Along its course many of the city’s eastern suburbs have been built up and its value as an urban green lung for Pretoria residents should not be underestimated.
And, while fences and gates restrict access to this nature area, for those in the know, there are stretches where one can hike, walk the dog, enjoy some bird-watching, picnic under a tree, or get to commune with nature.
The land along the river belong to the city council which takes care of basic upkeep, but the work done by volunteers aligned to the Adopt Moreleta Spruit Forum, is what really makes the difference.
The river is divided into sections with groups responsible for different stretches. Together they do what they can to clear rubbish and alien plants and try to ensure that their areas stay clean and safe for the community’s enjoyment.
Carol Martin's group, Friends of Serene Valley, has a corridor through Garsfontein and she hosted a walk and talk about its trees.
Martin was armed with green tree ID tags to nail on a number of indigenous trees - listing common and botanical names and reference numbers, something she has been doing since 2006.
Assisting her was Maeve Smit - a Grade 7 at St Mary’s DSG who is completing challenges towards the President’s award.
Martin says the purpose of the tree IDs is “if you think a tree is just a tree, you won’t look closer But, if it has a name, it has a personality, and then one becomes interested in it.”
Among the trees she tagged were the paperbark thorn, sweet thorn, hook thorn, monkey thorn, common spike thorn, buffalo thorn, fire thorn and wild pear.
As it was Arbour Day a tree was planted, a river bush willow to honour Anneli Kuhn, the founder and chair of Adopt Moreleta Spruit Forum, who died this year.
A wide variety of trees, both indigenous and invasive species like the river willow and fire thorn with its showy berries, can be seen along the river bank, with trees, birds and small animals including otters, genets, water mongoose, porcupines, and bush babies spotted by neighbours. Martin pointed to a hole under a fence, made by a porcupine to reach a fruit tree.
Perched on a branch above the river was a brown-hooded kingfisher and regular walkers have spotted many species of birds.
The friends groups care about the plants and the animals, and the general health of the river. They do regular tests and have removed more than 200 bags of litter from the river so far this year.
They watch for flooding and fires, alert the city of security breaches. One can tell how much they care simply by listening to Martin's stories of individual trees she's "known" for 40 years, her recounting of traditional tales of trees and modern evidence that they really do communicate.
She talks about their roots, their bark, their leaves and flowers, those with thorns and those without and those which are missing a mate.
There're the berries one can eat and the dombeya flowers which turn brown after pollination, the smell of different jasmine in the air, the weeping willows and a dozen other fascinating things city dwellers could learn.
It is clear as the walk comes to an end, not only the important work such friends groups do, but how much more they would be able to do were more to join. Such an asset should be better kept and used by the public.
* On Saturday there is an annual 16km hike along the Moreleta, from Moreleta Kloof to Pioneer's Museum.