FLOODS
AND
FLASH FLOODS
M.P.Singh
Superintending Engineer
Hydrological Observation Circle
Central Water Commission, Guwahati
FLOODS
FLOODS ARE NATURAL PHENOMENA.
FLOODS
 FLOODS ARE WATER RELATED DISASTER
 WATER
RESOURCES
MANAGEMENT
INCLUDES
MANAGEMENT
OF
THESE
DISASTERS
CAUSES OF FLOODS
 PRECIPITATION
 INADEQUATE CAPACITY (WITHIN BANKS)
 BANK EROSION AND SILTING
 LAND SLIDES
 TIDAL AND BACK WATER EFFECTS
 POOR DRAINAGE
 SNOW MELT AND GLACIAL OUT BURSTS
INDIA
FLOOD MANAGEMENT
AREA (M. Ha)
GEOGRAPHICAL
328
FLOOD PRONE
40
12%
PROTECTABLE
32
80%
16.4
45%
7.7
17.5
1.5
(1978)
(1965)
PROTECTED
FLOOD AFFECTED
 AVERAGE
 MAXIMUM
 MINIMUM
INDIA
FLOOD MANAGEMENT
FLOOD PRONE AREA - 40 M.Ha.
BIHAR
12.71%
ASSAM WEST BENGAL
7.91%
9.40%
ORISSA
4.18%
UTTAR PRADESH
21.90%
OTHER
STATES
43.9%
YEAR
1998
1995
1992
1989
1986
1983
1980
1977
1974
1971
1968
1965
1962
1959
1956
1953
6.7
6.17
2.55
13.25
11.46
11.91
11.46
11.79
8.87
9.02
10.71
8.38
8.81
8.89
4.63
9.3
6.17
6.12
3.99
4.1
7.12
7.15
6.2
6.46
4.74
4.63
2.75
6.11
7.4
3.85
7.18
2.09
1.46
9.44
9.24
7.49
4.86
6.26
5.77
7.53
6.56
6.12
3.49
4.9
2.29
AREA IN M.Ha.
16.29
17.5
INDIA
FLOOD MANAGEMENT
AREA AFFECTED BY FLOODS - 1953-99
YEAR
1999
1997
1995
1993
1991
1989
1987
1985
1983
1981
1979
1977
1975
1973
1971
1969
1967
1965
1963
1961
1959
1957
1955
1953
3344.53
2536.79
4630.3
4059.27
3748.53
5845.98
3702.31
2952.78
2831.18
2107.86
1415.88
1794.59
2405.33
1708.92
1488.33
2569.72
2491.61
1905.56
52.4
57.23
102.73
53.63
23.37
43.97
86.2
63.17
31.37
94.89
36.61
66.61
7.14
88.43
155.43
211.1
404.43
287.83
632.48
158.19
569
569.02
471.64
888.69
1201.85
1454.76
614.2
840.5
1196.5
1644.88
RUPEES IN CRORE
FLOOD DAMAGE IN INDIA DURING 1953-2000
INCREASED VULNERABILITY
CAUSES
 INDISCRIMINATE ENCROACHMENT
 INCREASING ECONOMIC AND DEVELOPMENTAL
ACTIVITIES IN FLOOD PLAINS
 LACK OF REGULATIONS
 INADEQUATE DRAINAGE SYSTEM
 INADEQUATE MAINTENANCE
 LACK OF DISASTER PREPAREDNESS
FLOOD MANAGEMENT
APPROACH
 FLOODS CAN NOT BE ABSOLUTELY
CONTROLLED
 FLOODS CAN ONLY BE MANAGED TO
REDUCE FLOOD LOSSES
FLOOD MANAGEMENT
STRATEGIES
 MODIFY THE FLOODS
 MODIFY THE SUSCEPTIBILITY TO FLOOD
DAMAGE
 MODIFY THE LOSS BURDEN
 BEAR THE LOSS
FLOOD MANAGEMENT
ORGANISATIONS
 STATE FLOOD CONTROL DEPARTMENTS
 CENTRAL WATER COMMISSION
 GANGA FLOOD CONTROL COMMISSION
 BRAHMAPUTRA BOARD
 MHA - NDM DIVISION
FLOOD MANAGEMENTMEASURES
 STRUCTURAL
MEASURES
: PHYSICAL WORKS FOR
MODIFYING FLOOD MAGNITUDE
( TO KEEP FLOODS AWAY FROM
PEOPLE )
 NON-STRUCTURAL :
MEASURES
PLANNED ACTIVITY TO MODIFY
SUSCEPTIBILITY TO FLOOD DAMAGE
( TO KEEP PEOPLE AWAY FROM
FLOODS )
FLOOD MANAGEMENT
STRUCTURAL MEASURES
 DAMS & RESERVOIRS
 EMBANKMENT
 CHANNEL IMPROVEMENT
 RIVER DIVERSION
 INTER BASIN TRANSFER
 ANTI EROSION WORKS
FLOOD MANAGEMENT
NON STRUCTURAL MEASURES
 FLOOD FORECASTING & WARNING
 FLOOD PLAIN ZONING
 FLOOD FIGHTING
 FLOOD PROOFING
 FLOOD INSURANCE
 RELIEF & REHABILITATION
FLOOD PLAIN ZONING
WATER SUPPLY
II
III
III
I
II
I
FACTORY
HOSPITAL
GOVT. OFFICE
POWER HOUSE
PARK
RESIDENTIAL AREA
UNIVERSITY
FREQUENT FLOOD
FLOOD ONCE IN 25 YEARS
FLOOD ONCE IN 100 YEARS
NORMAL CHANNEL
FLOOD PLAIN ZONING
WARNING
I
RESTRICTIVE
II
PROHIBITIVE
III
RIVER CHANNEL
RESTRICTIVE
II
WARNING
I
INDIA
FLOOD FORECASTING
BEGINNING
 STARTED BY
CENTRAL WATER COMMISSION
 YEAR
1958
 RIVER
YAMUNA
 FORECASTING STATION DELHI RAILWAY BRIDGE
FLOOD FORECASTING AND WARNING
STEPS
 DATA COLLECTION
 DATA TRANSMISSION
 DATA ANALYSIS & FORECAST FORMULATION
 DISSEMINATION OF FORECAST
FLOOD FORECASTING
DATA COLLECTION
 HYDROLOGICAL
RIVER WATER LEVEL
RIVER DISCHARGE
 HYDROMETEOROLGICAL
RAINFALL
OTHER RECIPITATION
eg. SNOW, HAIL ETC.
