Hai Phong — IntelliWhere Flood Risk

📍 District Detail

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Tap any district on the map to see its risk breakdown.

📊 Score Evidence

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Do Son

Very High — 5/5

Coastal peninsula at ~2m elevation, directly exposed to the Gulf of Tonkin. No natural barrier. Hai Phong's most typhoon-vulnerable urban zone.

Verified Incidents

Typhoon Mirinae (2009): 3m storm surge submerged the peninsula. 45,000 residents evacuated. — ReliefWeb UN OCHA.

Coastline lost 50–80m of beach over 20 years, reducing natural surge buffer.

MARD 2021 audit: Do Son dike systems rated sub-standard for Category 3+ typhoon loading.

Hai An (Port Zone)

Very High — 5/5

Hosts Hai Phong's primary container port at 2m elevation. Sits in the storm surge pathway from the Van Uc river mouth.

Verified Incidents

Typhoon Son Tinh (July 2018): port gates overtopped, 12,000 homes flooded, operations suspended 48 hours. — VnExpress, July 2018.

River surge + direct coastal surge arrive simultaneously, doubling peak water levels.

Tien Lang

Very High — 5/5

Hai Phong's lowest-lying district at under 1.5m average elevation. First to flood when any of three river branches overflow.

Verified Incidents

2008 Red River flood: inundated 3–7 continuous days, 60% of farmland lost.

2017 flood: secondary dikes overtopped, district isolated. — UNDP Vietnam 2019.

Duong Kinh

Very High — 5/5

Natural funnel between Do Son peninsula and Lach Tray river outlet for converging storm surge.

Verified Incidents

Typhoon Haiyan (2013): surge propagated inland. MARD 2021: dikes inadequate for 100-year storms.

Tidal flooding occurs 15–20 days per year during spring tides — worsening annually.

Hong Bang

High — 4/5

Historic urban core with dense development and ageing drainage infrastructure.

Verified Incidents

August 2022: 200mm in 6 hours — 40% of streets flooded, 1,500 homes affected. — Tuoi Tre, 2022.

Designated priority drainage upgrade zone in Hai Phong City Flood Management Plan 2023.

Cat Hai Island

High — 4/5

Accessible only by ferry. Post-storm isolation creates unique risk not captured by standard insurance.

Verified Incidents

Typhoon Bebinca (2024): 3,200 evacuated, ferry suspended 72 hours. — VnExpress, 2024.

Assets unreachable by adjusters or emergency crews for 2–5 days post-typhoon.

Vinh Bao

High — 4/5

Rural district at the confluence of multiple river branches. Flooded in 7 of the last 10 years.

Verified Incidents

October 2017: Vinh Bao isolated for 5 days. 8,000 residents displaced. All three access routes severed. — ReliefWeb, October 2017.

Thuy Nguyen

Medium — 3/5

Main industrial zone with moderate physical flood risk but elevated environmental liability post-flood.

Risk Basis

Physical risk: moderate — elevated terrain (5m) limits direct inundation frequency.

Liability risk: high — post-flood runoff has contaminated adjacent agricultural land.

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🔍 Interpretation

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How to read this map

Each coloured polygon represents one of Hai Phong's administrative districts. Colour signals flood risk. A small red district is more dangerous than a large yellow one.

Polygon colourReflects the combined score (1–5) from elevation, water proximity, typhoon history, and infrastructure ratings.

Tap any districtOpens a popup with the verified incident that justifies the score — a real recorded event with source citation.

Suitable vs. unsuitable zones

✓ Suitable

Kien An, Thuy Nguyen, An Duong — elevated terrain, manageable seasonal exposure. Standard development with normal insurance.

⚠ Conditional

Hong Bang, Le Chan, Ngo Quyen — urban core with drainage constraints. Viable only with flood-resilient design.

✕ Unsuitable

Do Son, Hai An, Tien Lang, Duong Kinh — direct coastal surge paths or delta flooding. High-value development not recommended without major mitigation.

Mitigation priorities

Dike reinforcementDo Son, Duong Kinh — MARD 2021: dike systems sub-standard for Category 3+ typhoon loading.

Drainage upgradeHong Bang, Le Chan — legacy networks overwhelmed at 80mm/hr. Investment required before densification.

Elevation compensationTien Lang, Vinh Bao — new construction should be raised minimum 1.5m above current grade.

📌 Risk Implications

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For lenders & MICs

Collateral impairmentProperties in Very High zones carry documented flood damage histories. Values may not reflect latent flood liability.

