Application of GIS/GPS for Landslide management

A case study of Ramche-9 and Dhaibung-7 of Rasuwa District

Submittedto

Emergency and Disaster Management Livelihood and Economic Rights Department

Action Aid Nepal

BYBinod Dhakal

Individual consultant/GIS Specialist

GIS (Geo-informatics Science

1. Geographic Information system(GIS)

2. Remote Sensing (RS)

3. Global Positioning System (GPS)

3 S Technology

Why GIS/GPS for Locating Landslide in this study

• These landslides occurs after topographic map 1995 published• Update the existing topographic map information with present

feature• Easy measurement and plotting of Shape and Size of Landslides• Easy Calculation of areas and distances• Buffer zone creation • Effective rehabilitation• Monitoring and Modeling• 70% of the information includes some geographical facts in the

decision making process• Ability of assimilate divergent source of data both spatial and non-

spatial (attribute data)• Visualization impact• Sharing of information• Analytical capability on a spatial context

Four M’s

Measurement ModelingMonitoringMapping

Background

• Rehabilitate mountain residence into the safe land permanently

• The livelihood of the mountain people is miserable and sensible condition due to the lack of accessibility

• The coping capacity of affected people could be strengthen

• Study is made in ward No.9 of Ramche VDC and, at Prangse village (Ward No.7) in Dhainbung VDC

Objective of the study

The general objective of the study is to know the situation of the landslide events at these two VDCs, particularly, Prangese at Dhaibung and Ramche. The specific objectives of the study are

1. Analyze these events in socio-economic and technical perspectives briefly.

2. Find out the appropriate interventions in future for the sustainable management of the sites.

Description of the sites

Soci-economic situation

Population of Landslide VDC's / Wards

VDC/Ward Dhaibung (Dhibung W.N.-7)(growth rate is 2.45%)

Ramche (Ramche W.N.-9)(growth rate is 2.25%)

Year Hhs Tot_pop Male Female Hhs Tot_pop Male Female

2001 953 4944 2475 2469 397 2153 1121 1032

1991 724 3880 1933 1947 296 1727 932 795

2001 (171) (786) (407) (379) (66) (337) (187) (150)

Land Use

Land use for Dhaibung (Dhobi Khola) and Ramche (Narkang Khola) Landslide

VDC Dhaibung Ramche

Descriptions Area (Ha) %Area (Ha) %

Cultivated Land 350.7 69.9286.3 35.1

Forest Land 7.5 1.5 196.3 24.1

Shrub Land 56.4 11.3 332.6 40.8

Grass Land 84.5 16.80 0

Landslide 2.5 0.50 0

Grand Total 501.6 100 815.2 100

Methodology and Study Processes

Field Visit for Primary data

Field data

Social data Technical data

Group discussion

Secondary dataRainfall

Existing maps and other information

Use of GPS

Landslides

Debris flow type of landslide is seen in both Dhaibung and Ramche area.

Dhaibung Landslide active old and dormant and reactivated slides, landslide of Ramche is reactivated old landslide.

A both natural and human activity seems to be responsible The human activities which initiates landslides include cultivation in the colluviums of old landslide deposits, extensive grazing and cutting of the slopes for road construction

Other causes for landslides are favorable dipping of beds (in Dhaibung area) and discontinuity plane (in Ramche area). Apart from Natural features, road cutting, accumulated rainfall and improper cultivation might have caused this landslide. As per the local people, debris flow dammed and latter on swept away the Army Barrack.

Landslide events Dhaibung

Events on: 15th August, 2003

Landslides Regions Dhaibung-7(Prangse)

• Affected population: 220• Death: 5 • Loss of livestock: 7 goats, 6 buff, 15 hens• Damaged households (Partly/totally): 45 • Damaged other infrastructures: Partly damaged primary school,

Drinking water reservoir tank, 16 irrigation canals • Loss of Ag. lands ( in Ropani): 642 Ropanies • Loss of Cereals Crops (in MT): 64-Maize, 129-potato, 29.70-Millete

1.5 vegetable

One person is still missing during event.

