “priority updating”, seven spatial demand indicators for “partial refinement”, and fourteen spatial demand indicators for “keeping on”. Finally, the specific indicators were ranked according to their priority index, clarifying the order of different spatial demand indicators in various types of demands for resource allocation and design improvement. These results provide a clear theoretical basis and decision-making guidance for the design improvement and resource allocation of waterfront public spaces in winter cities.
Compared to cities in other climate types, the climatic characteristics of winter cities, such as severe cold, snow, and ice, pose special challenges to the use of public spaces and the durability of facilities. The results of this study indicate that safety features and warming equipment are particularly important during the cold season. A study conducted in Salt Lake City, U.S.A., reported that safety issues in winter are positively correlated with ice, snow, and cold [
77]. The demand for water-friendly activities and open spaces was equally significant in summer. Other relevant studies conducted in Hokkaido, Japan, similarly found that people’s healthy activity levels are significantly lower in winter than in non-winter months and that outdoor activity levels are lower in cold places than in non-cold places [
78]. Therefore, the behavioral demands of the waterfront in winter are significantly different from those in non-winter. The seasonal fluctuations in behavioral demand are even more important to focus on in areas under the influence of cold climates. Therefore, the design of waterfront public spaces needs to be ‘seasonally resilient’ to provide functions under different climatic conditions. This categorization of demand is consistent with previous research in Khabarovsk, Russia [
79], which further validates the applicability of the KANO-IPA model in winter cities and provides a unique perspective for the optimal design of waterfront public spaces.
An orderly and hierarchical approach to optimal design is adopted to ensure that each step and resource input are as effective as possible to maximize efficiency. Winter cities experience significant seasonal variations and face resource constraints, so design optimization must consider both the time span and cost-effectiveness. Based on the spatial demand indicators in the types ‘priority upgrading’, ‘partial enhancement’, and ‘keeping on’ identified in this study, time-spanning optimization strategies are proposed. They are the near-term priority updating design strategy, the medium-term steady promotion design strategy, and the far-term glamour enhancement design strategy. In the case of conflicting resource allocations, the design tools corresponding to each spatial demand indicator are based on a combination of prioritization and practical considerations.
(1) The near-term priority updating design strategy emphasizes rapid response and problem-solving to enhance attractiveness and meet the urgent demands of users. In this sample river reach, the indicators of priority upgrading mainly focus on the improvement of functional facilities and landscape creation, especially safety anti-skid facilities (B3) and first aid facilities (B4), which are, respectively, ranked third and fifth. These two items are the basic security for waterfront public space activities in winter cities. Several studies showed that the layout and improvement of safety and emergency facilities significantly affect the willingness of urban residents to use waterfront public space [
80,
81]. Cold temperatures and icy conditions in winter make it more dangerous to go out at night. Paukaeva et al. reported that in winter cities such as Khabarovsk, Russia, the probability of people being out and about at night drops dramatically [
79]. Therefore, the addition of security monitoring and night lighting can reduce the safety risks caused by water and vegetation cover, enhance the safety of users, and increase the rate of nighttime use. Appropriate lighting design not only creates a warm atmosphere but also visually relieves the sense of cold [
82] and stimulates outdoor activities. Also, lighting can effectively respond to the reduction in sunlight and alleviate seasonal affective disorder [
83]. In addition, safety tips for winter ice sports should be added in winter cities. Climate shelter (D1) and heating facilities (D2) are in high demand during winter in winter cities [
84]. Outdoor activity spaces should provide cold buffer units, such as heat recharge and rest and shelter facilities, to enhance the activity experience of residents in winter. Studies have shown that cold weather significantly reduces residents’ willingness to engage in outdoor activities when the temperature is lower than 4.4 °C. In comparison, the number of outdoor activity participants gradually increases when the temperature rises above 4.4 °C [
85]. In terms of ground-based landscape design, the ice and snow resources of winter cities can be transformed into advantages by adding regional cultural symbols, shaping unique ice and snow landscapes, and creating weather-appropriate natural landscapes. The construction of ice and snow facilities such as igloos and snow houses is not only environmentally friendly and innovative but also encourages people to stay outdoors for a longer time. Iceland’s ice hotels and winter events highlight Viking traditions through ice sculptures of longships and shields, celebrating the region’s history and adding cultural richness to the landscape. Similarly, the Harbin Ice and Snow Sculpture Festival in China recreates landmarks such as the Great Wall and the Pagoda in ice. The sculptures also showcase traditional Chinese architecture, calligraphy, and symbols, linking art to local culture. In the meantime, the potential for multi-group, multi-temporal coexistence should be explored to create public spaces that are shared by all ages. Several studies have shown that increasing social support in urban public spaces in cold regions can attract more participants [
86,
87,
88]. Enhancing the site’s public facilities to be age friendly [
78] and child friendly [
89]. Smoothing area boundaries promotes mixed use by multiple groups to enhance mobility and accessibility between areas, stimulating the diverse behavioral coexistence of multiple groups. The information transfer pathway should be increased between spaces to enhance implicit communication. For example, the slow walkway fitness rating system platform in the Hunhe area of Shenyang makes it possible for the public to perceive the activities of other people through the platform while they are working out and entertaining themselves, thus enhancing spatial interactivity and connectivity.
