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

nrsc

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

nrsc

• 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

nrsc

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

nrsc

• 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

nrsc

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

nrsc

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