Landslide events Ramche

Events on: 15th August, 2003

Landslides Regions Ramche-9

• Affected population: 253• Death: 20 security personnel • Loss of livestock: 2-buff, 2-ox, 1-cow, 5-goats, 9-hens

• Damaged households (Partly/totally): 9 • Damaged other infrastructures: 3Arms houses with weapons,

2water mills, collapsed one primary school, one temple, 2-drinking water reservoir tanks.

• Loss of Ag. lands ( in Ropani): 527 Ropanies (Loss of lands and crops occupied by three wards (4,5&9) of Ramche) • Loss of Cereals Crops (in MT): 6.84 paddy, 32 maize, 86.25-

Potato14.74 Millete, 1.5-Vegetable

Both villages are high in Risk during monsoon season (Terman and Langsa ).

Dhaibung Landslide

Dhaibung Landslide

Dhaibung Landslide

Dhaibung Landslide

Dhaibung Landslide

Ramche Landslide

Ramche Landslide

Ramche Landslide

Ramche Landslide

Ramche Landslide

Ramche LandslideArea: 43.44 Ha.

Dhaibung LandslideArea: 83.67 Ha.

Slopes

Slope categories

Dhaibung (D) Ramche (R) D+R

Area (Ha.) % Area (Ha.) % Total (Area)

0-20% (I) 0 0 0 0 0

20-40% (II) 89.5 17.8 57.0 7.0 146.5

40-60% (III) 358.2 71.4 620.0 76.0 978.2

60-80% (IV) 47.6 9.5 51.9 6.4 99.5

>80% (V) 6.3 1.3 86.3 10.6 92.6

Total 501.6 100 815.2 100 1316.8

Proposed Land use

Description Dhaibung (D) Ramche (R) D+R

Area (Ha.) % Area (Ha.) % Total (Area)

C2 85.1 16.97 4.4 0.54 89.5

C3 248.1 49.46 260.6 31.97 508.7

C4 17.5 3.49 21.3 2.61 38.8

F2 0 0.00 47.6 5.84 47.6

F3 0 0.00 130.0 15.95 130.0

F4 7.5 1.50 18.7 2.29 26.2

S2 4.4 0.88 5.0 0.61 9.4

S3 29.4 5.86 229.4 28.14 258.8

S4 22.6 4.51 11.9 1.46 34.5

S5 0 0.00 86.3 10.59 86.3

G3 78.2 15.59 0 78.2

G5 6.3 1.26 0 6.3

LS 2.5 0.50 0 2.5

Total 501.6 100 815.2 100 1316.8

Recommendation of the Study– Networking should be developed among all stakeholders who

are taking interest in the events.– Form Community based Disaster management

Group/watershed users group and makes them strengthen coping capacity through formulation of the program/activities, implementation of the activities, monitoring, particularly, to the program and this part is also used during monsoon period in a watch whether emerging of spring or not and monitor the landslide during monsoon season.

– Train local people about the evacuation drill so that local people can evacuate the area during rainy season prior to the occurrence of landslide. Create awareness to the people regarding the landslides and its affects.

– All the cracks seen in the catchment area must be sealed with non-porous/non permeable, locally available clay materials. So that there should not be seepage.

– However or whenever possible at earliest drainage improvement and diversion of drainage for landslided area to safe channels is essentials.

Recommendation of the study

– Enhancing them in IGAs by promoting locally available materials/resources.

– Proper land use plan or integrated watershed management plan has to be prepared.

– Bioengineering activities might be a cost effective way to control landslides.

– Detail engineering study for drainage management/ landslide stabilization.

– Rainfall analysis over the regions.– Use of GIS, GPS and RS for data capturing and analysis

for further studies and training on maps and geographical data capturing process needs to forward.

– Further details study on Soil, Geology, and Hydrology, socio-economic analysis through households' survey.

Conclusion

• Landslides are mainly on cultivated areas of 40-60% slope.• Farming practice should be changed into On-farm

conservation like Terrace Improvement with proper water management

• Rainwater harvesting pond will reduce the surface run-off of monsoon

• Proper management of the land and water for better foodproduction is the present needs

• Problem identification for effective measures• People of the critical area need to be orient themselves • Study will be the milestone to push –up the concern

stakeholders to the right direction.

Conclusion

Problem Identification

Use of tool(GIS/GPS/RS)

Measurement

ShapeSizeArea

Mapping

ZoningBufferingCritical areaselection

Application of effective measures