SMORWAT a system for monitoring small-scale water sources using satellite data – is designed to cope with a “Super El Niño” as a tool for sustainable water management.

Currently, Thailand is confronting climate change impacts, including the Super El Niño, which is expected to emerge in mid-2026 and continue into 2027. It is predicted that Thailand may experience higher temperatures, reduced rainfall, and drought conditions in various areas, all of which will affect water management. In particular, water availability is essential for consumption, livelihoods, and people’s quality of life.

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However, an accurate identification of water availability is a significant factor in sustainable water management and in coping with potential disasters, including floods and droughts.

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Dr. Thitawadee Suwajananon, a Geo-informatics Scientist, at Geo-Informatics and Space Technology Development Agency (Public Organization), or GISTDA, explained that water sources in Thailand are currently classified into three categories according to the criteria of the Office of the National Water Resources (ONWR). Large water sources have a capacity of more than 100 million cubic meters, medium-sized water sources have a capacity between 2 and 100 million cubic meters, and small water sources have a capacity of less than 2 million cubic meters.

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Nevertheless, large and medium-sized water sources such as dams and reservoirs are managed by responsible organizations, including the Royal Irrigation Department and the Electricity Generating Authority of Thailand (EGAT). Therefore, estimating water volume for overall water management is relatively straightforward. However, small water sources are widely distributed across the country and are the closest source of water for local communities and agricultural areas, making ground surveys of every pond is therefore nearly impossible.

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To address the limitation of small water source monitoring mentioned above, GISTDA has applied space-based technology to develop the Satellite-Based Small Water Source Monitoring System (SMORWAT). The system is designed to monitor water sources with an area of more than 2 rai (or 3,200 sq.m.) and a storage capacity not exceeding 2 million cubic meters.

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The development of SMORWAT began around 8-9 years ago, when GISTDA sought to apply satellite technology to analyze water volume in small water sources as part of a nationwide water resource assessment. In the initial phase, the project involved collaboration with partner organizations such as the Ministry of Interior and the Office of the National Water Resources (ONWR), which supported field operations and primary data collection before satellite data and mathematical models were used to analyze water volume. The system was continuously verified for accuracy through field measurement and cross-checking with other monitoring technologies.

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The main process of this system is to identify the location and shape of water sources using medium-to-high-resolution satellite data, with a spatial resolution of  50 centimeters or finer. This allows objects larger than 50 centimeters to be clearly detected, enabling the identification of the boundaries and shape of small wells found throughout the country.

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Are water sources still being used as water resources? To assess this, satellite data in the near infrared spectrum are utilized to distinguish between vegetation and water bodies, allowing analysis of whether water sources still exist or have been converted into other utilizations such as agricultural areas. For water volume monitoring, GISTDA applies a technique called Interferometric Synthetic Aperture Radar (InSAR), an advanced remote sensing technology used to detect differences in water volume over time and determine whether water levels have increased or decreased.

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However, satellites can not directly measure water depth. Therefore, water volume is estimated using a mathematical model. This system integrates satellite data with depth data collected in collaboration with partner organizations, as well as hydrological and meteorological data, such as rainfall records. It also applies methods such as THUDCHAI’s Method for estimating water volume. Furthermore, the system is accurately verified using water volume sensors installed by GISTDA and distributed across the country. It also incorporates the WatRec application for officials to explore small water resources, as well as Geo Caching application for the public to report data from real locations, enabling direct data validation and model refinement.

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Dr. Thitawadee explained that various data sources are integrated to analyze and evaluate water condition in small water resources biweekly through the website  https://water.gistda.or.th. The dashboard presents  multi-scale information, from national to local levels. It also provides map-based visualization, a graph, and an API for other organizations and interested users to access and utilize the data in different formats. In addition, the data can be reviewed retrospectively over a selected time period or spatial scope.

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All data from the system can be used to more efficiently evaluate long-term trends in water volume across water management systems, as well as improve short-, middle-, and long-term water availability forecasting for continuous water management in both rainy and dry seasons. Furthermore, it can identify drought risk  areas for tracking and monitoring purposes.

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Currently, data from the SMORWAT system is sent to the ONWR, the main government organization for national water management policy.

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For monitoring small water resources in the present, a comparison  with the same period 2-3 years ago confirms a decrease in water volume, consistent with data indicating more frequent drought conditions and reduced soil moisture. Based on these three datasets, it is not surprising that, even though the rainy season has begun, many relevant agencies are becoming more alert and preparing to cope with a potential drought that may differ from previous patterns, possibly driven by Super El Niño.