16-10-2009, 11:48 AM
Abstract
Bio-engineering is the use of vegetation, either alone or in conjunction with civil engineering
structures, to reduce instability and erosion on slopes. It should be a fundamental part of the design
and construction of all roads in rural (and urban) hill areas, mainly because it provides one of the
best ways to armour slopes against erosion. Because of the steep and dynamic slopes found in the
Himalayas, most hill roads are engineered near to the margin of safety. Bio-engineering is an
effective way of enhancing civil engineering structures to increase stability as far as possible. It is
relatively low in cost uses local materials and skill, and provides livelihoods benefits through.
economically useful products..
A study has shown that many roadside slopes in Himachal Pradesh (HP) suffer from a range of
instability and erosion problems, many of which are conducive to the use of low cost remedies such as
bio-engineering. The Public Works Department (PWD) is examining alternatives to standardise civil
engineering approaches and in particular is looking at the possibilities offered by bio-engineering,
through the experience gathered in other parts of the Himalayas over the last few decades Between
1987 and 1990, the PWDâ„¢s Horticulture Wing was involved in soil conservation work to resolve
shallow failures on road cut slopes. Though this programme has diminished with time, it still
demonstrates the inherent capabilities that can be harnessed to good effect.
This paper describes the main types of slope instability found in Himachal Pradesh, their causes
(natural and man made), treatment options to safeguard the road network and reduce long term
maintenance costs; approaches to bio-engineering that are appropriate to the bio-physical and socio-
economic conditions found in the state; institutional mechanisms for these to be successful; capacity
enhancement means and tools; and examples of success and failures from other parts of the world. It
also documents early experience in the introduction of this type of approach through specific pilots of
critical road sections that have been considered under the World Bank funded Himachal State Roads
Project.
Bio-engineering: Introduction as a Science
Bio-engineering is the use of vegetation, either alone or in conjunction with civil engineering
structures, to reduce instability and erosion on slopes. It should be a fundamental part of the design
and construction of all roads in hill areas. This is mainly because it provides the best way to armour
slopes against erosion, and can also provide a significant contribution to soil reinforcement and other
anti-failure measures (Transport Research Laboratory, 1997). It is relatively low in cost, uses local
materials and skills, and provides livelihoods benefits through economically useful products. It is
often called soil bio-engineering to distinguish it from the bio-medical science that uses the same
term
