The sanctuary is set in a floodplain near the little town Nigel, close to Johannesburg. This part of the Blesbokspruit – a perennial river – has been declared a Ramsar wetland of international importance (Ramsar convention on Wetlands of International Importance, especially as Waterfowl Habitat).
Marievale has been shaped by mining – much of the water that fills its open areas is pumped up from underground. Yet this has created an extraordinary body of water attractive to birds.

The reserve is characterised by expanses of marsh with large reed beds and open patches of water (becoming mudflats during drier periods). Areas of natural grassland and farmland surround the wetlands and attract typical species such as long-tailed widows, African pipits and marsh owls. Water birds, particularly waders, are the main attraction. Marievale is one of the Highveld's best places to see black, squacco, purple, grey, Goliath and black-headed herons. There are also warblers, ducks and sandpipers.


This interesting provincial nature reserve has Gauteng province's highest bird count: 280 species. It is very oriented towards things winged, but you can also look out for reedbuck, blesbok, cape clawless otters, black-backed jackal, yellow mongoose and the odd cape hare.