Gokyo Lakes

The Gokyo Lakes are a chain of high-altitude glacial lakes occupying the Gokyo Valley of Solukhumbu District in north-eastern Nepal, within Sagarmatha National Park. They lie at roughly 4,700 to 5,000 metres (about 15,400 to 16,400 ft) above sea level, with the principal lakes spread between approximately 4,710 and 4,950 metres. Set beneath the giants of the upper Khumbu — close to Cho Oyu, the world's sixth-highest mountain, and within view of Everest, Lhotse and Makalu — they form one of the highest freshwater lake systems on Earth and are frequently described as the highest such system in the world.

Geologically the lakes are products of glaciation. They sit in a trough scoured and dammed by ice along the western flank of the Ngozumpa Glacier, the longest glacier in the Nepal Himalaya, which descends from the slopes of Cho Oyu and runs immediately east of the lake chain. The lakes are fed chiefly by seepage and meltwater from the Ngozumpa Glacier, a stream descending from the Renjo La pass to the north-west, and another stream issuing from the glacier to the east; the system ultimately drains southward toward the Dudh Koshi river. Because the basins are sustained by glacier melt and lie in an actively deglaciating landscape, the area is considered ecologically fragile and sensitive to glacial change.

The system is usually counted as nineteen lakes, spread over an area of about 196.2 hectares (485 acres), of which five or six are the well-known principal water bodies. Thonak Cho is the largest at about 65.07 hectares (160.8 acres) and, as the fourth lake of the trekking route, also the deepest at around 62.4 metres. Gokyo Cho — also called Dudh Pokhari, the 'milk lake' — is the main lake at about 42.9 hectares (106 acres) and roughly 43 metres deep; the village of Gokyo sits on its eastern shore. Other named lakes include Gyazumpa Cho (about 29 ha), Tanjung/Taujung Cho (about 16.95 ha) and Ngojumba/Ngozumba Cho (about 14.39 ha). The lakes take their collective name from the adjacent peak Gokyo Ri.

The Gokyo Lakes are oligotrophic — clear, cold, low-nutrient waters typical of high-altitude glacial systems — set among alpine meadows, moraine and rock at the upper limit of vegetation. Despite the harsh environment, the wetland and its surrounding pastures support a notable range of Himalayan plants and animals, several of them rare or threatened, which is a principal reason the site qualifies as a wetland of international importance.

The lakes form an important habitat and stopover for waterbirds in the high Himalaya. Species recorded at or around the Gokyo wetland include the Northern Pintail (Anas acuta), Common Pochard (Aythya ferina), Eurasian Woodcock (Scolopax rusticola) and Great Crested Grebe (Podiceps cristatus), together with globally threatened or near-threatened birds such as the Ferruginous Duck (Aythya nyroca) and the Wood Snipe (Gallinago nemoricola). The wider catchment lies within the range of iconic high-mountain mammals of Sagarmatha National Park, including the snow leopard (Panthera uncia) and the Himalayan tahr (Hemitragus jemlahicus).

The surrounding alpine flora includes economically important and Red-listed medicinal plants such as kutki (Neopicrorhiza scrophulariiflora), alongside sedges and cushion plants adapted to the cold, including species of Kobresia. This combination of rare flora, threatened fauna and a near-pristine high-altitude wetland ecosystem underpins the lakes' conservation value, while the same glacial dynamics that created the lakes also make the system vulnerable to environmental change.

The Gokyo Lakes are held sacred by both Hindus and Buddhists, lending the remote glacial basin a spiritual importance that adds to its scenic and ecological renown. For the Sherpa and other Buddhist communities of the Khumbu, the high lakes and surrounding peaks are part of a sanctified mountain landscape, and the waters are treated with reverence.

The lakes are also a site of Hindu pilgrimage. During the festival of Janai Purnima, which falls on the full moon usually in August, several hundred Hindu devotees — reported at around 500 pilgrims — make the arduous journey to the lakes to take a ritual holy bath in the cold, sacred water. The festival, when Hindu men change the sacred thread (janai) worn across the body, draws worshippers to many holy waters across Nepal, and the Gokyo Lakes are among the highest-altitude of these pilgrimage sites.

The Gokyo Lakes are the centrepiece of the popular Gokyo Valley trek, an alternative or complement to the classic Everest Base Camp route. Trekkers typically approach via Namche Bazaar and the Dudh Koshi valley, reaching Gokyo village on the shore of Dudh Pokhari. The signature viewpoint is Gokyo Ri, a peak rising above the village to roughly 5,300–5,360 metres, from whose summit climbers gain one of the finest panoramas in the Himalaya — taking in Everest, Lhotse, Makalu and Cho Oyu and a sweeping view down over the turquoise lakes and the Ngozumpa Glacier. Some itineraries continue west over the Renjo La pass or link to the Everest region via the high Cho La pass. As with all high Khumbu trekking, the principal hazard is altitude, and proper acclimatisation is essential.

The lakes lie within Sagarmatha National Park, a UNESCO World Heritage Site, and are protected under Nepal's National Parks and Wildlife Conservation Act, 1973 and associated buffer-zone regulations. On 13 September 2007 the Gokyo and associated lakes were designated a Ramsar Site (Wetland of International Importance, site no. 1692), covering 7,770 hectares (77.7 km²) of high-altitude wetland — recognition of the system's value for biodiversity and its role as a high Himalayan freshwater wetland.

Conservation concerns centre on climate change and glacial dynamics. The Ngozumpa Glacier that sustains the lakes is thinning and retreating, and a large meltwater pond known as the Spillway has been growing on its surface, raising scientific interest in supraglacial lake development and downstream hazard. Visitor pressure — the valley receives thousands of trekkers each year — together with the fragility of the alpine ecosystem makes responsible, low-impact tourism and careful wetland management central to preserving the lakes.