The Dam Planned for Silent Valley Was Abandoned in 1983, and 89.52 Square Kilometres of Kerala Rainforest Became a National Park Dedicated on 7 September 1985

Silent Valley National Park in Palakkad district, Kerala, has a core of about 89.52 sq km of tropical evergreen forest, and it stands because a hydroelectric dam planned for the Kunthipuzha river was abandoned. A Press Information Bureau feature says the Kerala State Electricity Board (KSEB) announced its plan to build the dam in 1976, that the then Prime Minister decided to abandon it in 1983, and that the park was dedicated to the nation on 7 September 1985.

Government pages disagree on the year the park was declared, and the sections below give each source’s figure by name.

What the dam would have done

KSEB’s project, as Mongabay India describes it, had an installed capacity of 120 MW and was meant to irrigate 10,000 hectares. The PIB feature says the board decided to go ahead with a hydroelectric project in the valley in 1973. Down To Earth, an environment magazine, gives the same year for KSEB’s proposal and adds that a British engineer had marked the valley as one of the best sites in Kerala for hydropower as early as 1929.

Down To Earth quotes the M. G. K. Menon committee, the expert panel the Centre set up to review the project, as finding that the dam would submerge 830 hectares of intact riverside forest, which the quotation calls riparian. When KSEB argued for a later project near the park in 2007, it cited the same figure, 830 hectares, for the abandoned one.

Who made the case

Onmanorama traces the first warnings to two people. Romulus Whitaker, who came to the valley in the early 1970s to study snakes, learned what the dam would mean for wildlife, and the American scientist Steven Green moved to the area in 1973 to study lion-tailed macaques. The macaque became the campaign’s mascot, Onmanorama says.

The Kerala Sastra Sahitya Parishad (KSSP), a people’s science movement popular in Kerala in the 1970s and 1980s, argued against the dam on figures. Mongabay India, drawing on Darryl D’Monte’s account of the case, says KSSP pointed out that Kerala exported 40 percent of the power it generated to neighbouring states and that the project would add only 7 percent to the state’s supply. The movement also argued that the irrigation could be served more cheaply from groundwater and surface water.

Outside bodies joined in. In September 1978 the International Union for Conservation of Nature (IUCN) passed a resolution at its 14th General Assembly, held in Ashkabad in the USSR, to preserve Silent Valley. The agricultural scientist M. S. Swaminathan toured the valley in October 1978 and reported to the government. His report, Mongabay India says, noted an evolutionary age of more than 50 million years for the forest and 23 mammal species, among them three endangered ones: the tiger, the lion-tailed macaque and the Nilgiri langur. The ornithologist Salim Ali appealed to Prime Minister Indira Gandhi in 1980, according to Onmanorama. Jairam Ramesh, a former Union environment minister who wrote a 2017 book on her record, dates her opposition to the project from 1979, Mongabay India reports.

The decision

Mongabay India records that Prime Minister Morarji Desai gave the dam conditional clearance in 1978. In January 1981, Mongabay India’s 2020 report says, Indira Gandhi declared that Silent Valley and its biodiversity would be protected. The same report says M. S. Swaminathan had proposed in 1979 a National Rainforest Biosphere Reserve of about 390 sq km.

The Centre then set up the Menon committee, with the ecologist Madhav Gadgil among its members. Down To Earth dates its report to 1982, while Onmanorama says it was submitted in 1983. Mongabay India gives the decision as 18 October 1983, when Indira Gandhi decided to deny permission for the project. Down To Earth says the project was shelved in November 1983.

The park’s declaration is where the record splits:

• The PIB feature says the forests were declared a national park on 15 November 1983.
• Mongabay India says Silent Valley was notified on 15 November 1984, about a fortnight after Indira Gandhi’s assassination.
• The Kerala Forest and Wildlife Department’s English page says the park was declared in 1985 and, a few lines later, that it was established in 1984.
• Down To Earth and Onmanorama both give 1984.

Two later dates are consistent across sources. Prime Minister Rajiv Gandhi dedicated the park on 7 September 1985, and a memorial to Indira Gandhi was unveiled at Sairandhri. The park was designated the core area of the Nilgiri Biosphere Reserve on 1 September 1986.

What the park holds

The PIB feature gives the altitude as 658 m to 2,328 m at Anginda peak, with most of the park between 880 m and 1,200 m. Kerala Tourism gives 725 m to 2,383 m. The Kunthipuzha river runs the entire 15 km length of the park from north to south and joins the Nila, or Bharathappuzha. Mongabay India notes that the Kunthi kept flowing through the dry summer of 2017, when the Bharathapuzha ran dry.

Rain is heavy and uneven. PIB reports a mean annual rainfall of over 5,000 mm in the western Neelikkal area and about 3,200 mm on the eastern side, with 80 percent falling between June and September. PIB ties the rain to the south-west monsoon, which our monsoon explainer covers. The Kerala Forest Department’s page says the park is part of the Western Ghats, a UNESCO World Heritage Site, and our article on the Western Ghats listing lists Silent Valley among its components.

