Large scale Engineering Geological and Geotechnical mapping between Kham and confluence of Kali Ganga and Mandakini River with an Emphasis on landslide studies, along Kali Ganga Valley, Garhwal Himalaya

Presented By

Neeraj RamolaSupervisor Co-Supervisor

Professor Y. P. Sundriyal Dr Vikram Gupta

Department of Geology Scientist ‘E’

HNBGU Srinagar Garhwal WIHG Dehradun

Uttarakhand Uttarakhand

THE HIMALAYA

Is a resultant of typical continent-continent collision.

The upliftment process is still continue.

There are numerous thrusts and faults in the Himalaya, along whom the movement activity is going on.

INTRODUCTION

• Landslides is one of the major damaging natural hazard occurs in geologically young and active Himalaya region. The landslide activities happens due to high and intense rain fall in the entire Uttarakhand Himalaya but MCT zone of higher Himalaya and southern mountain front is more prone to disastrous activities because it receives high rain fall comparatively to other places.

• Kali Ganga River valley is tectonically very sensitive and fragile, located within the MCT zone which is highly unstable domain and has highly sheared and pulverized rocks (Valdiya, K.S. 1985). And Majority of incidents of landsides is associated with this zone (Bhatt 1992, Kimothi et al., 1999).

Maximum horizontal compression along the MCT gave rise to high relief which forms the orographic barrier for the Indian summer monsoon also known as the southern mountain front.

Locality Year Lives claimed

Okhimath(Kuntha Village)

1979 50

Okhimath 1998 107

Phata- Byung 2001 27

Okhimath 2012 66

Kedarnath 2013 7000 (approx)

Major events of Cloud burst induced Disaster in Mandakini Valley

STUDY AREA

• The study area, Kali Ganga River valley lies between 79°4'30.75" to 790 4'56.90''E longitudes and 30°37'23.65" to 30°32'51.52" N latitudes in Okhimath tehsil of Rudrapryag district in the Higher Himalaya terrain of Garhwal Himalaya. The area falls under survey of India toposheet no 53 N/2.

• Kali Ganga River which is a main tributary of Mandakini River, originates from Dhaulagiri and Kaleunbank Glaciers located at the elevation of 4820 meter (approx). Kali Ganga River and Mandani Ganga (tributary of Kali Ganga) meets at Khunnu (1490 meters).Finally Kali Ganga River meets at the elevation of 1200 meters with Mandakini River downstream to Kalimath.

Fig. 1: Location map of the study area.

Objectives

• Geological and Geo-Engineering mapping of the study area at the scale of 1:10,000 and the mapping of critical zones at the scale of 1:1000.

• To find out causes of frequent occurrences of landslides in the area.

• Landslide hazard zonation mapping of the area.

• Stability analysis of the critical slopes

• Finally Risk assessment and Remedial measures of the landslides.

2 to 2.5 meter deep cracks developed due to sinking along the boundary of Kunjethi Village in which 150 families residing

Kunjethi Landslide

Cracks on the terraced agriculture fields of Kunjethi

Jal-Talla

Near Kabiltha

Downstream of Kalimath

Methodology

• To prepare the base map of area (using Total station, DGPS and field mapping).

• Geological Mapping (to demarcate various litho units and structure (thrust/ fault)).

• Geotechnical mapping (sampling of each litho and soil units will be collected).

• Engineering Geological mapping (SMR, RMR, over burden GPR (for strength cohesion, frictional angle of rock and soil)).

Continue……..• Geomorphological mapping and to demarcate the

boundary of flood during 2013.• Inventory of landslides or related mass movements

Overlay of all maps and found the critical landslide zones.

• To prepare various thematic maps in GIS environment and by using these maps critical landslide zones will be identified.

• Stability analysis of the critical landslide zones using the above data.

• Risk assessment and prevent measures based on the stability analysis results.

POSSIBLE OUTCOME• The result of proposed study will shed light on the wide

applicability for understanding the mechanism of landslide activities in the Himalayan region particularly within MCT zone which is highly sensitive tectonically as well receives high precipitation during Indian Summer Monsoon period and where majority of slope failures are resulted due high rain and cloud-burst.

• On the basis of the results of these studies, suitable and innovative remedial measures will be recommended for preventing the investigated slope to failure further.

Continue………..• Most vulnerable, Vulnerable, least vulnerable

zone will be marked on high resolution map will be prepared during the study on the basis of which rehabilitation locations may be find out.

• On the basis of the conclusions, recommendations and prepared geo-hazards map of the area further policies related to the development activities may be framed.

THANK YOU