Download - SOP for Flood Forecasting & Early Warning

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LIST OF ABBREVIATIONS

S. No

1. SOP Standard Operating Procedure

2. PMD Pakistan Meteorological Department

3. FFD Flood Forecasting Division

4. FFC Federal Flood Commission

5. NDMA National Disaster Management Authority

6. PMF Probable Maximum Flood

7. PMP Probable Maximum Precipitation

8. WAPDA Water and Power Development Authority

9. PID Provincial Irrigation Departments

10. PIDA Provincial Irrigation and Drainage Authority

11. RDFF Routine Daily Flood Forecast

12. GMT Greenwich Mean Time

13. PCIW Pakistan Commissioner for Indus Water

14. ERC Emergency Relief Cell

15. UNDP United Nation Development Programme

16. ADB Asian Development Bank

17. APT Automatic Picture Transmission

18. RTT Radio Telegraphic Transmission

19. H & WM Hydrology and Water Management

20. FWC Flood Warning Center

21. RC Relief Commissioner

22. SWH Surface Water Hydrology


Introduction

Planes of Pakistan have quite often been swept across by severe flood. In fact out of all the natural

hazards floods are the single most devastating natural hazard in Pakistan. Statistically every five

years a flood of exceptionally high level occurs in the Chenab, which is the flashiest channel out of

all the five major rivers. Every ten years a major flood of exceptionally high level passes through

all the five rivers. Even 15 years a super flood of 1988 or 1992 type occurs. Loss of life and

property associated with floods has been colossal. In the year 1973 more than 3 million homes

were destroyed and 160 persons lost their lives. The 1976 flood demolished over 10 million houses

while 425 lives were lost with losses amounting to Rs. 6 billion. In 1988 an unprecedented flood

occurred towards the end of September inflicting Rs. 17 billion worth of damage to the country.

The super flood of 1992 surpassed all previous records with the damage estimated at Rs. 50

billion.

The modern flood fighting strategy is always a blend of engineering as well as non-engineering

measures. This is because the meteorological phenomena causing the floods is outside the purview

of the human activity and thus the occurrence of the rainfall and floods cannot be checked.

However advance information of occurrence of meteorological events can be used to forecast

floods and adopt safety measures well in time.

The flood mitigation planning in Indus basin consists of both the engineering as well as non-

engineering measures. Watershed management above the rim station (the first gauging stations on

rivers after they enter in Pakistan) forms the starting point of the planning. Below the rim station,

several flood protection works have been provided to protect the facilities. Most important part of

the flood mitigation planning is the establishment of a reliable flood early warning system so as to

afford the timely evacuation of people from the threatened area, use of Mangla and Tarbela

reservoirs on the basis of the forecast of the expected in flows (through improved flood forecasting

facilities) is also an important aspect of the flood mitigation process for reducing the downstream

flood damages by phasing out the flood waves at the confluences.

The SOP contains the procedure of the flood forecast, early warning the stakeholder for data

collection, transmission and dissemination of the flood forecast and warning. Classifications of

floods, flood limits and travel time (from one headworks/sites to other all the agencies involved in

flood management process in Pakistan. Chapter I describes the causes of flood in Pakistan and the


three categories, which cause flooding in the catchments of the Indus basin river system and its

tributaries. The flood management process is also described in this chapter. The early warning and

flood forecasting system is covered in chapter 2. The responsibilities of the stake holders involved

in the management process are indicated in chapter 3. The process of flood forecast and flood

warning dissemination system is described in chapter 4 of this SOP.


Chapter 1

Flood Causes & Management

1.1 Define Floods

Flood is defined as the high stage of a river at which the stream channel gets filled up and above

which it overflows its banks and inundates the adjoining areas.

1.2 Classification of Floods

In Pakistan, floods are classified into five levels, shown in Table (1.1).

Table 1.1 Classification of floods

S.No. Classification Detail

1. Low Flood It is that flood situation when the River is flowing within

deep channel(s) but is about to spread over river

islands/belas.

2. Medium Flood The river is called in Medium Floods when River flows is

partly inundating river island/belas but below half of its

highest flood level

3. High Flood When the water level of the River is almost fully

submerging islands/belas and flowing upto high

banks/buds with encroachment on freeboard.

4. Very High Flood When the water level of the river flows is between high

banks/bunds with encroachment on freeboard.

5. Exceptionally High

Flood

It is that flood situation where there is imminent danger of

overtopping/breaching or a breach has actually occurred or

high bank areas become inundated.

1.3 Flood Limits of the River/Nullah

The limits of the flood in different rivers/nullahs at different places are shown in

Table 1.2 & 1.3


Table 1.2 Flood Limits (In Lacs of Cusecs)

RIVER SITE DESIGN

CAPACITY

LOW MED HIGH VERY

HIGH

EX.

HIGH

INDUS TARBELA 15.0 2.5 3.75 5.0 6.5 8.0

ATTOCK - 2.5 3.75 5.0 6.5 8.0

KALABAGH 9.5 2.5 3.75 5.0 6.5 8.0

CHASHMA 9.5 2.5 3.75 5.0 6.5 8.0

TAUNSA 11.0 2.5 3.75 5.0 6.5 8.0

GUDDU 12.0 2.0 3.5 5.0 7.0 9.0

SUKKUR 9.0 2.0 3.5 5.0 7.0 9.0

KOTRI 8.5 2.0 3.0 4.5 6.5 8.0

JHELUM KOHALA - 1.0 1.5 2.0 3.0 4.0

MANGLA 10.6 0.75 1.1 1.5 2.25 3.0

RASUL 8.5 0.75 1.1 1.5 2.25 3.0

CHENAB MARALA 11.0 1.0 1.5 2.0 4.0 6.0

KHANKI 8.0 1.0 1.5 2.0 4.0 6.0

QADIRABAD 8.07 1.0 1.5 2.0 4.0 6.0

TRIMMU 6.45 1.5 2.0 3.0 4.5 6.0

PANJNAD 7.0 1.5 2.0 3.0 4.5 6.0

RAVI JASSAR 2.75 0.5 0.75 1.0 1.5 2.0

RAVI SYPHON 4.5 0.4 0.65 0.9 1.35 1.8

SHAHDARA 2.5 0.4 0.65 0.9 1.35 1.8

BALLOKI 2.25 0.4 0.65 0.9 1.35 1.8

SIDHNAI 1.5 0.3 0.46 0.6 0.9 1.3

SUTLEJ SULEMANKI 3.25 0.5 0.8 1.2 1.75 2.25

ISLAM 3.0 0.5 0.8 1.2 1.75 2.25

KABUL WARSAK 5.4 0.3 0.45 1.0 2.0 4.0

NOWSHERA 0.45 0.47 1.0 2.0 1.0


Table 1.3 Flood Limits

S.No. NAME OF

NULLAH PLACE

LOW

FLOOD

MEDIUM

FLOOD

HIGH

FLOOD

VERY

HIGH

FLOOD

EXCEPT

HIGH

FLOOD

1. BEIN Chak Amru 1300 7000 20000 30000 35000 &

above

2. BEIN Shaker Garh 1600 3000 24000 26000 43000 &

above

3. AIK Ura 2000 9000 13000 16000 33000 &

above

4. BASANTAR Jassar 4100 4700 7500 11600 17800 &

above

5. DEG Q.S. Singh 3600 7500 15000 30000 35000 &

above

6. PALKHU Wazirabad 2500 3100 5000 25000 26000 &

above

1.4 Causes of Floods in Pakistan

Pakistan has unique flood forecasting problems, which can be appreciated only if the

