Nature-Based Solutions (NbS) for Flood Management in Malaysia

Abstract

Flash floods are a concerning social issue that affect urban areas all over the world. Flash floods can disrupt vital services, damage infrastructure, have socio-economic impacts on the earth’s surface, and significantly impact the community near the water body. Household and commercial damage, physical health issues from contaminated floodwater, mental health issues including post-traumatic stress disorder, and even fatalities are some of these common effects. Additionally, it is anticipated that climate change, continuous population growth, and urbanisation will increase flood events and flood risk exposure. Nature-based solutions (NbS) for flood management that lower flood risks include sustainable, economical methods that improve biodiversity, ecosystem resilience, and community well-being. This in-depth study analyses research and literature that previous researchers conducted related to flood management around ASEAN countries, as all these countries are closely located and share similarities in climate and temperature. This survey focuses on identifying the most suitable and effective NbS to overcome the problem and appropriate non-structural measures to support it in solving the flood problem in Malaysia. NbS provide a multi-benefit approach by improving ecosystem resilience, cutting costs, and offering co-benefits, including biodiversity conservation and better water quality, in contrast to conventional methods that put infrastructure before environmental sustainability. This survey also looks at the weaknesses in the existing flood management system and provides recommendations to overcome these problems. Additionally, this survey offers practical policy suggestions to help incorporate NbS into regional and national flood control frameworks, guaranteeing that the solutions are not only socially just but also ecologically sound.

1. Introduction

Floods are a natural hazard often striking Malaysia [1,2]. When the main body of water from a large river or other drainage overflows and causes water to stagnate outside the drainage, these events can lead to a disaster. According to researchers, flood dangers are among the most common and destructive natural disasters in the world, resulting in loss of life and damage to public property [3]. Floods are now Malaysia’s most important natural hazard regarding the number of people impacted, how often they occur, how much they cost, and how they interfere with socio-economic activities [4]. The Selangor State Department of Irrigation and Drainage (2022) states that floods happen when water overflows from lakes, rivers, or drainage systems, resulting in high tides, heavy rain, ice melting, and drainage system obstructions [5]. Malaysia often experiences monsoon floods around the peninsula’s east coast during the monsoon season, from November to March every year. In Malaysia, floods cause 90% of natural disaster damage, making flood catastrophies the most destructive natural hazard [6]. This phenomenon can damage property and infrastructure, threatening and taking lives.

According to the Malaysia Department of Irrigation and Drainage (MDID) (2016), the flood phenomenon can be categorised into two types: flash and monsoon floods [7]. Monsoon floods can hit an area for an extended period and are predictable, while flash floods occur quickly and are difficult to predict [8]. Floods can occur due to natural factors like rain that falls so heavily that the existing drainage can no longer accommodate the amount of water that falls [9]. However, human factors like uncontrolled garbage dumping can cause water drains to clog and cause water to overflow, also resulting in floods [10]. Indeed, studies have proven that various human activities are a primary factor related to natural hazards, as erroneous land use significantly and negatively impacts disasters related to floods and flash floods in basins [11].

Natural flood disasters have negatively impacted communities, significantly inhibiting development [12]. This adverse impact is said to exist because development is challenging to implement if the problem of flood disasters that can damage the built infrastructure often threatens it. Flood disasters simultaneously disrupt an area’s economic and social activities and bring losses to the community and people in the region [13]. For instance, in the 2020 Segamat flood, the estimated yearly damage (EAD) for residential areas (50,112 units) and business sectors (9318 premises) was MYR 12.59 million and MYR 2.96 million, respectively [2]. In addition, the flood disaster caused considerable losses to the government, and substantial recovery costs were incurred to cover the losses due to the flood disaster [14]. Losses can reach millions of ringgits, and more effective efforts must be implemented to prevent the same losses from occurring annually.

The primary hypothesis of this research is that NbS in flood management will ensure long-term environmental and socio-economic benefits while reducing the impacts of floods, or NbS in flood management have the potential to reduce the effects of floods while ensuring long-term environmental and socio-economic benefits. NbS provide affordable, climate-resilient substitutes for conventional infrastructure to lower flooding risks and restore ecosystems. However, NbS can be labour-intensive, land-intensive, site-specific, and challenging to integrate with policies and maintain.

