Miscellaneous

Abstract:

Semarang is a water front city situated on the lowland part of Central Java province in Indonesia. River and tidal floods frequently occur in this area. Local planners and decision makers are in need of accurate information on the spatial distribution, magnitude and depth of flooding, and on the land-use affected by it. Thus, the integration of GIS and hydrologic models into this topic is an important applied area of research. Our research objectives are:
1) to construct a river flood model in a GIS environment,
2) to construct a tidal flood model in a GIS environment, and
3) to validate and evaluate both models, and to assess flood hazards in the waterfront city.
The applied methodology comprises 5 phases; 1) Preparation 2) Fieldwork and data acquisition 3) Modelling 4) Validation, evaluation, and hazard assessment, and 5) Reporting.
The preparation phase comprises literature studies, ancillary data collection, and fieldwork preparation. The fieldwork and data acquisition phases comprise spatial and hydrological data acquisition (DEM, topographic map, land-use map, river flood map, tidal flood map, river discharge, manning coefficient, river cross sections, and drainage system). The modelling phase consists of the building and running of two types of models using hydrological software and the GIS environment (i.e.: the river flood model and the tidal flood model). The validation, evaluation, and hazard assessment phase comprises the validation of the models using a confusion matrix of model result against reliable source map to get the accuracy and reliability. The hazard assessment has been done by map calculations and table operations to analyze land-use affected by floods. On the reporting phase, the whole research process has been translated into conclusions and recommendations.
The spatial patterns of the river flooding and tidal flooding are depicted in maps. It indicates that the flooded area mostly covers coastal and alluvial landforms. For the tidal flood model, the highest tidal water level (155.43 cm in November 2000) was used in the iteration procedure. Some areas are known to have no flooding, such as the harbour and airport. Also the sea area should be left out of the tidal flood model calculation. Hence, the DEM values on these areas have been replaced with manipulated value. The average accuracy and reliability of the river flood model is 77% and 76% respectively. The average accuracy and reliability for the tidal flood model is 89% and 83% respectively. The total area of river flood is 1245 hectare, and the total area of tidal flood is 1514 hectare. Land-use types influenced by the river floods are: built-up area, fishpond, agriculture and others with affected areas of 512; 164, 1.3; and 712 hectares, respectively. Land-use types influenced by the tidal flood are: built-up area, fishpond, agriculture and others with affected areas of 815; 2.3; 233 and 462 hectares, respectively.

Recommendations:

Integrated hazard assessment is regarded as a necessary input to the development of a management and spatial planning strategy for the City of Semarang. This would involve not only an assessment as the present-one. But it would also include aspects of vulnerability and risk assessment. Local planning authorities (Bappeda) would benefit from such an integrated approach in which a prototype of a spatial planning support system would be developed. Such a SPSS would be capable of weighing different measures and strategies to adapt to and mitigate the relevant coastal hazards, such as land subsidence, flooding, sea level rise, and groundwater extraction.
In this study, river and tidal floods have been treated separately. The combined effect of the two floods has an even larger impact on the city and its population than shown in the present hazard assessment. Therefore, it is strongly recommended for future research to develop an model capable of dealing with both types of floods in an integrated way. It is, however, realized that such a dynamic modelling approach also involves intensive fieldwork with hydrological data collection.

Ongoing research (Dissertation):

Risk assessment of tidal inundation under the scenarios of sea level rise and land subsidence – the case study Semarang City, Central Java, Indonesia (supervised by Prof. Dr. L. King)

• Papers
  (Requests may be sent by email)
• Impact of the Escalated Tidal Inundation Due to Land Subsidence in a Coastal Environment
  being submitted to European Geosciences Union General Assembly 2006 Vienna, Austria, 02 – 07 April 2006.
• Geomorphological Mapping of the San Lorenzo Area Sant’arcangelo Region Southern Italy.
  Accepted in Indonesian Journal of Geography, Vol. 37, Number 2, December 2005.
• GIS Modelling Exercise Using ILWIS Software for Landslide Assessment.
  Journal of Scientific Development and Environmental Research, Tripura India. Vol. 4 Number 1, 2005.
• Carrying Capacity of Gajahwong River.
  Journal of Majalah Geografi, Indonesian. Vol 18 Number 2, September 2004. ISSN 0125-1790, p.81-97. (Indonesian language)
• Spatial Modelling of Tidal Flood Hazard on East Semarang Coastal Area.
  Journal of Forum Geografi. Indonesian. Vol. 18, No 1, July 2004. ISSN 0852-2682 p.60-69. (Indonesian language)
• Tidal Flood Hazard Assessment: Modelling in Raster GIS, Case in Western Part of Semarang Coastal Area.
  Indonesian Journal of Geography, Vol. 36, Number 1, June 2004. p. 25-38.
• Multitemporal Evidence Modelling for Landslide Hazard Susceptibility Mapping Middle Agri-river basin, Southern Italy.
  International Association of geomorphologist (IAG) Symposium on Geomorphology and Environment. Calcutta, INDIA 27-29 February 2004.
• Vulnerability Analysis and Risk Assessment For Seismic and Flood Hazard In Turialba City, Costa Rica.  _{(1,95 MB)}
• Monitoring of the Coastal Zone Dynamics by Means of Multi-Temporal Landsat TM.
  Annual scientific meeting of Indonesian Remote Sensing Society (MAPIN) XII, Bandung 29 Juli 2003.
• Modelling of West floodway River Semarang (Integration of Hydrological Model and GIS).
  Journal of Forum Geografi Indonesian. Vol. 17, No 1, July 2003, p. 39-50, ISSN 0852-0682. (Indonesian language)
• Physical Condition and Tourism Prospective of Gunungkidul Coastal Area,
  Preliminary Study. Preceding Coastal Ecosystem Management. Yogyakarta 16 October 2002. ISBN 979-8786-21-1 (Indonesian language)
• Vulnerability Index and Sea Level Rise Effect in Coastal Area.
  Preceding Coastal Ecosystem Management. BPPT and Geography Faculty GMU. Yogyakarta 16 October 2002. ISBN 979-8786-21-1(Indonesian language)
• Technical Guide of Reclamation and Modelling of Land Mining Reclamation.
  Proceeding Research Year Book. Geography Faculty. Gadjah Mada University. ISBN 979-8786-19-x. Page 55-66. 17 April 2002. (Indonesian language)
• Landslide Hazard Assessment and Mitigation.
  Proceeding Research Year Book. Geography Faculty. Gadjah Mada University. ISBN 979-8786-19-x. Page 36-42. 17 April 2002. (Indonesian language)
• Some Physical Phenomena of Urban Development on Semarang Municipality (Geomorphological Characteristics and Heat island Pattern)
  in Congress Indonesian Geographical Society. University of Indonesia. Jakarta. 26-27 October 1999. (Indonesian language)

Awards:

• 2005-2008:
  Ph.D. grant, The German Academic Exchange Service (Deutscher Akademischer Austauschdienst - DAAD) for Phd Program at Justus Liebig University, Germany
• 2004:
  International Association of Geomorphologists (IAG/AIG): young geomorphologist award for paper presentation in the IAG Symposium on Geomorphology & Environment (Calcutta) and International Workshop on Landslides (Darjiling and Sikkim Himalayas), held in India, 27 February - 6 March 2004
• 2001-2003:
  The Netherlands Fellowship Programmes (NFP) for Master program at ITC, The Netherlands
• 1998:
  Education and Culture Minister of Indonesia: the best contribution in student research competition