- Flooding in the sand sea of Mount Bromo every rainy season has been happening for a long time, but only went viral on social media this year.
- Flooding in the sand sea of Mount Bromo occurred due to compaction of the sand sea due to the speed of hundreds of tourist vehicles every day.
- Research by the soil department of the Faculty of Agriculture, Brawijaya University in 2017 identified the biophysics of a sea of sand. As a result, the soil profile that is frequently crossed by vehicles is relatively dense in the top layer. However, the particles do not bind to each other, causing puddles
- Walhi East Java saw the flooding in the sea of sand as a warning for the government to restore the Mount Bromo religious and cultural area, so it urged the TNBTS Center to limit the number of vehicles passing through the sea of sand.
A video of a convoy of jeeps crashing through puddles of water in a sea of sand in the Mount Bromo area, East Java has spread widely on various social media. The owner of the Twitter or " Flooding in the sand sea of Mount Bromo this afternoon," wrote Alex Journey.
Meanwhile, the second video is 30 seconds long, a motorbike rider falls. The motorbike was hit by a strong flow of water flowing in the sea of sand . Almost got swept away by the current of the 'river'. Four people were helping to hold the motorbike. Meanwhile, a motorbike rider was determined to cross the 'river'. Two people helped push the motorbike. Meanwhile, on the side of the 'river', dozens of people stood in a row while riding motorbikes. They waited for the water to recede.
One of the tourist guides, Amirudin alias Cak Amir, from Gondanglegi, Malang Regency, said that flooding in the sand sea of Mount Bromo occurred a long time ago. Since becoming a tour guide in 2011, every rainy season there has been a flood in the sea of sand. “Flooding usually doesn't last long. Five hours later, the water receded," he said.
However, there are large puddles of water that are dangerous if a car passes by. So, a number of jeep drivers transporting tourists avoid the puddle. Floods in the sea of sand occur when the intensity of rain is high. However, in the digital era, residents record these activities and upload them to social media. So it is busy and becomes a public conversation.
Chairman of the East Java WALHI Regional Council, Purnawan Dwikora Negara was in the Mount Bromo area when the flood occurred. Heavy rain fell on the Mount Bromo area. Purnawan said that ecologically the sea of sand is able to absorb rainwater. Naturally, the contour of the Tengger caldera area forms a river channel which flows with water when it rains.
When the carrying capacity is ideal, water flows in a river-shaped channel. During the dry season it dries up, while when it rains the water flows. Naturally, he said, nature can restore itself when damage occurs. Like stagnant water, it will naturally seep into the sea of sand.
However, there was a change in the function of the conservation area in the Bromo Tengger Semeru National Park (TNBTS) where the surface of the sea of sand hardened. The compaction of the sea of sand occurs because hundreds of tourist vehicles pass through the sea of sand every day. "Vehicles passing through exceed the carrying capacity threshold for the Tengger caldera area,
The Tengger Caldera region consists of savannah and desert. Culturally, the traditional people of Tengger call it land hila-hila , an area that is believed to be the land of gods. Starting from the Jemplang area, the Tengger indigenous people who adhere to the True Javanese Buddha believe that it is the boundary between the human world and the world of gods.
For the Tengger indigenous people, the Tengger caldera has eco-socio-religio-cultural meaning. The Tengger community cannot be separated from nature and the local environment. The religious ritual activities of the Tengger indigenous people always depend on the natural surroundings.
There has been a shift in cultural meaning, said Purnawan, the land of the hila-hila has become a commercial tourist area. Mount Bromo has changed since it was designated as a top ten national priority destination, so it has been promoted as one of the pillars of Non-Tax State Revenue (PNBP). "Restrict vehicles from crossing the sea of sand and restore the meaning of being a land of hila-hila ," said Purnawan, who is also a lecturer in environmental law and dean of the Faculty of Law, Widyagama University, Malang.
Tourism Commercialization
Since Mount Bromo was branded as a leading tourist attraction, there have been signs of commercialization of the Tengger Caldera area. The peak after Mount Bromo was designated as one of the PNPB potentials. Mount Bromo is one of the contributors to state finances. Mount Bromo is branded as an iconic tourist attraction.
The naming of the area around Mount Bromo, which has a local name, has been changed to a name that suits commercial interests. However, it ignores cultural meaning. Such as Teletabis hill, Love hill, and Kingkong hill. All presented for tourist purposes. "Flooding in the sea of sand is a warning sign for policy makers to restore the hila-hila land ," said Purnawan.
Now, there are activities to change the function of religious cultural areas into tourism economic areas. Even though the zone or zoning designation of the area in the National Park is appropriate, it is not culturally appropriate. “Eliminating the meaning of Tengger as a cultural area. Tengger is commercialized," he continued.
Purnawan demanded that the TNBTS Center as the area manager immediately return the Tengger area as tengering budiluhur (a sign of noble character). "Don't just emphasize commercial tourism, but we need to restore Tengger as a religious and cultural function," said Purnawan.
Based on research by Rein W van Bemmelen in 1970, the Tengger mountains were formed from the Pliocene to the Pleistocene era or more than two million years ago. Composed of pyroclastic breccia deposits, sand, tuff, breccia lava and lava flows from Mount Bromo, 2,329 meters above sea level (masl).
During the last eruption, Mount Tengger experienced subsidence and formed the Tengger caldera. Volcanic processes continue to produce several volcanic cones. During its growth period, explosive and effusive activities have formed the Nongkojajar cone, Ngadisari cone, Tengger Tua cone, Keciri cone and Cemoro Lawang cone.
These cones were partially destroyed and formed calderas in order from oldest to youngest, namely Nongkojajar Caldera, Ngadisari Caldera, Keciri Caldera, and Lautan Pasir Caldera. The Bomo volcanic cone in the sea of sand shows volcanic activity to this day.
Mount Bromo is a cinder cone type volcano in the caldera. This type of eruption is effusive and explosive, throwing up ash, sand, lapilli, lava chunks and volcanic bombs. Phreatic eruptions which are the result of contact between magma and the hydrothermal system in that place occur when rainfall is high.
Compaction of the Sand Ocean
Spokesperson for the TNBTS Center , Endrip Wahyutama, admitted that the development of physical conditions in the TNBTS area showed signs of disturbance and damage. Disturbances are caused by the accumulation of high levels of tourist activity and local communities. In plain view, floods and puddles and faults form river channels when it rains. "This symptom occurs due to damage or disruption of hydrological function in the sand sea ," he said.
The compaction of the sea of sand occurs because more and more vehicles are passing through the sea of sand. Compaction occurred in a number of different locations. Research by the TNBTS Center together with researchers from the soil department of the Faculty of Agriculture, Brawijaya University in 2017 identified the biophysics of the sand sea. As a result, the land profile is untouched by vehicles and human activities, which is still natural. Meanwhile, in locations frequently crossed by vehicles, the soil profile is not natural.
“Disturbed by human activities. The soil is dense but relatively at the top layer. "However, the particles do not bind to each other, causing puddles," he said.
In 2023, there will be 116 thousand motorbikes and 46 thousand cars entering the sand sea area. On average, 127 cars, 313 motorbikes and seven bicycles cross the sea of sand every day. Data collection from the TNBTS Center states that the number of jeeps serving tourists in 2023 will be 1,630 units.