Post on 11-Mar-2020
Cyclone impacts on engineering design
standards for Infrastructure
(case study: Sultanate of Oman)
Presented by:
Prof. Dr. Alaa El-Zawahry*
* Professor of Hydraulics, Irrigation & Hydraulics Dept., Faculty of Engineering, Cairo Univ. Email:ceeg@link.net
The 4th Workshop on Tropical Cyclones and Flash Floods )Evaluation of the Sultanate's Experience and Lessons Learned after Guno and Phet Cyclones)”
OUTLINE Introduction
Generation Mechanism of Cyclones
Cyclones Naming
Categories of Tropical Cyclones
Cyclones History in Oman
Gonu, Phet, and Mikono Cyclones
Meteorological Model
Ground Stations
Damage of Gonu and Impacts on Design Criteria
Risk Management
Generation Mechanism of Cyclones
What are the Necessary Conditions for the Formation of the Tropical Cyclones?
» Low-level relative Vorticity (ζr)
» Coriolis parameter (ƒ)
» Low vertical shear
» Sea surface temperatures
» Vertical gradient of effective potential temperature (θe)
» Middle troposphere relative humidity (RH)
Generation Mechanism of Cyclones
Convective Towers
Cyclones Naming Importance for naming tropical cyclones
It would help identify each individual tropical cyclone
Local and international media become focused to the tropical cyclone
It does not confuse the public when there is more than one tropical cyclone in the same area
The name of the tropical cyclone is well remembered by million of people as it is unforgettable event shoes name will long be remembered
Warnings reach a much wider audience very rapidly
Cyclones Naming Naming of tropical cyclones over north Indian
Ocean
The Panel member’s name are listed alphabetically country wise
The name will be used sequentially column wise
The first name will start from the first row of column one and continue sequentially to the last row in column eight. Example, this will be as Onil, Hibaru, Pyar, Baaz …………. Amphan
The names which have been already used from the list are highlighted
Cyclones Naming
Panel Member
Column One Column Two Column Three Column Four
Name Pron’ Name Pron’ Name Pron’ Name Pron’
Bangladesh Onil Onil Ogni Og-ni Nisha Ni-sha Giri Gi-ri
India Agni Ag’ni Akash Aakaa’sh Bijli Bij’li Jal Jal
Maldives Hibaru --- Gonu --- Aila --- Keila ---
Myanmar Pyarr Pyarr Yemyin Ye-myin Phyan Phyan Thane Thane
Oman Baaz Ba-az Sidr Sidr’ Ward War’d Murjan Mur’jaan
Pakistan Fanoos Fanoos Nargis Nar gis Laila Lai la Nilam Ni lam
Sri Lanka Mala --- Rashmi Rash’mi Bandu --- Mahasen ---
Thailand Mukda Muuk-dar Khai Muk Ki-muuk Phet Pet Phailin Pi-lin
Cyclones Naming
Panel Member
Column Five Column Six Column Seven Column Eight
Name Pron’ Name Pron’ Name Pron’ Name Pron’
Bangladesh Helen Helen Chapala Cho-po-la Ockhi Ok-khi Fani Foni
India Lehar Le’har Megh Me’gh Sagar Saa’gar Vayu Vaa’yu
Maldives Madi --- Roanu --- Mekunu --- Hikaa ---
Myanmar Nanauk Na-nauk Kyant Kyant Daye Da-ye Kyarr Kyarr
Oman Hudhud Hud’hud Nada N’nada Luban L’luban Maha M’maha
Pakistan Nilofar Ni lofar Vardah Var dah Titli Titli Bulbul Bul bul
Sri Lanka Priya --- Asiri Aa’siri Gigum Gi’gum Soba ---
Thailand Komen Goh-men Mora Moh-rar Phethai Pay-ti Amphan Um-pun
Categories of Tropical Cyclones