meteorological causes of the floods are first understood. Floods in Pakistan are mainly caused by

the heavy monsoon rains during the summer monsoon period from July to September. Officially,

the flood season extends a little further to cater for any possible exceptions and covers the period

form 15th

June to 15th

October. There are two situations which cause flood producing rains in the

upper catchments (Annex-1) of the rivers. The two meteorological situations in relations to

different conditions of intensity and movement of monsoon low/depression may produce three

categories of floods as described below.

i) Meteorological Situation For Category-I Floods

This is the situation when the seasonal low, which is a semi permanent weather system generally

sitated over south eastern Balochistan, south western Punjab and adjoining parts of Sindh gets

occasionally intensified (due to the passage of a westerly wave) and thus causes the moisture from

the Arabian Sea to be brought up to the upper catchments of Chenab and Jhelum rivers resulting in

the heavy downpour along the windward slopes of the mountain ranges due to the orographic

lifting of the moist air mass. Rainfall is generally short lived and occurs either in the late

afternoon/evening or during the early morning lasting for a maximum period of about six hours.

Floods under this condition are the Category-I floods, which may cause a short peak ranging from

3 to 5 lac cusecs under extreme conditions. Most common1y, the peak is limited to within 3 lac


cusecs only. This should pose no serious flood management problem for the Mangla reservoir due

to short Rhiration and thus less volume. Tarbela is affected to a much lesser degree.

Annex-2 depicts this condition, wherein the south westerly wind flow from the Arabian sea and the

south easterly air current from the Bay of Bengal are indicated reaching the upper catchments of

the Sutlej, Ravi, Chenab and Jhelum rivers.

ii) Meteorological Situation for Category-II & Category-HI Floods

The second flood generating meteorological situation is the one linked with a monsoon

low/depression. Such monsoon systems originate from the Bay of Bengal region and then moving

across India in a general west/north westerly direction arrives over Rajasthan or

any of the adjoining states of India. After this the monsoon depression may take any one of the

following three courses.

a. Continue moving straight west causing heavy wide-spread rains over Sindh/Balochistan.

However, no river flooding shall occur in this case.

b. Recurve in the north east direction towards the upper catchments of Sutlej, Ravi and Chenab

rivers causing extremely heavy rainfall and consequently the floods first across the border in

India and then (within hours) at the rim stations in Pakistan. This is the Category-II flood

situation as depicted in Annex-3. Under this situation floods first occur in river Chenab due to

its peculiar topographic features which provide the most favorable conditions for the

orographic lifting of the south west/south east monsoon currents. Ravi and Jhelum are affected

next in sequence, followed by river Sutlej.

The control structures over Sutlej & Ravi rivers in India significantly delay the arrival of

flood wave in Pakistan. Floods in Jhelum under this situation may be significantly greater

than the Category-I floods and may thus cause some flood management problem for the

Mangla reservoir. However, the problem can be safely resolved by resorting to safe (minimum)

pre-flood releases corresponding to the lower side of the forecast inflow range. Generally the

flood peak at Mangla is limited to below 5 lac cusecs, but may reach 7 lac cusecs under an

extreme condition.


c. Continue moving in the northerly direction under the effect of a strong westerly wave over the

plains of Lahore/Gujranwala Divisions to finally ending up over Rawalpindi/Hazara Divisions.

The upper catchments of Chenab, Jhelum and Indus rivers come under its influence.

Extremely heavy rains may occur over Mangla and/or Tarbela catchments under this situation,

depending upon the final position of the depression causing extremely heavy floods

(Category-III), as shown in Annex-4. The probable maximum flood (PMF) is an extreme case

of Category-III flood. These are the most threatening floods for Mangla reservoir, a typical

example of such floods was the 1992 flood. Forecasting of such floods at least 24 hours in

advance should pose no problem, specially when 'S' band weather radars at Lahore and Mangla

are available for system identification. Close coordination between FFD and WAPDA shall be

necessary for the safe routing of such floods through the Mangla reservoir. WAPDA, after

1992 catastrophic flood in Jhelum & Chenab rivers has devised an SOP for the routing of

category I, II & III situation to safely pass the high inflows in Mangla. The SOP for Mangla is

annexed as (5A, 5B, 5C).

The meteorological factors linked with each situation are generally well known and 24-hours

advance prediction should be quite possible in each case. In fact tracking of the depression is

commenced from the Bay of Bengal and its position is reported on continuous basis in the

daily flood forecast bulletin issued by FFD. Once a depression reaches Rajasthan, an extremely

close watch is started using meteorological charts, and satellite cloud pictures. As the

depression advances towards Pakistan and comes within the meteorological range of the

Lahore Radar, an intensive watch would be started and color coded Met Alerts are issued as

applicable.

1.5 Flood Management Process

(i) Flood management process in Pakistan is multi-functional involving a number of different

organizations. The very first step in the process is the issuance of the flood forecast/warning. This

function has been assigned to the Pakistan Meteorological Department (PMD) since the basic

cause of the floods in Pakistan is the rainfall which can be best predicted and monitored by PMD

utilizing the satellite cloud pictures and the quantitative precipitation measurement radar data, in

addition to the conventional weather forecasting facilities. For quantitative flood forecasting the

hydrological data is obtained (through the Provincial Irrigation Department and WAPDA.


WAPDA's telemetric system is an important source of hydrological data for the flood forecasting

purposes.

(ii) This is supplemented by the manually observed data from the Surface Water Hydrology

Project of WAPDA. In addition to data measurement sites at the main rivers, the Irrigation

Department also maintains limited network of manually observed hydrological stations at barrages

and important nullahs. This data is utilised for forecasting the floods in these nullahs, which

besides causing damage to the adjacent areas, contribute substantially towards the main river flows

during major floods.

