The focus of the case study is a degraded catchment, located at high altitude (2,800–4,200 m a.s.l.), home to 37 households, which is characterised by severe gullies and landslides. Gullies are continuously expanding, and constitute a significant proportion of the catchment. These cause considerable loss of cropland as well as downstream damage to the city of Cochabamba.
A combination of structural and vegetative measures was designed and implemented with the purpose of: (1) preventing affected areas from further degradation by safely discharging runoff from the surrounding area through the main gullies down to the valley; (2) gradually stabilising the land through the regeneration of vegetative cover; (3) reducing downstream damage through floods and siltation; (4) ensuring accessibility to the mountainous agricultural area during the rainy season.
Cut-off drains at the heads of the gullies, reinforced with stones inside the channel and grassed bunds below, concentrate runoff and cascade it down over stone steps back into the waterways. Flow is controlled by stone and wooden check dams and discharged safely. Sediment is trapped behind these structures and terraces develop. Bushes or trees are planted above and below the check dams. Depending on availability of materials, wooden check dams are sometimes used and associated with tree planting (four trees above and four below each check dam).
These practices are complemented by SWC measures throughout the catchment: biotrampas are staggered sediment traps located on the steep lateral slopes. They comprise ditches behind wooden barriers where soil accumulates. Biotrampas create suitable sites for tree/bush planting while stabilising the hillsides, reducing erosion, increasing infiltration and slowing siltation of the check dams in the watercourses. Supporting technologies include fenced-off areas for reforestation of the lateral slopes/upper edge of the gully, and finally large gabion dams at the outlets of the gullies, usually 10-25 m in length, but exceptionally up to 200 m.
After a few years vegetation should have stabilised the system, and effectively replaced the wooden and stone constructions. The various practices enhance each other. Establishment is labour demanding, but other costs are low, as long as the material in question is locally obtainable. Maintenance costs are also low. The technology was implemented over a period of six years, starting in 1996, through the Programa de Manejo Integral de Cuencas (PROMIC).
ទីតាំង: Pajcha Watershed Cordillera del Tunari, Cochabamba District,, ប្រទេសបូលីវី
ចំនួនទីកន្លែងបច្ចេកទេស ដែលវិភាគ: មួយកន្លែង
ការសាយភាយនៃបច្ចេកទេស: ត្រូវបានផ្សព្វផ្សាយត្រឹមតំបន់មួយ (6.0 km²)
តើស្ថិតក្នុងតំបន់ការពារអចិន្ត្រៃយ៍?:
កាលបរិច្ឆេទនៃការអនុវត្ត: 10-50 ឆ្នាំ
ប្រភេទនៃការណែនាំឱ្យអនុវត្តន៍៖
បញ្ជាក់ពីធាតុចូល | ឯកតា | បរិមាណ | ថ្លៃដើមក្នុងមួយឯកតា (ដុល្លារ) | ថ្លៃធាតុចូលសរុប (ដុល្លារ) | % នៃថ្លៃដើមដែលចំណាយដោយអ្នកប្រើប្រាស់ដី |
កម្លាំងពលកម្ម | |||||
Labour | ha | 1,0 | 48,0 | 48,0 | |
សម្ភារៈ | |||||
Tools | ha | 1,0 | 4,0 | 4,0 | |
សម្ភារៈដាំដុះ | |||||
Seedlings | ha | 1,0 | 19,0 | 19,0 | |
សម្ភារៈសាងសង់ | |||||
Stone | ha | 1,0 | |||
Wood | ha | 1,0 | 33,0 | 33,0 | |
Nails, wire | ha | 1,0 | 2,0 | 2,0 | |
Bio-fibre fleece | ha | 1,0 | 4,0 | 4,0 | |
ថ្លៃដើមសរុបក្នុងការបង្កើតបច្ចេកទេស | 110.0 | ||||
ថ្លៃដើមសរុបក្នុងការបង្កើតបច្ចេកទេសគិតជាដុល្លារ | 110.0 |
បញ្ជាក់ពីធាតុចូល | ឯកតា | បរិមាណ | ថ្លៃដើមក្នុងមួយឯកតា (ដុល្លារ) | ថ្លៃធាតុចូលសរុប (ដុល្លារ) | % នៃថ្លៃដើមដែលចំណាយដោយអ្នកប្រើប្រាស់ដី |
កម្លាំងពលកម្ម | |||||
Labour | ha | 1,0 | 12,0 | 12,0 | 100,0 |
សម្ភារៈ | |||||
Tools | ha | 1,0 | 1,0 | 1,0 | 100,0 |
សម្ភារៈដាំដុះ | |||||
Seedlings | ha | 1,0 | 1,0 | 1,0 | 100,0 |
សម្ភារៈសាងសង់ | |||||
Stone | ha | 1,0 | |||
Wood | ha | 1,0 | 1,0 | 1,0 | 100,0 |
Nails, wire | ha | 1,0 | 1,0 | 1,0 | 100,0 |
ថ្លៃដើមសរុបសម្រាប់ការថែទាំដំណាំតាមបច្ចេកទេស | 16.0 | ||||
ថ្លៃដើមសរុបសម្រាប់ការថែទាំដំណាំតាមបច្ចេកទេសគិតជាដុល្លារ | 16.0 |
Maintained: Due to prevention of further land loss
Maintained: Due to prevention of further land loss
High labour input for establishment (though paid in this instance)
farmers implementing SWC are not those benefiting most from the impact in the short term