What is the Mullai Periyar dam dispute between Tamil Nadu and Kerala?

Mullai Periyar Dam: Built in 1895 by British; located in Kerala (Idukki district) on Periyar river; operated by Tamil Nadu under a 999-year lease agreement (1886). Water stored in Kerala diverted east through a tunnel to Tamil Nadu for irrigation (Madurai, Dindigul, Theni, Ramanathapuram districts). Dispute: Kerala wants storage level capped at 136 feet (safety concern — claims dam is old/weak); Tamil Nadu wants to fill it to 142 feet (water need). Current status: Supreme Court (2006 and 2014 judgments) allowed Tamil Nadu to store water up to 142 feet — Kerala's safety concerns addressed through strengthening measures. Kerala wants a new dam; Tamil Nadu refuses (fears water diversion). Case ongoing in SC.

What are the constitutional provisions for interstate river water disputes?

Constitutional provisions: Article 262 — Parliament may by law provide for adjudication of any dispute relating to use, distribution, or control of waters of any inter-state river or river valley; Parliament may exclude Supreme Court's jurisdiction in such disputes. Interstate River Water Disputes Act 1956 — enacted under Art 262; provides for setting up of Tribunals; SC and HC jurisdiction excluded; Tribunal award is final and binding on states; cannot be questioned in any court. Inter-State River Water Disputes (Amendment) Act 2019 — set up a permanent Dispute Resolution Committee; single Tribunal with Benches for different river disputes; strict time limits (3 years + 2 years extension for Tribunal); Disputes Resolution Committee (DRC) to first attempt amicable settlement.

What is the Krishna water dispute and how are its waters allocated?

Krishna River: Originates in Maharashtra (Mahabaleshwar); flows through Karnataka and Andhra Pradesh. Basin states: Maharashtra, Karnataka, Andhra Pradesh, Telangana (after bifurcation). Krishna Water Disputes Tribunal I (Bachawat Tribunal, 1969–1976): Allocated 2,130 TMC: Maharashtra 560 TMC, Karnataka 700 TMC, Andhra Pradesh 800 TMC. After Telangana bifurcation (2014): AP and Telangana share the 800 TMC allocated to united AP. KWDT II (Brijesh Kumar Tribunal, 2004–ongoing): Reconsidering allocation due to additional water available. Dispute: Karnataka claims it is not getting its full share; AP/Telangana claim Karnataka over-uses.

Cauvery & Interstate River Water Disputes — TNPSC Group 1 Notes

Constitutional Framework for Water Disputes

Article 262 — Interstate Water Disputes

Parliament may provide for adjudication of disputes relating to use, distribution, or control of waters of any inter-state river or river valley
Parliament may exclude Supreme Court and other courts from exercising jurisdiction
Basis: Water in Entry 17 of State List (states have primary power over intrastate water)
Entry 56, Union List: Regulation and development of inter-state rivers = Parliament (if declared expedient in public interest)

Interstate River Water Disputes Act, 1956

Enacted under Art 262
If states cannot resolve by negotiation → either state can request Central Government
Central Government constitutes a Tribunal if negotiation fails
Tribunal award = final and binding on all parties
No appeal to Supreme Court or any other court (Art 262 + Section 11 of IRWD Act)

IRWD Amendment Act, 2019

Dispute Resolution Committee (DRC): First attempt amicable resolution (1 year)
Single permanent Tribunal with multiple Benches (instead of new tribunal per dispute)
Time limit: Tribunal must give award within 3 years + 2-year extension
DRC chaired by Secretary, Ministry of Jal Shakti

Cauvery River — Complete Profile

River Statistics

Parameter	Details
Total length	765 km
Length in Tamil Nadu	~475 km
Origin	Talakaveri, Brahmagiri Hills, Kodagu district, Karnataka
Joins	Bay of Bengal at Poompuhar (Nagapattinam district)
Major tributaries	Bhavani, Noyyal, Amaravathi (from south/TN); Kabini, Hemavathi, Shimsha (from north/Karnataka)
Major dams	Krishnarajasagara (KRS) — Karnataka; Mettur Dam (Stanley Reservoir) — Tamil Nadu
Districts fed in TN	Trichy, Thanjavur, Tiruvarur, Nagapattinam, Erode, Karur, Cuddalore + others

