Hills are of great importance to the country. Traditionally, hills have served as the sentinels guarding the country and checking invasion. They are endowed with great forest wealth and a variety of wild life. They are the sources of water in the major river systems of the country, sustaining large population and agricultural activity. The hill regions usually exhibit a variety of climatic, geological and ecological characteristics and because of their unique character, hill roads require special attention in planning, design, construction and maintenance.

India has a long experience of constructing hill roads. Based on the expertise available, the Indian Roads Congress brought out a standard (IRC: 52) on Alignment, Survey and Geometric Design of Hill Roads in 1973, which has been revised twice. The IRC had also organized a Seminar on Hill Roads at Nainital in July, 1985 wherein several Technical Papers from eminent professionals on seven Themes, viz., Survey and alignment of roads in hilly regions; Environmental considerations in selection of alignment of roads in hilly regions; Design of hill roads including retaining structures; Construction and maintenance of hilly roads including use of modem equipment and snow clearance of roads; Landslide problems and road drainage practices and Water crossings in hilly regions were presented and discussed. The Seminar was aimed to focus attention of highway engineers on various problems connected with the selection of alignment and adoption of design standards, construction specifications and maintenance strategies on hill roads, to stress the need to preserve eco-system in the hilly region when constructing roads. Besides Proceedings, some important Papers on design, construction and maintenance of Hill roads, presented during the Seminar have also been published. Another Special Publication, 'IRC:SP:48 Hill Road Manual' was brought out by IRC in 1998 which also covers the issue of ecology and environment.

When aligning new roads, some simple precautions, such as, avoidance of unstable terrain having deep blanket of loose soil and boulders susceptible to seepage and water saturation, selection of mild slopes in preference to steep slopes, avoidance of forest land as far as possible, avoidance of landslide prone locations, selection of alignment causing least disturbance to the natural drainage courses, etc: should be taken into account. Tunnels, though costly, provide eco-friendly solution, besides reducing the travel length.

While designing hill roads, special considerations, such as, balanced cut and fill with a retaining wall, use of reinforced soil to minimize earthwork and provision of adequate erosion control measures should be considered.

During construction, the drainage arrangement should proceed side by side with the earthwork; retaining walls wherever required should be constructed before hill cutting so that cut soil can be used as back fill; cross fall should be on hill side to control runoff over valley side; replantation should be resorted and young plants should be protected by fencing; and use of emulsions should be encouraged to minimize use of wood for heating.

As massive programme of widening the existing roads to 4/6 lanes and providing connectivity to villages have been launched by the Government of India and a large proportion of proposed roads pass through hilly areas, there is an urgent need to provide due consideration for preserving the ecological balance. Cutting of hillsides and felling of forests on hill faces, which are necessary concomitants to any developmental activity, have disturbed such balance and sometimes brought disaster in its wake. Large and rapid developmental activities may cause alarming degradation and depletion of natural resources resulting in ecological imbalances. Therefore, while planning and constructing roads, the conservation of forests and ecological balance should be maintained. Similarly, planning of important roads through potential landslide zones should be avoided.

The Government of Uttaranchal has established a Disaster Mitigation and Management Centre (DMMC) which is preparing a comprehensive database on areas prone to earthquake, landslides, flash floods, road accidents, etc. using remote sensing and GPS techniques to map the landslide zones, etc. which may prove to be helpful in planning of new road alignment and also in mitigating the problem on existing road network. Similarly, soil-nailing techniques are being evolved for control of erosion. Use of gabion walls in place of conventional reinforced concrete or masonry structures also provide eco-friendly solution. Considering its importance and special significance to the State of Uttaranchal a few technical presentations on control of erosion and landslides on hill roads have been planned during the forthcoming mid-term Council meeting of IRC scheduled for the l2th May, 2004 at Nainital. Some of the Technical Papers are published in this issue of Indian Highways for the benefit of IRC members at large.