Water and flood control requires clever, nature-based inventions and advancements due to climate and socio-economic changes. NbS constitute concepts of environmentally, socially, and economically sustainable uses of nature to address today’s issues [15]. The World Bank mentioned the term NbS [16], which the IUCN further defined [17], and for which the European Commission provided a more straightforward explanation [18]. Scientists have described NbS as “actions to protect, sustainably manage and restore natural or modified ecosystems, which address societal challenges (e.g., climate change, food, and water security or natural disasters) effectively and adaptively, while simultaneously providing human well-being and biodiversity benefits” [19]. NbSs can effectively address flood risks, water security, and water quality issues through various methods, including simulating evapotranspiration, infiltration, and phytoremediation [20].

To lessen the negative effect of this natural hazard, flood-related studies should be conducted to identify problems and deficiencies that can be repaired to prevent losses to any party. Natural hazards are indeed phenomena that are difficult to predict. Still, if authorities can establish and implement protective measures, these measures can help reduce the risk of flood disasters while minimising the losses that all parties must bear. This study focuses on identifying the most suitable and effective NbS to overcome the problem and appropriate non-structural measures to support it in solving the flood problem in Malaysia. This study also looks at the weaknesses of the existing flood management system and provides recommendations for overcoming the problem. NbS are novel for flood management because they combine ecological processes with engineering techniques to provide multifunctional, adaptable solutions that improve ecosystem health, biodiversity, and societal benefits while reducing flood risks. These technologies make them a sustainable substitute for conventional infrastructure.

In many aspects, NbS generally outperform conventional solutions. Theoretically, NbS seek to create a multipurpose, robust infrastructure that links to sensitive places and lasts longer than its grey competitors. Unlike risk-based, strong, but short-lived grey solutions, NbS techniques aim for flexible, adaptive, resilience-based planning and design procedures [21]. Malaysia already has a complete structure in flood disaster management with various forms of different agencies with multiple scopes of duties. However, the extensive management structure involving dozens of agencies causes the delivery of unclear instructions and the deployment of assets to be too slow. One significant drawback of using NbS for flood control in Malaysia is the lengthy implementation period needed for natural systems, including reforestation and mangrove restoration, to reach their full potential. Furthermore, land-use conflicts and a lack of policy integration may prevent NbS from being widely adopted, particularly in metropolitan locations with limited space. This vulnerability is unacceptable, particularly regarding calamities threatening community members’ lives.

Relevant research publications were gathered from journal portals, including Google Scholar, Scopus, and Web of Science (WoS), to conduct this review. The search terms NbS and flood mitigation were used to find articles published between 2019 and 2024 that were taken from the journal portals. The survey was limited based on the ten members of ASEAN countries, Brunei Darussalam, Cambodia, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam. The most suitable techniques for a flood mitigation plan for Malaysia identified via this review would contribute to better and more comprehensive flood risk management by identifying its effectiveness to be used in Malaysia.

2. Benefits of NbS for Flood Management

Working with natural solutions is one primary method in ensuring that ecosystems and the environment can be restored back to normal and preserved [22]. This method helps protect the environment and allows the environment to return to stability while guaranteeing well-being in people’s lives worldwide. Natural hazards that occur worldwide are one form of response from nature when humans have damaged the environment too much. The more pollution or any other form of development that threatens the environment that humans have, the higher the risk of natural hazards occurring due to the instability of the ecosystem because of human development [23]. Natural hazards such as floods that happen yearly in various areas in Malaysia are caused mainly by unplanned development that disrupts the stability of the ecosystem. For example, large-scale felling of trees in the forest makes the soil less stable and can cause landslides that can destroy property and life [24]. The same situation can also be seen in flood disasters, where flash floods can occur unexpectedly, resulting in uncontrolled waste disposal in the drainage system, which can cause clogs and overflows [25]. As a result, a disaster will hurt a community and various parties by causing facilities, property losses, and loss of lives. Therefore, the appropriate action to overcome this problem is to take natural flood prevention measures. Flood management is essential for controlling urban disasters and economic losses, planning for future development, and developing a sustainable urban structure in Malaysian urban areas. Therefore, NbS are more helpful in implementing those conditions (Figure 1).