Kallanai (Grand Anicut) Dam

Built by Karikala Chola (2nd century CE) across Cauvery near Trichy
One of the oldest water regulation structures in the world still in use
Diverts water to Cauvery delta for irrigation
UNESCO recognition for its historical engineering significance

Cauvery Water Dispute — Chronology

Year	Event
1892	First agreement — Madras Presidency + Mysore State; no new reservoirs without consent
1924	Second agreement — detailed allocation; valid for 50 years
1974	Karnataka began new reservoirs (Kabini, Hemavathi, Harangi) without renegotiating
1990	Cauvery Water Disputes Tribunal (CWDT) constituted under IRWD Act
1991	Interim Order — Karnataka to release 205 TMC to Tamil Nadu annually
1991 protests	Anti-Kannada violence in Tamil Nadu; anti-Tamil violence in Karnataka
2002	Severe drought; Tamil Nadu vs Karnataka at SC; distress releases ordered
2007	CWDT Final Award issued
2012, 2016, 2023	Repeat crises — Karnataka drought; Tamil Nadu demanding releases; SC interventions
2018	Supreme Court modified CWDT award; directed CWMA formation
2018	Cauvery Water Management Authority (CWMA) constituted

Cauvery Water Allocation — Final Award (2007) + SC Modification (2018)

State	CWDT 2007	SC 2018 (modification)
Tamil Nadu	419 TMC	404.25 TMC (reduced by 14.75)
Karnataka	270 TMC	284.75 TMC (increased by 14.75)
Kerala	30 TMC	30 TMC
Puducherry	7 TMC	7 TMC
Environmental flow	10 TMC	10 TMC
Total	736 TMC	736 TMC

TMC = Thousand Million Cubic Feet

Distress-sharing formula: In drought years, all states share reduction proportionally.

Monthly releases from Karnataka to Tamil Nadu: Specified month-wise — highest in August–October (Kharif season); lower in dry months.

Cauvery Water Management Authority (CWMA)

Constituted: June 2018 (after SC directed formation)
Under: Ministry of Jal Shakti
Functions:
Supervise and regulate water releases from Karnataka's reservoirs to Tamil Nadu
Prepare monthly release schedule
Monitor compliance with SC order
Address grievances of states
Chairman: Secretary, Jal Shakti Ministry
Replaced earlier Cauvery River Authority (CRA) (which was chaired by PM — now disbanded)

Mullai Periyar Dam Dispute (Tamil Nadu–Kerala)

Background

Parameter	Details
Dam location	Idukki district, Kerala
River	Periyar
Built	1895 (British era, by Pennefather)
Operated by	Tamil Nadu (999-year lease from 1886)
Water diverted to	Tamil Nadu — Madurai, Dindigul, Theni, Ramanathapuram districts
Current storage level	142 feet (as per SC direction)

Dispute

Kerala's position:

Dam is 125+ years old; structurally weak; safety risk
Downstream population at risk if dam bursts
Wants storage capped at 136 feet

Tamil Nadu's position:

Water stored at 142 feet — SC authorised; essential for farmers
Expert committee reports say dam is structurally sound after strengthening
Opposes new dam (fears diversion of water to Kerala)

SC Judgments

2006: SC allowed Tamil Nadu to store up to 142 feet; safety measures to be taken
2014: Three-member Supervisory Committee constituted; dam structure assessed as safe; 142 feet maintained
Case is still pending in SC (constitutional bench)

Other Major Interstate River Disputes

Krishna River

Parameter	Details
River	Krishna (1,400 km); origin — Mahabaleshwar, Maharashtra
Riparian states	Maharashtra, Karnataka, Andhra Pradesh, Telangana
KWDT I (Bachawat, 1976)	Total 2,130 TMC: MH=560, KA=700, AP=800
After Telangana (2014)	AP + Telangana share 800 TMC
KWDT II	Reconsidering; still pending final award