Tropical Cyclone Intensity Scale
Category Wind Speed
Super Cyclonic Storm > 222 km/h
Very Severe Cyclonic Storm 118 – 221 km/h
Severe Cyclonic Storm 88 – 117 km/h
Cyclonic Storm 62 – 87 km/h
Deep Depression 52 – 61 km/h
Depression ≤ 51 km/h
Storms affecting the Arabian Peninsula by month
Month Number of storms
May
14
June
18
July 3
August 1
September 3
October 7
November 8
December 5
Storms affecting the Arabian Peninsula by period
Period Number of storms
1800s 5
1900–49
10
1950s 3
1960s 6
1970s
11
1980s 2
1990s 6
2000s 5
2010s
11
Gonu Cyclone (June 2007)
Weather Research and Forecasting Model
Wind Speed (kts) Forecasted (June 1, 2007) Dis = 5 km Do3
a) 00:00UTC
b) 06:00UTC
c) 12:00UTC
d) 18:00UTC
Gonu Cyclone (June 2007)
Weather Research and Forecasting Model
Wind Speed (kts) Forecasted (June 7, 2007) Dis = 5 km Do3
a) 00:00UTC
b) 06:00UTC
c) 12:00UTC
d) 18:00UTC
Gonu Cyclone (June 2007)
Weather Research and Forecasting Model
Lat:19.2N Lon:64.9E
Lat:18.7N Lon:66.0E
METEOSAT-7 RGB = CH (1,4)
Gonu Cyclone (June 2007)
Weather Research and Forecasting Model
Lat:23.9N Lon:59.4E Lat:23.0N
Lon:60.4E
Gonu Cyclone (June 2007)
Weather Research and Forecasting Model
Results and Discussion
Weather Research and Forecasting Model
Parameter SI WRF-ARW Range of Error
Win
d S
pee
d (
inte
nsi
ty)
June 1 D (in late the day) D (in late the day) Generally, in the model
forecast period, the intensity
of the tropical cyclone was
relatively weaker than the
observed.
The system attained peak
winds SuCS late on June 4,
While the model attained
peak winds VSCS early on
June 6.
June 2 DD – CS (Along the day) D – DD (Along the day)
June 3 SCS - VSCS
Along the day
Within 3 and 4 June the model
upgraded the system gradually
until reached SCS. June 4
SuCS – VSCS
In late the day
June 5,
6
The system stills VSCS
until early on June 6, and
the system downgraded
to SCS until late on
June 6.
The model upgraded the system
gradually until reached VSCS in
early on June 6, and the
system downgraded gradually.
June 7
The system downgraded to
CS until weakened at the
late of the day.
The system downgraded to CS
until weakened at the late of the
day.
Category
Super Cyclonic
Storm
Very Severe
Cyclonic Storm
Severe Cyclonic
Storm
Cyclonic Storm
Deep Depression
Depression
Phet Cyclone (June 2010)
Weather Research and Forecasting Model
Wind Speed (kts) Forecasted (May 31, 2010) Dis = 15 km Do2
a) 00:00UTC
b) 06:00UTC
c) 12:00UTC
d) 18:00UTC
Phet Cyclone (June 2010)
Weather Research and Forecasting Model
Lat:22.5N Lon:57.8E
Lat:22.9N Lon:59.5E
Results and Discussion
Weather Research and Forecasting Model
Parameter SI WRF-ARW Range of Error
Win
d S
pee
d (
inte
nsi
ty)
May31 D D Generally, in the model
forecast period, the intensity of
the tropical cyclone was
relatively as the observed.
The system attained peak
winds VSCS at June 3, While
the model attained peak winds
VSCS at the same time.
June 1 DD – CS
Along the day
DD – SCS
Along the day
June 2 SCS - VSCS
Along the day
SCS – VSCS
Along the day
3, 4 June The system stopped as VSCS
along the 2 days
5, 6 June
The system gradually downgraded
to CS along the 2 days and
dissipated early on June 7.