This survey provides an organised summary of flood management strategies and NbS advantages. The four stages of flood management are described as follows: pre-flood (risk assessments, mapping, and preparation), during the flood (protection, monitoring, and evacuation), after the flood (rehabilitation and damage assessment), and long-term measures (mitigation plans and structural improvements). Ecological (biodiversity preservation, groundwater recharge), flood management (risk reduction, increased resilience), socio-economic (job development, tourism), and environmental (carbon sequestration, soil stability) benefits are the categories under which NbS benefits fall. Examples of NbS are highlighted, including wetlands, green roofs, permeable surfaces, and their financial benefits (shared funding opportunities and reduced expenses). For implementation to be successful, integrated planning, upkeep, and regulatory support are needed.

One advantage of using natural flood prevention measures is that their implementation does not impact the environment because the method used is natural and does not require the development of complicated structures [26]. Among the examples of approaches used in building a water catchment area is a lake accommodating excess water that falls into place after heavy rain. Developing a catchment area such as a lake can form a new ecosystem and simultaneously be categorised as a naturally sustainable development [27]. In addition, natural flood prevention is also seen as more cost-effective than focusing on other methods. This cost-effectiveness is said to be so because this preventive measure focuses more on prevention, that is, making efforts before a disaster occurs. Among the examples of focusing on prevention are implementing an awareness campaign for the community related to flood management and stricter law enforcement to teach irresponsible parties a lesson [28]. Implementing initiatives has a positive impact in addition to saving costs instead of bearing the loss of damage after a flood disaster. Overall, this solution naturally provides a positive impact without having any side effects on the environment and helps create a sustainable ecosystem and lifestyle in an area.

3. Observations from Literature

The findings successfully obtained from the research highlight that most studies focus on preventive measures rather than prioritising measures to repair the damage after the disaster subsides in an area. For example, an article entitled Flood Mitigation Master Plan for Shah Alam, written by Aida Ahmad in 2022, focuses on the Shah Alam municipal council preparing a drainage master plan to overcome drainage problems that cause major floods around the Shah Alam area [29]. The Shah Alam Sustainable Urban Drainage Master Plan (SAsud) was for three years between 2022 and 2024 and included multiple types of mitigation, such as structural and non-structural methods [30]. This plan sought to upgrade the existing drainage system to lower the risks of water overflowing after heavy rains around Shah Alam. In addition, water catchment areas were also created to hold more water when there is heavy rain.

Another article on preventive measures is The Proposed Framework for the Flood Disaster Management Cycle in Malaysia, which focuses on the weaknesses of the existing drainage system and some other types of deficiencies that are the main challenges in managing flood disasters in Malaysia [31]. The suggestions included upgrading the existing drainage and drainage system to be deeper and better, creating an early warning system against impending flood disasters, and conducting an awareness campaign for the community to educate about flood management. These recommendations argue that efforts to overcome the flood problem should begin with prevention techniques and practising natural methods. Therefore, the results of previous studies support evidence that the preservation and conservation process of the environment dramatically impacts flood management.

The study found that of the 96 papers from the keyword search, 17 research articles completely satisfied the search parameters after a thorough full-text inspection (Figure 2). The applied keywords to identify the literature were “Nature-based Solutions” and “Flood management” and “Flood risk reduction” and “Ecosystem-based solutions” and “Green infrastructure” and “Wetland restoration” and “Urban flood mitigation” and “Sustainable flood management” and “Coastal flood management” and “Climate change adaptation” and “Stormwater management” and “Flood resilience” and “Bioswales” and “Permeable pavements” and “Floodplain restoration” and “Nature-based Solutions for flood management ASEAN” and “Flood risk reduction Southeast Asia” and “Green infrastructure flood management ASEAN” and “Ecosystem-based adaptation Southeast Asia” and “Urban flood resilience ASEAN” and “Mangrove restoration Southeast Asia” and “Flood mitigation in ASEAN countries” and “Coastal flood management ASEAN” and “Sustainable flood management ASEAN” and “Watershed management in Southeast Asia”.

