Eventful ecological goings-on mark animal, bird and insect life near these watercourses that only flow from seasonal rains. Shrubs and trees provide food and shelter of a richer, more dramatic kind here than away from the line drawn in the lowest land, hollowed by concentrated run-off. There is water here, but invisible, deep down in the ground, the green of the trees confirm its presence. A few metres beyond, in the dry scrub and grass, no sign of relief comes before the next rain.

Grinding and rounding of riverbed rock over countless ages by force of fast storm water expose the route where no plants may resist the brief spells of strongest flow. A few dry seasons and some seeds will try their luck again. Only for anything green that roots in the wake of the sudden deluge to be taken for a terminal downstream swim. The next wet season is already closer than last year.

Trees and some long taproot shrubs are established close together on the banks. They forego the obligatory plant rest periods, when nourishment becomes unreachable to less fortunate neighbours as the dry season hits next-door; that’s why the privileged are tall after all.

These places, sometimes hard to hike along through dense growth, are valued homes to many shy species, unless alien plants have taken over and destroyed the indigenous habitat.