North Sumatra moves to control flooding
Apriadi Gunawan, The Jakarta Post, Medan
The extensive trail of destruction that recent floods have wreaked in North Sumatra has prompted the provincial government to announce that they will take some preventative measures.
The first local government initiative will be the construction of 1,500 flood dikes along the two main water catchment areas.
North Sumatra's forestry office is seeking Rp 15 billion in state funds from the central government to build the dikes. In addition, it is also aiming to replant 10,000 hectares, as deforestation was widely considered to have been a major factor in exacerbating the magnitude of the floods.
The floods hit Medan and Deli Serdang on Jan. 13 and claimed 13 lives with four victims declared missing. Thousands of houses were damaged.
The head of the forestry office, Darori, told The Jakarta Post that the large floods, which swept through the provincial capital and other areas over the last two weeks, proved that the region's high level of rainfall exceeded the capacity of the province's rivers, necessitating the construction of flood embankments.
Medan's water cycle is dictated by three water catchment areas, namely Deli, covering an area of 48,595 hectares (ha) across the city, Percut (39,834 ha) and Belawan (57,655 ha). The three originate in Karo regency and Deli Serdang regency.
The forests of Deli in particular, according to Darori, covers only 7.59 percent of its catchment area and is dwindling as a result of poaching, nomadic farming and settlement. All these human activities have hampered the area's water cycle and caused an increase in levels of runoff.
In fact, Deli is mostly composed of protected and limited production forests. "Currently Deli, Percut and Belawan each feature a low water absorption rate because the forested area is too small," Darori pointed out.
"In order to anticipate further flooding in Medan by overflowing rivers and streams, reservoirs are needed," he said.
Based on the 1999 forestry law, at least 30 percent of a catchment area's forested land must be maintained or proportionally distributed. This means that Deli needs an additional 24.41 percent, or 10,885 ha, of forest.
To increase the wooded area, the forestry office has launched a reforestation program, as part of its 15 long-term schemes to combat flooding in the Medan area. The building of flood dikes along rivers is only a short-term plan.
The expansion of forests is imperative as Medan has no water absorption sites like marshland or paddy fields. This only exacerbates the levels of local floods.
Meanwhile, local environment observer Jaya Arjuna said that the recent floods were more due to the failure of the forests' water-regulating function, which involves wood and humus. If any of these two elements is lacking, the water absorption capacity is reduced.
Jaya proposed that forest denudation should be stopped, particularly upstream around Lau Gedang, Karo regency, in order to surmount the floods downstream.
The forests at Lau Gedang are in a critical state, with around 1,000 ha of vegetation destroyed every year, largely due to illegal logging. It also controls the level of water that flows to three areas -- Medan, Langkat and Binjai.