Malaysia’s flood management strategy aims to reduce flood risks and impacts by coordinating efforts among communities, government agencies, and stakeholders. Malaysia’s position and climate make it vulnerable to floods. Recent notable floods include the East Coast floods in 2014–2015, which caused damage of MYR 2.6 billion (USD 630 million), the 2020–2021 East Coast floods, which caused damage of MYR 1.1 billion (USD 260 million), and the Kuala Lumpur floods in 2022, which caused extensive disruption and destruction. Malaysia intends to improve its capacity to control floods via community involvement, legislative measures, and infrastructure development. Based on the literature review on flood management in Malaysia, researchers are focused on different keywords like flood management, flood hazard, flash flood, and urban flood (Figure 3). Researchers in Malaysia and other countries have examined flood management issues (Figure 4). In this current survey, 17 NbS articles on flood management were studied, and detailed implementation strategies were added to find the best solutions for flood management in Malaysia (

Table 1. Details of the literature for flood management 2019.

Ref.	Study Area	Objectives	Results	Recommendations
[32]	Rangsit Canal area of Thailand	To provide a framework for evaluation to measure the advantages and co-benefits of NbS implementation.	Water storage and reuse and education and research were the two NbS categories that performed the best. This is because there are many furrows in the area and many letters about the advantages of furrows with other communities. Local flood mitigation, historical flood mitigation, and water quality were the indicators that performed the worst. These indicators, which include more frequent dredging of canals and furrows, confirm these advantages.	Expand storage space, furrow networks, and deepen or widen furrows. Maintain furrows frequently to avoid silt accumulation, fill them up more before the dry season, plant crops that can withstand drought throughout the dry season, utilise more effective irrigation techniques, and encourage others to use furrows.
[33]	Sukhumvit area in Bangkok (Thailand)	To offer a framework that optimises potential for NbS to improve thermal comfort and lower the risk of flooding.	Overall, the findings indicate that implementing various strategies at various sites is probably the best way to mitigate flooding and improve thermal comfort.	The NbS type that demonstrated the best flood control performance in Sukhumvit was “green roofs”. This approach is explained by its greater appropriateness, which increases the stopping area and, when combined with other NbS kinds, improves the success rate for reducing urban flooding.

,

Table 2. Details of the literature for flood management 2021.

Ref.	Study Area	Objectives	Results	Recommendations
[34]	Chindwin River basin in Myanmar	To create a probabilistic risk analysis framework that can be used to quantify these benefits in three ways: (1) it can be applied to huge basins and contexts with limited data; (2) it can account for frequent small occurrences and less frequent major events; and (3) it can quantify economic gains and the decrease in the number of impacted individuals.	Small but frequent storms are the primary driver of loss reduction, indicating that present methods that depend on big storms may undervalue the advantages of nature-based solutions. The framework facilitates mainstreaming nature-based solutions in infrastructure planning or insurance practice by providing average yearly losses. Using this paradigm, they discovered that the Chindwin River Basin’s forest cover significantly affects the danger of flooding.
[35]	Ayutthaya, Thailand	To answer the effectiveness of various NbS kinds (small- and large-scale NbS) and their hybrid configurations with grey infrastructure.	According to the findings, small-scale NbS are only successful during smaller rainfall events. At the same time, more extensive (or extreme) storms call for hybrid interventions—a combination of several strategies implemented at different scales.
[36]	Segamat River Basin, Malaysia	To assess the effects of climate change and LULC change on floods in the Segamat River Basin in Johor, Malaysia, using InfoWorks Integrated Catchment Modelling (ICM) for 1D–2D hydrodynamic river modelling.	The simulation findings for this agriculturally based rural basin in a tropical climate indicate that only the detention pond mitigation method significantly lowers floods. In contrast, the other two mitigation techniques have less influence.

,

Table 3. Details of the literature for flood management 2023.

