A guidance manual for green infrastructure application
Bogor’s reputation as the ‘city of rain’ and ‘city in the garden’ suggests it is ideal for transformation to a Water Sensitive City. With its natural greenery, amenity and botanic gardens drawing people to the city, the importance of ornamental greenery is clear throughout the city. The government seeks to build upon this foundation to become a green city of the future. Positioned upstream of Jakarta on the banks of the Ciliwung and Cisadane Rivers, and alongside hundreds of natural lakes, water is also a key feature of Bogor and commonly believed to bring good fortune.
This upstream position means Bogor’s water management is of high significance to Jakarta, with a local saying that if it is raining in Bogor it is flooding in Jakarta. This natural, social and political capital is a solid foundation for the application of green water treatment technologies or green infrastructure, which utilise natural filtration processes.
Certain green-blue infrastructure or green technologies, referred to as green infrastructure (GI), have different functions in terms of providing essential water services such as water treatment, flow attenuation, storage for reuse, and secondary benefits such as landscape value and urban cooling. They can be applied at a range of scales and used for a range of applications (notably urban farming, food production, and so on). Almost all green infrastructure requires the presence of vegetation and soil of adequate volume, nutrient content and drainage characteristics. Porous pavements and rainwater tanks are exceptions to this. They are considered water-sensitive technologies and have relatively low environmental impact; they are similar low-cost and low-energy systems and are thus regarded as part of the same group.
Selecting which GI systems to use in urban designs is essential to delivering a range of water management outcomes. In a water-sensitive city model, green infrastructure is used for stormwater treatment, flow attenuation/control and storage for reuse. GI can also provide secondary benefits such as improving the look and value of the landscape, urban cooling and flood mitigation. Most green technologies are multi-functional, and can be applied at a range of scales and used for a range of applications. With these benefits, GI can help strengthen Bogor’s economy and improve the health and quality of life of its residents.
Green infrastructure measures to treat, control or store water should be selected based upon the individual site characteristics, urban planning objectives and the benefits the community or city wish to achieve. GI provides environmental, socio-cultural and economic benefits to a community. The environmental benefits include:
- Water-quality treatment (through pollutant removal).
- Flood mitigation (by reducing flow).
- Protecting human and ecological health.
- Providing a source of water for reuse (through stormwater harvesting or greywater treatment and re-use).
- Enhancing water security and resilience and reducing demand on other water sources.
- Urban greenery, biodiversity and amenity.
- Groundwater recharge through infiltration.
The socio-cultural benefits of Gi include:
- Enhancing human wellbeing and health
- Cooling the city’s microclimate and buildings
- Providing habitat for flora and fauna
The economic benefits of GI are:
- Increased property values and avoiding future costs for remediation and grey infrastructure.
- Possible economic benefit from harvested plants for products or food.
Bogor is ideal for transformation to a Water Sensitive City through the integration of GI into development plans for tackling challenges such as dry season water shortages, flooding and water management.
Results and achievements
The research revealed several key findings. Green infrastructure, such as bioretention systems, constructed treatment wetlands, green roofs and others, has been demonstrated to have multiple benefits in tropical climates. There are solid foundations for the adoption of GI in Bogor, with many examples to build upon and existing local skills and resources.
Case studies highlight how multiple issues at a site can be mitigated by green infrastructure due to its multi-functional nature. The most appropriate technologies will differ between sites and should be selected to suit the site and available resources for construction and maintenance. In order to have a more sustainable and resilient water supply, diversification of water sources offers potential.
Given Bogor’s high rainfall, rainwater harvesting offers significant potential to supplement existing sources of water. Treated greywater through GI systems could also provide an alternative water source for less personal end-use applications and help reduce wastewater discharge.
In designing GI in Bogor, system sizing is critical to ensure sufficient treatment capacity and protect the system from high flows. Protecting systems from sediment and gross solids is vital for long-term functioning, hence investing resources in solid waste management campaigns will help GI performance. There are multiple widely cultivated local plant species that offer potential for use in green infrastructure, with many plants also associated with potential economic uses.
The research recommended that a standardised document be developed to facilitate implementation and design of GI in Bogor. This document would ideally include target design objectives for stormwater and wastewater management (that is, the key pollutants and their reduction limits as well as flow reduction targets). Testing of GI systems under local conditions would also help refine design.
Associate Professor David McCarthy
ARC DECRA Fellow, Head of Water Engineering
Professor Hidayat Pawitan
Professor, Water Sources Hydrology
Institut Pertanian Bogor (IPB)
Dr Dwita Sutjiningsih
Associate Professor, Department of Civil Engineering
Professor Hadi Susilo Arifin
Division Head, Landscape Management
Institut Pertanian Bogor (IPB)
Dr Emily Payne
Research Fellow, Department of Civil Engineering
Dr Harsha Fowdar
Dr Dwinanti Rika Marthanty
Senior Lecturer, Department of Civil Engineering
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