(2) The medium-term steady promotion design strategy focuses on the long-term planning and continuous optimization of waterfront public spaces in winter cities, aiming at solving bottlenecks in the development of the spaces through phased implementation, enhancing multi-dimensional shared services and increasing the playability and comfort. These strategies include optimizing resource allocation, increasing diversified activities, and enhancing visual comfort to lay the foundation for the long-term development of the space. The installation of shared lockers can facilitate users’ storage of personal belongings, such as luggage, rain gear, and bicycles. For example, providing outdoor lockers makes it easier for cyclists to engage in other activities after cycling while protecting the equipment from the elements. In addition, car parks should be designed to reduce pedestrian and vehicular interference with each other, with additional planted areas for snow storage and snowmelt absorption. Snowfall may reduce visibility [
90]. Landmark elements should be installed at the main entrances, using LED lighting and reflective materials to enhance visibility at night and in snowy weather so that they are still recognizable in winter when they are covered in snow. Additional seasonal variable spaces should be created to ensure year-round activity, and the waterfront public spaces should be fully developed for seasonal activities. For example, frozen water surfaces in winter can be transformed into snow and ice recreation sites, adding temporary designs to meet seasonal demands [
79]. The resilience measures can help enhance the resilience of waterfront public space and promote its sustainable development.
(3) The far-term glamour enhancement design strategy focuses on long-term planning and strategic layout to develop spatial glamour and features to enhance the soft power of waterfront public spaces in winter cities. This type of strategy focuses on spatial demand indicators that, although less urgent, require higher resource inputs and costs to improve satisfaction significantly. These strategies focus on the following areas: improving accessibility through the enhanced maintenance of facilities, increasing the detailing and refinement of design, guiding public participation, and enhancing cultural infiltration and educational outreach. The ultimate goal is to improve the operational stability, safety, and convenience of the space, enrich the content of public activities, and highlight the city’s image. In the sample area, there is a mismatch between the slow-moving transport facilities and the demand, especially in the cold climate, and it is especially necessary to improve the slow-moving transport. Slow-moving transport is the preferred choice of citizens for short trips, such as walking, jogging, and cycling [
91]. Therefore, it is important to protect the right of way for slow-moving traffic. Drawing on the experience of Copenhagen, the gradual reduction in on-street parking, the increase in bicycle lanes, and the use of physical separation measures have effectively improved the protection of the right of way and the safety of traveling. In terms of design details, the demands of different user groups need to be taken into account. For example, height-adjustable equipment is installed to accommodate users of different heights and sizes. Natural materials, such as wood, are used to provide a warm touch in areas of frequent contact, compensating for metal materials that are too cold in winter. The freezing and thawing phenomenon in winter cities creates unique natural landscapes and activity experiences. Winter festivals, winter sports, and snow-related outdoor activities can make cities in cold regions more attractive [
92]. The ice and snow resources in the public space along the waterfront can be used to develop winter ice and snow education programs, such as ice fishing, ice and snow sports training, ice sculpture making, and snow survival skills, to enrich the winter cultural life and educational experience of the residents.
In the actual optimization and updating process, the three types of optimization and design strategies are carried out simultaneously. However, in the case of resource constraints, in principle, the updating can be carried out in the priority updating in the near term, steady promotion in the medium term, and glamorous enhancement in the long term. The updating of spatial demand indicators included in different categories of optimization and design strategies can also be carried out in the order of priority index. Overall, optimization design strategies should be flexible to respond to the dynamic changes in the supply of waterfront public spaces and the demands of citizens in winter cities. The design should not only address current issues but also consider the potential for future development. As cold climate changes intensify, spatial design strategies must continuously adapt. Therefore, the optimization of spatial design should be a dynamic process that requires continuous assessment and adjustment in line with urban development and climate change to ensure that spatial design consistently meets the demands of residents and possesses long-term sustainability.
Although this paper has achieved certain results, there are still shortcomings, and the following three aspects need to be further explored in depth in subsequent studies. First, the number and scope of data acquisition should be further expanded to improve the comprehensiveness and representativeness of the sample. In the future, more waterfront public spaces in small- and medium-sized cities should be included in the study to collect multi-source and extensive data. Additionally, a more targeted approach focusing on specific populations, such as the elderly and children, could provide more refined insights into their needs and preferences. Second, the satisfaction evaluation of the spatial demand indicators is based on current data, which reflects the needs of waterfront public space users in winter cities at this stage. However, demand changes over time, especially in cold regions, and physical conditions, user expectations, and perceptions of space may change due to technological advances, policy changes, and other factors. Therefore, the practice should consider the time gap between the research results and the actual application to ensure that the measures are feasible. Future research should introduce a temporal dimension to explore cyclical and cross-cyclical changes in satisfaction. By analyzing satisfaction across different seasons or even over multiple years, researchers can identify seasonal or annual trends and adapt recommendations accordingly. This would enable the development of more precise optimization strategies that can provide better theoretical support for the practical application of waterfront public spaces in winter cities. Third, although preliminary optimization strategies have been proposed in this study, these strategies are currently based on preliminary experimental results only and have not been subjected to in-depth feasibility and cost–benefit analyses. This deficiency can be remedied in the future, and the practicality and impact of the study can be further enhanced. Collaboration with researchers in related fields, such as management and finance, can be carried out in future studies to conduct exhaustive feasibility and cost–benefit analyses of the optimization strategies to make the renewal of waterfront public spaces in winter cites more economical, green, and sustainable [
93]. In addition, small-scale experiments can be implemented in the local areas of waterfront public spaces in winter cities to verify the practical effects of the strategies and provide empirical support for future strategy adjustment and optimization.