22/11/2025
ENGINEERING RECOMMENDATION
Proposed 14-Meter Flood Wall System and Elevated Esplanade for Tuguegarao City
By: Flood Control & Hydrologic Risk Specialist
The extreme flooding brought by Super Typhoon Uwan has once again highlighted the vulnerability of Tuguegarao City to large-scale inundation from the Cagayan River. Based on hydraulic modeling, satellite analysis, and post-disaster assessments, a 14-meter High Flood Wall remains the most effective long-term structural solution to protect the regional capital from catastrophic flooding.
1. Rationale for a 14-Meter Flood Wall
The Cagayan River experiences sudden and extreme water level surges during strong typhoons, compounded by massive upland runoff and dam releases. Similar to Japan’s tsunami mitigation walls built along coastal prefectures, a high, continuous barrier can prevent river water from overtopping into densely populated barangays.
A 14-meter elevation is recommended because:
Flood heights during Super Typhoon Uwan and Typhoon Ulysses approached 12–13.3 meters in critical zones.
Future typhoons may produce even higher water surges due to climate-driven rainfall intensification.
This height provides a safety buffer to prevent overtopping during extreme events.
It serves as protection in the highly unlikely but devastating scenario of a Magat Dam failure, which could generate a tsunami-like flood wave.
2. Proposed Alignment and Priority Segments
The structural flood wall should run along the most vulnerable stretch of the Pinacanauan River to Cagayan River corridor:
• Starting at Barangay Tanza
High risk due to river backflow from Cagayan River to Pinacanauan River.
• Through Barangay Centro 10
One of Tuguegarao’s lowest points and historically among the first to submerge.
• Extending to Cataggaman District to Linao District in Tuguegarao City
A portion of Cataggaman has already been cut away by river erosion, indicating the urgent need for both:
14-meter flood wall, and Comprehensive Riverbank Protection (revetment, soil nailing, sheet piling, riprap, geotextile reinforcement).
3. Benefits of a 14-Meter Flood Wall System
A. Flood Protection
Shields 100,000+ residents in low-lying barangays.
Protects homes, hospitals, schools, utilities, and business districts.
Prevents repeat of “Ulysses and Uwan-level” devastation.
B. Tsunami-Like Flow Protection (Dam Break Scenario)
While a Magat Dam collapse is unlikely, engineering ethics requires preparedness.
A 14m wall would dramatically reduce fatalities by blocking or deflecting a sudden surge.
C. Riverbank Stabilization
Prevents lateral river expansion.
Protects agricultural and residential zones from being eaten away by river migration.
Reduces annual spending on emergency riprap and temporary repairs.
D. Long-term Resilience Infrastructure
A flood wall is a 50- to 100-year structure, far more cost-effective than repeated post-typhoon rehabilitation.
Enables urban development without fear of annual destruction.
4. Supporting Evidence
The before-and-after flood images and satellite views of the Cagayan River overflow during Super Typhoon Uwan clearly show:
● Massive overbank flooding breaching natural levees.
● Loss of entire land sections in Cataggaman.
● Multiple barangays submerged beyond safe levels.
● Hydrologic patterns showing increasing severity year after year.
The data confirms that conventional solutions—dredging—are no longer enough for Tuguegarao City.
5. Recommendation Summary
To safeguard Tuguegarao City’s future, the following must be prioritized:
✔ Construction of a Continuous 14-Meter Flood Wall
From Tanza → Centro 10 → Cataggaman to Linao District
✔ Reinforced Riverbank Protection
Especially for Cataggaman where erosion is already severe.
✔ Integration with Early Warning Systems
Including sensors to monitor real-time water levels and dam releases.
✔ Multi-agency Collaboration
DPWH, LGUs, NIA-Magat, DENR, and private hydrologic firms must work as one.
Image Sources:
A. FLOODING IN TUGUEGARAO
📧 [email protected]
🌐 www.geospectrum.com.ph
📸 Geospectrum Marketing Services
B. FLOODING IN CAGAYAN
Here's a comparison of the satellite imagery showing the situation in Tuguegarao City, Cagayan before (September 19, 2020), and after (November 13, 2020) the flooding.
Image Courtesy of Ley Meynard Opeña
Source: EOS-Landviewer
Change Detection Using Landsat-2 L2A
C.The flood maps using different DEM data in Tuguegarao city. (A) Copernicus DEM GLO-30 with 30 m resolution. (B) IfSAR DEM with 5 m resolution. The red circles represent the flooded houses. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article. at https://www.sciencedirect.com/science/article/pii/S221242092400829X)
