Etosha Pan, Lake Oponono and the Cuvelai drainage system

This is the first in a series of articles which will focus on the wetland treasures of Namibia 

MAIN PHOTO: Flamingo Pan by Paul van Schalkwyk

Text Edward Jenkins

The Convention on Wetlands of International Importance (the Ramsar Convention) is an international treaty created in 1971 to support national action and international cooperation in the conservation and wise use of wetlands worldwide. To date, 167 countries have joined the convention, including Namibia, which has identified four Ramsar sites, with a fifth one currently undergoing evaluation. The first site – the Etosha Pan and the associated drainage system that feeds it – was designated in 1995.

Flamingos on the Etosha Pan. Photo ©Hu Berry

Etosha, the crown jewel of Namibia’s national parks, evokes images of antelope and elephant seen through shimmers of heat waves and dust, scattered over a seemingly never-ending savannah of dry brush. The Etosha Pan itself, blindingly white and ostensibly lifeless, is the backdrop for countless photographs captured by tourists. And yet, thanks to a highly unusual drainage system, rain falling in the highlands of Angola slowly wends its way south, and in the best of years ends its journey in the Etosha Pan.

Annual flooding, referred to as efundja in local parlance, is a fact of life in north-central Namibia, as the Cuvelai drainage system channels the runoff from the Angolan rainfall, which may exceed 700 mm per year. The flooding is guided to and through the Omadhiya Lakes/Lake Oponono system, by a complex series of shallow channels, referred to locally as oshanas.

It is estimated that these oshanas support from 30% to 40% of the Namibian population during the wet season through subsistence farming or fishing on the seasonal wetlands and floodplains. However, this annual bounty does not come without cost, as the flooding regularly displaces the very population it supports. In March 2011 alone, seasonal flooding displaced more than 21 000 people.

In the years when the rainfall is sufficient (generally about 15% of the time), the water overflows the Omadhiya Lakes/Lake Oponono system and reaches the Etosha Pan via the Ekuma River.

Efundja. Photo ©Paul van Schalkwyk

In an otherwise arid country, the changes brought by seasonal rains and subsequent flooding can be nothing short of breathtaking. The peak rain months of January and February begin filling small depressions in the beds of dry rivers, creating ponds where fairy shrimp, snails, tadpoles and ostracod (a small crustacean also known as seed shrimp) can develop, safe from most predators.

In the meantime, runoff from the big rains falling in Angola slowly moves south, arriving in Namibia in March and April, carrying with it small fish, including African pike, Zambezi parrotfish, cyprinids (carp-like fish) and the many-spined climbing perch. By the end of their journey some of them will have travelled almost 200 km. As the waters rise, the pond fauna join the fish in the nutrient-filled floodplains, where they thrive and grow. Scientists have identified at least 43 species of crustaceans and 19 fish species in these areas, which are dry for most of the year.

Shallow pans are a magnet to birds, in particular greater and lesser flamingos and eastern white pelicans. They may breed at Fischer’s Pan in the Etosha National Park, which generally contains water during average rainy seasons. But during major flood years, when the Etosha Pan becomes inundated, up to a million flamingos may congregate here. It is one of only two sites in Southern Africa where greater and lesser flamingos share a breeding/nesting territory. The drainage system also supports the globally threatened blue crane, (critically endangered in Namibia), as well as the endangered wattled crane.

Blue cranes. Photo ©Pompie Burger

Rare and endangered mammals of international concern, including the black rhinoceros, African elephant, and roan antelope, all rely on the system, as do the multitude of other animals that share the Etosha biosystem.

As the human population grows in Angola and Namibia, this important wetland system will face major challenges, including increased subsistence farming, fishing, poaching, and development projects that may divert water for other uses. As a signatory of the Ramsar Convention, Namibia’s wetlands are afforded increased publicity and prestige, and access to expert advice. Furthermore, members may access Ramsar’s in-house small-grants assistance programme, or make use of their contracts with outside support agencies. Finally, Ramsar membership encourages international cooperation in transboundary shared wetlands systems, such as the one found in Etosha.

Elephants in Etosha. Photo ©Paul van Schalkwyk

Clearly, participation by the Government of Namibia in the Ramsar Convention shows its commitment to the protection of sensitive wetlands. With the help of all stakeholders, both inside Namibia and internationally, this precious resource will remain available to serve future generations.

Ramsar sites in Namibia

Namibia currently hosts four designated Wetlands of International Importance as prescribed by the Ramsar Convention:

• Etosha Pan, Lake Oponono and the Cuvelai drainage system (central northern Namibia)
• Sandwich Harbour (Atlantic coast, approximately 55 km south of Walvis Bay)
• Walvis Bay Lagoon (Atlantic coast, immediately south of the Municipality of Walvis Bay)
• Orange River Mouth (Namibia/South Africa border, on the Atlantic coast)

A fifth site, the Lower Okavango River/Mahango Section of the Bwabwata National Park, located in the Caprivi Strip in far north-eastern Namibia, has been proposed for inclusion on the list by the Namibian Ministry of Environment and Tourism, based on the large diversity of bird species and vegetation found in the area.

Sandwich harbour ©Ron Swilling

WETLAND TYPES

Generally, wetlands are areas where water is the primary factor controlling the environment and the associated plant and animal life. They occur where the water table is at or near the surface of the land, or where the land is covered by water.

Five major wetland types are generally recognised:

• marine (coastal wetlands including coastal lagoons, rocky shores, and coral reefs)
• estuarine (including deltas, tidal marshes, and mangrove swamps)
• lacustrine (wetlands associated with lakes)
• riverine (wetlands along rivers and streams)
• palustrine (meaning ‘marshy’– marshes, swamps and bogs)

The Ramsar Convention, recognising man’s influence on the environment, has simplified wetland definitions into three categories:

• Marine and Coastal Wetlands
• Inland Wetlands
• Man-made wetlands, such as fish and shrimp ponds, farm ponds, irrigated agricultural land, saltpans, reservoirs, gravel pits, sewage farms and canals.

http://www.ramsar.org