We did the rafting trip in August with Wild Horizons (see Peterhouse Zambezi Trip). On the Multi day rafting trip enusure you camp below Lower Muwemba. The site looks West onto Lower Muwemba - a massive water fall and rapid. The current google image is at very high water - you would certainly not be able to raft here at this level.
This cache is on top of a rock Island in the middle of the Zambezi River - Batoka Gorge.
There is an AMAZING beach that we spent the second night on. You can walk north from this and will find the Cache. Walking West will take you to a look out point to see the magnificant Lower Muwemba. You MAY be able to drive into the Dam Site (I have put in the way point) there is even an old air strip there. It will be a difficult walk up the river bank to the site. I suggest you wear a life jacket if you are going to walk near the river.