Fish Hoek Beach #4.3: River-Side
The cache, a camo-taped flip-top dispensing pot, is hidden towards the northern end of the beach (which is called Clovelly Beach) where the Silvermine River which originates up in the Silvermine Mountains above Silvermine Valley and drains down past the Clovelly Country Club, through the Clovelly Wetlands, under Clovelly road and rail bridge and into the bay. Surface flow across the beach is only seen during the wet season - in drier periods the river ends in a small lagoon.
To reach the cache location:
Park at S 34 7.928 E 18 26.271 and locate the beach access trail/rail crossing point either to the north-east (may be inaccessible due to road works) or (over the river bridge) to the south-west, get onto the beach and head south-west to the cache location. Alternative on-road parking is available on Abinton Road @S 34 7.941 E 18 26.192.
For detailed information on the river, see (or preferably do!) omni W's excellent Earth Cache GC5JJA8: Silvermine River - Source to Sea.
It is directly out from the river outlet where the notorious shark attack of September 2011 took place - see here and here. Because it has had a number of shark bite incidents, Fish Hoek beach is the only beach in Cape Town with a special exclusion (shark) net, introduced in 2013, to keep sharks out of the swimming area which is at the south end of the beach.
Since 2004 there have been two fatalities and one very serious bite when a man lost his leg (in 2011). There have
also been a number of close calls, where surfskis were bitten and people had close encounters with sharks.
In October 2011 there were 55 shark sightings at Fish Hoek in one month . . . although it is one o the best swimming beaches in Cape Town, it had a stigma as being 'the shark beach'.
Traditional shark nets are designed to catch and kill sharks. Exclusion nets, like the one used in Fish Hoek, just prevent sharks from entering an area. The City of Cape Town’s approach to shark attack 
prevention is that not only must people be protected but also the sharks and the environment, and that one protection must not be at the cost of the other. Fish Hoek also gets humpback whales and southern right whales in the middle of the bay, so anything put into the water must not potentially entangle whales, dolphins, or anything else.
The exclusion net is deployed in summer, from October to Easter (March/April). In October it is used for school holidays and weekends but from November-March it is used daily depending on 
the weather. It is not deployed the wind is too strong or the swell too big. The aim to have it up for about 20 days/month.
During the initial shark net trial period from March 2013-May 2014, Shark Spotters recorded 39 great white sightings on 22 different days. However, none entered the exclusion zone when the net was deployed. Furthermore, the design of the net meant it was able to withstand weather and sea conditions, and there was hardly any entanglement of birds or other fish. It was deployed 140 times during the trial, at R1 200 per use. The project also created nine job opportunities. It was concluded that 'overall, the results of the trial indicate that the exclusion net is a cost-effective, non-lethal shark safety measure with minimal impact on marine life.'
See here for a short video on the shark nets at FHB.
For more information on Fish Hoek Beach, see GC77HMH Fish Hoek Beach #1: Overview.