5. Analysis of coastal problems and bottlenecks

5.1 Problems in the coastal zone

The most commonly known coastal problem in Central Java is coastal erosion: large areas with severe erosion can be found in Semarang, Demak, Brebes, Tegal and Kendal. Shifting coastlines are a natural phenomenon and some of the coastal erosion can be attributed to natural dynamics. However, this natural process has been accelerated by human interference like uncontrolled groundwater extraction (leading to accelerated land subsidence and sea intrusion), transition of mangroves to fish ponds and other land use changes.

Flooded coastal area Northern Java

In line with the natural dynamics of erosion-sedimentation, large areas with sedimentation can be found close to the eroded areas, like in Brebes and Tegal and Kendal. Managing coastal erosion and sedimentation is one of the key priorities in Central Java’s coastal protection and in conversations, ICZM is often narrowed down to solving this problem.

However, the coastal area of Central Java faces many more challenges, most driven by land use changes. Both national, provincial and local governments stimulate industrial development in the coastal zone as this will provide employment and socio-economic development. This industrialisation also accelerates the urbanisation as citizens are drawn to these opportunities.

The Kendal Industrial park (2.200 ha) is an example of such a development, but the Central Java province has selected in total 8 regions (regulation no 10/2017) for such a development:

1. Kedungsapur region, including industry development in Semarang (capital city of Central Java), Kendal, Demak, Ungaran, Salatiga, and Purwodadi. Three cities in this region (Semarang, Kendal, and Demak) has even appointed by Indonesia government to be priority areas to be developed during 2015-2023.
2. Wanarakuti region, including industry development in Juwana, Jepara, Kudus, and Pati.
3. Subosukowonosraten region, including industry development in Surakarta, Boyolali, Sukoharjo, Karangayar, Wonogiri, Sragen, and Klaten.
4. Bergasmalang region, including industry development in Brebes, Tegal, Slawi, and Pemalang.
5. Petanglong region, including industry development in Pekalongan (city), Batang, and Pekalongan (regent).
6. Barlingmascakeb region, including industry development in Banjarnegara, Purbalingga, Banyumas, Cilacap, and
7. Purwomanggung region, including industry development in Purworejo, Wonosobo, Temanggung, Magelang (city), and Magelang (regent).
8. Banglor region, including industry development in Rembang and Blora.

Artist impression of Kendal Industrial Park

The industrialization creates both (socio-economic) opportunities and environmental/coastal challenges. In general, industries require large quantities of (ground-)water, often produce substantial volumes of industrial waste water (potentially containing toxic chemicals) and industrial solid wastes. If there is no infrastructure to process and manage such volumes, industrialisation will inevitable lead to serious pollution of rivers and coastal waters, in direct contrast with the ICZM ambitions.

In areas with soft coastal soils, large industrial and residential groundwater extraction will lead to land subsidence, accelerated coastal erosion and flood risks.

Building in the water

Given the ambitions, the vulnerable coastal locations of the industrial parks and magnitude of the industrialisation in Central Java, steering the industrialisation into a sustainable direction might be the highest priority from an ICZM perspective. Conserving groundwater reserves in subsidence-prone areas, state-of-the art waste water treatment and effective waste management should be integral part of the development of these parks. However, such a balanced development idea including ICZM principles was not encountered or mentioned in meetings and communications, leading to an impression that steering the industrialisation will be without ICZM ambitions and strategic planning and will be largely left to the local authorities and permitting officers.

Another transition is the development of aquaculture in low-lying areas. In parts of the coastal zone, this aquaculture seems to be following the land subsidence and intrusion of the sea: fish ponds were created where rice fields are no longer possible. But the aquaculture also has a dynamic of its own: in some areas (like Brebes and Kendal), aquaculture is expanding into the mangrove areas, posing a threat to the robustness of mangroves and the ability to protect the coastal zone.

Sustainable aquaculture is, next to managing coastal abrasion, sustainable industrialisation and urbanisation, a key ICZM topic in Central Java.

5.2 The underlying mechanisms and solutions

The mechanisms underlying the problems in the coastal zone of Central Java are related to the transitions of land use: industrialisation, urbanisation and aquaculture. Managing this transition according to ICZM principles is of utmost importance.

Some key elements of this sustainable management are:

• Controlling groundwater use (and providing alternatives), especially in subsidence prone coastal areas;
• Mandating state-of-the-art water sanitation techniques for industrial and residential areas to avoid pollution of rivers and coastal waters;
• • Creating an effective waste management system, also for industrial wastes and plastic wastes from residential areas;
• Allowing sufficient (future) space for rivers, canal and water retentions;
• Create sufficient buffer zones between mangroves and aquaculture;

In the development of the coastline, more attention should be given to natural dynamics. The planned Tegal port, for instance, is planned in one of the most sediment-prone areas in Central Java and operations of this port will be expensive as substantial maintenance dredging will be required.