(iii) Cross Border Data: Pakistan has a unique flood forecasting problem in the season that

flood generating rains occur across the border (in India and held Kashmir) and as a consequence

floods flow down into Pakistan. This situation calls for obtaining the hydrometerological data of

important river sites from across the border. This has been provided in an agreement between

Pakistan & India (through the respective Commissioners for Indus waters). The agreement which

is renewed annually, provides for the supply of river flows data of the selected sites at Sutlej, Ravi,

Chenab and Jhelum rivers on the basis of reimbursement of the actual cost of data measurement

collection and transmission to Pakistan. Generally the arrangement works satisfactorily, except

when the data measurement sties in India/held Kashmir, are subjected to such severe floods which

may cause interruption of the data communication system as it happened in 1988 flood season.

(iv) Provincial Irrigation Departments (PIDs) are also actively involved in the flood mitigation

process from the warning dissemination to the flood fighting stage. Flood fighting is mainly done

at the Divisional level by the concerned Executive Engineers, while the overall flood related

functions are looked after by a Superintending Engineer, who is designated as the Director Floods

and Secretary Flood Commission.

(v) Pakistan Army’s Corps of Engineers is involved in the flood relief operations and

breaching of the flood bounds as and when required at the advice of the Provincial Irrigation

Departments. Lately, however, Punjab Irrigation Department has decided not to involve Army in

the breaching operations and instead to use bulldozers for creating the breach.

(vi) At the Federal Government level, most of the flood management functions are planned and

executed by the Ministry of Water & Power through the Federal Flood Commission (FFC), which

provides the necessary Support to the provinces in the flood fighting process. FFC provides both


the financial and technical support to the provinces in executing the flood protection works. In

addition to this, FFC is supporting WAPDA and PMD in establishing a modern flood forecasting

and warning system in the country. Three most modern ‘S-Band’ Doppler weather radars at

Lahore, Sialkot & Mangla have been provided to PMD, while a new hydrometric data

measurement and transmission system has also been established for WAPDA. The information on

the extent and depth of inundation along both sides of the river is also available. Such information

will enable issuance of early flood warnings to potential inundated areas.


Chapter 2

Flood Forecasting and Early Warning System

Indus basin encompasses all the five major rivers. Indus is the main river of the system,

while Jhelum, Chenab, Ravi and Sutlej are its main tributaries. Upper catchments of all

the rivers are mountainous with some of the highest peaks of the world located within the

Indus catchment.

2.1 Types of System

There are two systems, one is westerly wave & other is monsoon system.

i) Precipitation in winter (which is mainly in the form of snow) is on account of

eastward moving low pressure weather systems called westerly waves, which mostly

move above 35 degrees latitude and deposit snow over the mountains. Snow deposited

during winter becomes the major source of water supply into the rivers during summer.

ii) Rainfall in summer is on account of monsoon weather system. Unlike the westerly

waves the monsoon weather system is a low level weather system with heaviest rainfall

limited to below five thousand feet elevation. Approach of the monsonic winds as well as

that of the monsoon lows/depressions in from the east, south and south west directions.

Mountains along the west, north and north east constitute the physical barriers, beyond

which the monsonic winds cannot penetrate. Pir Punjal range along the east, the lesser

Himalayas range to the north and the Suleman range to the west constitute the limits of

monsoon activity and thus the areas of heavy rainfall.

During summer, even though monsoons are the dominating weather system, yet the

system of westerly waves also continues to affect the country along the Northern

latitudes. Intensification of the monsoon weather system and northwards recurving of the

monsoon depressions is due to the westerly waves.


Heaviest and the most frequent summer rainfall. occurs within the upper catchment of

river Chenab, making it to be the most flood prone river of the Indus river system, while

Indus being mainly the snow fed river is the least flood affected river of the basin.

2.2 Flood Forecasting System

Process of flood generation undergoes three stages of development.

a) First is the precipitation stage during which the excessive rains occur over the

upper catchments of the rivers. Most of these catchments are mountainous areas

lying on both sides of the border between Pakistan and India/held Kashmir.

Prediction and monitoring of this rainfall forms the meteorological component of

the flood forecasting system.

b) Next is the flood formation stage which starts with the generation of runoff to

form ultimately a flood wave at the confluence of the incremental flood flows.

Forecasting of the flood flows using the actual and predicted rainfall and the flow

data of the upstream stations constitutes the hydrorneterological component of the

flood forecasting system.

c) Lastly, the routing of the flood wave below the rim station of the rivers at the

downstream sites is the hydrological component of the forecasting system. The

flood wave while traveling from one site to another site takes some time. FFD on

the basis of previous record and history has calculated the travel time from one

site to another site for an average flood wave. Travel time is shown in table 1"+:


Table 1.4 Showing Time of travel (normal flow i.e. Below low flood level)

S.No. River From To Travel Time

in

1. RIVER INDUS Mandori

Kalabagh

Chashma

Taunsa

Guddu

Sukkar

Kalabagh

Chashma

Taunsa

Mithankot+Guddu

Sukkar

Kotri

24

I 1

72

48+24

24

72

2. RIVER JHELUM Mangla

Rasul Rasul

Trimmu

12

72

3. RIVER CHENAB Marala

Khanki

Qadirabad

Trirnmu

Panjnad

Khanki

Qadirabad

Trimmu

Panjnad

Mithankot

12

06

48

48

24

4.

RIVERRAVI

Madhopure

Jassar

Shahdara

Balloki

Jassar

Shahdara

Balloki

Sidhnai

18

36

18

72

5. RIVER SUTLEJ

Sulemanki

Islam

Islam

Panjnad

48

72

Schematic diagram IS shown at Annex-6

Computer models are used to get outputs from the hydrometerological as well as

hydrological components of the system. The output from hydrometerological component

gives the forecast of the flood peaks and flood levels at various downstream sites. The

highest flood elevation thus fOnTIS the basis of estimate likely areas to be flooded along

both banks of river by using the flood risk maps prepared for various flood magnitudes.

2.3 Flood Forecasting

Flood forecasting and early warning is used for alerting the likely damage center well in

advance of the actual arrival of flood, to enable the people to move and also to remove

the movable properties to safer places or to raised platforms specially constructed for this purpose.

There are three kinds of flood forecasts


i) Qualitative flood forecast

ii) Quantitative flood forecast

iii) Early warning

Flood Forecasting Division (FFD) is the organization responsible for issuance of such

forecasts as and when needed during the flood season. The detailed description of the

various forecasts is given below.

