Flood protection

The Cheonggyecheon Stream Restoration Project saw the dismantling and removal of an elevated freeway and the uncovering of a 5.84km section of the Cheonggyecheon historic stream in the centre of Seoul, South Korea (Ref. 2). One of the world’s largest and most densely populated cities, the revitalisation of the Cheonggyecheon Stream has provided Seoul with an ecologically sensitive green pedestrian corridor in an area that was previously recognised as being congested, overpopulated and polluted (Ref. 4). The restoration has provided environmental, social and economic benefits within its immediate proximity (Ref. 2). In addition to becoming a "vehicle for revitalisation, urban renewal and economic development", it has "also signified a shift in Korean planning priorities", with both city authorities and residents now placing an emphasis "on health, sustainability and social responsibility" (Ref. 4). It has further "become a template for planning intention and action across South Korea" (Ref. 4).

A combination of green and grey coastal infrastructure is being developed off the coast of Semarang, Indonesia in response to the increased risk of coastal flooding as a result of sea-level rise (Ref. 1). Due to its geography as a coastal city, "Semarang deals with various physical challenges...such as tidal flooding, erosion, land subsidence and rising sea levels" (Ref. 1). Tidal flooding is becoming increasingly worse as a result of climate-induced sea-level rise and increasingly extreme weather events (Ref. 1 and 3). Coastal protection which was historically afforded by naturally occurring mangrove systems has been reduced as a result of the mangroves being largely lost to urbanisation, fish farming and other forms of agriculture (Ref. 2). One proposed sub-project of the Integrated Protective Coastal Zone, Coastal Balance Project 01: Coastal Balance Pilot in Genuk/Sayung, will focus on the northeast of Semarang. Using the 'Building with Nature' approach, it will leverage nature-based solutions through the deployment of green infrastructure, primarily focusing on mangrove restoration (Ref. 3). Mangrove restoration is hoped to stabilise the coastline, therein reducing erosion, encouraging sedimentation and increasing resilience against sea-level rise (Ref. 3).

The revitalization and conservation of the Butuah Wetlands work started in 2020 by a Ghanian NGO, called Friends of the Nations, in collaboration with some public institutions and an American charitable foundation that makes small grants to grassroots environmental causes around the world. In the past, the wetland has been a major flood reservoir that channelled excess water from different parts of the metropolis into the sea as well as a beacon of biodiversity. The weak monitoring regime of this wetland has led to massive encroachments by both private and industrial developers, therefore, causing biodiversity depletion and contributing negatively to climate change. (1)

The wetlands to the east of Kolkata are well known over the world for their multiple uses. The locals are using the naturally occurring wetlands for wastewater fisheries and vegetable farming on garbage substrate & effluent irrigated paddy cultivation. In the process, the wetlands treat the wastewater and have saved the city of Calcutta from constructing and maintaining a wastewater treatment plant. Currently, encroachment has deteriorated the wetland ecosystem significantly. This intervention is about the management of the degraded wetland to recover it the best way possible. The goal of management planning is to „maintain East Kolkata Wetlands in a healthy condition to enable the delivery of its full range of ecosystem services and sustain biological diversity values’. [1, 2, 3]

The Green Urban Infrastructure in the municipality of Beira project aims to increase Beira’s resilience to climate change and flooding (Ref. 2). It is a two-part project that consists of rehabilitating the Chiveve River and constructing a public park along the river (Ref. 1). The river rehabilitation was completed at the end of 2016 and restored the natural flow of the river, enabling better flood control (Ref. 5,6). The public park was completed at the end of 2020 and serves as a recreation, catchment and overflow area through three basins of the river (Ref. 1,2).

