Sebrian Mirdeklis Beselly Putra, a Water Resources Engineering lecturer in Faculty of Engineering Universitas Brawijaya who is currently pursuing his PhD research at IHE Delft, take the International Day for the Conservation of the Mangrove Ecosystem on 26 July 2020 as an opportunity to share some insights on his mangrove-related research.

The focus of Sebrian’s current research is to understand the dynamics of the mangrove-mudflat system, mainly on a prograding delta by taking the Porong River Delta in Indonesia as a case study.

He chose Porong as his research location because the LUSI mudflow in the Delta was the largest mud eruption in the world. On 29 May 2006, the boiling mud erupted at a peak flow rate of up to 180,000m³/day. Sixty thousand people were forced to evacuate, and 7 km² of residential area was submerged with mud. LUSI is still actively erupting mud material, gas, water, clasts, and oil, albeit at a reduced rate.

The Indonesian government built 10m tall embankments to hold the continuous mudflow and regulate the diversion to the Porong River. These mudflow diversion operations profoundly influenced the estuarine morphology.

The diversion operation has caused rapid delta development, with mangrove belt expansion. In over 12 years, the delta has expanded to a total area of 1.75 km² in comparison to 0.05km² before the eruption.

With no end to the mudflow in sight, its influence on delta formation and mangrove ecosystem dynamics urges research on the expected delta progradation and mangrove belt expansion.

The excessive LUSI mudflow is highly likely to have a significant influence on delta formation in Porong. However, it is also argued that the landscape of the delta is also affected by the existence of mangroves.

Mangroves altered the flow and therefore affected the sediment transport and followed by intertidal area development. Therefore, by understanding the dynamics in Porong Estuary and with their vast dataset, it will be useful for the development of Sebrian’s model.

Sebrian is focusing on mangrove-mudflat dynamics because mangroves form a buffer between land and sea, offering protection against erosion and reducing wave energy during storm surges.

In the event of global climate change, mangrove forests can act as an eco-defense, providing a protective barrier against wave impact and coastal erosion mitigation, which also actively provides ecological benefits. Mangroves have adaptable vegetation, able to cope with several hydrodynamic forcing and with the dynamics of sediment transport.

The product of Sebrian’s research will be a model that can describe the individual interaction between mangrove trees by describing their growth, mortality and the competition of each tree, specific to species and their environmental settings.

This model will be useful for those who want to do an environmental analysis of a site, to assess the design of a landscape that can sustain both human and nature harmoniously, side-by-side, quantify the role of vegetation on coastal morphology, and any analysis related to the interaction between vegetation and coastal development.

The developed methodology can also be used to monitor mangrove forest and mudflat by using freely available satellite and off-the-shelf drone imageries.

The International Day for the Conservation of the Mangrove Ecosystem is celebrated each year on 26 July. With this, UNESCO aims to raise awareness of the importance of mangrove ecosystems as “a unique, special and vulnerable ecosystem“, and to promote solutions for their sustainable management, conservation, and uses.

More information: https://en.unesco.org/commemorations/mangroveday

Source: https://www.un-ihe.org/news/mangrove-related-phd-research-ihe-delft