Phân tích rủi ro bờ biển Nam Ô Đà Nẵng

Nam O Resort Development, Da Nang, Vietnam Flood Risk Study Interim Report Rev01 10 August 2017... Peak storm surge occurs with high tide  Highest measured water level Maximum Water Le

Nam O Resort Development,

Da Nang, Vietnam

Flood Risk Study

Interim Report Rev01

10 August 2017

Flood Risk Levels at Coastline

3 M

DaNang Tide Table

Month HHWL LLWL Jan 0.5 -0.5 Feb 0.4 -0.5 Mar 0.3 -0.5 April 0.3 -0.5 May 0.4 -0.6 June 0.3 -0.6 Jul 0.3 -0.7 Aug 0.4 -0.6 Sep 0.5 -0.4 Oct 0.7 -0.2 Nov 0.7 -0.3 Dec 0.6 -0.3

Mean Sea level +0 mND

MLLW -0.4 m ND

Site

Son Tra StationStudy Site and Son Tra Station

5 Measured Water Level (1980-2014)

Son Tra Station – Annual Maximum Water Level

Peak storm surge occurs with high tide  Highest measured water level

Maximum Water Level vs Storm Surge

 Use of historical typhoon tracks

1986 to 2016 (30 Years)

 40 Selected Typhoons to generate

the storm surge near site

Simulated Wave Height during passage of Typhoon Haiyan 2013

Historical Typhoon Tracks hitting Vietnam

Storm Surge Modelling

Climate Change Impact to Central Vietnam

• Based on Climate Change and Sea Level Rise in

Vietnam, published by MONRE 2009

Dựa trên Báo cáo Biến đổi Khí hậu và Nước biển dâng tại Việt Nam của Bộ

TNMT ban hành năm 2009

Climate Change and Sea Level Rise in Vietnam, MONRE 2009

Báo cáo Biến đổi khí hậu và Nước biển dâng tại Việt Nam của Bộ TNMT ban hành năm 2009

Scenario

Mực nước biển dâng so với năm 1990

Medium emissions B2

High emissions A1FI

Climate Zone

Vùng khí hậu

Changes in Annual Rainfall (%) relative to 1990

Thay đổi về Lượng mưa (%) so với năm 1990

 Based on MONRE (2009), the projected Sea Level Rise in

Vietnam is about 0.30 to 0.33 m at Year 2050

 Suggest 100-year Flood Risk Level to be +2.52 mND

(=2.19+0.33)

 Assuming the freeboard (safety margin) for any drainage

channel/culvert is 0.3m along the coast, the site formation level near the coastline is suggested at +2.82mND, say +3.0mND

Flood Risk and Site Formation Levels

100 year flood level

100 year flood level+SLR

Mean Higher High Water Level

Mean Lower Low Water Level

Invert

Flood Risk and Site Reclamation Levels

Flood Risk Levels along Cu De River

Cu De River Basin

Basin Area: 413.7 Km 2

Historical Flood Events

Year Flood Peak (m 3 /s)

Source: Report on Hydrologic and Hydraulic Calculation of Cu De River Basin,

Environment Research and Protection Centre of Da Nang University, 09/2012

Site

Cu De River and Cross-sections

-8 -6 -4 -2 0 2 4 6

CuD e Pla n: With ou t_1 00 yr 0 9/0 8/2 01 7

Ba nk Sta

-1 0 -8 -6 -4 -2 0 2 4 6 8

-1 0 -5 0 5

Ba nk Sta

Chainage 0+110

Chainage 0+315 Bridge

WL=+2.52 mND

 The flood flow from Cu De River will increase the flood risk

level along the study site; the larger the flood flow the higher

the flood risk level

 With a moderate flood flow, say 2300m3/s in 2010, the flood

risk level will be increased to +2.8mND at the site

 If a flood flow of 4600m3/s in 2090 hits the study site at the

same time with the 100year storm surge, the flood risk level

could go to +4.4mND at the study site However, we consider that this case is unlikely to happen

 Hence, we suggest that the 100-year Flood Risk Level near the river mouth will be around +2.8 mND, say +3.0 mND

Flood Risk Levels

Flood Risk Area under +3 mND

 Based on our flood risk level assessment, the minimum site formation level near the river mouth could be +3mND;

however the inland area may be needed to be filled up to

+4mND depending on the drainage strategy to be adopted in this area

 It should also be noted that in the “Amended Comprehensive Master Plan 2030 of Danang City – A Vision to 2050”, the

urban area along Cu De River shall be constructed with

minimum ground level of +3.84m with frequency P= 2%

 The final site formation levels at Nam O Resort will be

determined probably in an iteration process with the evolving masterplan layout and drainage strategy to be adopted for the masterplan

Site Formation Levels

Fill Volume

Potential fill area up to +3mND

Estimated fill volume: 209,000 m3

Potential fill area up to +4mND Estimated fill volume: 368,000 m3

Thanks