2.3.1 Qualitative Flood Forecast

Qualitative flood forecasts are meant to provide advance information about the

approaching weather systems, which may cause such rains as may result in the generation

of significant flood wave in the Indus basin river system. Qualitative flood forecasts are

issued at the time when the approaching weather system is still outside the river

catchments but may move into it in the due course of time. Such forecasts have longer

lead time and are thus extremely important in providing a reasonably advanced

information to activate the flood fighting measures at all levels. The forecasts are always

in the descriptive form which can be easily understood by the flood related agencies.

2.3.1.1 Colour Coded Qualitative Flood Forecast.

As already explained, major floods in the country occur under the effect of a monsoon

low/depression. Category-Il and Category-Ill floods occur when a monsoon depression

upon reaching Rajasthan state of India recurves to the north or north east. Chances of

major flood may thus develop in case the monsoon low arrives over Rajasthan. This is the

time that all the concerned Government agencies need be alerted to face the possible

flood situation. A suitably worded information to this effect constitutes what is called the

"Blue Alert", which shall be meant to indicate the possibility of flood within 24 to 72

hours depending upon the future movement of the monsoon low/depression.

In case a monsoon low/depression starts to stagnate over the same position it shall either

fizzle out or may become stronger depending upon the availability of moisture into it. In


case it starts to intensify, the chances of recurring shall increase and as it starts to move

northwards, occurrence of flood may become imminent. Consequently, this is another

important stage when another' Alert' is issued. This is a more alarming' Alert' than the

previous one and is called "Yellow Alert". In case the low/depression starts to directly

affect the catchment area and the heavy flood producing rains start, a 'Red Alert' is

immediately issued. Quantification of the flood peak can only be done after the total

storm rain becomes available. This, however, may be too late for rescue purposes as the

time to peak flood, after the rain, is relatively small in case of most of the rivers on

account of steep slope of the upper catchments.

Thus, three qualitative flood forecasts called Blue, Yellow and Red alerts are issued to

alert the concerned Government agencies. Typical formats of the three colour coded

messages is given below.

BLUE ALERT

A monsoon low/depression arriving from Bay of Bengal has reached the Indian state of

(Rajasthan/Haryana etc) and at present is located near _____________. Possibility of

this low/depression moving towards the upper catchments of the Indus Basin rivers, to

cause flood producing rains has now developed. Situation is being watched and further

information shall follow as required.

YELLOW ALERT

Monsoon low/depression has now started to move north/northeast towards the country.

Risk of heavy flood generating rains over the upper catchments of rivers _______________ has

increased during the next 1 to 3 days.

RED ALERT

From 0700 to 1400 hrs _____________ inches/mm approx. of rainfall has fallen in the

catchment areas of rivers Indus/Jhelum/Chenab/Ravi/Sutlej. High/Very High / Exceptionally


High/Critical flood equivalent to ___________ to _____________ cuses is likely at

____________________________________________ during next 12/24/36/48 hours.

2.3.2 Quantitative Food Forecast

Routine Daily Flood Forecast (RDFF)

Routine daily flood forecast is issued once a day and is based upon the discharge measurements of

0600 hrs (PST), latest APT picture, date of Lahore, Sialkot, Mangla and Islamabad radars, and the

Indian discharge data as received through PCIW. The forecast is issued before the mid day for 24

hrs period.

The flood forecast has seven parts issued in two Bulletin A & Bulletin B. The Bulletin A contains

five parts. The first part is the general situation of river flows describing the level of rivers in plain

language. It also contains the future trend in the river flow at any gauging site. The second part

gives the meteorological features i.e. the prevailing synoptic situation and weather pattern. The

third part is the weather forecast expected during next 24 hours. The emphasize should be on rain.

The fourth parts contain the amount of rainfall recorded during the last 24 hours in the country.

The fifth part gives the general weather outlook next 48 hours. The forecast is generally rain

oriented.

The sixth & seventh parts are included in the Bulletin B. The sixth parts contain the weather / rain

forecast in the upper catchment areas and in the lower catchment areas of all the rivers. The upper

catchment is the area above rim stations and lower catchment is the areas below rim stations. The

seventh and important part in main flood forecast. This is the quantitative forecast of river flows at

22 sites including rim stations. First two columns indicate the rivers and their gauging sites. Third

column is design capacity i.e the maximum flow that can pass through the particular site without

any damage. The sixth & seventh column indicates the expected range of the river flow in cusecs

& corresponding flood level. The last & eight columns show the level of very high flood flow at

particular site. (Forecast Bulletins A& B attached as Annex- 7&8)


23.3 Early Warning

a) Significant Flood Forecast

Under the effect of an approaching weather system the flood situation undergoes rapid

fluctuations. The quite often necessities the issuance of a special flood forecast pertaining to a

specific site . This is in fact the most important forecast issued by FFD. Most commonly it is

issued in respect of the rim station but can also be issued for any other site downstream. A

common early warning format is as given below:-

GOVERNMENT OF PAKISTAN

PAKISTAN METEOROLGICAL DEPARTMENT

FLOOD FORECASTING DIVISION

46-JAIL ROAD LAHORE-54000

Sr No_________ Dated_________

SIGNIFICANT FLOOD FORECAST

River ____________________________ at _____________________________

Likely to cross ______________________________________________ cusecs

(_________________________________________________ Flood Level)

during the period from ________________________________ hours PST of

_______________________________to_____________________ hours PST of

_______________________________________________

For Chief Meteorologist

Time of Issue_______________ Hrs PST


b) Areal Flood Inundation Flood Forecast

This forecast will be issued on the basis of flood inundation maps corresponding to different flood

levels when the flood exceeds the exceptionally high flood level and the spillover is expected to

occur causing inundation of the areas along the river channel.

The forecast may take the shape as given below:-

River Sutlej between the reach Sulemanki to Islam is likely to reach an exceptionally high flood

level amounting to discharge ranging between ______ and ________ Consequently , the under

mentioned areas are likely to come under water to extent as mentioned against each .

District Village Depth of Water

2.4 Miscellaneous Flood Forecast / Information

a) Weather / Flood Forecast

Such important Government functionaries as are directly or indirectly related to the flood

mitigation process but are not involved in the flood fighting operation do not need the flood data at

each flood measurement site but definitely need to be kept informed of the flood and weather

situation in general . In order to cater for this, weather and flood forecast has three parts. Part-1

indicates the prevailing meteorological situation .Part-II gives the rainfall recorded during the last

24 hours. Part III gives the weather and the flood forecast in descriptive form which can be easily

understood by a non technical person.

b) Flood Information to Media

Flood information to the electronic and press media is often passed to the public through press

briefings conducted in the office of the Chief Met FFD. Invitation to the press is sent through the

press Information Department ( PID) of the Punjab Govt .A representative of the PID is made

available on two shift duty roster basis to be present during the morning as well as evening hours

in the Flood Warning Centre. Press briefings are generally conducted in the evening at about 6


PM, only on occasions when flood situation is serious enough to call for such briefings to filter out

unauthorized and incorrect flood information from reaching public. A written report to be passed

to radio and TV is also given out by the press representative.

