the iron and wooden ships that were abandoned between 1909 and 1945 are now bird roosts and a canoeing attraction. The ships in the graveyard were launched from 1856 to 1920 and include the Santiago and Dorothy H. Sterling, as well as other sailing ships, steamships and iron barges. In 2023 the biggest ship in these graveyards collapsed nearly 160 years after it was built. Estuarine environment The ecology of the estuarine area includes and is dependent on the health of its component parts: the waters, intertidal zone, and lands on the shore. The area includes breeding and feeding grounds for several species of fish and prawn (in particular western king prawns and King George Whiting) a combination of resident and migratory birds (including a rookery), and a sanctuary for dolphins. The area is also home to the largest area of mangrove forest, shallow seagrasses and mudflats in Gulf St Vincent. Attempts are being made to restore the once extensive reefs of shellfish, including native mud oysters (ostrea angasi), cockles and razorfish (pinna bicolor), which had almost disappeared since European settlement. Prior to European settlement of the Adelaide Plains, winter rains over the catchment of the River Torrens created large seasonal inflows of fresh water into the Reedbeds wetlands, which drained north into the Port River and south to the Patawalonga River. In their natural state, the interconnected creeks and channels of the Port River estuary and Barker Inlet were surrounded by mudflats, mangroves, and saltmarshes colonised by samphires. Many of these remain, although the water flows have changed significantly. Tidal movement has a substantial influence on the ecology of the estuarine area's flora and marine fauna. Flows occur from the north (via Outer Harbor) and south (West Lakes, which draws in seawater via an engineered tunnel at Grange). Since settlement and industrialisation, stormwater has caused pollution in the estuary. Industrial enterprises variously impacted the ecology, with nutrients boosting the growth of algal blooms, various contaminants reducing water quality. Temperature changes caused by effluents from gas-fired power stations at Torrens Island and Pelican Point persist. Sometimes high loads of solid materials have also been discharged into the river, and hyper-saline brine from adjacent saltfields. Since construction of the Breakout Creek outlet in 1937 to drain the Reedbeds (see above), and the closure of the former Port Adelaide Wastewater Treatment Plant with the diversion of wastewater to Bolivar Waste Water Treatment