Ref.	Study Area	Objectives	Results	Recommendations
[37]	Thu Duc City, Ho Chi Minh, Vietnam	To reduce urban floods, the strategy for green infrastructure development should investigate the kind of soil.	The findings may indicate how soil type affects the design of green infrastructure, which is a natural way to reduce urban flooding. Less than 10% clay soil is ideal for green infrastructure, improving groundwater recharging and reducing stormwater runoff.
[38]	Bangkok, Thailand	Creating and testing an assessment methodology for assessing ecosystem services in Bangkok Thailand’s peri-urban area.	The agrihood design performed better than it in all ecological service categories, including aesthetics and habitat quality. Since the main drainage canal’s design included artificial wetlands, the agricultural design also had lower mean concentrations and yields of sediment and nutrients than the site’s present (natural) circumstances.
[39]	Bantul Regency-Yogyakarta, Indonesia	To identify possible sites for developing the Nature-based Solutions (NbS) concept near flood-vulnerable areas in Bantul Regency, Yogyakarta, Indonesia.	According to the data processing and analysis results, the pilot project area has multiple locations where floodplain-based NbS can be deployed, especially at the junction of the Opak and Oyo rivers. At this point, different forms of NbS can be identified and applied.	The proposed NbS consists of riparian zones, inland wetlands, detention basins, and porous pavements. To avoid flooding, the sites of the four NbS are determined by the nearby environment and the unique qualities of each NbS object.
[40]	Rangsit Area, Thailand	To investigate whether Real-Time Control (RTC) may be used for NbS operations to decrease flooding and increase their efficacy.	The results demonstrate that the RTC system fruitfully lowers the water level at the Western Raphiphat Canal Station during typical flood events compared to the system without RTC or with additional storage. Also, the RTC system facilitates achieving the required minimum volume and increasing the volume of retentions.
[41]	Pekalongan, Indonesia	To investigate how eco-infrastructure might be used to reduce coastal flooding.	According to the simulation results, the area’s current drainage conditions were insufficient to manage the flood. In contrast to the proposed eco-infrastructure, which primarily provides a buffer zone to keep water out of the settlement zones, the grey infrastructure might limit tidal overtopping.
[42]	Mun River Basin, Thailand	Developing and testing MCDA-GIS analysis to map potential natural techniques that could reduce flood dangers in the Mun River Basin, Thailand, will help close the gap.	Re/afforestation, shifting agricultural kinds, and wetlands were identified as the top three options for flood and drought concerns. According to the data, flood hazard diminished when NbS were implemented in the watershed, chiefly for A/Reforestation, and this effect increased when a combination of NbS were used.
[43]		To examine the current development of Sponge City and concentrate on the aesthetics that should be considered when Sponge City is operating.	The main visual richness and sensory perception elements are the typology of green space elements, climate comfort, and material. Sponge City’s attributes are closely related to one of the branches of aesthetics.

and

Table 4. Details of the literature for flood management 2024.

Ref.	Study Area	Objectives	Results	Recommendations
[27]	Iligan City, Mindanao, Philippines	To evaluate how stakeholders’ perceptions and levels of understanding of climate change and NbS relate to their willingness to participate. The aim is to ascertain how stakeholders’ perceptions of climate change, awareness, and desire to participate vary depending on their sociodemographic origins.	The results reveal significant variations in awareness and perceptions across stakeholders’ various socio-economic backgrounds; respondents with higher incomes and education levels exhibit higher awareness, perception, and willingness.	The study suggests future-focused plans and sharp drives for climate change and sustainable solutions, like incorporating NbS into adaptation and mitigation programs to promote multi-level stakeholder alliances.
[26]	Guangzhou, China	For NbS integration, assign priority sectors to an industrially enhanced appraisal at fine spatial resolutions. Urban planners and investors can improve urban flood risk governance by evaluating the helpful effectiveness method. Examining the complex interactions between urban design, socioeconomics, and space to develop a carefully considered plan for maintaining historic urban land.	The results highlight how crucial urban design is for managing flood risk and show how effective vegetation-based strategies are for vegetated swales and bioretention cells, which make up 8.41% and 7.08% of the total area, separately reducing the effects of urban flooding.	One of the approvals for heritage city innovation is prioritising road layouts that incorporate greenery and gradually improve the grey infrastructure in historic districts.
[28]	Pathumthani Province, Thailand	To determine the ideal location for NbS at Bangkok Thailand’s Asian Institute of Technology (AIT).	The MCDA approach was appropriate for identifying the optimal location for NbS using various technical, environmental, and economic factors. According to the data, Site-1 is a good substitute for implementing NbS on the AIT campus. Research shows that a bioretention system can cut pollutants by at least 14–20% and runoff volume by at least 14%.
[29]	Reok District, Indonesia	To report on an assessment of how well ICBRR and NbS integrate into community-level program execution.	In short-duration projects, the overall idea of NbS is challenging to tool and quantify since they take longer to see meaningful and balanced changes in each module, which are mainly net gains in biodiversity, livelihood, and regional policy integration. However, the program has succeeded in starting an operation that puts NbS in the context of civic needs and skills and is simple to understand locally.
[30]	Bengawan Solo Watershed, Indonesia	Descriptive and policy analysis will be used to investigate the planning and execution of NbS in Bengawan Solo Watershed, as well as opportunities, gaps, and stakeholder involvement.	The analysis found some linked NbS in the Bengawan Solo Watershed’s upstream and downstream regions. The analysis also showed that NbS installations can be combined with socio-economic endeavours to raise locals’ standard of living. The NbS idea is only partially connected to the current water-related policies and initiatives, which is made worse by a lack of coordination among stakeholders and concerned parties.	Policy enforcement, regulation, and stakeholder cooperation must be improved to predict how climate change may affect flood and drought risks and the declining socio-economic settings in the Bengawan Solo Watershed.