C ) Special Press Briefings By Minister of Water & Power / Chairman FFC or Chairman

NDMA

Chief Met FFD may advise the Minister of Water & Power/ Chairman FFC or Chairman NDMA to

conduct special press briefings with a view to providing such information to the public as is

considered extremely useful in the context of flood mitigation. This advice is rendered as and when a

serious flood situation is positively developing or has actually developed. The outline for the briefings

is to be prepared by the Chief Net FFD under the advice of the authority, i.e Minister of Water &

Power / Chairman FFC or Chairman NDMA.

Withstanding and specific instructions given to Chief Met FFD by the Authority (conducting the

briefings) a general outline of such briefings may be as follows:

i ) A brief mention of the prevailing weather system indicating its past track , present position and

future track . Indicate the areas under heavy rain.

Ii ) Mention of a few heavy rainfall amounts in ( India or Pakistan ) and any reported damage . In

case heaviest point rainfall data is not available; Radar based rainfall may be mentioned indicating the

time duration and areas of the heaviest rainfall.

Iii ) A brief on present and future flood situation in respect of each river indicating any damages

(If so far reported)

Iv ) Mention of the flood mitigation arrangements to cope with flood emergency. Advice to the

Flood prone population to remain vigilant and follow the advice to refrain from publishing unauthentic

flood information for incorrect reporting.

V ) Question / answer session ( Indicate answers to the commonly asked question )

Vi ) Concluding remarks.


Chapter 3

Responsibilities of the FFD and Stakeholders

3.1 General

Flood management is a multifunctional process involving organization. The stakeholders, which

play major role in the flood management , is PIDA , WAPDA, provincial relief organization,

Pakistan Army, NDMA, PCIW, Emergency Relief Cell, FFC and FFD. Proper understanding of

functions of these organizations is briefly described below.

3.2 Responsibilities of Flood Forecasting Division (FFD)

FFD of the Pakistan Meteorological Department plays a pivotal role in the entire flood mitigation

process. Hydro meteorological data from the various national and international sources is received

in this office which is then processed to produce flood forecasts and warnings to be disseminated

outwards to various national organizations (Annex-9)

Major actions required to be taken by the FFD before, during and after the flood season are

summarized below.

Flood preparatory Measures

I ) Ensure serviceability of the meteorological equipment including QPM Radars Lahore,

Mangla and Sialkot, Teleprinter network, FAX, APT& Internet.

Ii ) Ensure availability of the following items in sufficient to last for the whole of flood season:

Surface and upper air meteorological charts, isohyetal maps, various forecast forms, data

tabulation sheets stationery etc.

Iii ) Update the calibration of the radar and flood forecasting models

Iv ) Ensure availability of sufficient staff strength to maintain round the clock roster of duties

for the meteorological and hydrological work.


V ) Liaison with PTC’s Coordination officer provide 24 hours maintenance services for the

teleprinters, Internet & the office and residential telephones of all the flood related

functionaries.

Vi ) Conduct a familiarization training of the senior cadre and junior cadre government ,

functionaries actively involved in the process of flood mitigation. Senior cadre training

may be limited to one day only and must include such functionaries as the Relief

Commissioner, Director General ( Relief) , Chief Engineer, Hydrology WAPDA, Chief

Engineer FFC , Chief Engineer, Hydrology and drainage PIDA, Director Flood PIDA ,

Director PDMA.

Training for the junior cadrs may extend to a period of one week for the persons from

various provincial and federal departments actually posted on flood duties.

3.2.1 Functions during the Flood Season

Chief Met, FFD is personally responsible for the issuance of timely and reliable flood

forecast/warning to afford pre-flood imitation measures to reduce damage to the life and

property due to floods. He is required to remain in touch with his office even outside the

working hours to maintain a close watch on the flood generating weather situations. In case

situation for Category-II or category-III floods develop he is to give advance verbal

briefings to R.C. Punjab, Chairman FFC, DG Engineers ( Army), DG Met, Chairman

NDMA and Member (water) WAPDA. Such briefings should be over and above the

written qualitative forecasts issued when the approaching monsoon low/ depressions draws

closer. In order to avoid undue public panic, flood forecasts to the public should be given,

only when the possibility of floods has positively developed, in which case suitably tailored

flood forecast must be provided to the press and the electronic media in time. The benefit

of the improved flood forecasting system must reach the public by way of more reliable

and more advance flood information to them. It is also important that the necessary trust be


placed in the forecasts issued by Chief Met FFD and under no circumstances the forecast

issued by him allowed to be amended without his consent. This is because the flood

forecasting is the sole prerogative of the Chief Met FFD and no one else in the present set-

up has the necessary technical means or the know-how to make any change.

Under a serious pre-flood situation Chief Meteorologist FFD may invite director Floods of

irrigation Department, Chief Engineer (H & WM) of WPADA and necessary flood related

actions. Additionally, daily press briefings may be commenced in consultation with the

Relief Commissioner Punjab.

In case of category-III flood situation a forecast of PMF in respect of Mangla / Tarbela be

issued in yes/ no terms and Member (water) WAPDA be personally informed of it by Chief

Meteorologist, FFD Lahore.

3.3 Stakeholders

3.3.1 Provincial Irrigation and Drainage Authority (PIDA)

PIDA plays a front line role in the process of flood forecasting as well as flood mitigation.

Major flood related functions include.

I ) Flow measurements at the specific sites at rivers , canals and nullahs

Ii ) Planning , design construction and maintenance of flood protection works.

Iii ) Maintenance of data communication network to provide the river flow data to FFD.

Iv ) Supervision of the flood warning center ( on behalf of Relief Commissioner ) to

ensure timely dissemination of the flood forecasts / warning.

Vi ) Occasional updating of the divisional flood fighting plans and execution of such

plans during flood emergency.

Vii ) Implementation of the divisional flood fighting plan and ezxecution of such plans

during flood emergency.

3.3.2 National Disaster Management Authority ( NDMA)


The National Disaster Management Authority and Provincial Disaster Management

Authorities Whose raisings were recently approved by the Govt. Immediately

mobilized the relief effort in a coordinated and synchronized manner .

