Idukki

Idukki district · KSEB · Periyar basin · report 18 Sep 2026, 11:00 IST

Storage

61.0%

Previous 61.1%

Water level

721.42 m (2366.9 ft)

FRL 732.43 m (2403.0 ft)

Spillway release

—

Latest report

Rain forecast

11 mm

Next 72h 37 mm

Storage & water level — last 30 days

Risk breakdown

Flood risk26

Landslide risk13

Reservoir stress52

Watershed saturation10

River overflow12

• Level 721.42 m is below the blue alert level of 726.81 m

Rate of rise(derived)

-0.18 ft / 24 h

Downstream exposure

Periyar below Cheruthoni / Idukki towards Lower Periyar and Neriamangalam

Local bodies on this reach: Vazhathoppu, Konnathady, Vellathooval, Neriamangalam, Kuttampuzha

District control room: 1077 / 04862-233111

Rule curve — seasonal operating target

Revised after the August 2018 Kerala floods

Target today

92%

Actual storage

61.0%

Against curve

-31.2 pts

May 20 — Pre-monsoon minimum — maximum flood cushion (indicative)
Jul 10 — Confirmed KSEBL checkpoint: 82 % full, 18 % cushion retained (confirmed)
Nov 1 — End of north-east monsoon filling (indicative)
Basis: % of gross storage.
Provenance: Post-2018 revised operating practice. The 10 July checkpoint — reservoir held at 82 % of gross storage, i.e. an 18 % flood cushion — is the confirmed KSEBL value; the rest of the curve is an indicative shape derived from the published seasonal operating pattern, not an official table.
2018 trace — Reconstructed from KSEBL daily reservoir bulletins for the 2018 south-west monsoon (gross-storage %). The 9 August spillway opening at Cheruthoni is the confirmed event; intermediate points are indicative daily readings, not an official series. Peak: 2018 peak — reservoir at full reservoir level, all shutters in operation.
2019 trace — Reconstructed from KSEBL daily reservoir bulletins for the 2019 south-west monsoon (gross-storage %). Indicative daily readings held for comparison with 2018; not an official series. Peak: 2019 season high — no emergency spill required.

Rainfall forecast — next 48 hours

Spillway releases

Current weather at the dam

Temperature: 21.7°C
Humidity: 97%
Rain 24h: 11.7 mm
Wind: 6 km/h
Gusts: 15 km/h
Pressure: 934 hPa

AI analysis

Idukki is at no alert level, with storage at 60.83% (up from 58.38%) and the water level at 721.382 m, 11.048 m below the 732.43 m FRL; there is no spill. The rise is being driven by 75.7 mm of rain in the past 24 hours, though only 15.7 mm is forecast in the next 24 hours and 39.5 mm over 72 hours; the next alert would be triggered when the water level reaches the applicable alert threshold, which is not provided.

Warning alert — Idukki · 03 Aug 2026, 10:14 IST

Reservoir information bulletin

Commissioned: 1976
Dam type: Double curvature arch
Height: 168.9 m (554.2 ft)
Length: 366 m (1200.3 ft)
Gross capacity: 1460.0 MCM
Live capacity: 1460.0 MCM
Catchment area: 649 km²
Full reservoir level: 732.43 m (2403.0 ft)
Power station: Moolamattom (Idukki HEP)
Installed capacity: 780.0 MW
Purpose: Hydroelectric
Operator: KSEB
River: Periyar
Basin: Periyar
Nearby towns: Cheruthoni, Thodupuzha, Kattappana
Emergency contact: 1077 / 0486-2222011

Idukki is India's first double-curvature arch dam, built across the Periyar between the Kuravan and Kurathi hills and commissioned in 1976. Together with the Cheruthoni and Kulamavu dams it forms the Idukki reservoir, which feeds the 780 MW underground powerhouse at Moolamattom — the largest hydroelectric station in Kerala.

Periyar river system — levels & flow

Every monitored structure on this river, ordered by how much water it is passing downstream right now.

Structure	Level / FRL (m)	Storage	Inflow	Outflow	Status
Bhoothathankettu (Barrage)Ernakulam	31.00 / 34.95101.7 ft / 114.7 ft	—	—	800 m³/s	Controlled release — water is being released in regulated quantities, not a danger warning
MullaperiyarIdukki	— / 46.33— / 152.0 ft	—	—	—	No warning — below every published alert level
Lower Periyar (Pambla)Idukki	249.90 / 253.00819.9 ft / 830.1 ft	71.5%	—	—	No warning — below every published alert level
NeriamangalamIdukki	— / —— / —	—	—	—	No warning — below every published alert level
IdukkiIdukki	721.42 / 732.432366.9 ft / 2403.0 ft	61.0%	—	—	No warning — below every published alert level