Kathmandu, January 12

The Department of Soil Conservation and Watershed Management has begun collecting data to formulate watershed management plan.

According to the department, a team led by the department’s Director General Bijaya Raj Poudyal completed inspection of soil conservation and watershed management offices in the Valley recently.

“We have begun inspection of district offices to collect information and understand ground reality,” Poudyal said, adding, “The team will inspect all 61 district offices before preparing a draft of the watershed management plan.” The team also inspected Makawanpur office last month. Makawanpur, Kathmandu and Lalitpur have 8, 15 and 18 watersheds respectively.

According to the department, over 6,000 rivers and rivulets constituting watersheds of varying sizes intersect the physiographic regions of Nepal. These watersheds possess distinct characteristics depending on the origin of the rivers and rivulets in different physiographic regions.

The four major rivers in Nepal are the Sapta Koshi in the eastern region, Sapta Gandaki in the central region, Karnali in the west and Mahakali in the far-west. These are class one rivers which originate from High Himalayas.

Tributaries of these rivers are class two and class three rivers which originate from Mahabharat range and Siwaliks, respectively. Many watersheds of Nepal are in a state of physical and biological degradation due to over-exploitation by local inhabitants.

A reconnaissance survey carried out using imageries had assessed the watershed condition of major ecological land units. Watershed condition is an estimated index representing the current state of soil erosion in an area in comparison to the area under natural or well managed condition.

Watershed conditions are categorised into five classes: excellent, good, fair, poor and very poor.

Excellent indicates in or near undisturbed condition. Natural erosion processes including landslides may be present. Good indicates minor disturbances, correction can come about through normal management practices. Education and extension have a major role here. Productivity of land is not significantly impaired.

Similarly, fair indicates significant disturbance in soil mantle or stream channel exist. Productivity of land is diminished. A combination of education and structural remedies are required.

Poor indicates disturbance by accelerated erosion is serious and have resulted in considerable stream sedimentation and reduced land productivity. Extension, structural and land use changes are required to upgrade the land to a productive condition.