---
title: "Periyar River: Kerala's Longest River (UPSC GS1)"
description: "The Periyar River, Kerala's longest at 244 km, is crucial for UPSC GS1 due to its role in dams and inter-state disputes."
url: "https://modeldiplomat.com/learn/glossary/periyar-river"
---

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Model Diplomat Research Team · Last reviewed June 22, 2026

TL;DR

- The Periyar is the longest river in Kerala, flowing westward for about 244 kilometres from the Western Ghats to the Arabian Sea.
- Why is the Periyar called Kerala's lifeline?
- How does the Mullaperiyar Dam dispute differ from the Kaveri dispute?
- Why does Periyar water flow eastward into Tamil Nadu?
- What role did the Periyar play in the 2018 Kerala floods?

[Civil Service & Diplomatic Exams](https://modeldiplomat.com/learn/civil-services/glossary)Updated June 22, 2026

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In its May 2014 judgment in State of Tamil Nadu v. State of Kerala, the Supreme Court of India upheld the 1886 Periyar lease and allowed the Mullaperiyar reservoir level to be raised to 142 feet.

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