Mitigating Urban Flooding thru Green Infrastructures

Rapid urban expansion exposes assets and people to increasing flood hazards. Urban sprawl and the increase of built settlements can result in the loss of permeable surfaces, decreasing the ability of water to seep underground. As a result, runoff, discharge, and sedimentation increase the rate of urban flooding like those that affect the City this past few months.

Cities need a strategic mix of “grey” and “green” infrastructure or so-called Low-Impact Developments (LID) to mitigate these hazards. Low-Impact Developments (LID) can help increase a city’s resilience while providing co-benefits such as sustainability, biodiversity, and eco-tourism.

In the previous years, IDIS conducted studies on the status and importance of various green infrastructures in building disaster-resilient cities. And with the data gathered, IDIS utilized this in lobbying for the integration and promotion of green infrastructure to various local policies and plans such as the Local Climate Change Action Plan (LCCAP) and Comprehensive Land Use Plan (2022-2032).

𝗦𝘂𝘀𝘁𝗮𝗶𝗻𝗮𝗯𝗹𝗲 𝗨𝗿𝗯𝗮𝗻 𝗗𝗿𝗮𝗶𝗻𝗮𝗴𝗲 𝗦𝘆𝘀𝘁𝗲𝗺𝘀
SuDS mimic nature and typically manage rainfall close to where it falls. SuDS can be designed to transport (convey) surface water, slow runoff down (attenuate) before entering watercourses. They provide areas to store water in natural contours and can be used to allow water to soak (infiltrate) into the ground or evaporated from surface water and lost or transpired from vegetation (known as evapotranspiration).

𝗣𝗲𝗿𝗺𝗲𝗮𝗯𝗹𝗲 𝗣𝗮𝘃𝗲𝗺𝗲𝗻𝘁𝘀
Permeable pavement is a low-impact design that can infiltrate water runoff into underlying soils, mitigate flood, provide cooling and reduce heat than conventional cemented pavements.

𝗚𝗿𝗲𝗲𝗻 𝗦𝗽𝗮𝗰𝗲𝘀
Urban green spaces generally include parks, public green spaces, allotments, green corridors, street trees, urban forests, roof, and vertical greening, private gardens, and domestic gardens. Increasing urban green spaces is considered an effective approach to reducing the adverse impacts of urbanization on the hydrological cycle. Urban green spaces intercept water from the canopy and stem areas and enhance infiltration into the soil and root systems.

𝗨𝗿𝗯𝗮𝗻 𝗪𝗲𝘁𝗹𝗮𝗻𝗱𝘀
There are several wetlands in Davao City, and most people seem to neglect its importance, especially in flood mitigation. Wetlands act as natural sponges, soaking up and holding water until it can infiltrate into the ground. Wetlands also provide immense water storage benefits while slowing water to reduce the height of floods and erosion rates. Currently, IDIS conducts ecological profiling on various wetlands in the City. Data gathered on this study will be utilized for lobbying for the protection of urban wetlands in the City.

𝗥𝗮𝗶𝗻𝘄𝗮𝘁𝗲𝗿 𝗛𝗮𝗿𝘃𝗲𝘀𝘁𝗶𝗻𝗴
Managing, controlling, and making use of rainwater within the vicinity of rainfall is known as rainwater harvesting. Rainwater harvesting decreases peak flows as well as reduces flooding and the damages resulting from flooding.

These are just few of the infrastructures that can help mitigate flooding in the City. In addition to this, IDIS believes that by collaborating across the disciplines of urban planning, public policy, and disaster risk management and integrating grey-green infrastructure into the urban landscape, we can create robust cities and healthier communities.