FLOOD FORECASTING
DATA TRANSMISSION
 WIRELESS
 SATELLITE
 TELEPHONE
 TELEGRAPH
 FAX
 TELEX
FLOOD FORECASTING
DATA ANALYSIS & FORECAST FORMULATION
 CORRELATION
 MATHEMATICAL MODELS
FLOOD FORECASTING
DISSEMINATION
CIVIL AUTHORITY
FORECAST
OTHER AGENCIES
PRESS, A I R
DOORDARSHAN
OTHER USERS
LOCAL REPRESENTATIVES
FLOOD FORECASTING AND WARNING
PRESENT SYSTEM - SCHEMATIC DIAGRAM
WEATHER FORECASTS
RIVER STAGE &
DISCHARGE AT
BASE STATION
REGIONAL OFFICES
OF I.M.D.
F.M.O OF I.M.D
C.E., S.E.
PRESS
P&T
POLICE
RIVER STAGE &
DISCHARGE AT
FORECASTING STATIONS
RAINFALL
REGIONAL OFFICES
OF I.M.D.
FLOOD FORECASTING
CENTRES & CONTROL ROOMS
FORMULATION OF
FORECAST
CWC HQ
F.M. O. OF I.M.D
MINISTRY OF WR
CIVIL AUTHORITIES
RADIO
DOORDARSHAN
FLOOD COMMITTEE
STATE GOVT.
CONTROL ROOM
ENGG. AUTHORITIES
DEFENCE
INDUSTRIES
RAILWAYS
FLOOD MANAGEMENT
scope
 Use of Remote Sensing and GIS
 Research and Development
 Weather / Rainfall Forecasting
 FF Modelling
 Capacity Building
 International Cooperation
INDIA
FLOOD FORECASTING NETWORK
 COVERS MAJOR AND INTER STATE RIVER
BASINS.
166 STATIONS :- INFLOW 27 & STAGE 139
INDIA
FLOOD FORECASTING STATIONS
85
27
17
GANGA
B’PUTRA
GODAVARI
15
WEST
FLOWING
9
8
EASTERN KRISHNA
RIVERS
3
MAHANADI
2
BARAK
INDIA
FLOOD FORECASTING STATIONS
35
32
23
15
14
11
11
6
4
4
3
2
2
2
1
FLOOD MANAGEMENT ACTIVITIES
During flood
Pre flood
Post flood
FLOOD PLAIN ZONING
CONCEPT
 AN IMPORTANT NON-STRUCTURAL MEASURE.
 REGULATES LAND USE IN FLOOD PLAINS TO
RESTRICT DAMAGE BY FLOODS.
 INVOLVES DEMARCATION OF ZONES IN FLOOD
PLAINS
COMPATIBLE
WITH
FLOOD
RISKS
INVOLVED.
FLOOD PLAIN ZONING
ZONE REGULATION
PRIORITY - I
ACTIVITY
LIMITED
CORRESPONDING
TO
TO
100
WATER
YEARS
LEVELS
FLOOD
FREQUENCY AND DRAINAGE CONGESTION FOR
50 YEARS RAINFALL.
FLOOD PLAIN ZONING
ZONE REGULATION
PRIORITY - II
ACTIVITY LIMITED TO LEVELS CORRESPONDING TO
25 YEARS FLOOD FREQUENCY AND DRAINAGE
CONGESTION
FREQUENCY.
FOR
10
YEARS
RAINFALL
FLOOD PLAIN ZONING
ZONE REGULATION
PRIORITY - III
LESS ECONOMIC AND COMMUNITY ACTIVITY IN
AREAS VULNERABLE TO FREQUENT FLOODS.
FLOOD MANAGEMENT
FUTURE STRATEGIES
 Focused Approach
 Basin Wise Action Plan
 Flood Plain Zoning
 Role of Central Government
 Funding of Planned Flood Management Works
 Adequacy of Flood Cushion in Reservoirs
THANK YOU