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Lower Periyar (Pambla)

Idukki district · KSEB · Periyar basin · report 04 Aug 2026, 14:00 IST

Storage

100.0%

Previous 100.0%

Water level

253.00 m (830.1 ft)

FRL 253.00 m (830.1 ft)

Spillway release

80.0 cumecs

Latest report

Rain forecast

35 mm

Next 72h 75 mm

Storage & water level — last 30 days

Risk breakdown

Flood risk50
Landslide risk30
Reservoir stress85
Watershed saturation30
River overflow26
  • Storage at 100.0% of live capacity
  • Only 0.00 m of freeboard left below FRL
  • Level 253.00 m is at or above the official red rule level of 252.00 m
  • Controlled outflow of 80.00 cumecs (gates not reported open)

Rule curve — seasonal operating target

No rule curve (seasonal guide curve) is published for Lower Periyar (Pambla) in a form this platform can verify, so none is shown. Where an operating curve is published — as for Idukki after the 2018 floods — it is plotted against actual storage instead of being estimated.

Rainfall forecast — next 48 hours

Spillway releases

Current weather at the dam

Temperature
20.9°C
Humidity
98%
Rain 24h
52.2 mm
Wind
3 km/h
Gusts
19 km/h
Pressure
956 hPa

AI analysis

Lower Periyar (Pambla) is at red alert, with storage at 100%—up from 98.11%—and the water level at the full reservoir level of 253 m; it is spilling 144 cumecs through upper vents 3 at 40 cm and 4 at 50 cm. The rise is driven by 52.2 mm of rain in the past 24 hours, with another 35.4 mm forecast in 24 hours and 75.2 mm in 72 hours; as red is already the highest level, further inflow would trigger increased spill-gate releases rather than a higher alert.

  • Danger alert — Lower Periyar (Pambla) · 03 Aug 2026, 10:14 IST

Reservoir information bulletin

Commissioned
1997
Dam type
Concrete gravity
Height
Length
Gross capacity
Live capacity
Catchment area
Full reservoir level
253.00 m (830.1 ft)
Power station
Lower Periyar HEP (Pamblassery)
Installed capacity
180.0 MW
Purpose
Hydroelectric
Operator
KSEB
River
Periyar
Basin
Periyar
Nearby towns
Neriamangalam
Emergency contact
1077

The Lower Periyar scheme at Pamblassery uses releases from the upstream Periyar cascade and was commissioned in 1997 with an installed capacity of 180 MW.

Periyar river system — levels & flow

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

StructureLevel / FRL (m)StorageInflowOutflowStatus
Lower Periyar (Pambla)Idukki253.00 / 253.00830.1 ft / 830.1 ft100.0%80 m³/sDanger
BhoothathankettuErnakulam28.00 / 34.9591.9 ft / 114.7 ftNormal
MullaperiyarIdukki / 46.33 / 152.0 ftWatch
NeriamangalamIdukki / / Watch
IdukkiIdukki715.49 / 732.432347.4 ft / 2403.0 ft43.7%Normal