The Interface Development Interventions (IDIS) has called on the City Government of Davao to adopt nature-based solutions to address the city’s worsening flooding, warning that decades of wetland loss and unsustainable urban development have weakened Davao City’s natural ability to absorb rainwater.
In a statement, IDIS said the recent flooding that affected several communities should not only be viewed as a temporary inconvenience but as a sign of a deeper environmental problem that requires long-term solutions.
“Davao City has once again experienced flooding in several communities, affecting the daily lives of many Dabawenyos. While floodwaters may eventually recede, these incidents raise important questions about how we understand, manage, and respond to flooding in a rapidly developing city,” the group said.
According to IDIS, Davao City was originally built on an extensive network of wetlands, rivers, creeks, and estuaries that naturally absorbed rainwater and reduced flooding.
The group cited historical land-use records from the Spanish and American periods, which show that these wetlands were concentrated in areas that now include Poblacion, Agdao, Cabaguio, Matina, and Talomo.
However, the group said years of rapid urbanization have resulted in the loss of about 95 percent of the city’s wetlands since 1945.
It said high-density residential developments accounted for 51.6 percent of the loss, while commercial developments made up another 33 percent.
“These wetlands once absorbed rainfall, retained surface water during monsoons, and guaranteed water supply during dry spells. Their disappearance has left many communities more vulnerable to flooding,” IDIS said.
The environmental organization cited several examples, including Laverna near Davao International Airport, which was once a wetland but has since been developed into residential and commercial areas. Bajada Avenue, it added, used to be a large wetland connected by creeks before being converted into drainage canals.
In Matina Aplaya, Matina Crossing, and Pangi, IDIS said developments have been built on former natural catchment areas, causing rainwater to collect on the surface instead of being absorbed into the ground, resulting in recurring floods that have displaced hundreds of families.
The group also challenged the common belief that flooding is not a serious issue because floodwaters usually drain quickly.
“A common response to flooding in Davao is that it isn’t a serious problem because the water recedes quickly. This reasoning misses the bigger picture. The speed at which floodwater drains says nothing about whether an area should be flooding at all,” IDIS said.
It stressed that areas now experiencing floods were once naturally protected because wetlands, creeks, and vegetation allowed rainwater to flow or soak into the ground before reaching roads and communities.
According to IDIS, relying solely on drainage systems is not enough because engineered infrastructure cannot match the water storage capacity once provided by natural wetlands.
“Engineered drainage systems, however well-built, were never designed to hold the same volume of water that the city’s natural wetlands and marshlands once did. Davao City paved over the very terrain that used to do this job for free and is now paying to replace it with concrete,” the group said.
To reduce flood risks, IDIS urged the city government to integrate nature-based solutions (NBS) into its planning and development programs.
These include creating more green spaces that can temporarily store floodwater, restoring and protecting remaining wetlands, watersheds, and mangroves, and strictly implementing the Davao City Rainwater Ordinance of 2009 to encourage rainwater harvesting in homes and commercial establishments.
The organization also encouraged residents to help make Davao City more flood-resilient by installing rainwater catchment systems, using permeable surfaces around their homes, and planting native trees and vegetation.