On life, the PIB feature records 966 species of flowering plants in 134 families, about 108 orchid species, and at least 34 mammal species, including the lion-tailed macaque, the Nilgiri langur, the Nilgiri tahr and the Malabar giant squirrel. A 2006 winter bird survey it describes recorded 138 bird species, 17 of them new to the valley, and PIB counts 16 species listed as threatened or restricted by BirdLife International. Kerala Tourism’s page gives more than 170 bird species and about 95 butterfly species, so bird totals depend on the survey cited.

The name needs a note. PIB says Silent Valley was so called because of a perceived absence of cicadas, and lists two other explanations: an anglicised form of Sairandhri, and the lion-tailed macaque’s scientific name, Macaca silenus. In Malayalam the forest is Sairandhri Vanam. Sairandhri is the name the Mahabharata gives Draupadi during the Pandavas’ final year in hiding, which the epic places at the court of King Virata (see what the Mahabharata is). PIB adds that it is believed the Pandavas stayed in a cave on the river’s bank. Maari, a tribal forest protection staff member, told Mongabay India in 2020 that cicadas have returned to the valley.

The macaque count

The valley’s best-known animal is the lion-tailed macaque. A review in the Journal of Threatened Taxa by Mewa Singh and colleagues names Silent Valley as one of four regions with potentially viable populations. It gives the valley about 14 groups and roughly 275 individuals, citing a 2000 study by Ramachandran and Joseph, and says the number appears to have remained stable over the years. The review puts the whole wild population at 3,000 to 3,500 animals in 49 sub-populations and says the IUCN lists the species as Endangered.

Other descriptions credit the valley with more. PIB says the park is home to the largest population of the species, and Mongabay India’s 2020 report says over half the global population is estimated to live in these forests, without giving a count. The Journal of Threatened Taxa review reports about 790 macaques in 32 groups in 2004 in the Sirsi-Honnavara forests of Karnataka, which is more than its figure for Silent Valley. No newer count of the valley’s groups turned up in the sources opened for this article.

The buffer zone and the Pathrakadavu proposal

Mongabay India’s 2020 report says the forest had been a reserve forest since 1914. A buffer zone came much later. The Kerala Cabinet approved a 148 sq km buffer zone on 6 June 2007, covering land in the Mannarkkad and Nilambur South forest divisions, according to OneIndia. PIB gives the figure as 147.22 sq km, and Mongabay India says the Centre and Kerala added about 147 sq km in November 2009. Adding the 89.52 sq km core to 148 sq km gives the 237.52 sq km that Kerala Tourism lists as the area.

In August 2020, The News Minute reported that Kerala’s Forest Minister announced the state wildlife board’s recommendation to turn the buffer zone into a Bhavani Wildlife Sanctuary. Mongabay India said it would be Kerala’s 25th protected area and that about 560 tribal families live in six settlements inside it. A notification of the sanctuary did not turn up in the sources opened here.

A smaller dam proposal followed on the same river. Down To Earth’s 2007 report describes the Pathrakkadavu project, with a 64.5 m dam, 70 MW capacity and a cost of Rs 247 crore, which the Kerala government approved administratively on 18 April 2007. KSEB said the site is 500 m from the park’s boundary, while the environmentalist M. K. Prasad said it lay inside the buffer zone. India Environment Portal reported on 17 December 2004 that the Minister for Environment and Forests told the Lok Sabha no such proposal was before the Ministry for clearance. The Hindu reported on 27 December 2012 that KSEB had revived the project earlier that year and that the Forest Department had told the state it had reservations, saying the site is less than half a kilometre from the boundary and the earlier environmental assessment was not legally valid. No later decision appeared in the sources opened for this article.

Visiting from Mukkali

Visits run through Mukkali, the base camp. Kerala Tourism says the park is 60 km from Palakkad via Mannarkkad to Mukkali, 69 km from Palakkad railway station and 91 km from Coimbatore International Airport. The Sairandhri trip, Kerala Tourism’s day programme, takes about five hours in the forest development agency’s vehicle, with a walk to the Kunthi’s bank and a 100-foot watchtower, and visiting hours of 8 am to 1 pm on one page and 7:30 am to 1 pm on another. There is no accommodation inside the park, and bathing in the river is prohibited. A forest cottage at Bommiyampadi, about 13 km from Mukkali, serves overnight guests. Both Kerala Tourism pages give the Wildlife Warden, Silent Valley Division, Mannarkkad, as the contact, and the trek page asks visitors to confirm availability beforehand. Those pages were read on 28 October 2026, and one is a newsletter dated April 2017, so hours, fees and booking rules should be confirmed with the division before travel.