Flood Mapping
and
Flood Hazard Mapping
P V Raju
National Remote Sensing Centre
Indian Space Research Organisation
raju_pv @ nrsc.gov.in
Flood Disaster Scenario: India nrsc
• Floods are the most frequent of all disasters that cripple India, in terms of loss of human lives, damage to property, annually.
• As per National Flood Commission estimates, about 40 million hectares of land is prone to floods.
• It is important to provide information during early warning, response, mitigation (hazard, bank erosion, etc)
• Satellite inputs are being used during all phases of flood management.
• Satellites helps in deriving precise information on extent of flooding, hazard, bank erosion, apart from flood forecasting and inundation modelling with other hydro-meteorological inputs.
• Kashmir Floods (2014), Uttarakhand Floods (2013), Assam Floods (2012), Bihar & Odisha Floods (2011), etc are some of the examples
Major Flood Events
Kosi Breach-2008
Kedarnath Floods-2013
Assam Floods-2012
Odisha Floods-2011
Godavari Floods-2006
Leh Flash Floods-2011
Ghaggar Floods-2010
Ganga Floods-2010
• 40 million hectares (mha) or nearly 1/8of Indian geographical area is floodprone
• Annual average area affected byfloods is about 7.57mha
• Affected crop area is about 3.5 mha.
• Average loss in financial terms isabout Rs 13,000 millions.
• Indo-Gangetic & Brahmaputra riverbasins are most chronic flood proneareas.
Jhelum Floods-2014
Yamuna Floods-2010
Gujarat Floods-2005
• Disasters cost India $10bn per year which includes more than $7 billion loss on account of floods.
• India has more of its annual GDP exposed to river flooding each year, on average, than any other country.
Krishna Floods-2009
Flood Disaster Management : Satellite Technology
• Near real time flood inundation mapping
• Flood hazard zonation: Assam, Bihar ,
Orissa & U.P
• Flood Forecast Modeling- Inundation
Modelling
• Scientific assessment of Flood Prone
Area
• River Morphological Studies & River
Bank Erosion
State-Level Flood Map Detailed Flood Map District-Level Flood Map
Flood Response- Products
Flood Depth Maps Cumulative Flood Maps Flood Persistence Maps Flood Progr/Recess Maps
Dissemination
DMS- VPN network
Bhuvan web portal (bhuvan.nrsc.gov.in) NDEM web portal (ndmcc.gov.in)
NRSC website (www.nrsc.gov.in) E-mail
FTP process
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Floods - 2016
ASSAM FLOODS -2017
• The first flood wave hit Assam on 02-June-2017 affecting Lakhimpur, Jorhat and Biswanath districts.
• NRSC analyzed Radarsat-2 SAR data of 03-June-2017 (0600hrs) and observed flood inundation in Lakhimpur, Jorhat,
Biswanath, Cachar, Karimganj, Dhemaji and Hailakandi districts. About 91, 725 ha was observed to be inundated.
• The flood inundation information was disseminated to the concerned Nodal Ministries and Assam State Govt. departments.
• The following satellite images shows the flood situation in Assam. Dark signature denotes river and flood waters. Cyan color
indicates the flood extent delineated from satellite data.
Flood Inundation
Roads
Railway
Pre-flood situation Flood situation – 03 Jun, 2017 Flooded Area
MANIPUR FLOODS -2017
• Floods were reported in Manipur on 02-June-2017 inundating low lying areas in Imphal, Thoubal and Bishnupur districts
• NRSC analyzed Radarsat-2 SAR data of 03-June-2017 (0600hrs) and observed flood inundation in Imphal, Thoubal and
Bishnupur districts. About 8,714 ha is observed to be the inundated.
• The flood inundation information was disseminated to the concerned Nodal Ministries and Manipur State Govt. departments.
• The following satellite images shows the flood situation in Manipur.
Pre-Flood Image Post-Flood Image Flood Map
Imphal
Flood
Inundation
Imphal
Loktak
LakeLoktak
Lake
ASSAM FLOODS -2017
• The first flood wave hit Assam on 02-June-2017 affecting Lakhimpur, Jorhat and Biswanath districts.
• NRSC analyzed Radarsat-2 SAR data of 03-June-2017 (0600hrs) and observed flood inundation in Lakhimpur, Jorhat,
Biswanath, Cachar, Karimganj, Dhemaji and Hailakandi districts.