The city of San Salvador was built at the foot of a volcano and down its slopes, it is prone to droughts, floods and landslides. In 2020, Tropical Storms Amanda and Cristobal struck the city with torrential rainfall and gale-force winds triggering landslides and floods, causing damage to homes, infrastructure and roads, and with severe impacts on topsoil depletion affecting the fertility of economically and environmentally central coffee plantations[3].
To meet the economic and environmental challenges caused by such events, the United Nations Environment Programme (UNEP) together with El Salvador’s Ministry of Environment and Natural Resources, local organizations and coffee growers launched an project focusing on the Arenal Monserrat watershed located on the slopes of the volcano [3,4]. Through the integration of Ecosystem-based Adaptation (EbA) the initiative aim to address the effects of climate change by restoring coffee plantations and forests and digging infiltration ditches to be used as sponges to reduce flood risks for 115,000 people by 2022 [1,4,5]. The project was launched as part of the multi-city CityAdapt Project of UNEP and GEF, aiming to provide tools to local governments plan for adaptation and mitigate greenhouse gas emissions from their cities while conserving their ecosystems.

The green roof pilot project is part of eThekwini Municipality's Climate Protection Programme, initiated in 2004, it was focused initially on understanding the vulnerability of the city of Durban to the impacts of climate change. A strong emphasis has been placed on identifying climate change adaption projects that will improve the resilience of the city to future developmental, social and environmental challenges. Basically, the green roof pilot project is a response to the higher temperatures and increase in the frequency and severity of floods and droughts that are expected as a result of climate change. From an urban environment perspective, these changes will exacerbate the already high temperatures experienced as a result of the Urban Heat Island effect and the high levels of surface run-off and flooding that result from the hardening of permeable surfaces. (1,3)

Taru Leading Edge initiated a lake conservation project in Indore with support from the Rockefeller Foundation and Indore Municipal Corporation as part of the Asian Cities Climate Change Resilience Network (ACCCRN).
Urbanisation and the increase of impermeable surfaces reduced the capacity for groundwater recharge. The climate change risks indicate increasing rainfall variability and more intense and/or more frequent storms as well as an increase in dry periods. With less permeable soils the city needs to optimally use existing lakes to capture runoff, creating buffer supplies and helping to increase groundwater recharge. The main objective of this project was “ensuring availability of local water resources during emergencies”, through developing a replicable model for peri-urban lake rejuvenation and conservation. The expected outcomes of the project include a stakeholder-managed process for stabilising/improving the water quality of the restored lakes and generating interest among multiple stakeholders to conserve urban lakes. TARU has restored and worked on 2 water bodies, demonstrating methods and processes required to revive lakes that have co-benefits of groundwater recharge, aesthetic enhancement of the area, cool microclimate and possible livelihood restoration. The names of the lakes restored are Khajrana talab and Lasudiya Mori talab. [2, 4]

In 2015 an innovative project called the "Sweet City" (Ciudad Dulce) was launched in Curridabat. Its main goal was to bring wild spaces into 21 urban neighbourhoods of Curridabat ("spaces of sweetness") and eight corridors ("transitions") and thus linking neighbourhoods and parks through a participatory re-design approach with local stakeholders [3]. The main objective of the Sweet City model is to reintroduce biodiversity into the urban space by focusing on five fundamental dimensions: Biodiversity, Infrastructure, Habitat, Co-existence and Productivity. The interventions of this project included park improvements, sustainable drainage systems, the protection of wetlands, spring water recovery, promoting organic farming practices, and many strategies that help improve biodiversity and motivate citizen participation, finally, as ecosystem-based disaster risk reduction measures and climate change adaptation actions [1].

Assiniboine Landing is a 21 ha housing development to raise the bar for environmental responsibility and evolve the landscaping practices in local communities, particularly regarding stormwater runoff and retention, and parklands. It is one of the neighbourhood communities developed by Qualico Communities in cooperation with Native Plant Solutions, a branch of Ducks Unlimited Canada. The project resulted in integrated systems of native grasses, shoreline vegetation and wetlands, creating communities conducive to the cycles of nature and offering stunning natural landscapes for residents to enjoy (1,5,6,7)