).

4. Discussion

The growing frequency and intensity of floods in Malaysia highlight the pressing need to implement efficient flood control measures. A viable approach is to use nature-based solutions (NbS), which use ecosystems and natural processes to reduce the risk of flooding. The review of 17 literature studies and initiatives conducted in Southeast Asia and other areas offers crucial knowledge about the suitability and efficiency of NbS in Malaysia’s flood control environment.

Preventive measures are prioritised over post-disaster reparative actions as a recurring theme in the reviewed studies. Research on the Shah Alam Flood Mitigation Master Plan, which provides a thorough strategy for resolving drainage problems that result in substantial flooding, articulates this emphasis [39]. The plan aims to lessen the risk of water overflow during heavy rains by integrating structural and non-structural methods to improve the current drainage system. A researcher who emphasises the significance of modernising drainage systems, implementing early warning systems, and launching community awareness campaigns further supports this proactive approach [31]. Such steps are essential for Malaysia, where frequent floods result in considerable damage and disruption. Preventive measures align with the overall objective of reducing flood risks before they become catastrophic [44].

As shown in Guangzhou, China, implementing NbS into urban planning highlights the vital role that urban design plays in flood risk management [26]. The study shows that vegetation-based techniques, like vegetated swales and bioretention cells, are effective in lessening the effects of urban flooding. These techniques effectively reduced the risk of flooding and covered a sizable portion of the land. Similar vegetation-based strategies can be incorporated into urban planning in Malaysia, especially in flood-prone areas like Kuala Lumpur and Penang. Malaysia may lessen the risk of flooding by creating green areas, permeable pavements, and urban forests, which will improve water absorption and decrease runoff.

Another crucial point that the studies emphasise is the implementation of NbS at the community level. For example, the community-scale research conducted at the Asian Institute of Technology (AIT) in Thailand shows how well bioretention systems reduce pollutants and runoff [28]. At the local level, putting such localised NbS into practice can improve resilience and encourage community involvement. Similar strategies can be implemented by community centres and educational institutions in Malaysia to efficiently manage stormwater and support larger flood control initiatives.

As mentioned in the Reok District, Indonesia [29], measuring long-term benefits and matching these solutions to local needs are two challenges of implementing NbS. Malaysia can address these issues by creating precise frameworks for implementing NbS and guaranteeing strong stakeholder engagement. The Bengawan Solo Watershed study in Indonesia also highlights the significance of stakeholder coordination and policy enforcement [20]. Strong policies and cooperative efforts among government agencies, local communities, and private stakeholders will be necessary to implement NbS in Malaysia to ensure these solutions are successfully integrated into flood management plans.

Research conducted in Ayutthaya, Thailand, emphasises the various levels of effectiveness of NbS on a small and large scale [35]. While larger-scale or hybrid measures are required for extreme events, small-scale NbS are effective for managing smaller rainfall events. To effectively manage floods at different scales, Malaysia can take a hybrid approach, utilising larger-scale initiatives like wetland restoration and smaller-scale interventions like rain gardens. With its ability to address frequent, minor floods and infrequent, extreme events, this hybrid approach guarantees comprehensive flood risk management.