Category
Super Cyclonic
Storm
Very Severe
Cyclonic Storm
Severe Cyclonic
Storm
Cyclonic Storm
Deep Depression
Depression
Mukono Cyclone
Ground Stations at Gonu Cyclone
Ground Stations at Phet Cyclone
Gonu, Phet, & Bell Design Storms
Wadi Aday Flows
Road Damage & Remediation Bridges
Road Damage & Remediation Bridges
Road Damage & Remediation Culvert & Road Pavement
Road Damage & Remediation Side Ditch
Branch from Wadi
Alansab with Area
17.85 Km2 The Study Area
Effect of Cyclones on Properties
0 100 200 300 400 500 600 700 80010
12
14
16
18
20
22
Main Channel Distance (m)
Ele
va
tio
n (
m)
Legend
WS PF 1
WS PF 2
Ground
ghala ghala
-50 0 50 100 150 200 250
14
16
18
20
22
Bridge Scour RS = 465
Station (m)
Ele
va
tio
n (
m)
Legend
WS PF 1
Ground
Ineff
Bank Sta
Contr Scour
Total Scour
0 100 200 300 400 500 600 700 80012
14
16
18
20
22
Main Channel Distance (m)
Ele
va
tio
n (
m)
Legend
WS PF 1
WS PF 2
Ground
ghala ghala
-20 0 20 40 60 80 10014
16
18
20
22
24
26
RS = 340 10
Station (m)
Ele
va
tio
n (
m)
Legend
WS PF 1
WS PF 2
Ground
Ineff
Bank Sta
.03
Effect of Cyclones on Dams
Al Ansab Dam
Inflow & Outflow Hydrographs
0
200
400
600
800
1000
1200
0 5 10 15 20 25Time (hrs)
Flo
w (
m3
/s)
InflowOutflow Initially DryOutflow Initially Half FullOutflow Initially Full
100 Yrs
Inflow & Outflow Hydrographs
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 5 10 15 20 25Time (hrs)
Flo
w (
m3
/s)
InflowOutflow Initially DryOutflow Initially Half FullOutflow Initially FullPMF
Effect of Gonu on Road Design
128 After Screening 67 North and 10 Dhofar 105 Rain stations
Effect of Gonu on Road Design Rainfall
Item Old Manual, (1994
and Its addendums)
New Manual (After Gonu) 2010
IDFCs One for All Oman Sultanate of Oman is divided to four zones. Each zone has its own IDFC
I (mm/hr) corresponding to 100 Yrs at 0.25 hr
140 174 (for IDFC of Zone 1)
Gonu Effect ----
If the catchment has a time of concentration less than 2 hours, there is no need to include cyclone effect (The manual IDFCs will be used). While if the time of concentration is more than 2 hours, cyclone effect should be taken into consideration (The manual IDFCs will not be used)
Effect of Gonu on Road Design Flood Estimation
Item Old Manual, (1994 and
Its addendums) New Manual (After Gonu) 2010
Used Methods
Rational and old set of Empirical equations. The regression equations are generated using very limited rainfall and flow records
Rational, SCS Unit Hydrograph, and new generated set of Regression Equations. The regression equations are generated using huge number rainfall and flow records measured all over the Sultanate and taking into consideration Gonu effect
Limits
Rational method used for catchment areas less than or equal 10 km2
Rational method used for catchment areas less than or equal
1.3 km2
The Empirical Equations are used for catchments larger than 10 Km2
SCS unit hydrograph method is recommended for medium and large catchments
Effect of Gonu on Road Design Flood Estimation
Item Old Manual, (1994 and
Its addendums) New Manual (After Gonu) 2010
Regression Eqn ----
Two sets of regression equations are recommended for all catchment sizes (one for All Oman except Dhofar while the other one for Dhofar region). These equations should be used in conjunction with Rational or SCS unit hydrograph method
Effect of Gonu on Road Design Culvert
Item Old Manual, (1994 and Its
addendums) New Manual (After Gonu) 2010
Dimensions
Pipe 600 – 1050 mm Pipe 1000– 1500 mm
Box S (1-4 m),
H (max 4 m) Box
S (1-4 m), H (1.5-4 m)
Return Period
Primary road
1 in 50 Yrs
National & Arterial Road
1 in 50 Yrs Secondary
road Secondary
road
Local Road
1 in 20 Yrs
Distributor Road
1 in 25 Yrs Access Road
Access Road
Effect of Gonu on Road Design Culvert
Item Old Manual, (1994 and
Its addendums) New Manual (After Gonu) 2010
Min. Overburden 300 mm 600 mm
Max. Upstream Water Depth
1.5 culvert depth 1.2 culvert depth
Protection No recommended
Protection
Upstream
