Manado

Abstract

Manado, the capital city of North Sulawesi in Indonesia, is rapidly developing. The last years Manado has been extending into the sea, which changed the hydraulics and morphology of Manado Bay. This had negative effects on the currents, inducing erosion along the coast. Also Manado has problems with the presence of garbage in the rivers and river flooding. Now the municipality is planning to build a new reclamation, which might even increase these problems. Based on the requests of our client Mr. Assa, head of the Planning Department of the City Manado, the following project goal has been formulated. eThe goal of the project is to give a research]based advice on the erosive and littering influences on Manadofs surrounding nature, induced by hydraulic and morphological changes caused by the planned land reclamation, and to describe measures to mitigate the detrimental effects to support Manado's vision of becoming a model city of ecotourism. The to be constructed land reclamation is expected to have the following effects on its environment: 1) Sedimentation and garbage settlement at the mouth of Tondano River are likely to happen. This will lead to an increase of flood risk upstream. Which can be prevented by dredging the river mouth; 2) Both sedimentation and erosion are expected near the Tumumpa Dua coastline. By implementing a beach in the reclamation design the sedimentation can be used beneficial and also the erosion will be stopped; 3) Increased erosion and mangrove retreat due to the construction of the new land reclamation is not expected. But a cure for the existing erosion and mangrove retreat is proposed and designed; 4) The proposed canal between the existing coastline and the new land reclamation is expected to be silted within a few years. Placing the canal above sea level can prevent this. A new reclamation will have large influences on the environment of Manado Bay. Sedimentation and garbage settlement at several spots around the reclamation are likely, coral reefs will be affected during its construction and higher water levels on Tondano are also expected. All the researched negative effects of the planned land reclamation can be prevented or mitigated separately by above mentioned measures. But failure to implement one of these preventing or mitigating measures will result in a large threat for the people or the environment of Manado. This risk might only be justified if a demand for further city expansion has been proven and if all other development options for unused land within Manado city and less preferably the mountainous hinterland have been excluded.