 | This article needs additional citations for verification. (January 2021) |
| Pa Sak River (แม่น้ำป่าสัก) | |
|---|---|
 The Pa Sak River flowing east of Ayuttaya's old city | |
 | |
| Location | |
| Country | Thailand |
| Physical characteristics | |
| Source | |
| • location | Phetchabun Mountains |
| Mouth | |
• location | Chao Phraya River at Ayutthaya Island |
| Length | 513 km (319 mi) |
| Basin size | 16,291 km2 (6,290 sq mi) |
| Discharge | |
| • average | 2.4 km3 (0.58 cu mi)/yr |
The Pa Sak River (Thai: แม่น้ำป่าสัก, RTGS: Maenam Pa Sak, IPA: [mɛ̂ːnáːm pàː sàk], Pronunciation) is a river in central Thailand. The river originates in the Phetchabun Mountains, Dan Sai District, Loei Province, and passes through Phetchabun Province as the backbone of the province. It then passes through the eastern part of Lopburi Province and Saraburi Province, until it joins the Lopburi River northeast of Ayutthaya Island, before it runs into the Chao Phraya River southeast of Ayutthaya near Phet Fortress. It has a length of 513 km (319 mi) and drains a watershed of 16,291 km2 (6,290 sq mi). The annual discharge is 2.4 km3 (0.58 cu mi).
The valley of the Pa Sak through the Phetchabun mountains is a dominant feature of Phetchabun Province. Water levels vary seasonally. To address drought problems in the lower Pa Sak valley, in 1994 the construction of the Pa Sak Cholasit Dam (เขื่อนป่าสักชลสิทธิ์) in Lopburi Province was built. The 4,860-meter (15,940 ft) wide and 36.5-meter (120 ft) high dam retains 0.785 km3 (0.188 cu mi) of water. The dam also supplies about 6.7 MW of electricity.