This is another of my favorite spots to bring the boys and dogs to splash on hot days and watch them throw rocks in the water. Koornalla Park has been revamped countless times as it has been destroyed by vandals repeatedly over the years, to the heartbreak of many. Luckily the area never loses it's beauty (at least to me!). The riverbed is very pretty and accessible, and a good STARTING point on this occasion!
Watch any youngens near the water!
The cache you are looking for is a camouflaged eclipse tin.
Good luck!