Travel · History · 7 min read

Ponmudi Dam: A Quiet Reservoir in the Cardamom Hills of Idukki

Not the Ponmudi of Thiruvananthapuram, but a still, green lake on the Panniyar river near Rajakkad, held back by a 1960s masonry dam and ringed by spice farms and misty hills. Its engineering story, its views and hanging bridge, its wildlife, and how to get there.

By GK Global, Adimali, Munnar · Trails & Tales by GK

The road from Munnar to Rajakkad does not hurry. It loops down through cardamom shade and pepper-hung trees, past little roadside temples and churches, past streams that slip under the tarmac and vanish into the green. Then, at a bend near Konnathady, the trees open, and below you lies a sheet of still water filling a fold of the hills: dark green in the shade, silver where the sky touches it, its far shore lost in mist. This is the Ponmudi reservoir, one of the quietest and loveliest lakes in Idukki.

A word first, to avoid confusion: this is not the well-known hill station of Ponmudi near Thiruvananthapuram. This Ponmudi, "the golden peak", lies in the heart of Idukki's cardamom country, on the Panniyar river, a short drive from Munnar and Adimali, and it sees only a fraction of their visitors.

A river put to work

In the years after Independence, the young state of Kerala looked to its mountain rivers for electricity. The Pallivasal scheme near Munnar, Kerala's first hydroelectric project, had shown what the falling waters of the High Range could do (read the Pallivasal story). The next step was to harness the rivers that flowed into the Muthirapuzha from the east, among them the Panniyar.

The Panniyar rises in the hills around Chinnakanal and Anayirangal, flows south-west through a valley of farms and forest, and joins the Muthirapuzha on its way to the Periyar. Engineers of the Travancore-Cochin and then Kerala State Electricity Boards planned a chain of works along it: a storage reservoir high up at Anayirangal, a diversion at Kuthungal, and, lower down at Ponmudi, a main dam whose reservoir would feed a power station in the valley below.

The dam

The Ponmudi Dam is a masonry gravity dam: a massive wall of stone masonry that holds back the water by its own sheer weight. It rises about 57.7 m from its deepest foundation and runs for about 289 m across the valley. Its spillway, of the curved ogee type, is fitted with three radial gates to release floodwater in the monsoon. Behind it, the reservoir holds about 51.5 million cubic metres of water at full level. Work was carried out in the early 1960s, and the dam was completed around 1963–65.

The Panniyar power station

From the reservoir, the water does not simply flow on down the river. It is drawn into a tunnel and a set of penstocks, great steel pipes that carry it steeply down the hillside to the Panniyar power station at Vellathooval, on the bank of the Muthirapuzha. There, two turbines, first commissioned on 29 December 1963 and 26 January 1964, turn the falling water into electricity, with an installed capacity of about 30–32 MW. After passing the turbines, the water returns to the river system.

It is a modest project by the standards of the Idukki arch dam, but it was an important part of Kerala's early drive for power, and it still contributes to the grid six decades later. Its history has had darker moments too: on 17 September 2007, one of the penstock pipes burst at Vellathooval, sending a torrent through the village below; lives were lost and homes and farmland were flooded. The penstocks were later repaired and the station restored to service.

(Read about the great dams of the district in The Titans of the Ghats.)

The viewpoint and the landscape

The finest views come from the road above the dam and from the dam area itself. From here the reservoir winds away between steep, wooded hills, its arms reaching into side valleys. On a clear morning the water mirrors the slopes perfectly: rows of cardamom under tall shade trees, pepper vines on their standards, the occasional red roof of a farmhouse. As the day warms, clouds gather on the higher peaks to the north and east, and in the monsoon the whole valley fills with drifting mist, so that the dam and the far shore appear and vanish like a dream.

About a kilometre from the dam, a slender hanging bridge crosses the Panniyar. Walking across it, swaying gently above the rushing water and the rocks, is one of the small thrills of a visit, and the bridge offers its own view up and down the river valley.

What makes Ponmudi special is its quiet. There are no crowds, no rows of souvenir shops, no traffic jams. On most days you will share the view with a few local families, a farmer passing with a load of cardamom, and the birds. It is a place to stop, breathe, and watch the light change on the water.

Nearby

• Waterfalls along the Munnar–Rajakkad road, including the cascades often called Ripple Falls and Kuthumkal, at their best in the monsoon.
• Rajakkad and Rajakumari, small spice towns with busy markets.
• Viewpoints over the valleys around Kallimali and the hills towards Kunchithanny.
• Anayirangal reservoir and the tea country of Chinnakanal, upstream.

The ecology of the Panniyar valley

The Panniyar flows through a landscape that is part forest, part farm. The upper basin, around Anayirangal and Chinnakanal, still has patches of evergreen and moist deciduous forest and grassland, and it was the home range of the famous wild tusker Arikkomban. Wild elephants still move through the area, and gaur, sambar, wild boar, Nilgiri langurs and bonnet macaques live in the forest patches.

Lower down, around Ponmudi, most of the land is under cardamom, pepper, coffee and mixed spice gardens, in the agroforestry system typical of the Cardamom Hills, where crops grow under and on tall shade trees. These farms are surprisingly rich in wildlife: hornbills, barbets, bulbuls, drongos and treepies call from the shade trees; kingfishers, egrets and cormorants fish the reservoir; and in the evenings bats and nightjars take over. The streams that feed the river are home to small fish and endemic frogs, and butterflies gather on the wet sand of the banks.

(Read cardamom, the Queen of Spices, black pepper, human–wildlife conflict around Munnar and the birds of the Western Ghats.)

Visitor's guide

How to get there

• From Munnar: about 25–30 km (around an hour) towards Rajakkad, via Kunchithanny.
• From Adimali: about 30 km via Kallarkutty and Rajakkad, along the valley of the Muthirapuzha.
• From Rajakkad: a short drive of a few kilometres to Konnathady and the dam.
• Nearest railway station: Aluva (about 110 km). Nearest airport: Cochin International (about 110 km).

Best time to visit

• June to December: the monsoon and post-monsoon months, when the reservoir is full, the hills are green and the waterfalls along the road are at their best.
• January to March: clear, pleasant weather and good light, though the water level falls.
• April and May: warm, with the lowest water levels; mornings and evenings are best.

Safety tips

• The dam is a protected installation: follow the instructions of KSEB staff and security, keep out of restricted areas, and check before taking photographs of the structure.
• Never swim in the reservoir or the river; the water is deep and cold, and gates may open without warning in the monsoon.
• Cross the hanging bridge a few people at a time, hold the railings and do not rock it.
• The hill roads are narrow with sharp bends; drive slowly, especially in rain and mist.
• Wild elephants may cross roads in the area, especially at dusk; keep a safe distance and never stop to feed or photograph them at close range.