Manamatta sub-watershed area is situated in south east of Kathmandu, which is 22 km apart from the Kathmandu and covers the area of Gagalphedi, Bajrayogani, Aalapot and Indrayani VDCs. Manamatta sub-watershed is considered as one of the vulnerable place by the soil erosion and land slides. The implications if bioengineering technique is applied there to control the soil erosion and slope stabilizations, which is one of the best examples.

The objectives of this study were to find out the effectiveness of bioengineering technique in Manamatta watershed, to find out the environmental impacts by bioengineering, to find the outcomes of bioengineering in watershed management.

This case study is prepared by the primary and secondary data collection. Primary data collections include the questionnaire to the local people and field staff of BIWMP and DSCO. Different literatures, Internet, case study, reports are secondary data sources to make the study relevant. With respect to the studies, necessary field visit was also made. Different group discussions were conducted with local people and related staff and professional.

In Manamatta watershed area, bioengineering technique is applied for the slope stabilization and erosion control with integration of various civil structures. Different civil structure like Retaining wall, Check dams, Drain, Stone pitching are constructed there for the slope stabilization and erosion control in conjunction with bioengineering.Some of the bioengineering systems used there are Grass planting (diagonal grass line and Herring bone grass line), shrub and tree planting, brush layering and palisades. The effectiveness and practices of different techniques are analysed through landslide and soil erosion. To treat and solve these problems the implementations of bioengineering technique applied in the catchments area of Manamatta watershed. The bioengineering technique enriches the plants and trees, which control the pollution by sinking carbon dioxide and provide greenery to the environment. Societies are the beneficiaries with bioengineering technique. In its implementations, local labours are used, which provide them opportunities and vegetative implication would benefit them coz they are the users of the products (Khar, fuel wood, fodder, grass etc). The implementation of the vegetation reduces the steepness of the slope, which increases the factor of the safety, and the stability of the slope may increases.

Bioengineering is the use of living plants for engineering purpose. Vegetation is carefully selected for stabilizing slopes of watershed according to its suitability to the site. Incorporating bioengineering techniques offers more effective solution to the problem of watershed. Bio- engineering is used in watershed management for the protection of slope against erosion to reduce the shallow planer sliding to improve surface drainage. To overcome this problem bioengineering is the most effective and most economic solution.

A technician should reach (assess) every site individually to determine the stabilization procedures and know the site condition and its characteristics. History cause mechanism of the instability or erosion should be known during feasibility study. The seedlings for bioengineering techniques should be of good quality i.e. proper height developed root and shoot, non-diseased etc and should be transported to the site with great care.

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