Recent reports of a Nile Crocodile having been spotted in the Etaka Dam, also known as the Olushandja Dam, has attracted a lot of interest and questions as to how the reptile got there in the first place.
Crocodiles occur in the Kunene River and the most likely explanation is that the adventurous crocodile make its way from the river or the surroundings of the Calueque Dam to Etaka Dam. This would have required it to undertake a 24 km journey – a 2.5 km uphill walk from the dam to the open concrete-lined water canal and then for 12 km along the canal to Omahenene from where it is another 9.6 km to the Etaka Dam.
Dieter Noelle, one of the owners of the Otjiwarongo Crocodile Farm, says it is difficult to estimate the age of the crocodile in the Etaka Dam. In captivity, where they are fed, they reach a length of 1.4 m in two to three years, but life in the wild is harder and they grow much slower. He estimates the crocodile in the Etaka Dam to be between four and five years old.
Asked how far crocodiles can walk, Noelle pointed out that crocodiles are low-energy reptiles because they are cold-blooded. Although they are slow-moving creatures, they are, however, mobile.
It would appear that the Etaka Dam crocodile is quite happy with its new ‘home’ – even though it might not have company. At the time of writing, it has evaded two attempts to capture and relocate it – most likely to the Kunene River. People have been advised to avoid the dam until then.
The Nile crocodile owes it scientific species name, niloticus, to the Nile River where it was collected in 1768, described and classified scientifically. It is the largest semi-aquatic freshwater predator in 26 African countries with an average length of between 2.5 m and 3.5 m, but can reach up to about 6 m in length. It can live for up to 70 years in the wild and longer in captivity.
The Etaka Dam is unique because it was built on the watershed between the Oshana Etaka, which slopes southwards and drains into the Omadhiya Wetland Complex and the Oshana Olushandja, which drains towards the Kunene River. Earth-filled embankments were constructed about 18 km apart on either side of the watershed and the dam’s width varies from 200 m to two kilometres. It has a maximum depth of 4.5 m when full and a surface area of 29 km².
The dam forms part of a complex water supply network constructed in the early 1970s to supply water to Owambo. It was designed as a storage dam to accommodate peak demand and to ensure an emergency supply of water in the event of a disruption of the water supply from the Calueque Dam in southern Angola.
From the pump station at the Calueque Dam the water is pumped to the watershed which is about 18 m higher than the level of the dam. It then flows along a 12 km-long concrete lined canal to Omahenene on the Namibian border and continues for 9.6 km to the Olushandja Dam where water is diverted into a 146 km-long concrete-lined canal to Oshakati. A pipeline from the purification works provides treated
water to Eunda, Onesi, Tsandi and Okahao. The scheme also made provision for the release of water from the dam’s southern outlet into the unlined Etaka canal to provide water for the livestock of people living downstream.
The dam is an important source of freshwater fish which is caught for household consumption, while residents of Epalela township catch fish to generate cash income. The name Epalela, near the northern dam wall, is said to be derived from the Omupalala trees growing in the area. They produce sprays of yellow flowers between October and December and its English common name (Weeping Wattle), as well as its Afrikaans common name, Huilboom (which means crying tree) refers to the abundance of nectar that drips from its flowers which creates the impression of weeping.