Furthermore, research conducted in Thu Duc City, Vietnam, on the influence of soil type on green infrastructure planning highlights the significance of regional environmental factors in NbS design [31]. In Malaysia, the implementation of green infrastructure can be prioritised in areas with suitable soil types, thereby improving the reduction of stormwater runoff and replenishing groundwater. Using a focused approach, NbS maximised its effectiveness by adapting to the local context.

In conclusion, integrating NbS into Malaysia’s flood management plans offers several possible advantages. The studies reviewed emphasise the significance of policy coordination, community involvement, integration of urban planning, and preventive measures. Malaysia can enhance flood resilience and promote sustainable water management practices by implementing a comprehensive approach that incorporates both small- and large-scale NbS, customised to local environmental conditions [45]. In addition to reducing the risk of flooding, this proactive and coordinated strategy will improve the general sustainability and resilience of Malaysia’s urban and rural environments.

5. Why Policy for Flood Management Is Difficult to Implement in Malaysia

In a country that often experiences flood disasters every year, the government has succeeded in creating a complete operational structure and framework for flood management as well as a government body responsible for handling flood disasters that occur, in order to deal with and reduce the risk of losses from disasters that occur [46,47]. However, until today, all forms of policies and acts that have been created are still seen as failing to reduce the impact of flood disasters on the public in the country. The subnational partnership would include routine river basin upkeep as part of Malaysia’s all-encompassing strategy for identified vulnerable and significant areas. In the modified Eleventh (2016–2020) and Twelfth Malaysia (2021–2025) plans, MYR 5 billion for shoreline preservation and MYR 19 billion for flood mitigation projects are now included. Nature-based solutions, such as creating space for water and integrating nature into buildings, might be applied more extensively to non-structural flood control [48]. Enhancing water retention capacity, implementing resettlement plans for floodplain areas to reduce the risk of disasters, gazetting wetlands, river reserves, and flood-prone areas as flood mitigation areas, and implementing integrated flood Management, integrated water resources management, and integrated river basin management are further steps that will be required to achieve this [49]. Malaysia seeks to factor climate change into flood construction and coastal protection systems to increase the average recurrence interval level. Flood adaptation and disaster risk reduction are mainstreamed through resilient development and transmitting flood hazards and risk maps to relevant authorities. Malaysia has been enhancing flood control effectiveness and mainstreaming climate change adaptation in response to climate change forecasts. Enhancing flood mitigation can contribute to achieving SDGs 11 and 13, which will enhance SDGs 1.5, 2.4, 6.5, and 9.1 [48].

Among the main weaknesses and challenges that can be observed in creating an efficient and systematic flood management system is the lack of cooperation between the federal government and local governments. Addressing this deficiency is necessary because cooperation from the local level is essential to ensure that any form of initiative and effort formed by the federal government can be implemented promptly and in a planned manner. This can be observed from the entire flood management, where the framework formed is thorough with a clear work specialisation. However, such systematic planning will still fail if both parties fail to cooperate in conducting an operation to deal with the problem of flooding. An online newspaper clipping from 21 December 2021, where the Malaysian prime minister, Ismail Sabri Yaakob, admitted that there were weaknesses in flood management, supports this conclusion [50]. He insisted that managing flood disasters was not solely the responsibility of the federal government but also of the authorities at the state and district levels. As a result of this lack of cooperation from both parties, the people are heavily affected as the authorities have been slow to act, leading to enormous losses for the government and the people affected by this flood disaster [51]. Collaboration between different government levels and agencies is crucial as every party has roles to be fulfilled to save people from disaster.

