Nainital: a landslide town of Uttarakhand (India)

Abstract

PurposeThe purpose of this paper is to show that Uttaranchal is a hilly State, recently constituted in the Himalayan region. Over 80 percent of Uttaranchal state is prone to slope instability because of weak and highly folded and fractured rocks, steep slopes, high seismicity and unfavorable hydro‐geological conditions. In addition to this, unsystematic development construction activities contribute to the problem. Newly formed Uttaranchal state is in the process of development, required to expand the existing infrastructure.Design/methodology/approachThe paper gives a full description: Bending of rock beds, their disjointing, disruption and drag‐folding are characteristic features of a creeping mass. Tilted trees and poles are indicative of creep movement as seen on a number of hillslopes in and around Nainital town. The curvature of the tree trunks bears record to the rate of creep during the period of growth of the tree. It hardly needs stating that the rate of creep movement is quicker during the rainy season, and there may be long periods stretching over years when no movement at all takes place. The temporal span of this phenomenon stretches over thousands of years. The rate is accelerated by clear‐felling in forests and by construction on steeper slopes. The depth of the creep movement is variable, and depends largely on the nature and degree of weathering of rocks, the sub‐surface structure and amount of water present within.FindingsIt was found that, to meet the requirement, construction activities are in full pace, which have given rise to the new landslide problems or have aggravated the existing slope instability problems. In order to keep the landslide problems to a minimum, systematic studies are required on every aspect of the slope instability problems.Practical implicationsOn the basis of slope instability evidence, past occurrence of landslides, deformation of civil structures and geological conditions, three zones have been identified – safe, moderately safe, and very unsafe.Originality/valueThe paper describes the natural problems with which Uttaranchal is faced and proposes systematic studies which are required to deal with every aspect of the outstanding problems of slope instability.