Acacia spathulifolia
Identifying Acacia species is very hard as there are so many of them and in Florabase (The Western Australian Herbarium's online database) there are several pages of Acacia sp - known species without a species name. However for the beginner like me there is another excellent resource called World Wide Wattle which gives photographs and detailed descriptions of all the Acacia species.
This one has phyllodes (a modified leaf stalk or petiole) which can be cylindrical near the flowering tip or more flattened lower down. It also has a small gland in the upper middle of the phyllodes but neither of these characters allow it to be distinguished from the very similar Acacia leptosperma which unfortunately for the amateur botanist, grows in the same region so can't be separated like so many species through geographical distribution. One character which puts an advantage to Acacia spathulifolia though is the yellow margin on the phyllodes. This can just about be seen in the close-up photo. So without betting much on this, I think it is probably Acacia spathulifolia.
Acacia spathulifolia grows along the coastal strip north of Perth from about Eneabba to beyond Shark Bay and approaching Caravan. There is a little inland and one or two outposts further south but Kalbarri National Park is well into the main part of its distribution area according to Florabase.
Kalbarri National Park. Western Australia 2nd September 2012
Added on January 26th 2013, updated 12th March 2013, Updated 17th July 2015