Practical Urban Water Tools for Flood Risk Reduction in Asian Coastal Cities

Challenge

Coastal cities need reliable ways to monitor storms and runoff, assess flood and water quality risks, and choose measures that work on the ground.

Solution

Integrate on-the-ground sensors, online models, and clear plans so agencies can track storms, test options, and reduce flood and water quality risks.

Overview

Coastal cities in Asia face frequent flooding, polluted runoff, and aging drainage systems. With support from the Asia-Pacific Network for Global Change Research (APN), Bin He (Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, China) led a project that linked real-time monitoring, modeling, and planning in Sri Lanka, China, and Thailand, with Japan contributing additional training and methods support.

The project coupled real-time observation with analysis and planning so that city engineers and local agencies could act before and during storms. An Internet of Things (IoT) platform on Google Cloud retrieved real-time sensor data at roughly 15–30 second intervals, archived it in an online database, and provided live graphs and warnings via the EnviForecasting server. Data fed three cloud databases – observations, forecast simulation, and impact analysis – for retrieval by users.

For forward-looking risk, the project applied climate projections at the city scale to examine how heavier rainfall can shift future flood and water quality patterns. Hydrological and river water quality models were used to assess sediment and nutrient changes and to guide practical plans for flood risk mitigation and water quality improvement. The study team applied and downscaled the latest CMIP6 SSP scenarios in three study cities to assess future rainfall-driven changes in flooding and water quality.

To support drainage design and training, the project deployed the Storm Water Management Model (SWMM) online with a simple interface and paired it with an infiltration-storage model. A digital twin of a real catchment lets users test infiltration-system layouts to reduce storm-runoff and assess the benefits of nature-based solutions. Videos and course materials were prepared to build skills and apply the tools in real settings.

Methods and tools

MiSOILiE weather stations were documented for low-cost deployment and integration with the EnviForecasting server; partners could view last-hour, 12-hour, and 24-hour plots, download tables, and access JSON via the API. A generalized setup and configuration guide was produced, along with a flooding and water‑quality index manual and an awareness booklet.

Country workstreams

China

An experiment base was built in Guangzhou with laboratory and analytical equipment for applied urban-water modeling and training. An online SWMM course trained postgraduate students from three Chinese universities, taught by professors from Sri Lanka and Japan.

Sri Lanka

A real-time dashboard for the Kelani River basin and Metro Colombo used data from 50 weather stations and more than 45 water‑level measuring devicesto show rainfall, water levels, and recent extremes. The dashboard displayed basin and city rainfall and water‑level summaries, with time‑series views and recent extremes to track rising water. Real‑time observations provided lead time for riparian flood management, while improved weather forecasting accuracy was flagged as necessary for city flood prevention.

Thailand

A flood-analysis case study in Hua Wiang Municipality, Ayutthaya Province used satellite data to identify repeatedly flooded areas and assess community vulnerability. Collaboration with Kasetsart University supported methods and outreach; SWMM training for postgraduate students was delivered online by instructors from Sri Lanka and Japan. The project also summarized Thailand’s flood-related health impacts, highlighting physical, mental, and community health effects and lessons from major flood events.

Policy and training

Training materials, manuals, and awareness booklets explained how to use the monitoring and modeling tools in daily work. Short courses and workshops supported city engineers and students to read real-time maps and graphs, run online models, and test infiltration and storage options for runoff reduction. The objectives were to improve early warning and guide investments in infiltration systems, maintenance, and operations.

Outcomes and results

• Systems and resources: Built 1 IoT real-time monitoring system, developed 1 online system for continuous monitoring, analysis, and visualization, constructed 1 experiment base in Guangzhou with laboratory equipment, and updated 1 platform and 1 database on the project webpage.
• Databases: Maintained 3 cloud databases for observations, forecast simulations, and impact analyses to support direct sensor transmission and user retrieval.
• Early warning: Real-time hydrology dashboard for the Kelani basin and Metro Colombo with rainfall and water-level summaries, time-series inspection, and recent extremes; findings emphasize coupling observations with improved weather forecasting for city-scale prevention.
• Planning tools: SWMM deployed online with an easy-to-use interface and coupled with an infiltration–storage model; a digital twin let users test infiltration configurations and quantify runoff-reduction benefits from nature-based solutions.
• Engagement and field work: 30 events, including 6 field trainings in China (50 early-career professionals trained), 2 virtual trainings, 5 field trips, 3 field-monitoring systems installed, 12 focus-group discussions, 2 socio-economic surveys, and 4 conferences or symposium sessions where the platform and outcomes were presented.
• Publications and materials: 22 publications produced (17 journal articles, 3 books, 2 reports including this final report), plus a flooding and water‑quality index manual and an awareness booklet.

Project details

Acknowledgements

This project was supported by the Asia-Pacific Network for Global Change Research (APN) under its Collaborative Regional Research Programme (CRRP). Acknowledgements also go to North China Electric Power University (China); Center for Urban Water (Sri Lanka); University of Peradeniya (Sri Lanka); Kasetsart University (Thailand); University of the Ryukyus (Japan).