Semarang.  The Semarang-Demak toll road has become one of Indonesia’s most unique infrastructure projects due to its use of bamboo as a foundational material. Bamboo is employed to stabilize the soft soil near the construction site, which lies close to the northern coast of Java, where the ground is particularly prone to subsidence. This toll road also serves as a crucial barrier against tidal flooding (rob), providing a dual function as both a transportation route and a flood defense.

Semarang, the capital of Central Java, is a rapidly growing urban hub that connects surrounding areas such as Kendal, Grobogan, and Demak. The region’s economic expansion has led to increased traffic congestion along the northern coast road, known as Pantura, which links various cities across Central Java. To alleviate this issue, the government has fast-tracked the construction of the Semarang-Demak toll road, part of the National Strategic Project (PSN).

Built during the presidency of Joko "Jokowi" Widodo, the toll road spans two sections: Section I (Semarang-Sayung), stretching 10.69 kilometers, and Section II (Sayung-Demak), extending 16.31 kilometers. The project is slated for completion in February 2027.

Ardita Manurung, who oversees the construction of Section II, explained that the bamboo mattress method is being used to reinforce the toll road's foundation due to the soft soil conditions, which extend 30-50 meters deep. “We have used bamboo as a foundation material in Indonesia before, but this is the first large-scale implementation on a toll road,” she said.

The bamboo, sourced from various regions in Java, is chosen carefully—each piece must be straight, in good condition, and at least 8 meters long. Around 9-10 million bamboo poles will be stitched together with nylon thread to form 13 layers of bamboo mattresses.

"Atlantis" Toll Road: A Lifeline Against Tidal Flooding

The Semarang-Demak toll road, nicknamed the "Atlantis" toll due to its path over the sea, is integrated with a sea wall and features retention ponds. This innovative design helps mitigate the effects of tidal flooding, a growing concern for coastal communities in northern Java.

Tidal flooding (rob) has been a persistent issue in Demak Regency, where sinking land and rising sea levels have displaced residents and caused significant damage. The toll road is seen as a critical solution to manage these increasingly severe floods.

Four districts in Demak—Sayung, Karangtengah, Bonang, and Wedung—are especially affected, with Sayung being the hardest hit. In areas like Bedono Village, homes have been submerged, leaving only roofs visible, or built on stilts as residents struggle to adapt.

Noor Waris, a Bedono resident, shared how his home, elevated by two meters, was eventually abandoned as flooding worsened. "The water rises about a meter every 10 years," he explained. "During the rainy season, the floods are especially bad. We hope the toll road will stop this flooding so we don’t have to keep raising our homes."

Another resident, Ansori, echoed this sentiment, noting that flooding has become more unpredictable and severe over the past two decades. Despite the challenges, he expressed gratitude for the government's efforts, including the construction of the toll road, which he hopes will bring much-needed relief to Demak’s coastal communities.

During a visit to the sea embankment project in Semarang on June 17, 2024, President Jokowi emphasized the importance of the ongoing tidal flood control project. "This is a project for controlling tidal floods. The tidal flood barrier stretches 3.6 kilometers. I believe this barrier can effectively prevent tidal flooding for at least 30 years," he said.