1. Michael DiGregorio PhD
Planning for Climate Resilience:
learning from typhoon Mirinae

2. Typhoon Mirinae: 30 Oct-2 Nov 2009
• On the morning of 2 November 2009, tropical storm Mirinae, with wind speeds
of 109 kph, makes landfall in Phu Yen province. It is the 11th tropical storm to hit
Vietnam that year.
• Deputy Prime Minister Hoang TrungHai issues disaster preparation instructions
on 30 October. In BinhDinh, schools are closed on 2 November and people are
advised to prepare for the storm.
•Phu Yen, the province hardest hit by Mirinae, reports that floods and strong wind
has claimed at least 78 lives. In BinhDinh, 22 people are reported dead and 3
reported missing. In KhanhHoa, further to the south, 14 deaths are reported.
• Between 2-3 November, 801 mm of rain falls in Van Canh, BinhDinh.
• In late October, Bùi Minh Tăng , director of the Central Storm Forecasting
Agency, announces that the storm is powerful, rapid and will produce up to 400
mm of rain in Central Vietnam.
• Provincial governments report a total of $280 million in damage to property.

3. Rainfall by hour, Van Canh&QuyNhon
2-3/11/ 2009
4-5 pm 8-9 pm 12-1 am

4. Sông Hà Thanh
Đầm Thị Nại
Tỉnh Phú Yên
P. Nhơn Phú
TT Vân Canh
TT TP Quy Nhơn
TT Diêu Trì
4-5 PM
8-10 PM
P. Nhơn Bình
7-9 PM 6-7 PM10 PM-4 AM
Typhoon Mirinae: Evolution of a Flood
Flood chronology by area. Time flood first noticed in yards. Based on interviews.

5. Source: http://www.aprsaf.org/data/aprsaf16_data/D3-1445_AP16_SA_Vietnam.pdf
Satellite image: 05-11-09
TT Diêu Trì
P. Nhơn Phú
P. Nhơn Bình
P. Đống Đa
TT Tuy Phước
P. Bùi Thị Xuân
TT TP Quy Nhơn
P. Nhơn Hội

6. Ward or
Commune
Damage Assessment
Coastal
fisheries, boats
and tackle
$373,495 including $305,470 in damage in Dong
Da and $68,025 in Nhon Binh. Damage to fish
ponds accounted for 88 percent of the total.
Industrial
zones
$10,432,171 in damage to industrial zones in
Nhon Binh ($9,937,853), Bui Thi Xuan
($440,121) and Phuoc My ($36,392).
Housing
$1,343,430 in total damage to homes. 2,061 of
the 2,302 homes damaged or destroyed during
the flood were in Nhon Phu.
Dikes, roads
and irrigation
systems
$1,445,888. The largest losses were in Nhon
Phu ($481,944) and Phuoc My ($472,370).
Together, Nhon Phu and Phuoc My accounted
for 67 percent of all damages to dikes, roads and
irrigation systems.
Agriculture
and livestock
$3,183,528. In Nhon Phu and Nhon Binh, loss
of livestock and loss of rice in storage accounted
for a majority of the $1,760,820 in damage. In
Phuoc My, loss of livestock and damage to fruit
trees accounted for a majority of the $647,388 in
damage.
Forestry
$2,708,023. 98 percent of the total damage
occurred in Phuoc My, where 19 sq. km. of
industrial forest was damaged or destroyed.
Đống Đa
Nhơn Bình
Nhơn Phú
Bùi Thị Xuân
Phước Mỹ

7. Floods and Farming

8. Historical Flood Pattern:
With Few Barriers in the Flood Plain, Water Drained Quickly
bridges
Van Ha RR Hwy19
Hung Vuong
Thi Nai Lagoon
agricultural villages agricultural villages fisheries villages
low roads low
embankmentSeasonal floods generally
rose and fell gradually
over a 8-12 hour period,
often at night.
During severe and
extreme floods, water
could easily and quickly
pass over the top of low
roads.
Because settlements in the
floodplain were few and
concentrated, floodwater
could spread out over a
large area.
Slope of 8 meters in 8
kilometers from Van Ha to
Thi Nai allowed water to
drain quickly

9. Floods and Infrastructure

10. Nhon Phu
Dong Da
Dieu Tri
Nhon Phu
Weir
Weir
Kon river
Tuy Phuoc
Nhon Binh
Hwy 19
Hung Vuong St.
Northern Dike
Eastern Dike
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Typhoon Mirinae:
Impacts of Infrastructure and Urbanization on Flooding
bridge
river river RR Hwy 19 & Hung Vuong dike lagoon
agricultural villages agricultural villages fisheries
villages
bridge
dike
barrage
CCN KTDC
ĐHQT
low roads
2.0m 2.0m 2.0m 2.0m
Thi Nai Bridge
bridgedike
Flooding in the lower Ha
Thanh River occurs when
when the flow of water in
the riverbed is greater than
1,226 m3/second.
During the 2009 flood,
river flow reached 3,328
m3/second.
Barriers in floodways and
insufficiant drainage
capacity raised the level of
flooding.
+11 cm
+03 cm
+70 cm
+07 cm
⏏ Bridge
Railroad
Upgraded Dike Section
Old Dike Section
Main Road
LEGEND
+13 cm
+40 cm
IMPROVING DRAINAGE IS KEY TO REDUCING FLOOD RISKS

11. ⏏ Bridge
Railroad
Upgraded Dike Section
Old Dike Section
Main Road
LEGEND
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Dong Da
Dieu Tri
Nhon Phu
Nhon Binh
Area Plan for Nhon Binh: Impacts on Flooding
Nhon Phu
If the current area plan is
built as planned, a flood
similar to Mirinae would
produce deeper flooding.
⏏
+33 cm
+50 cm
+70 cm
+76 cm
The Area Plan for Nhon
Binh proposes filling in
roughly one third of the
ward’s area.
It also reduces the flood
channel to a narrow area
between Bridge No. 7 and
8, and Barrage No. 2.

12. Floods and Urban Development

13. ⏏ Bridge
Railroad
Upgraded Dike Section
Old Dike Section
Main Road
LEGEND
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Dong Da
Dieu Tri
Nhon Phu
Nhon Binh
Area plan for Nhon Binh:
Impacts on Flooding under Climate Change and Sea Level Rise
Nhon Phu⏏
Based on our hydrological
model, by 2050, under
conditions of Climate
Change and a Sea Level
Rise of 26 cm, a storm
similar to Mirinae, which
produced floods greater
than 2m in depth in most
areas of Nhon Binh and
Nhon Phu, would produce
much deeper flooding.
+41 cm
+77 cm
+90 cm
+89 cm

14. Hydrological impacts of urbanization
Nhon Phu
Dong Da
Dieu Tri
Nhon Phu
Tuy Phuoc
Nhon Binh
⏏ Bridge
Railroad
Dike/Dike Road
Main Road
LEGEND
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If all the plans for Quy
Nhon are implemented,
floodways would be
severely narrowed,
creating the potential
for overtopping in
newly urbanized areas,
worsening flooding in
low areas of Dieu Tri
and Tuy Phuoc.
increasing risks for
people living in
floodways, and
Tuy Phuoc

15. • Manage upstream threats
• Improve flood warning and the training of community leaders
• Restore and improve drainage in the Ha Thanh River floodplain.
• Limit new residential, industrial and infrastructure development in the
floodplain of the Ha Thanh River.
Recommended actions