Storage dam
Ratchaprapha Dam
เขื่อนรัชชประภา
Ratchaprapha Dam is a storage dam on the Phum Duang River in Ban Ta Khun District, Surat Thani province. Its reservoir holds 5,639 million m³. It was completed in 1987 and is run by the Electricity Generating Authority of Thailand (EGAT). Commonly called the Chiew Larn Dam. It dams Khlong Saeng, a tributary of the Phum Duang River.
Reservoir storage today
74.9% of capacity at normal storage level
- Water in the reservoir
- 4,223 million m³
- Usable water
- 2,871 million m³ (67% of usable capacity)
- Inflow
- 6.8 million m³ a day
- Released
- 7.9 million m³ a day
As of 14 Nov 2026 Data from the National Hydroinformatics Data Center (ThaiWater), HII, refreshed every 10 minutes
Storage this year and last
Down 16.7 million m³ over the last 7 days
268 million m³ less than on the same day last year
- 2026
- 2025
- Normal storage 5,639 million m³
- Upper and lower rule curves
Daily storage from the National Hydroinformatics Data Center (ThaiWater). The rule curves are the range the dam is meant to be kept within through the year.
Try the reservoir
Change the inflow, the release and the rain over the dam's catchment, and see what the reservoir would do over the next 90 days, starting from today's figures.
The reservoir would hardly change
Over the next 90 days the reservoir reaches neither normal storage, a rule curve nor dead storage
In 90 days it would hold about 4,118 million m³ (73% of capacity)
- Actual storage
- Projected
- Normal storage
- Upper and lower rule curves
- Dead storage
Today's storage, plus the inflow and the rain that runs in, less the release, a day at a time; evaporation and seepage are left out. It is arithmetic on the figures you set, not a forecast.
Key facts
- River
- Phum Duang River
- Location
- Ban Ta Khun District, Surat Thani province
- Coordinates
- 8.9727, 98.8068
- Reservoir capacity
- 5,639 million m³
- Maximum capacity
- 6,144 million m³
- Dead storage
- 1,352 million m³
- Dam height
- 95 m
- Dam type
- Rockfill dam
- Installed power capacity
- 240 MW
- Completed or opened
- 1987
- Operator
- Electricity Generating Authority of Thailand (EGAT)
Maximum capacity and dead storage from the Royal Irrigation Department
Frequently asked questions
- Where is Ratchaprapha Dam?
- Ratchaprapha Dam is in Ban Ta Khun District, Surat Thani province.
- What is the water level of Ratchaprapha Dam today?
- Ratchaprapha Dam is 74.9% full, holding 4,223 million m³, as of 14 Nov 2026.
- How much water can Ratchaprapha Dam hold?
- The reservoir of Ratchaprapha Dam holds 5,639 million m³.
- When was Ratchaprapha Dam built?
- Ratchaprapha Dam was completed and opened in 1987.
- Who runs Ratchaprapha Dam?
- Ratchaprapha Dam is run by the Electricity Generating Authority of Thailand (EGAT).
- What is the Ratchaprapha Dam called in Thai?
- In Thai the Ratchaprapha Dam is เขื่อนรัชชประภา.