NDMA provides a well coordinated, synergized and timely relief to affected areas

with a view to bringing normalcy of life in the shortest possible time:-

I ) Short Term Implication

(a) Rescue / Crisis management of affected population in distress.

(b) Provision of immediate relief in the form of food, water, shelters

and health care.

(c) Restoration of communication infrastructure and essential services.

(d) Distribution of compensation to affected households.

(e) Early recovery of affected areas.

(2) Long Term Implication

(a) Capcity building of PDMAs, Sindh, Baluchistan, Punjab and

NWFP to handle relief , rehabilitation and reconstruction.

(b) Rehabilitation and Reconstaruction by PDMAs through line

ministries in coordination and under the direction of NDMA.

3.3.3 WAPDA

WAPDA is actively involved in the Flood Forecasting process by providing the

much needed river and rain data from its telemetric gauge sites within

the upper catchments of Indus , Jhelum &Chenab rivers. During the

previous flood forecasting project ( from 1977 to 1987), WAPDA was

assigned the responsibility to establish and maintain a telemetric

network of river and rain stations to support the flood forecasting

models. A total of about 40 such stations were established . The number

was gradually reduced to about 20 due to maintenance problems,


especially in respect of the river gauging equipment which developed

frequent problem. It was decided to assign three categories to the

telemetric stations in relation to their relative importance in flood

forecasting. WAPDA maintained only fifteen catergory-1 stations during

the last years. The system has now been replaced with a new set of

equipment using the meteor burst based communication system.

WAPDA‘s telemetric network is directly linked to FFD and is looked

after by an officer of the level of research office whose office is located

within the premises of FFD.

Beside WAPDA‘s involvement is providing the hydrometric flood data,

it is also involved in providing the data from such hydraulic structure as

Mangla and Tarbela dams and the Chashma Barrage

A great scope exists in future in assigning the flood mitigation role to

Mangla and tarbela reservoirs by linking up the operation of the two

reservoirs with flood forecasting system. Resorting to pre-flood releases

on the basis of the flood forecasts can create necessary flood storage.

3.3.4 Provincial relief Organization

Ultimate aim of flood warning is to reduce the potential loss to the life

and property of the community living in the flood liable areas.

Provincial relief organizations are charged with the responsibility

pertaining to disaster preparedness, emergency response, and post

disaster activities pertaining to all disasters including flood.

Consequently, under the present set up the flood Warni8ng Center has

been placed under the Relief commissioner in addition to his normal

duties. Relief department primarily functions through control and

coordination of the personnel and resources of other govt departments


generally organized asd committee like flood commission and flood

Warning Center. Relief function at the district and Tehsil level are

performed through the DCO, who coordinates with the other

departments to execute the flood mitigation function at the district level.

Flood preparatory actions required to be taken the Relief Commissioner

include:-

i) Arranging inspection of the flood protection works by the

Irrigation Department and Pakistan army to ensure that all vital

flood protection bunds etc. are in a satisfactory state of

maintenance.

ii) To establish flood warning center and the flood centers at the

district and Tehsil Levels.

iii) To ensure that all flood related agencies / department involved in

the process of flood mitigation are fully geared to perform the

functions pertaining to their respective areas in the process of the

flood mitigation.

iv) To ensure that flood forecasts / warnings are disseminated

without loss of time to all concerned and they are fully aware of

the action to be taken under each situation.

These are some of the major actions required to be taken by the

Relief Commissioner before the onset of the flood season.

During the flood emergency, however, he is to supervise the

flood relief functions carried out by the district administration

with help of Pakistan Army and other government Departments.

These are some of the major actions required actions required to

be taken Relief Commissioner before the onset of the flood


season. During the flood emergency, however, he is to supervise

the flood relief functions carried out by the district administration

with the help of Pakistan Army and other govt departments.

3.3.5 Pakistan Army

Pakistan army’s corps of engineers under the command and

control of Engineer-in-Chief ( E-IN-C) is charged with the

responsibility to provide the necessary help to the civil authority

to carry out the rescue and relief operations during and after the

floods. It is the responsibility of the provincial govt to provide all

the support equipment ( boats, life jackets, vehicles , tents etc ) to

the Army for such operation.

Pakistan Army’s flood related function encompasses all the three

phases of flood operation from the pre-flood to post flood phases

including the all important flood phase. Pre-flood phase is the

flood preparatory phase during which the adequacy and the

serviceability of the flood fighting equipment are ensured. A

number of pre-flood meetings are held at the level of E-IN-E to

help coordinate the activities of the other organizations / agencies

in providing the required support to the Army. Since Punjab is

the most flood province, it is the Relief Commissioner Punjab ,

who provides the bulk of the flood fighting equipment to the

army. The CC Engineers 4 Corps of the Army that is stationed at

Lahore acts as liaison officer for the purpose. P0re-flood

inspections of the flood protection structures are also carried out

by the respective commander corps of engineers for their


respective areas to ensure that the structures ( bunds , barrages ,

spurs etc ) are in satisfactory stae of maintenance .Discrepancy ,

if any is brought to the notice of the relief commissioner and

PIDA. Sometimes joint inspections with PIDA are carried out to

save time

Pakistan Army’s major flood related starts after the flood occurs. An officer of the 4 Corps engineers is placed on duty

in the flood warning center to keep a close watch on the flood situation. All flood forecasts and warni9ng are

communicated to the CC Engineers 4 Corps in time to be transmitted to the D.G. Engineers and all other CC Corps of


the Engineers. Lack of understanding of the flood forecast has been a major problem faced by the Army in the past,

since they are no acquainted with the commonly used. Hydro meteorological terms and no arrangement of the pre-

flood training of the concerned CC Engineers corps has so far been made As the flood arrives , units of the Army

move out to their respective areas of responsibility and carry out relief and rescue operations in coordination with civil

administration . A major post flood meeting is held under the chairmanship of E-IN-E to discuss the performance of all

the flood related agencies with the view to bring about the necessary improvement in future.

3.3.6 Pakistan Commissioner for Indus Waters (PCIW)

Pakistan has a unique flood- forecasting problem in the sense that greater part of the flood producing upper catchments of

the Sutlej, Ravi and Chenab rivers lies across the border in India / held Kashmir. Further more a number of control

structure like dams and barrages etc, exist over the rivers across the border with the result that the free conditions are

destroyed making the operation of the rainfall / runoff model extremely difficult. The situation underlines the need for the

river flow data from across the border in respect of the important sites over the rivers in India / held Kashmir.