6. Flood Management Recommendations

Flooding poses a significant threat to Malaysia due to its frequent occurrence and extensive damage to lives, property, and socio-economic activities. The monsoon season and human factors like improper waste management exacerbate this issue. Floods in Malaysia, such as the devastating event in Segamat in 2020, underscore the urgent need for effective flood management strategies. The NbS offers a promising approach, harnessing natural processes and ecosystems to reduce flood risks while promoting sustainable development. Case studies from China, Thailand, and Indonesia illustrate the effectiveness of NbS at various scales, emphasising the importance of preventive measures over-reactive responses. For Malaysia to enhance its flood resilience, integrating NbS into urban planning, community initiatives, and robust policy frameworks is crucial. This holistic approach mitigates flood risks and fosters sustainable development, ensuring a safer and more resilient future for Malaysia.

The NbS for flood control in Malaysia emphasise using natural ecosystems to lower flood risks while offering economic, social, and ecological advantages. Essential tactics include wetland conservation to improve water absorption and lower urban runoff and mangrove restoration to shield coastal regions from storm surges. Urban green infrastructure, such as green roofs, rain gardens, and permeable pavements, is being integrated to manage city stormwater. At the same time, reforestation and watershed management help control soil erosion and regulate river flow. These NbS boost resilience to climate change and provide affordable, sustainable flood mitigation measures. NbS can enhance conventional infrastructure and help Malaysia develop a more comprehensive flood management strategy if given the proper backing. Incorporating natural processes into the design of NbS for flood management in Malaysia lowers flood risks while fostering environmental sustainability. Some possible remedies include strengthening shorelines, improving biodiversity, shielding coastal towns from storm surges and coastal flooding, restoring damaged wetlands to reduce the risk of flooding and absorb excess rainfall, particularly in low-lying locations, reducing surface runoff, and encouraging natural water infiltration in urban environments by implementing vegetated swales, permeable pavements, and green roofs. In upstream catchment regions, planting trees can improve water retention, curb soil erosion, and lower the chance of floods downstream. Native vegetation supports riverbanks and stops erosion to control river flow. These NbS lessen reliance on traditional infrastructure while enhancing water quality, preventing flooding, and conserving biodiversity.

Among the suggestions that can be given to improve flood management quality in Malaysia is to ensure good collaboration between the various parties responsible for flood management. This collaboration can help improve communication between several government and private agencies and facilitate the coordination and movement of important assets in flood management. This facilitation should be a priority in every project carried out in flood management because various experts should be brought together in the same team to ensure that the flood problem can be comprehensively overcome. This comprehensive solution guarantees effectiveness in overcoming the flood problem while saving the government costs. The lack of a comprehensive solution is often seen as a major problem in flood management in Malaysia when all efforts and initiatives fail to stop the flood problem from occurring when there is a lack of cooperation from the parties who play a leading role in flood management. The government should address weaknesses in the emphasis and coordination of this task focus to ensure that all flood management efforts can be implemented more efficiently and systematically.

7. Conclusions

NbS provide creative and sustainable flood management strategies in Malaysia in response to the nation’s rising flood threats brought on by deforestation, urbanisation, and climate change. Flood resilience can be improved by reforestation, wetland conservation, and mangrove restoration, enhancing water infiltration, lessening flood severity, and providing essential ecosystem services. Additionally, NbS can improve urban green space quality and aid in biodiversity conservation, benefiting ecosystems and residents. Nonetheless, several obstacles stand in the way of effective NbS implementation in Malaysia. Enabling extensive restoration projects requires improved knowledge and comprehension of NbS, the integration of policies, and suitable funding sources. NbS are advantageous, but their efficacy depends on long-term maintenance and appropriate site-specific design. It will be essential to incorporate NbS into flood management plans if the government is to maintain environmental sustainability through laws and regulations.

Computing traditional engineering solutions, and the cost-effectiveness of NbS provides major benefits in Malaysia, particularly in metropolitan locations where traditional flood control methods are frequently costly and unsustainable. NbS can provide long-term advantages and lower infrastructure costs using natural processes. Further highlighting the significance of NbS in enhancing resilience to future flood occurrences is the increasing awareness of the effects of climate change. NbS offers a promising and practical solution for flood control in Malaysia; their integration necessitates resolving several issues, including conflicts over land use, policy gaps, and increased public awareness and involvement. With the correct backing, government dedication, stakeholder cooperation, and ongoing observation, NbS might emerge as a critical element of Malaysia’s flood risk management plan. Adopting NbS supports long-term sustainability, community well-being, and environmental protection to reduce the risk of flooding.