Godavari River

Parameter	Details
River	Godavari (1,465 km — India's 2nd longest); origin — Nasik, Maharashtra
Riparian states	Maharashtra, Telangana, Andhra Pradesh, Odisha, Chhattisgarh
Godavari Tribunal (Rajwade, 1980)	Allocated water to states; Polavaram project controversy

Narmada River

Parameter	Details
River	Narmada (1,312 km); origin — Amarkantak, MP
Riparian states	MP, Gujarat, Maharashtra, Rajasthan
Narmada Tribunal (1979)	MP=18.25 MAF, Gujarat=9 MAF, Maharashtra=0.25 MAF, Rajasthan=0.5 MAF
Controversy	Sardar Sarovar Dam height increase — displaced tribal communities; Narmada Bachao Andolan (Medha Patkar)

Ravi-Beas River (Punjab–Haryana–Rajasthan)

Parameter	Details
Issue	Sutlej-Yamuna Link (SYL) Canal — Haryana demands its share of Ravi-Beas waters
Status	Punjab terminated its agreement; SC directed construction; Punjab resistance continues
Political sensitivity	Punjab water rights; farmers' protests

Mahanadi River (Chhattisgarh–Odisha)

Chhattisgarh building barrages upstream; Odisha claims reduced flow downstream
Tribunal constituted 2018; ongoing

Key Concepts

Riparian Rights

Upper riparian state: Upstream — controls flow by building dams, diverting water
Lower riparian state: Downstream — dependent on upper riparian's actions
In most TN disputes: TN is the lower riparian (Karnataka upper for Cauvery; Kerala upper for Periyar)

Interlinking of Rivers

National Perspective Plan (1980): Propose linking 30 rivers (14 Himalayan + 16 peninsular)
Ken-Betwa Link: First inter-linking project; approved 2021; MP to UP
Tamil Nadu's interest: Peninsular interlinking — Karnataka rivers to TN could ease water shortage
Criticism: Environmental disruption; displacement; limited evidence of water surplus

Board Exam Tips — Water Disputes

Art 262 = Inter-state water disputes; Parliament can exclude SC jurisdiction
IRWD Act 1956 = Tribunal awards final; no SC appeal
Cauvery origin = Talakaveri, Kodagu, Karnataka; joins Bay of Bengal at Poompuhar
CWDT Final Award (2007): TN=419 TMC; SC 2018 modified to TN=404.25, KA=284.75 TMC
CWMA = Cauvery Water Management Authority; constituted June 2018; under Jal Shakti Ministry
Kallanai (Grand Anicut) = built by Karikala Chola (2nd century CE); still in use
Mullai Periyar: In Kerala; operated by TN; 142 feet storage level (SC authorised); 999-year lease
Mettur Dam (Stanley Reservoir) = TN's major Cauvery dam; Erode/Salem district
Krishna KWDT I = Bachawat Tribunal (1976); TN is NOT a riparian state of Krishna
Narmada = Sardar Sarovar controversy; Narmada Bachao Andolan (Medha Patkar)
SYL Canal = Punjab-Haryana-Rajasthan Ravi-Beas dispute; still unresolved

Frequently Asked Questions

Cauvery River (765 km total, 475 km in Tamil Nadu) originates at Talakaveri, Kodagu, Karnataka. Four riparian states: Karnataka (upper riparian), Tamil Nadu (lower riparian), Kerala, Puducherry. Dispute history: 1892 — first agreement between Madras Presidency and Mysore State; 1924 — second agreement (50-year deal); 1974 — Karnataka began Kabini, Hemavathi reservoirs without consent; Tamil Nadu demanded renegotiation. CWDT (Cauvery Water Disputes Tribunal): Constituted 1990; Final Award 2007: Total allocation 740 TMC (Thousand Million Cubic Feet): Tamil Nadu 419 TMC, Karnataka 270 TMC, Kerala 30 TMC, Puducherry 7 TMC, environmental flow 10 TMC. Supreme Court 2018: Modified Karnataka's allocation slightly upward by 14.75 TMC; directed formation of Cauvery Management Board (CMB) — renamed Cauvery Water Management Authority (CWMA). CWMA constituted in 2018 — permanent body to implement the final award.