Moderately hazardous: 4-6
Highly hazardous: 7-8
Extremely hazardous: 9-10
Pyramids beach (WA 777) is a 1.4 km long beach that commences against the northern beachrock boundary of Florida beach and terminates at the 500 m long Dawesville Channel training wall. The channel is part of the large Port Bouvard and Dawesville development, which cut the 1 km long, 200 km wide channel to connect the Harvey Estuary with the Indian Ocean. The beach is backed by the Pleistocene calcarenite dunes rising to 40 m, which are now covered by the southern Southport part of the development. The beach commences immediately north of the reef with a low tide terrace and waves averaging just over 1 m. The waves pick up in height toward the channel and the northern half has a centre beachrock section with a boundary rip, then a 50 m wide bar cut by a central beach rip. In addition there is a strong permanent rip against the training wall, and a small spur groyne off the wall. The spur causes the beach to spiral round to face south against the wall. There is surf on the small reef break at the southern end and beach breaks along the bar. The groyne has been built to trap sand at the northern end of the beach. This sand is then periodically pumped under the channel to the northern side, to assist in the longshore sand transport. This will need to be an ongoing process otherwise the northern beaches will be deprived of sand and continue to erode. The beach is patrolled by the Port Bouvard Surf Life Saving Club, founded in 2004. As there are usually a few rips along this beach, particularly towards the northern end, make sure to swim only when patrolled and in the patrol area.
The northern side of the Dawesville Channel has a shorter training wall, just 50 m in length, with a 150 m long groyne located 100 m to the north and a seawall linking the two walls and continuing for 500 m to the north. The training wall has been built to control or train the flow through the channel, while the groyne is designed to presumably stop sand moving southward and into the channel. The seawall is a result of the severe beach erosion that has occurred since the channel and walls were constructed. While sand is pumped under the channel from Pyramids beach, erosion is continuing on the northern side, as it is starved of the sand that would normally move northward along the coast. This sand is part of a beach system that extends northeast for 11 km to Robert Point at Mandurah, where the sand moves around the point and into the next long sediment cell. In between are 13 near continuous beaches (WA 778-790) most separated by low beachrock reefs and calcarenite outcrops. The first seven beaches are located along the 5 km of northeast-trending shore between the channel and Falcon.
Between the northern wall and Falcon, 3 km to the north, are four beaches (WA 778-781). The first two have been heavily modified by the walls and groynes.