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Land reclamation activities can, directly and indirectly, impact the environment. Examples of direct effects include alterations in coastal geomorphology, variations in the chemical content of water and changes in biological composition along the littoral zone. The indirect impacts can involve geological changes and increase vulnerability to natural disasters. Reclamation processes also result in greenhouse gas (GHG) emissions from vehicle and machinery fuel use and through the release of carbon stored in vegetation, soils and sediment in mangroves and seagrass ecosystems. Considering the global extent of land reclamation, the scale of these emissions is likely to be of widespread interest. The case of Jakarta Bay provides useful insights that can contribute to the improved environmental management of kindred land development projects in Indonesia and other parts of Asia. More than 5,100 ha of new land mass is planned from the Jakarta Bay reclamation. Preliminary analysis suggests that 30% of the planned area will require more than 150.7 million cubic metres of sand sourced from 8,628 ha of marine quarry area. In this study, we examine the sources of GHG emissions in these activities and the potential opportunities available to reduce them. The audience for this paper includes policymakers, environmental practitioners, city developers and postgraduate scholars dealing with land reclamation or other major infrastructure developments.

The Cilemer River is a river which flowing to Lada Bay in west coast of Pandeglang District, Banten Province. The influence of the tide, the high flood discharges and settlements located at the flood plain has caused flooding every year. In order to understand flood overtopping mechanism and inundation map, numerical model simulation for flood and inundation area were conducted. The numerical model of the river were conducted using cross sectional of the river, result of these simulations were further integrated with Geographical Information System (GIS). The objective of this study is to obtain inundation map area. The input for GIS is a Digital Elevation Model which is obtain from Advanced Spaceborne Thermal Emission and Reflection Radiometer Digital Elevation Model (ASTER DEM). The simulation results shows the capacity of Cilemer River upstream is 210 m3/s while on the downstream segment was only 100 m3/s. Simulation shows with overtopping of the dike of 0,96 m generate 546 Ha of inundation area for 2 year return period of flood discharge. The overtopping of 1,1 m has generated 592 Ha of inundation area for 5 year return period of flood discharge. With overtopping of 1,26 m of 10 year return period flood discharge has caused 682 Ha inundation area, while 2,56 m overtopping has generated 912 Ha inundation area for 25 year return period of flood discharge. Effect of flood control structure on the outlet of bypass has generated 19 cm increase of water level.