LTV adjustmentStandard 70–80% LTV is inappropriate for Very High districts without flood insurance confirmation. Recommend 55–65% cap.

Portfolio concentration30%+ of portfolio in Very High districts creates correlated risk — a single typhoon can trigger simultaneous defaults.

For insurers

Single-peril gapStandard policies cover river overflow OR storm surge — not both simultaneously. Five districts face compound events. This gap is not priced.

Island isolation premiumCat Hai assets require a post-event accessibility surcharge. Adjusters cannot reach these districts for 2–5 days post-typhoon.

Industrial liabilityThuy Nguyen floods spread contaminants into adjacent agricultural land, creating third-party liability claims beyond the insured boundary.

For developers

Design standardsConstruction in High or Very High zones must reference Vietnam MARD flood resilience guidelines. Raised foundations non-negotiable in red zones.

Permit riskVietnam's National Climate Change Strategy (2021) signals tightening controls in coastal flood zones over 20-year horizons.

👥 Recommendations

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For insurers

Immediate actions

• Require compound flood cover (surge + river overflow) for all new commercial policies in Very High districts
• Add Cat Hai island isolation rider to all policies there
• Commission elevation surveys for policies above $500K USD in red zones

Portfolio strategy

Apply a 25–35% premium loading in Very High districts vs. Medium districts. Tien Lang and Duong Kinh are currently underpriced relative to documented loss history.

For developers

Site selection priority

1. Kien An & Thuy Nguyen — lowest flood exposure
2. An Duong — residential viable with standard drainage
3. Ngo Quyen — viable with drainage investment
4. Avoid Very High districts without major dike works

For lenders / MICs

Underwriting policy

• Very High: flood insurance confirmation + independent appraisal required
• High: flood risk disclosure; cap LTV at 65%
• Medium: standard underwriting with annual review
• Flag portfolio concentration above 20% in any single risk tier

For local government

Infrastructure priority

1. Do Son & Duong Kinh dike upgrade — highest return on risk reduction
2. Hong Bang & Le Chan drainage modernisation
3. Cat Hai pre-positioned emergency supply depot
4. Tien Lang managed retreat planning

Informational guidance only. Does not constitute legal, engineering, or financial advice. Contact intelliwhere@gmail.com for a site-specific assessment.

🏙️ City Context

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Why Hai Phong floods

Hai Phong sits at the mouth of the Red River Delta where Vietnam's largest river system meets the Gulf of Tonkin. Most urban areas sit just 1–4 metres above sea level. Three flood mechanisms converge simultaneously:

Typhoons — The Gulf of Tonkin is one of Asia's most active typhoon corridors. Storms funnel directly toward Hai Phong's coast.

River overflow — The Thai Binh and Van Uc rivers drain the entire northern highlands and back up into low-lying districts after monsoon rain.

Storm surge — Typhoon winds push seawater inland. A 1m surge typical in a Category 2 storm inundates most of the urban core.

Historical impact

14 significant typhoons within 100km of Hai Phong between 1990 and 2024 (NOAA IBTrACS)

45,000 evacuated during Typhoon Mirinae (2009) — Do Son peninsula submerged under 3m surge

12,000 homes flooded in Hai An during Typhoon Son Tinh (2018) — port gates overtopped

$4M+ USD crop loss in An Lao when Thai Binh River dikes failed 2017 (FAO Vietnam)

Climate trajectory

Sea level rise of 20–30cm by 2050 projected for the Red River Delta coast (UNDP Vietnam 2019)

Typhoon intensification: storms reaching higher wind speeds faster due to warmer sea temperatures

Monsoon rainfall increasingly concentrated into shorter, more intense events — overwhelming legacy drainage

Key incident timeline

2005Thai Binh River dike breach — An Lao flooded

2009Typhoon Mirinae — 45,000 evacuated, 3m surge Do Son

2017River flood — Vinh Bao 8,000 displaced, $4M crop loss

2018Typhoon Son Tinh — Hai An port overtopped, 12,000 homes

2022200mm rainfall — Hong Bang 1,500 homes flooded

2024Typhoon Bebinca — Cat Hai evacuated, 72hr ferry cutoff

Data sources

OpenStreetMap · NASA SRTM 30m · NOAA IBTrACS · ReliefWeb / UN OCHA · FAO Vietnam · Vietnam MARD · VnExpress · Tuoi Tre · UNDP Vietnam 2019

Prepared by Ryan Nguyen, B.Eng Geomatics Engineering (EIT) — intelliwhere@gmail.com