Length of protection is 3 m of loose riprap with filter
Downstream
Length of protection is 3 – 10 Culvert Depth of loose riprap with filter
Effect of Gonu on Road Design Bridge
Item Old Manual, (1994 and Its
addendums) New Manual (After Gonu) 2010
Protection ----
Heavy protection using at least 1.5 m depth of loose riprap and filter with length varied with computed scour
Return Period
Primary road
1 in 100 Yrs
National & Arterial Road
1 in 100 Yrs
Secondary road
Secondary road
Local Road
Distributor Road
Access Road
Access Road
Effect of Gonu on Road Design Irish Crossing
Item Old Manual, (1994 and Its
addendums) New Manual (After Gonu) 2010
Protection Mortared and loose riprap
Using R.C. cutoff with 1 m depth for the most dangerous type in addition to at least 1.5 m loose riprap with the same depth
Return Period
Primary road
1 in 50 Yrs
National & Arterial Road
N/A Secondary
road Secondary
road
Local Road
1 in 20 Yrs
Distributor Road
1 in 25 Yrs Access Road
Access Road
Risk Management
What to do before and during a cyclone?
Have your dwellings checked before a cyclone season starts and carry out whatever repairs that are needed
Talk to children and explain about cyclones without scaring them
Create storm awareness by discussing effects of a cyclonic storm with family members so that everyone knows what one can and should do in an emergency
Keep your valuables and documents in containers, which cannot be damaged by water
Risk Management
What to do before and during a cyclone?
Keep information about your blood group
Keep lanterns filled with kerosene, torches and spare batteries. These must be kept in secure places and handy
Make plans for people who are either sick, suffer from disabilities, aged and children
Store up at least seven-day stock of essential food articles, medicines and water supply
Risk Management
What to do before and during a cyclone?
Keep blankets & clothes ready for making beds. Also keep cotton bandages and several copies of photographs of family members in case they are needed for identification purposes after the storm
Store some wooden boards so that they can be used to cover windows
Keep trees and shrubs trimmed. Remove damaged and decayed parts of trees to make them resist wind and reduce the potential for damage. Cut weak branches and make winds blow through
Risk Management
What to do before and during a cyclone?
All doors, windows and openings should be secured
Continue to listen to warning bulletins and keep in touch with local officials. Keep radio sets in working condition. Battery powered radio sets are desirable
Evacuate people to places of safety when advised
Take steps to protect your assets
Store extra drinking water in covered vessels
Remain calm
Risk Management
What one should not do during a Cyclone?
During the storm do not venture out unless advised to evacuate
If you have a vehicle and wish to move out of your house, leave early before the onset of a cyclone. It is often best to stay at home
Avoid remaining on the top floor of dwellings. Stay close to the ground
Fishermen are advised not to venture out into the sea. They should keep boats and rafts tied up in a safe place
Risk Management
What one should not do during a Cyclone?
Avoid taking shelters near old and damaged buildings or near trees
Do not touch power lines. One may get electrocuted
Risk Management
What to do after the storm?
Watch out for broken glass and other sharp items in debris
Watch out for snakes and insects. Try to call for help
Listen to the advice of local officials and emergency workers
Be sure that the storm has subsided before venturing out
It is advisable to wait for the "all clear message" on radio and TV networks
Risk Management
What to do after the storm?
Wait for emergency relief teams to arrive. It may take a little time before relief becomes effective
Stay away from flooded areas
Fishermen should wait for at least 24 hours before resuming fishing
Volunteer to help people who may need assistance