• The flood inundation information was disseminated to the concerned Nodal Ministries and Assam State Govt. departments.
• The following satellite images shows the flood situation in Assam.
nrscCyclone “ Phailin” in Odisha– Oct 2013Daily Monitoring
12-hourly Monitoring
12-hourly Monitoring with RISAT-1Baleswar, Odisha
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• Severely affected districts like Balasore, were monitored on 12-hrly basis
during peak floods and changes in inundated areas / village can be seen
13-Oct-20131800 hours IST
14-Oct-20130600 hours IST
13-Oct-20130600 hours IST
Baleswar
Inundation
Inundation
Baleswar
Baleswar
Bay of Bengal
Bay of Bengal
Bay of Bengal
Baleswar
Inundation recession during 2-4 Nov,1999
Inundation recession during 4-8 Nov,1999
Inundation recession during 8-11 Nov,1999
Inundation recession during 11-13 Nov,1999
Inundation as on 02nd Nov, 1999Inundation as on 04Nov, 1999Inundation as on 08Nov, 1999Inundation as on 11Nov, 1999Inundation as on 13 Nov, 1999
nBijbehara
Panjgam
Awantipora
Pulwama
Kakapora
Galandhar
Pampore
Flood inundation as on 08-Sep-2014 overlaid on shaded relief
map
River/Water Bodies
Flood Inundation
• Severe floods were reported in
Jammu & Kashmir during first
week of September, 2014.
• Heavy rains coupled with rise
in the water levels of Jhelum
river had led to flooding in the
districts of Anantnag,
Pulwama, Badgam, Kulgam,
Rajouri etc.
• DSC/ NRSC had mapped and
monitored this event in near
real time using satellite data
from RISAT-1,
RESOURCESAT-1 & 2,
CARTOSAT-1 & 2 and other
foreign satellite data.
• Value added products like flood
inundation maps, persistence
and recession maps,
cumulative flood maps,
annotated satellite image maps
were generated and
disseminated to MHA, NDMA,
CWC, IMD and Govt. of J & K.
• The information was also
uploaded on Bhuvan, NRSC
and NDEM web portals.
Floods in Jammu & Kashmir – Sep 2014nrsc
Affected areas
1. Press colony; 2. Kothi Bagh; 3. Nohata; 4. Munshi Bagh; 5. Wazir Bagh; 6. Hazur Bagh; 7. Raj Bagh; 8. Maharajpur; 9. Jawahar Nagar ;
10. RamBagh; 11. Mehjoor Nagar; 12. K.P.Bagh ; 13. Padshahi Bagh
Mehjoor Nagar Ram Bagh
Bund
1
2
3
4
5
67
8
9
10
11 12
IRS Resourcesat LISS-IV images showing flooding around Srinagar
area
Floods in Jammu & Kashmir - 2014
n
Pre-
Flood
During
Flood
1
2
3
4
5
67
8
9
10
11 12
13 13
Inundation
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CARTOSAT
image showing
flooding in
Bemina area in
Srinagar City as
on 09-Sep-2014Housing colony
nFlooded
River/Water
SDA colony
Govt. Degree college
Bemina
Police Public school
Floods in
Jammu &
Kashmir -
2014
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• FF & FIM constitutes important non-structural FM measures and given impetus by GOI during 12FYPEO derived inputs viz. LU-LC
• DEM/DTM, soil etc. are invaluable inputs for both flood forecasting & Flood inundation studies
• FF models: Godavari & Mahanadi – developed, tested implemented in real-time
• Improved forecast lead-time, desirable accuracies in discharge estimation and the time of peak prediction at all critical points were demonstrated in real-time mode
• FF Development in progress for another critical 5 basins (Ghagra,
Gandak, Kosi, Brahmini & Krishna)
• Paradigm shift from point to spatial flood early warnings -CWC is gearing towards development of spatial flood early warning systems
• NRSC, ISRO is planning to provide high resolution DEM’s for all important & Critical flood prone areas and capacity building to states in HP-III project
• Capacity build at CWC through on the job training
• National and regional (state-wise) scientific assessment of flood prone area is underway with critical inputs from EO data.
