KOPI Delft 10 May 2013

Floods: Not Only in Jakarta! Sumatra also Suffered by Floods and Significant Land Subsidence

by:

Ida Nurhamidah, doctoral candidate at Delft University of Technology

Date : Friday, 10 May 2013

Time : 16.30 – 19.00 CET

Place : Room A1b 1st Floor -UNESCO IHE university

ABSTRACT

Due to land pressure, substantial areas of peat swamps are being reclaimed for agriculture, plantation and for other land use. In natural conditions, peat land functioned as retention areas by storing flood water, thereby preventing or mitigating flooding in downstream areas. Unfortunately, large areas of the original peat land forest have disappeared due to human activities such as logging and fires. Before reclamations, Middle Sumatra was covered by nearly 80% forest, 50% of which was peat forests and most of them were located at downstream areas.  In this area, conversion of forest into agriculture practices and palm plantations have strongly influenced the natural hydrological processes on this delta. Flooding along rivers occurs frequently, particularly during heavy rainfall and spring tides. A number of flood defence measures have been implemented. These measures include levees, pumps, and drainage canals. Non structural measures within communities who live in the flood prone areas were implemented for flood mitigation as well. But, the flooding still occurs yearly in many parts. There is no much correlation between rainfall and river discharge, the water level moreover increase due to tide propagation. The situation getting worse in places since the land subsidence are found. It has been analyzed higher temperature due to climate change and lowering groundwater table have strongly affected oxidation process on peat layer. Thus in Sumatra delta, flooding occurrences are not only due to combination rainfall and spring tides like in many deltaic areas, but also due to land subsidence which vary from 2.5 until 13 cm per year.

MEET THE SPEAKER

Born in Dumai on September 12 1971, Ida Nurhamidah got her Master degree in UGM and Master of Engineering Science in UNESCO-IHE. She has extensive experience as a lecturer in many Universities such as Medan Institute of Technology, North Sumatra Islamic University, North Sumatra Muhammadiyah University, Medan Area University, and Andalas University (ongoing lecturer in Engineering Faculty).  Right now, Ida continue her study as doctoral candidate focusing on Water Management at Civil Engineering & Geosciences Faculty, Delft University of Technology.

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