[1] The Brede flows through a wide valley in its lower reaches, surrounded by marshland which is at much the same level as the river.

[2] During the 12th century, large areas of marsh were enclosed, beginning at the edge of Cadborough Cliff, and working southwards towards the river.

At some point, the shingle bank was breached, and the River Rother carved a new course through the gap to enter the sea near Rye.

The winter of 1287-88 was particularly bad, and the village of Old Winchelsea was overwhelmed, as was much of the reclaimed marshland near Cadborough Cliff, which remained flooded for 15 years.

It protected 1,036 acres (419 ha) to the west of it, and provided a convenient way to cross the valley, although tolls were collected for its use.

Ships were loaded with firewood for onward transfer to London and Europe, while other timber products included a shipment of hurdles for Dover Castle.

Lead was carried for Battle Abbey,[8] and in the Tudor period, an iron furnace was built at Brede, which continued to operate until 1766.

[9] Access to the sea from Winchelsea and Rye was continually changing, as the whole area is subject to deposition of shingle and silt.

[10] The Harbour Commissioners consulted the naval officer and civil engineer John Perry, who estimated that the project would cost £13,732, and a second act of Parliament[which?]

Building of the foundations was overseen by Edward Rubie, Perry's foreman, and the contract for the main stonework was awarded to Christopher Cass and Andrews Jelfe.

The grand sluice was the largest of its kind at the time, having five gates, each of which was 6 feet (1.8 m) wide, and had huge abutments and a large central pier.

Wharfs were built, and the canal had been excavated to its full depth for 275 yards (251 m) from the piers at its southern end by the time Rubie left the project in 1748. Cooper continued making the channel deeper, built a 200-foot (61 m) jetty on the end of the west pier, and finally removed the shingle bank which kept the water out of the workings.

The Commissioners then attempted to obtain another act of Parliament, to authorise additional charges to shipping to cover the cost of the work.

[13] Meanwhile, the commissioners asked for advice from the civil engineer John Smeaton, who recommended that the Brede, the Tillingham and the Rother should all be diverted into the new channel.

The historian John Collard has suggested that this latter phase was marked by incompetence and failure at a managerial level.

[15] The Commissioners of Sewers for the Levels of Brede and Pett were required, under powers granted by the Rye Harbour Act 1833 (3 & 4 Will.

[8] They were unloaded by a steam crane, and transferred to an 18 in (457 mm) gauge tramway, operated by an 0-4-0 saddle tank and four waggons.

[16] A regulation to abolish the right of navigation became effective in 1934, although boats continued to deliver fuel to the Brede Valley Waterworks until 1935, when a road was built from the village to the works.

At Pond Bay, Rat Gill joins the river, which turns to the east, to pass under a railway bridge on the Hastings Line.

An area of 60 acres (24 ha) is being returned to marshland, and water levels are gradually rising to recreate a traditional waterside landscape.

Large areas of the town are listed as a Scheduled Ancient Monument[25] Station Road, which leads to Winchelsea railway station, crosses the river at Ferry Bridge, and the A259 Royal Military Road, built in 1805 as part of the defensive Royal Military Canal crosses at Strand Bridge, on the eastern side of the town.

Immediately beyond the bridge, the western section of the Royal Military Canal heads southwards towards Cliff End, near Pett.

[26] The Saxon Shore Way long-distance footpath follows its eastern bank, and continues to the south of the river.

As the river progresses towards Rye, there is a sewage treatment works on the east bank, and the remains of Camber Castle, which was built in 1538 by King Henry VIII,[27] but abandoned in 1640 after the sea retreated.

The structure and the grounds are a Scheduled Ancient Monument, and the remains have been restored and repaired since they were bought by the Department of National Heritage in 1977.

Like most rivers in the UK, the chemical status changed from good to fail in 2019, due to the presence of polybrominated diphenyl ethers (PBDE) and mercury compounds, neither of which had previously been included in the assessment.