Yongker Rumthe, The Jakarta Post, Manado

Locals and tourists are no longer able to enjoy the beauty of Lake Tondano, some 37 kilometers north of here in Minahasa Regency, as it has been suffering from serious environmental deterioration for many decades.

Fewer and fewer locals and tourists picnic along the lake's shores following the disappearance of tourist resorts and recreation spots due to increasing population. Many locals now use the lake's shores for fishing and farming.

"The lake is no longer attractive for visitors as it has suffered serious environmental degradation. This is just one of negative impacts the environmental degradation has had on local people and the local administration's income," Sri Hardiyanti, a researcher from the National Resources Management organization, told The Jakarta Post here on Wednesday.

She regretted that so far the local administration had taken no action to stop the deterioration of the once-beautiful lake.

Sri pointed out that even more serious was the fact that the lake would soon no longer be able to function as a reservoir for millions of people living in Minahasa and its surrounding areas, including Manado, because of the environmental damage caused by human activities.

"The water level has dropped to 15 meters now from around 47 meters in the 1950s because of intensive sedimentation in the lower courses of the rivers flowing into the lake over the last six decades.

"The sedimentation is caused by the conversion of thousands of hectares of forested areas around the lake into farmland, the appearance of water hyacinths in the lake (eutrophication), as well as fish farming," she explained.

She said that besides irrigating hundreds of hectares of farmland in Minahasa regency, the lake's water was also used to drive a hydropower plant that supplied electricity to the province.

According to Sri, the fish farms had also resulted in sedimentation and provided fertilizer for the water hyacinths.

"Besides, a large part of the fertilizers used on the surrounding farms are washed into the lake, providing further fertilizer for the water hyacinths and damaging the ecosystem of the lake," she said.