Tempe lake suffers from severe sedimentation

Andi Hajramurni, The Jakarta Post, Makassar

Lake Tempe in South Sulawesi was once called the "fish bowl of Indonesia". Today, as a result of chronic sedimentation caused by erosion and water plants, fishing is drying up.

The sediment piles on at a rate of five centimeters per year, causing the lake to shrink away in the dry season and overflow in the wet season.

Three regencies border the lake -- Wajo, Soppeng and Sidenreng Rappang. Wajo, in particular, is at risk from seasonal floods which threaten thousands of private and public buildings.

Once the lake was 30,000 hectares in area and 10,000 meters deep. Now, Tempe is never larger than 10,000 hectares and shrinks to 1,000 hectares with a maximum depth of two meters in the dry season.

The Wajo regency administration and several environmental organizations say the lake may remain only a memory in future years.

Nine rivers flow into the lake and sedimentation is attributed to upstream erosion. The condition is worsened by household waste and the rampant growth of water hyacinth, called eceng gondok.

Wajo environmental agency head Andi Tenri Lengka explained the Eceng gondok speeds up sedimentation because dead plants accumulate under water instead of rotting. They choke the lake during rainy season and are still there when it dries out.

While eceng gondok is sometimes suitable for handicrafts, the Tempe variety is not, Lengka said.

Tempe's receding shoreline bodes ill for fish including bungo, biawang and bete-bete. A handful of other species are hanging on.

In the 1960s, Lengka said, the lake produced some 50,000 of fish per year, which helped feed the country's prison population. Today only about 10,000 tons are caught annually.

"We could catch a lot of fish easily (even) during the dry season, several years ago. Now, it is not easy to find them," said Wahid, a fisherman.

Most local fishermen have had to start farming when the lake dries up, sowing corn and soya beans on the lake bottom.

Lengka said he welcomed solutions to the environmental disaster from whatever quarter.

Wajo administration mitigation efforts include excavation of Cenrenae River and attempts to channel rainy season overflows into smaller lakes and rivers in the Tempe drainage.

Lengka said the administration needed Rp 43 billion (US$4.70 million) to implement its programs and hoped the province and central government would help.