The Sundays River estuary is located in South Africa. It is approximately 12 miles (20 km) long. It discharges into Algoa Bay (Indian Ocean) through its permanently open mouth. Sundays River receives freshwater from the Orange River which is one of South Africa's largest rivers. Stratification within the estuary occurs rarely therefore the water within the estuarine system is well-mixed throughout the year. Water temperature within the Sundays River estuary vary from 75°F (24°C) in the summer to 63°F (17°C) in the winter. The average salinity of the estuary is approximately 17 parts per thousand and the average depth is 13 feet (4 m). The watershed area encompasses 8500 square miles (22000 km2). Within in the watershed and along the river, sheep farming and citrus cultivation are the main activities. The freshwater is often contaminated by the residues and fertilizers used in the citrus orchards. Recreational activities such as fishing and sailing are popular within the Sundays River estuary.

Useful Web Sites for Sundays River Estuary:
• Consortium for Estuarine Research and Management