Ryde Harbour serves as the final outlet point for Monktonmead Brook on the Isle of Wight. North of Simeon Street the brook disappears underground and is pumped through the centre of Ryde, emerging into the harbour via a concrete outfall.

The area has a long history of flooding when heavy rainfall coincides with high tides, as the elevated sea level prevents the brook from draining freely.

Sand accumulation associated with the construction of Ryde Marina threatened to block the brook's original outfall, and in 2018 a multi-million pound project relocated it into the harbour.

The marina itself acts as a large groyne, trapping sand to its east and forming a new strand that has gradually extended seaward in recent years.