Indonesia

The geological formation of the Cipatat karst region was shaped by side pressure. Bandung Institute of Technology students strive to find water.

Wasin once again set out to perform the annual ritual bathing in public. Clad in a sleeveless T-shirt and wrapped in a towel, Wasim, 34, carried bathing essentials including two moldy buckets.

"The water in my house has dried up since a month ago," said the resident of Rancamoyan hamlet, Gunung Masigit village, West Bandung regency in West Java.

Last Sunday, as noon approached, the father of two patiently awaited his turn under the porch of a small mosque. A mother could be seen still rinsing a pile of clothes at a half open-air public washing place, where water seeps from limestone rocks.

More than 500 residents from the neighborhood sections 13 and 14 rely on this water source. Rancamoyan village has three such water sources; two located in the front and back or east and west of the mosque. The two places have become public facilities to perform ablution, to bathe, to wash clothes though it does not have a proper toilet.

One more water source is a rock, the surface of which is used as a path for pedestrians and motor cycles. This source of clear water located on the left or south of the mosque creates a small shallow ditch which has become a home for small fish.

The dry season has left the water in these wellsprings low. The scorching sun and clouds of dust became part of everyday life for the locals in the karst or Citatah limestone rock area in west Bandung. The arid air can be heavily felt as one enters the residential settlement close to Pawon Cave, or the 'abode' of the primeval humans who inhabited the area around 5,600 to 9,500 years ago.

Near the villages stands Mount Masigit flanked by Pawon and Leuit hills. Part of Masigit is gone, excavated by the heavy limestone mining machinery. Black smoke from the limestone factory billowed from the east side of the peak. Below, along the main Cipatat road that links Bandung and Cianjur, chalk dust is blown away whitening the trees and building roofs.

According to head of Mount Masigit village, Ruhiat, the 10.51-square-kilometer area under his administration is inhabited by 15,560 people. Out of 24 neighborhood sections, five experience water scarcity when the dry season comes, like now. The water shortage was especially felt during the middle of the last fasting month.

The drought occurs in Lampegan, Cinta Asih, Pamucatan and Rancamoyan villages. "Most of the villages are in karst area," he said. The primary source of water in the limestone rocky area is the rocks itself. Those outside the area can still enjoy ground water. "Those who can't cope have already moved to other areas, even to Sumatra," he said. There are also those who chose to endure because it is hard to find land outside the village.

The area worst-hit by water scarcity is Rancamoyan village. In neighborhood community 14 in section 12, for example, out of 50 households, only two have wells, around 10 to 15 meters deep. Skillful well diggers have to work extra hard for a week, pounding limestone rocks.

Not surprisingly, the villagers do not have their own wells due to high digging costs which can exceed Rp5 million. The majority of the locals, Ruhiat said, work as hard laborers or factory workers. They can enjoy the overflow from the water sources only during the rainy season where water flows continuously.

Geological engineering lecturer from the Bandung Institute of Technology (ITB), Budi Brahmantyo, said that such is the typical condition of the karst area. Limestone rocks can indeed function as a water catchment area, however, the water absorbed into the rocks' pores is relatively small.

Like a piston, the water in the rocks is pushed out once the rains pour down, because under the limestone rock layer is a dense clay soil that water cannot easily penetrate. "The water then comes out from the section where the limestone layer and clay soil meets," explained the chairman of Geological Engineering of ITB.

The water often must pass through rock crumbs or layers that cover the limestone rocks. The rock crumb layer is usually existent on the karst slope, made into a road or became rocks near the water source.

The major problem, said the doctorate holder in karst geology from ITB, is the folded geological condition of the Citatah karst area. The contour of the hilly area was formed by the earth's tectonic pressure from the sides. Budi illustrated an example by pushing the two sides of a book with his right and left hands, causing the center of the book to rise like a hill.

The terrain of Citatah itself results from the previous rise of the shallow seabed. It can be seen from the coral fossil at the top of Pawon Cave or Pawon Stone Garden.

As written in the book Wisata Bumi Cekungan Bandung (Bandung Basin Tour) by T. Bachtiar, the Citatah limestone hill until the Rajamandala area stretches from the southwest to northeast. The height of the risen seabed now reaches 700-1,000 meters above sea level.

The Moluska foraminifera fossils from the Camerina fichteli-intermedia species found in the karst region date back to the Oligocene Epoch in the Tertiary Period, around 30-20 million years ago.

When lifted to the surface and doused by rainwater, limestone rocks went through dissolving process or karstification. On a small scale, this process caused cracks, and on a bigger scale, it managed to knock down the rocks forming caves. Under the ground, these caves became water reservoirs.

This can be seen in the Mount Sewu karst region where the karst formation process was not caused by side pressure, but by pressure from below. However, the Citatah karst region had a different formation process. As a result, Budi said, the region does not have water conserving caves, leaving Wasim and hundreds of Gunung Masigit in water shortage when the dry season comes.

By Anwar Siswadi
Tempo
No. 02/13, September 04, 2012

Photo caption
ITB students drill the earth to find fresh water source.