The Benefits of Green Infrastructure (GI) for Flood Damage Reduction

Introduction

The risks associated with floods have made green infrastructure the best strategy for local governments to provide mitigation measures for such hazards. There are different benefits of green infrastructure that qualify it as the best approach for offering solutions to risks related to flooding. These benefits are demonstrated in floodplain restoration and stormwater management. As a result, local governments should understand the reasons for using green infrastructure in floodplain restoration and stormwater management. Furthermore, it presents the costs, how the local governments can accomplish them, and the benefits of these processes.

Floodplain Restoration

Exploiting green infrastructure in restoring floodplains entails using ecologically friendly and natural techniques to manage water, decrease risks associated with flood, and reestablish the natural conditions of floodplains. Some ways of restoring floodplains include riparian buffer zones, planting trees, using rain gardens, and green roofs. Placing vegetation strips like shrubs and trees along the banks of streams or rivers assists in absorbing and slowing down floodwaters, decreasing erosion, and filtering pollutants. Additionally, planting trees, especially native plants, along the banks of rivers and within floodplains prevent soil erosion, stabilize the soil, and absorb excess water. Other GI practices, such as green roofs and rain gardens, enable water to infiltrate the ground instead of contributing to surface runoff, which is fundamental in restoring floodplains. However, the cost of establishing and using green infrastructure in restoring floodplains varies according to area, region size, degree of required restoration, and particular restoration methods used in the restoration process.

Cost-benefit analysis is significant for guiding green infrastructure design, planning, and construction. According to Tiwari et al. (2016), installing riparian buffer zones in one hectare was cheaper than fixed-width zones, demonstrating that establishing and maintaining riparian zones is more cost-effective than traditional techniques(selected width zones) for restoring floodplains. Based on Kousky et al. (2013), findings show that careful investing in green infrastructure is cost-effective. However, they argued that the cost of establishing may be higher than the benefits of GI practices, and this is where detailed investing comes to reverse the equation (Kousky et al., 2013), making GI approaches more appropriate than traditional ones in restoring floodplains.

Furthermore, GI practices’ benefits compared with traditional floodplain restoration strategies prove effective. For instance, GI practices enhance biodiversity by restoring natural habitats, such as wetlands and forests, for different animal and plant species (Kousky et al., 2023). On the other hand, traditional techniques involving structures such as concrete channels disrupt natural habitats, leading to biodiversity loss. Additionally, natural features such as vegetated buffer zones absorb and slow down floodwaters, reducing the risk of downstream flooding (Kousky et al., 2013). This is opposed to traditional methods like dams and levees, which provide protection but are expensive to construct and maintain.

Furthermore, they can upsurge cases of catastrophic failures. Natural and restored floodplains offer aesthetic benefits and create community recreational spaces (Kousky et al., 2013). Unlike natural and restored floodplains, traditional techniques are less visually appealing and may offer different recreational opportunities.

Stormwater Management

There are different GI techniques for managing stormwater. Some techniques are green roofs, permeable pavements, and constructed wetlands. Green roofs cover building rooftops with vegetation, creating a living, permeable surface that absorbs rainwater. Permeable pavements involve pavers, permeable concrete, or asphalt to permit water to pass through them and infiltrate the ground. As a result, it enhances groundwater recharge, decreases runoff, and filters pollutants.

Additionally, wetlands are constructed to manage stormwater. Usually, constructed wetlands mimic natural wetland ecosystems and are designed to capture and treat stormwater runoff (Kousky, 2013). Wetlands act as natural filters, removing sediments and pollutants from stormwater. They also provide habitat for wildlife.

According to Liu et al. (2016), a framework for calculating the benefits and costs of different green infrastructure for reducing stormwater in an area of 54,783m² in Being, China, the year costs for installing green infrastructure facilities(storage pond, porous brick pavement, and green space depression) required between 40.54 and 110.31 thousand yuan. Moreover, the yearly average cost for reducing and utilizing stormwater in m³ is 4.61 yuan (Liu et al., 2016). The annual significance of stormwater reduction and utilization by green infrastructures in the Bejein community is between 63.24 and 250.15 yuan, while its importance per m³ is between 5.78 and 11.14 thousand yuan (Liu et al., 2016). Based on the findings of Liu et al. (2016), implementing GI practices to reduce and utilize stormwater is cost-effective. As a result, it should be encouraged to manage urban stormwater in China, which applies to other local governments.

The comparison between GI practices and traditional techniques in managing stormwater shows that GI approaches are the best. GI practices slow down stormwater runoff, allowing for increased infiltration and reducing the overall volume of runoff reaching water bodies. This is different from traditional strategies of managing stormwater, which focus on rapid conveyance, leading to increased peak flows and higher runoff volumes. Moreover, GI practices encourage biodiversity by creating habitats with features like rain gardens, wetlands, and green roofs. On the other hand, traditional approaches always negatively affect habitats, leading to the destruction of biodiversity.

Conclusion

Urbanization and climate change pose various challenges, such as floodplains and stormwater destruction. These challenges require appropriate mitigation measures, which justifies the significance of green infrastructures as imperative for sustainable urban development. Green infrastructures are associated with various benefits and are essential for local governments in the USA, China, and other parts of the world. Furthermore, establishing green infrastructures is more cost-effective than the traditional strategies for addressing challenges associated with flooding. Therefore, local governments should carefully choose green infrastructures based on their costs and associated benefits. Adopting green infrastructure is not merely an option; it is a responsibility to safeguard communities, enhance environmental well-being, and pave the way for cities that thrive in harmony with the natural world. For this reason, for better results (costs and benefits of GI), local governments should adopt green infrastructures to restore floodplains and manage stormwater.

References

Kousky, C., Olmstead, S.M., Walls, M.A., & Macauley, M. (2013). Strategically planning green infrastructure: Cost-effective land conservation in floodplain. Eviron. Sci. Technol., pp. 47, 3563–3570. dx.doi.org/10.1021/es303938c |

Liu, W., Chen, W., Feng, Q., Peng, C., & Kang, P. (2016). Cost-benefit analysis of green infrastructures on community stormwater reduction and utilization: A case of Being, China. Environmental Management, 58, 1015-1026. DOI 10.1007/s00267-016-0765-4

Tiwari, T., Lundstrom, L., Kuglerova, L., Laudon, H., Ohman, K., & Agren, A.M. (2016). Cost of riparian buffer zones: A comparison of hydrologically adapted site-specific riparian buffer zones with traditional fixed widths. Water Resources, pp. 52, 1056–1069. Doi: 10.1002/ 2015WR018014