This paper reviews both sustainable infrastructure and green infrastructure, a description of developments in these areas, major facets, and advantages of utilizing them, and policies that promote such development. Thus, through these aspects, the paper lays down the preliminary steps towards a more critical analysis of the possibilities of green infrastructure in the sustainable development of cities.
2.1 Overview of Sustainable Infrastructure
Sustainable infrastructure therefore involves a broad umbrella that can be regarded as associated with practices, products, and technologies designed to minimize the impacts on the environment and maximize infrastructure sustainability and economic profitability [11]. It encompasses the organization, coordination, and management of infrastructure at the planning, design, construction, operation, and maintenance stages to ensure that it is efficient in resource use, embraces sustainable development principles, and is designed to adapt to current and future climate change conditions [12].
The idea of sustainable infrastructure has, therefore, emerged over the years as people came to recognize the fact that infrastructure requires sustainability, especially in current complex cities [13]. The behavioral measures include energy efficiency, water conservation, disposal of waste, and construction of structures from eco-friendly materials. Sustainable infrastructure also focuses on how to draw or achieve a lifecycle of the project and its impacts on the environment in its overall development and up to the time of deconstruction [14].
Historical analysis and evolution of sustainability precepts in urban planning
The history of sustainable urban planning can be attributed to the environmentalism movements in the early 1960s and 1970s industrialization and population growth leading to urbanization were identified as the main causes of environmental degradation. It was around 1962 when a book named “Silent Spring” was published by a lady named Rachel Carson which was the initial step and later different environmental regulations paved the way for sustainable development concepts [15].
The international acknowledgment of the sustainable development idea can be attributed to the 1990s, in particular, owing to the Brundtland Report, where this term was defined as development that can fulfill the needs of the present generations, without generating negative impacts on future generations [16]. This same period can also be considered as the beginning of utilizing green building certifications such as LEED and BREEAM, as practical guidelines that incorporated principles of sustainable development [17].
2.2 Green Infrastructure
Green infrastructure means the interconnected systems and functions of natural and bio-active features functioning as environmental, socio-economy benefits systems within a city spatial area [18]. While grey infrastructure identifies infrastructure conventions that are commonly implemented in urbanization, green infrastructure calls for the utilization of natural systems in solving challenges experienced in the growing urban centers. Key components of green infrastructure include: Key components of green infrastructure include:
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Green Roofs: Roofs that involve vegetation that assists with thermal performance, modulation of/holding of stormwater and water, as well as affording habitats for animals [19].
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Urban Forests: New avenues that have enhanced vegetation that aids in purifying the air and any area designated as a park with increased tree cover to support the increased wildlife in our cities [20].
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Rain Gardens: Pavement structures such as sodalite that enable management and purification of rainwater thus preventing flood episodes [21].
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Green Walls: Integrated Concepts that can include active insulation layers, purification of atmospheres, and creativity in appearance [22].
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Permeable Pavements: Impervious materials that gradually let infiltration and seepage occur, thereby preserving runoff and replenishing water table streams [23].
Comparison of Grey Cost with Conventional Grey Structures
Classic grey infrastructure which embraces roads, bridges, and stormwater drainage involves rigid structures and works mainly of impervious material hence being more of a nuisance to the environment [24]. For instance, typical drainage systems in urban areas are typically employed to rapidly transport water downstream, and this can result in further occurrence of floods in other areas.
While the conventional approach tries to convey stormwater in the shortest time possible or hold it in a container for a limited time, green infrastructure tries to mimic the tendencies of the hydrological cycle, where the water can infiltrate, filtrate, and store the rainwater [25]. Thus, this approach contributes to the reduction of the flooding risk The same strategy impacts Water Quality and Ecology positively and positively. However, there are also other advantages of green infrastructure concerning urban climate mitigation, increasing people’s opportunities to access high-quality green areas for leisure time, and improving public health [26].
Benefits of Green Infrastructure
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Environmental Benefits: Green infrastructure is an efficient urban planning concept that mitigates urban heat islands, enhances air and water quality, and supports vegetation, which in turn helps capture carbon dioxide [27].
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Economic Benefits: Even though they may incur initial outlay in terms of research and construction, they are likely to bring about such benefits as low energy cost, optimal stormwater management, and better property appraisal [28]. Also, it can employ people and generate business for green industries and start-ups.
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Social and Health Benefits: Recreational benefits and enhanced health status, stress reduction, and even social benefits and quality of life are some of the advantages of owning a green area [29]. They also promote greater social inclusion through the establishment of buildings that enable communal interactions.
2.3 Policy and Regulations
Overview of International, National, and Local Policies:
Policies created and accepted at the international, national, and local levels facilitate sustainable and green infrastructure practices. Currently, global policies towards climate change mitigation are presented in agreements like the Paris Agreement that call for city planning with favorable climate resilience [30]. Government activities mean that over fifty percent of sustainable development measures are driven and implemented through fiat and subsidies such as grants, tax credits, and code provisions [31].
Local governments are also tasked with the responsibilities of enforcing green infrastructure through local regulations and ordinances, regulating the improvement of parcel zoning, and planning for urban environments [32]. For years, many cities have received critical sustainable development programs that focus on green infrastructure as the main approach to attaining sustainability objectives.
Analysis of Regulatory Frameworks and Incentives:
Stakeholder policies that are typically addressed in city regulation for green infrastructure include green building standards, retention pond or water management, and incorporating greenery into the built environment [33]. This involves reimbursement such as grants, tax credits, and rebates that can boost green infrastructure practices among private developers and property owners.
For instance, there is a credit system from U.S Green Building Council (USGBC) LEED certification that mainly involves incentives and recognition for green buildings that meet certain sustainability standards or levels [34]. Likewise, the green infrastructure policy at the EU calls for the consideration and incorporation of the concept of green infrastructure in spatial planning and governance across governmental jurisdictions [35].