Some small vessels could almost reach Dinas Powys, but, like the River Thaw a few miles west, it is likely to have silted up, and the mouth became a mud channel before being redeveloped.

However, due to environmental regulation the water quality is now improving and the river supports fish, including trout.

On 19 April 2005, most of the river's trout were killed when dangerous pollutants leaked from a vehicle travelling to the Barry chemical plants, seeping into Bullcroft Brook and thus damaging the ecosystem.

Originally it met the sea at the eastern edge of Barry Island, where the present dock entrance is situated today.

It flows through a wooded ravine for much of its course, and just upstream from the confluence with Bullcroft Brook, several weirs dam the river, creating many ponds.

It has a few small tributaries, the largest of which is called the Nant yr Argae, which in turn starts at St Andrews Major and has a length of 2 miles.

[4] Another, much smaller stream with a length of about 1 kilometre also drains this area, and converges with the Colbrook just upstream from where it joins the Cadoxton.

Flooding was caused by the floodwater overtopping the banks of the Cadoxton River among others and ordinary watercourses, restrictions to flow in channels and surcharging of drains.