followed the course of the River Blackwater to Heybridge, and from there via a canal to the sea lock at Colliers Reach. A weir connected the navigation to the tidal river Blackwater at Heybridge, where it powered a water mill. Heybridge mill was demolished after severe flooding in this area in 1953, but the mill house still stands. The river (known here as Heybridge Creek) was dammed between Heybridge Hall and Potman marsh in 1954 as part of a programme of flood defence improvements. Most of the water flowing down the River Blackwater nowadays flows over a weir at Beeleigh and along the tidal section of the Chelmer before rejoining the Blackwater at Heybridge Basin. In 1865 HM Government passed the Maldon Harbour Act authorized construction of a wharf on the west side of the southern end of Heybridge Creek on land belonging to the Great Eastern Railway Company, and improving the channels of the rivers Chelmer and Blackwater. Ten thousand pounds were spent on widening, deepening and improving the river from the Fullbridge to just downriver from Herring's Point, near Heybridge Basin. After this, vessels had to pay a toll of 3 pence a ton if they were under 50 tons register or 6 pence a ton if they were over that. A medieval 5-arched stone bridge over the River Blackwater at Heybridge (from which that village got its name) was replaced in 1870 by a 2-arched brick one. That bridge was at the north end of the Causeway, at its junction with Heybridge Street and Holloway Road, but the bridge there now is hardly distinguishable as such. Industry The Maldon Crystal Salt Company produces crystalline sea salt by traditional panning techniques from the waters of the Blackwater. Osea Island Osea Island is situated on the Blackwater Estuary, north of Steeple. Northey Island Northey Island owned by the National Trust, is approximately one mile to the west of Osea Island. It is part of an ancient landscape and is connected to the shore by a tidal causeway. It is believed by some to have been the site of the Battle of Maldon in 991 AD and offers birdwatching opportunities. See also Chelmer and Blackwater Navigation Cooks Yard – shipbuilding and repair yard on the Blackwater at Maldon Museum of Power – Langford pumping station extracts from the Blackwater References Rivers of Essex Braintree District Maldon District