NEPAL ENGINEERING SERVICES

Monday, July 1, 2019

Introduction to Bioengineering






The indigenous methods similar to bioengineering are in practice for centuries in our hills. Not only in our hills, the practice of bioengineering can be traced to ancient peoples of Asia and Europe. Chinese historians, for example, recorded use of bioengineering techniques for dike repair as early as 28 BC. Early western visitors to China told of riverbanks and dikes stabilized with large baskets woven of willow, hemp, or bamboo and filled with rocks. In Europe, Celtic and Illyrian villagers developed techniques of weaving willow branches together to create fences and walls. Later, Romans used fascines, bundles of willow poles, for riverbank protection.
By the 16th Century, bioengineering techniques were being used and codified throughout Europe from the Alps to the Baltic Sea and west to the British Isles. Much of the development and documentation of bioengineering techniques, since the Industrial Revolution, has been done in the mountainous areas of Austria and southern Germany. By the turn of the century, European bioengineers had begun to find new applications for old folk technologies, using them to develop methods to deal with the new environmental problems. The biggest boost to development of new bioengineering techniques in Europe came as a result of political developments during the 1930’s. Financial restrictions of pre-war years in Germany and Austria favored use of low cost, local materials and traditional construction methods for public works projects.
In 1936, Hitler established a research institute in Munich charged with developing bioengineering techniques for road construction. Although this development work was lost, a forester named Arthur von Kruedener, the head of the institute, continued to work in the field and is known as the father of bioengineering. In United States of America, bioengineering works started from the stabilizing degrading slopes in the national forests of central and southern California. There is still resistance to the techniques in many countries. Bioengineering approaches most often use locally available materials and a minimum of heavy equipment, and can offer local people an inexpensive way to resolve local environmental problems. The public’s increased environmental consciousness often makes bioengineering solutions more acceptable than traditional “hard” engineering approaches.
Despite, and may be because of, the differences in approach and philosophy between bioengineering and other engineering methods of addressing environmental problems, bioengineering technologies are especially appropriate today. The scale and range of environmental problems require consideration of new technologies even when they are in fact centuries old.

Bioengineering can be applied in different fields. For example, slope stabilisation on embankments and cut slopes, erosion control, water course and shoreline protection, wind erosion control, noise reduction, traffic control, mining and reclamation, construction sites, waste disposal and public health, reservoirs and dams, buildings, highways, railways, and the like. Bioengineering is an excellent tool for stabilizing areas of soil instability. On areas of potential or existing mass wasting, it may be best to use a civil engineering system (such as check dam, toe wall, catch wall, stone pavement etc) alone or in combination with bioengineering.

Benefits of bioengineering in an watershed includes:

· Projects usually require locally available excavation equipment. As a result, there is less cost and less impact on slope. In addition, limiting hand crews to one entrance and exit route will cause less soil disturbance to the site and adjoining areas.

· Erosion areas often begin small and eventually expand to a size requiring costly traditional engineering solutions. Installation of bioengineered systems while the site problem is small will provide economic savings and minimize potential impacts to the slope and adjoining resources.

· Use of native plant materials and seed may provide additional savings. Costs are limited to labour for harvesting, handling and transport to the project site. Indigenous plant species are usually readily available and well adapted to local climate and soil conditions.

· Bioengineering projects may be installed during the dormant season of late fall, winter, and early spring.

· Bioengineering work is often useful on sensitive or steep sites where easy accessibility is not feasible.

· Years of monitoring have demonstrated that bioengineering systems are strong initially and grow stronger with time as vegetation becomes established. Even if plants die, roots and surface organic litter continues playing an important role during reestablishment of other plants.

· Once plants are established, root systems reinforce the soil mantle and remove excess moisture from the soil profile. This often is the key to long-term soil stability.

· Bioengineering provides improved landscape and habitat values in the watershed.



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