Consequently, an agreement has been signed between the two countries through their respective Commissioners for Indus

water which includes a provision to receive from India such river flow and rainfall data as is considered important for flood

forecasting in Pakistan.

A number of river flow stations are specified for this purpose. Normally once a day the data is received by the Pakistan

Commissioner for Indus waters. The data is then passed on to the Chief Met FFD. Frequency of data reception is increased

to six hourly and even to hourly in relation to the prevailing flood situation. Pakistan commissioner for Indus waters is thus

responsible to provide to the Chief Met FFD the much needed data from India for use in the flood forecasting models.

Many problems have occurred in the past when the India data in respect of river Ravi was passed on to the press which

resulted in the issuance of false alarm to the public. This is because large-scale attenuation of the flood wave occurs

between Madhopur (India) and Jassar due to the physiographic characteristic of the catchments and the river bed.

Incidences are not uncommon when the flood peak at Jassar is reduced to 1/4th

of its size at Madhopur.It has thus decided

that the India data as received through the Commissioner for Indus waters must not be made public to avoid false alarm

arising out of the wrong interpretation of the data. .Leakage of this data to the press must be specially guarded since the


press may publish threatening front wave as given in the India report for Madhopur. Eventually when nothing arrives as

compared to what was reported; press may start to criticize India for providing the incorrect flood information. This puts

Pakistan Commissioner for Indus waters in an embarrassing situation viz, a viz , his Indian counterpart.

It has therefore been decided that flood forecast as issued by chief Met FFD only be given to the Media ( both electronic &

press ) and all other concerned agencies.

Pakistan Commissioner for Indus Waters is the only forum through which any clarification or further information can

be obtained from India with regard to flood data or the flood control structures etc.

3.3.7 Emergency Relief Cell (ERC)

Emergency Relief Cell has been established under the cabinet division and is controlled by the Cabinet Secretary. The DG

Relief heads the cell. Main function of the Emergency relief cell includes

i) Planning and assessment of relief requirements of major disasters

ii) Stock pilling of basic necessities needed during emergency such as dry ration, tarpaulins, blankets etc.

iii) Establishing emergency fund upon declaration of any part of the country as calamity affected.

iv) Maintaining contact with UNDP and other international aid giving agencies.

v) Making arrangements of disaster relief assistance from other countries.

ERC maintains two warehouses for stocking relief goods and the cell also maintains relief goods dispatch

organization. For the dispatch of the relief goods ERC maintains a fleet of helicopter which are given under the control

of Army aviation base at Dhamial and are flown by the Army pilots for the relief missions under the instructions of

ERC.

Located at Islamabad ERC maintains contact with Federal Flood Commission (FFC) and is one of the recipients of the

daily flood report issued by FFC.

3.3.8 Federal Flood Commission (FFC)


FFC was established in 1977 to provide the necessary infrastructure at the federal level to help the provinces in

meeting the technical and financial resources required to carry out the Flood mitigation Measures.

During the recent past FFC has played a unique role in remodeling the flood mitigation policy of the country on

modern lines with the help of the foreign loan mostly obtained from Asian Development bank ( ADB)

The policy being implemented by the FFC encompasses both the engineering as well as the non-engineering measures.

Non-engineering measures mainly pertain to establishment of a modern flood forecasting and warning system to

provide timely and reliable flood information to the concerned flood mitigation agencies and the public in general .

One big step towards this end is establishment of the QPM Doppler radar at Lahore , Sialkot & Mangla to afford the

acquisition of the much needed rainfall data from across the border over Sutlej , Beas , Ravi, Chenab & Jhelum

catchments through the process of remote sensing. Flood inundation maps are prepared to facilities the identification

of the villages likely to be inundated as against those considered safe, for a specific level of flood to be determined on

the basis of running the hydrodynamic model.

A number of flood protection worked have been executed and some are still in the process of implementation by the

provinces through financial and technical support provided by FFC.

In the context of flood warning dissemination Chairman FFC ( being also the Chief Engineering Advisor to the

Federal Govt ) renders suitable advice to the President and Prime Minister as and when the situation so demands. He

carries out this function either directly or thorough the Minister of Water & Power.


Chapter 4

Flood Forecast & Early Warning Dissemination System

4.1 Background Information

Since the establishment of the flood forecasting and warning system , the dissemination of the flood forecasts /

warning was entrusted to an office designated as the Flood warning Center ( FWC) , which was temporarily

established every year within the premises of the Flood Forecasting Division ( FFD) for the duration of the flood

season ( 15 June to 15 Oct ) . The FWC was constituted of the representatives from such departments / agencies which

are directly or indirectly related to the flood problem. This includes WAPDA, Pakistan Railways, Pakistan Army,

Irrigation dept; Highways dept; and Information department of Punjab. The center functioned under the overall

control of the Relief Commissioner Punjab, who was the Senior Member Board of revenue and performed flood duties

as an additional assignment. Operation control of center was exercised by the Director Flood of the Punjab Irrigation

Department while the logistics of the center were looked after by DG, Relief Department, who was in turn assisted by

his two Directors i.e. , Director Operation and Director Technical.

The FWC was supported by the Police Tele Communication center which was simultaneously established within the

premises of PMD’S Flood Forecasting Office at 46-Jail Road Lahore under the orders of the Relief Commissioner.

The Police Tele communication Center provided the necessary communication links through police wireless sets

between the e FWC and all the Irrigation sites (including the river headwork) and District / tehsil Level flood centers

temporarily established during the flood season under the control of Deputy Commissioners. Reception and

dissemination of the flood data and the flood forecasts / warning respectively was done by FWC through the Police

Tele Communication center. Flood data constituted the rain and discharge data of the river as well as that of the natural

streams / nallahs considered vial for the flood forecasting purposes. Flood data of the WAPDA sites was received

through WAPDA communication center Sunny View Lahore, where it was passed on to WAPDA sub-office at the

Flood forecasting Office. Flood data of the river sites of river Indus in the province of Sindh was received through HF

radio sets placed at WAPDA sub office ( at 46-Jail Road Lahore ). Discharge data and the flood forecast of Guddu ,


Sukkur and Kotri barrages were received and disseminated respectively using this HF radio communication link

between FWC Lahore and Tughlaq House Karachi

Under the above mentioned flood warning system, the forecasting and the dissemination function were completely

bifurcated and entrusted to Flood Forecasting center of PMD and FWC of the province of Punjab respectively.