Flood Forecasting & Flood Inundation Modeling
Flood Early WarningFlood Inundation Modelling
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ALTM –DTMKonta
Kunavaram
Resoursesat-2
23 Aug,2012
Time 10:30
Simulation Results
23 Aug,2012
Time 06:00
Radarsat-2
06-Aug-2013
Time 06:00
Simulation Results
06-Aug-2013
Time 06:00
RESULT:Upto 90% accuracy
Flood Prone Area Assessment nrsc
Flood inundation extent
Flood inundation (Kosi breach)
Map showing the flood extent in various parts of the country
Scientific assessment of Flood Prone Area Assessment in the countryApex Committee and State-wise Committees are formed
Flood Prone Area (Ver. 1.0)1. Satellite Data - 10 years (2003-
12) 2. Layer preparation (plains) based
on1. CWC HFL info for major
rivers2. NRSC Flood info for other
areas
Next Steps
• Hilly regions are to be included(which are not included in version 1.0)
• This will be addressed using Carto-DEM / ACE-SRTM and CWC HFLs
Flood
Damage information system
Base map
Land use map
Settlements
Road & Rail network
Flood inundation map
. . .
Brahmaputra River Floods - 2000Villages affected in Marigaon district
Flood damage statistics derived from
RADARSAT SAR data of Jun, 2000
--- Flood inundation
--- Pre-flood river course
District No. of villages
affected
Area affected
(Ha)
Crop area
affected (Ha)
Dhemaji 73 5,658 3,611
Sibsagar 271 10,000 7,436
Jorhat 262 14,843 8,346
Lakhimpur 244 22,857 16,636
Marigaon 459 37,253 10,874
Darrang 278 11,708 5,254
Nalbari 211 6,528 3,457
Goalpara 297 16,668 10,510
Dhubri 647 41,511 16,425
LEGEND
Cropped Area
Submerged Crop
Based on the analysis of RADARSAT SAR data of 10th July 2002
Crop Area Submerged - Dhubri District, Assm
Flood Hazard Assessment
Flood Hazard Atlas of Assam Flood Risk Index for Nagaon District,
Assam
Wt 0.0 0.3 0.6 1.0
Flood
Hazard
No
Hazard
Low
Very Low Moderate
High
Very High
LU/LC
Swampy,
Marshy
Others
(plantations) - Cropped
Population - <2000
2000-
5000 > 5000
Infrastruct
ure - Other roads -
Major
roads
Inputs and Weightages (Wt)
(Village as a unit)
Village Flood Risk Index (VFRI) = Hazard Index * Vulnerability Index
(VFRI ranges from 0 to 3)
Hazard Index = Hazard Wt
Vulnerability Index =
(LU/LC Wt + Population Wt + Infrastructure Wt)
10 years of satellite data (1998-2007)
• Hazard based on frequency of flood
occurrences
• 5 categories – very low, low, moderate, high
and very high
Flood MitigationBihar Flood Hazard Atlas - Methodology
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13 Years (1998-2010)128 satellite datasets
Flood Hazard Index
∑ (Hazard Category (Hw)X Hazard Area (Aw))X Intra Annual Variations (IAVw)
Hw = Weightage for Hazard CategoryAw = Weightage for % Hazard AreaIAVw = Weightage for intra annualvariation
Flood Hazard Index Top 10 Districts
Flood Hazard Map of Bihar
River/Water bodies
River bank
Major Roads
Data Used:13 Years (1998-2010)- 128 satellite datasets.Approach:Based on Annual Frequency of Inundation and Intra Annual Flood Variations
Bihar Flood Hazard Map
Darbhanga FloodHazard Map
Flood Mitigation: Flood Risk Assessment
Flood Risk Index Map Flood Risk Index for Jagatsingpur
District, Orissa
Flood Hazard
Flood Frequency
Flood Duration
Flood Depth
Vulnerability
Socio-Economic Info
Infrastructure
Land use / Land cover
Additional Inputs
• ALTM DTM
• Detailed census of 2011
• 1:10K Database
Legend
River
Low Risk (< 1)Moderate Risk (1-2)
High Risk (2-3)
Brahmaputra River
Nowgong.
Lankagaon.
NEXT
Web Dissemination – Flood Hazard – Odisha State
Web Dissemination
Thank You