Demonstration Basin( Bhutan)
Karma Chhophel
Hydro-meteorological Services
Thimphu: Bhutan
1

Why Punatsangchhu or Basin I• Economic development through construction ofhydropower projects.
• Add on social benefits such as schools, healthfacilities etc.
• Basin prone to GLOF’s, so appropriate for flood
studies as GLOF is a real threat now as a resultof global warming due to climate change.
• Climate change impacts – changes in flow
regimes of rivers.
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Punatsangchhu
Basin or Basin II

Country: Bhutan
Basin Name: Punatsangchhu orBasin II
Basin Area: 13, 263 km2
Latitude: E89021’’ – 90024’’

Punatsangchhu Basin

Longitude: N26042’’ – 28018’’
Altitude: 100 masl - >5000 maslIssues• Climate ChangeImpacts– Retreat of Glaciers– Increases risk ofGlacial Lake Outburst
Floods– Impacts water
availability, hence
necessary to monitor
flow regimes

Potentially dangerous glacial lakes of Bhutan
Pho Chu Sub Basin : 9
Mo Chu Sub Basin : 5 14
Chamkhar Chu Sub Basin: 3
Kuri Chu Sub Basin: 1
Mangde Chu Sub Basin: 7

Out of 2674 glacial lakes, 25 has been identified as potentially dangerous lakes.
Source: DGM & ICIMOD publication

Issues• Floods¾ Flash floods due to shortduration high intensity rainfall
are recurrent phenomena in
Bhutan during the monsoon
season in the southern part ofthe basin¾ Determination of an adequate
warning system a necessity

Issues• Floods¾ Sediments affect the optimal
performance of hydropower
plants.
¾ Study the nature of thesediment load and identificationof particles causing damages
important.

Kurichhu Hydropower Plant
Dam of 1020 MW Tala Dam underConstruction

IssuesPuna 1, 1095 MW,implementing in 2008

Puna 2, 995 MW,implementing in 2012

Dagachhu, 114 MW, under
implementation as a CDM
project• Hydropower
Development– Socio-economic
development– Issues likely due toenvironmental flows,
upstream anddownstream linkages
which need to betaken care of while
designing a water
management plan

Basin Characteristics

Sub-basin 32

Sub-Basin 13 (Punatsangchhu)

Sub-basin 23

Basin Characteristics
Main N/SRiver

Tributaries

N/S River
OriginSub-Basin 13Punatsangchhu

Punatsangchhu,Mochhu,
Phochhu

Dangchhu,

BhutanBhutanBhutanMulti-RiverBasin 13 –Gelephu

Sum for basin

Sarpang Khola
Mau Khola

BhutanBhutanBhutanMulti-River
Basin 32 –Drainage to thenorthSum for basin

Approx.
Length of N/SRiver (km)Table I: Basin II River System Characteristics

BhutanDrainage Area
km2

10,355

1,956
145
811

952

Approx.
Average River
Slope (%)

134
84
86
57

0.8
4.3
3.6
4.6

Na
2121Na7.6
1.0nanaClimatic Condition
SUMMER MONSOONWINTER MONSOONBHUTANSOU(J THun W
e t ESo TMSept ONem SO
be ONr)NORT(O H E
ct A
BHUTANob STerM
to ON
Ma S
rc O Oh) N

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Climatic Condition• Bhutan Climatic is generally dominated bymonsoon winds– Dry winter and wet summer monsoon• Climate of Bhutan is affected byz Latitude
z Altitude
z Prevailing Wind Directionz Orientation of Mountain Ranges
z Local Windsz Vegetation

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Land Use and Soil Type•Land use– Agricultural Land Use: 517km2 (3.9 %) of basin area
– Sub-basin 13: 418 km2 (17.8%)– Sub-basin 23: 89 km2 (3.7 %)– Basin 32 has no agriculturalland•

Soil Type321323– Detailed soil survey report notavailable for the whole basin.
Soil survey reports withvarying levels of details
available for specific locationsin the basin.
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Socio-economic Information• Population: > 200.000• Migration: Evidence of rural-urban migration• Income and Expenditure: Income from agriculture andlivestock, expenditure on food, health and religious ceremonies• Employment: Agriculture main source of employment, others
include tourism, casual worker, civil service and trade• Poverty: Some areas in the basin vulnerable (vulnerabilityarrived at by considering income, food security, access to facilitiesand services)• Social Infrastructure: Basin has 17% of the educational
infrastructure. Has access to health through 7 hospitals, 58 basic
Health Units and 170+ Outreach Clinics

Observation System
Meteorological Stations ( )Automatic Weather Stations( 7 parameters) : 5 No.

Hydrological Stations ( ): 5 No.
Climatological stations : 17 No.

Models and GIS Data Availability• Database: HYDATA (CEH Wallingford)• Hydrological Models– DAMBRK, HEC-RAS for simulating Glacial Lake Outburst Floods– Working on Mike 11 mathematical modeling for the Punatsangchhubasin– GeoSFM (USGS): Geo stream flow model with inputs from rainfall
estimation software• Meteorological Models– RFE (Rainfall Estimation) using IR, AMSU, SSMI (NOAA)• GIS data
– RS: Aster and IRS– GD: Aster and SRTM DEM– PD: Hydro-met stations

Implementation Schedule
2008/I

2008/II

2009/I

2009/II

2010/I

2010/II

Hydro-meteorological and water
quality monitoring
Data integration system (input
data preparation, quality check)
Improvement of in-situ
observation network system
Setting-up a Distributed
Hydrological Model (Optional LSS)
Scenario Studies: Land usechange analysis, dry periods, etc
Capacity building on Floods,
Droughts and Water Quality
Parallel testing of the system atoperational stage
IWRM plan development floods,
droughts and water quality

TASHI
DELEK

2011/I

2011/II