Consequently, the Director Flood Forecasting Center of PMD had no say in the dissemination of the flood forecasts

issued by him. His responsibility ended after the forecast issued by him was handed over to the FWC , since the

dissemination was the sole responsibility of the FWC under the control of the Relief Commissioner ( RC ) and through

him the Director Flood ( Irrigation department )

4.2 Prevailing Flood Warning Dissemination System

With the passage of time, operation of the earlier dissemination system inherited some discrepancies, which raised

confusions in the mind of the public and the Govt agencies which are listed below:

a) Police telecommunication system (for the reception of Flood data and the dissemination of flood

forecasts/ warning) be replaced with some advanced automatic data communication system. However, until such time

a system becomes available the police operator posted on flood duties be given some training to enable detection of

simple data errors and also to understand the urgency and importance of timely data and flood forecasts

communications.

b) Dissemination of the flood / warning at least to the important recipients be done by the Flood Forecasting

division to ensure timely dissemination under the overall supervision of the Chief Meteorologist FFD .

c) some mechanism to ensure proper coordination between the various departments / agencies involved in

the flood mitigation process be established. This could be done by an authority having the full legal

jurisdiction over all the concerned agencies.

The problem and the possible remedies were frequently discussed in flood meetings at Provincial and Federal

government levels. As a result of such efforts the earlier flood warning dissemination system underwent

gradual changes as reflected in the system currently in vogue. Salient features of current flood warning

dissemination system are as follows:


i) a pre-flood familiarization training has been started since last few years to acquaint the newly inducted

people of Irrigation and WAPDA with the commonly used hydromet terms.

ii) Flood forecasting and warning Center was redesignated as the National Flood Forecasting Bureau

(NFFB) having the following constitution.

Director PMD (Head)

Director Hydrology WAPDA (Member)

Representative of Indus Water Commission (Member)

Director Floods (Irrigation) (Member)

In 2001, PMD has upgraded the post of Director NFFB and now Chief Met. (BS-20) is heading this office with the

new name Flood forecasting Division. The chief meteorologist FFD is authorized to call the meeting of

the FFD as and when the serious flood situation occurs and / or lack of coordination comes to his notice

calling for immediate remedial action.

Iii ) FFD has taken in hand the dissemination of the flood forecasts/ warning to considerably a large number

of recipients directly or indirectly concerned with the flood mitigation process, over and above the

dissemination being done by the FWC.

iv) Press briefings have been started in the office of the Chief Meteorologist FFD as a regular feature to

ensure correct and authentic and weather information to the public. Such briefings are arranged through

the representative of the Punjab information department on duty at the FWC, only when the flood

situation is or likely to become serious enough to call for such briefings.

Considerable improvement has been made in the dissemination system since the time that it was initially started. A

much better coordination now exists with WAPDA Regular meeting or verbal advice is given by Chief

Meteorologist FFD to G.M (Planning & Coordination) WAPDA during the flood season as and when

asked for .

4.3 Updated Flood Warning dissemination Procedure

The existing dissemination process has been reviewed and lists of the recipients of flood information have been

streamlined. Basically there are two types of flood information required to be provided for use by the


appropriate recipient: the flood forecasts and the flood data. Whereas the flood forecasts are disseminated

by FFD as well as by the FWC, the flood data is disseminated by the FWC only.

4.3.2 Dissemination of Flood Data

Besides the flood forecasts, the flood data is also disseminated to such Govt functionaries as are required

to closely monitor the flood level at various headworks. The data consists of the gauge and discharge

data measured at every six hours.

Recommendations

The SOP has been prepared after many years of practical experience and it has been found that SOP can

only be practicable when a general consensus exists between all the stakeholders. Otherwise the spirit of

the SOP would not be alive. The understanding of the social scenario of the country is very vital

otherwise operation of the SOP in isolation would add burden on the poor and unaware people.

Keeping in view the above, some recommendations have been proposed for better operation of the SOP:

(i) Proper Training & Understanding

The general public specially the stakeholders must have adequate knowledge of the weather system and

the forecasting of the system. For this purpose some training education must be imparted to the

responsible section of the people and amongst the stakeholders so that dissemination of the forecast may

be realized in true sense.

(ii) Media Role

Local print & electronic media should also understand the purpose of the flood forecast and should

refrain from dishing out wrong or confused information to the public which may result in spreading panic

& chaos in the civil population.

(iii) Single voice

The flood forecast issuing authority has a unique role in this SOP which should not be compromised,

because the focal person has all the knowledge and data regarding the building or recession of the flood


wave. Any wrong or mutilated picture of flood may result in increasing the difficulties and aggravating

the situation.

(iv) Infrastructure development

The general public should be aware of the flood prone areas and may be discouraged to raising any

structure within the area. Govt should mark & advertise flood prone areas through the print and

electronic media for the information of the public. No utility services like gas, telephone, electricity

should be provided in the flood prone areas particularly within the river banks. Proper record may be

maintained regarding the raising of building in the specified areas.

In the hilly areas where flash flooding usually creates havoc, construction of building should also be

disallowed in the vicinity of the hill torrents paths. Similarly edges of the roads near rivers should also be

banned for construction of any big structure like shopping centers, educational institutions, hotels, Govt

office buildings etc.


Annexture -5A

FLOOD ROUTING THROUGH MANGLA RESERVOIR

(CATEGORY-I FLOODS)

2 TO 5 LAC CFS

1. Flood built up confirmation at EL 1202 feet

2. Balance inflow, outflow upto high flood limit 150,000 cfs

3. Watch till elevation rises to 1203 feet

4. If inflow still rising increase outflow to 250,000 cfs


6. if inflow still rising increase outflow to 300,000 cfs





11. If reservoir level still rising with: Continue same outflow and

a) Evidence of still rising with: then start reducing gradually

as the situation permits.

b) Evidenc4 of further flood buildup Open the main spillway to cater for inflow /

outflow

Note:

Flood warning station data and FFD forecast shall be kept in view all the time. As soon as inflow hydrograph recession

is confirmed the outflows should be reduced gradually for downstream relief, subject to the safety of the project.


Annexture-5B


(CATEGORY-II FLOODS)

5 TO 7 LAC CFS






6. if inflow still rising increase outflow to 425,,000 cfs





11. If reservoir level still rising with: Continue same outflow and

a) Evidence of still rising with: then start reducing gradually

as the situation permits.

b) Evidenc4 of further flood buildup Open the main spillway to cater

for inflow / outflow

Note:




Annexture-5C


(CATEGORY-III FLOODS)

ABOVE 7 LAC CFS








8. If inflow still rising increase outflow to 475,,000 cfs



11. If reservoir level still rising with: Continue same outflow and then start reducing

gradually as the situation permits.

a) Evidence of still rising with:

b) Evidenc4 of further flood buildup Open the main spillway to

cater for inflow / outflow

Note:



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