ICZM Central Java: Issues and Challenges
The coastal zone is an interface between land and sea. The coastal zone boundaries can be defined differently in each country/area due to regulation, political issues, and interest. In Indonesia, the coastal zone is stipulated in UU No 27 the year 2007, whose transition between terrestrial and marine ecosystems are highly affected by the dynamics between land and sea (up to 12 miles from the coastline).
This zone is constantly changing due to the dynamic interaction between the land and sea. Land-based activities along the watersheds have proven to have impacts on the sea. Upstream deforestation will decrease water discharge and result in sedimentation in the river body and sediment will not deposit to the sea. In the midstream, pollutants from industries and sewage treatment plants have poisoned aquatic biota, including aquaculture that is the source of livelihood of the local community. Activities such as canalization and sand river mining led to decreased sedimentation downstream. In the midstream where industry, canalization, sand river, mining, tourism, and settlements occur produce both solid and water waste causing sea pollution. These are worsened by the conversion of mangrove forests into fishponds in the downstream leading to the loss of natural protection from waves and erosion.
Similarly, the dynamic processes in the sea such as storms, waves, and currents will affect the intertidal area and land. Waves coming inland, instead of being attenuated by mangroves that are the natural barriers, directly hit the coastlines leading to coastal erosion. In the long run, this will cause coastline retreat that will destroy not only human settlements but also fishponds along the coastlines that are the livelihood of the local community.