Adam Pamudji Rahardjo

Evaluation of Flood Risk Reduction Project at Tenggang River, Semarang City, Central Java Province, Indonesia

Evaluation of flood risk reduction at Tenggang River is needed to reduce the urban and coastal flood from high-intensity rainfall and sea level rise. This paper mainly discusses rainfall frequency analysis, simulation of hydraulic structure performed by HEC-RAS 5.0.3, and the proposed alternative flood mitigation for 25-year flood return period. Hydrology and hydraulic was analyzed to investigate the flooding risk. The result of simulation illustrated the improvement channel condition by normalization the riverbed and the increase of levee to solve flood inundation at Tenggang River using the designated flood return period (25 years of return period, Q 25 = 119 m 3 /s). The result of simulation showed that the hydrologic-hydraulic modeling is acceptable compared to the report from the office of public work in Semarang City.

Flash Flood Disaster in Huamual District, West Seram Regency, Maluku Province, Indonesia, Its Potential and Management

Huamual District which is located in west peninsula of Seram Island within Ambon Province is one of the under developed areas since its remote location and limited transport facilities from its regency capital and other developed areas. Therefore, the development program for that area needs to be boasted and secured. One of drawback of the economic development growth in Huamual District caused by current frequent flash flood disaster occurrences. Therefore, disaster resilient of both the local government and communities need to be strengthened. The Provincial Disaster Mitigation Agency of Maluku points that Huamual District was the most severe hit area by flash flood in Maluku beside Ambon City areas in 1^(st) August 2012. In order to prepare a program for increasing disaster resilient in that area, investigation of the disaster risk condition along the west coast of Huamual Peninsula within Huamual District has been conducted and reported in this paper. Reference study has been conducted followed by a field survey in the period of July 14^(th) to July 19^(th) 2014. The field survey was conducted on several sub-villages such as Nasiri, Mange-mange, Amaholu Losi, and Hatawano. The activities in the field survey were secondary data collection, interview to Local Disaster Management Agency (BPBD) of West Seram Regency staffs, to sub-village leaders, to local community members, visual observation survey and river bed material sampling. This paper discusses disaster risk aspect found in the areas which consists of hazard, vulnerability, capacity and also mitigation aspect which consists of pre-disaster, disaster response and recovery phases. The results of this study are the following six findings. 1) The flash flood is the main cause of the natural disaster beside landslide. 2) Although the community settled in the prone area, they do not have knowledge about disaster mitigation but now, they are more aware. 3) BPBD in West Seram Regency has no yearly program related to capacity building, standard operating procedure, and disaster mitigation plan due to limited budget on local government budget and limited employee although 2 years of its establishment. 4) There is no community preparedness dealing with any kind of natural disaster except for their experiences in facing the past disaster. 5) The community still relies on their own members when facing any disaster response. 6) In recovering their sub-village condition the community relies on gotong royong spirit an Indonesian indigenous spirit of working together and also on their own resources.

Development of Debris Flow Early Warning System for Volcanic Rivers at Mt. Merapi Area

The 2010 Mt. Merapi eruption has produced approximately 140 million m3 of pyroclastic deposit, in which more than ten million m3 deposits are potential to move downstream through Boyong/Code River towards Yogyakarta City. The flow behavior of Code River may be affected by the presence of accumulated sediment at the upstream of the river (namely Boyong River). By rainfall trigger, this potential source can cause debris flow disaster that may contribute damage to the settlement areas in Yogyakarta City. This paper presents the development of early warning system to mitigate the impact of debris flow disaster along Boyong/Code River as revealed by most adaptive, least cost, and collaborative-based technology. The system was developed by considering the community aspiration in determining the types and placement of monitoring equipment, and maintaining its sustainability.