Plant in 2005, the upper reaches of the Port River now receive only limited amounts of locally derived stormwater, and are now largely marine. Flushing of West Lakes occurs through a one-way system that draws in seawater from the Gulf through an inlet off the coast at the southern end. The Lakes discharge into the upper reaches of the Port River at Ethelton. The water quality has improved since the reduced flows and improved quality of Bolivar sewerage, and since the closure of Penrice soda ash plant in Osborne in 2014. The soda ash plant was a major ammonia pollution source. Regular testing by the Environmental Protection Authority took place until 2008, after which only informal testing has occurred. In December 2016, SA Health testing showed very low counts of bacteria, enabling the annual "Long Swim" in the Inner Harbour to recommence after many decades of absence. Mangrove forests (consisting of only one species, Avicennia marina var resinifera) remain at Ethelton and New Port, along the shores of Torrens Island, the North Arm (which connects to Barker Inlet) and adjacent to the Mutton Cove Conservation Reserve on the Lefevre Peninsula. Spring tides are over and at low tide mudflats are exposed near the outlet of the river, forming a breeding ground for blue swimmer crabs and other species. Protected areas Several protected areas are covered by legislation in order to help to maintain the biodiversity of the area, comprising: Adelaide Dolphin Sanctuary; Adelaide International Bird Sanctuary; Barker Inlet – St Kilda Aquatic Reserve: Gulf St Vincent Important Bird Area (the mudflats at the mouth of the river); Mutton Cove Conservation Reserve; St Kilda – Chapman Creek Aquatic Reserve; and Torrens Island Conservation Park. The Adelaide Dolphin Sanctuary is a dolphin sanctuary which was enacted by the Adelaide Dolphin Sanctuary Act 2005, covering all of the Barker Inlet and the Port River. Bottlenose dolphins are often seen in the river, examining and following small boats and have become a well known tourist attraction with dolphin cruises departing from Queens Wharf. The industrialised nature of the Port River has led to concern for the welfare of the bottlenose dolphin population and studies have shown that some of the dolphins have very high heavy metal burdens in comparison to dolphins elsewhere. Future environmental risks Climate change is resulting in rising sea levels that threaten to cause erosion and further loss of the mudflats,