Bob Dunn Bridge. Dartford library and museum provides a wealth of evidence that both creeks have been used for trade since pre-Roman times. Trade reached a modern zenith during the Industrial revolution and beyond. In 1835, almost was carried in or out, servicing and supporting considerable industrial activity. Navigational factors meant that single cargoes were limited to even on spring tides. A ship canal was proposed in the early 1800s but failed to achieve momentum. In 1839 a new proposal achieved an Act of Parliament allowing development to proceed and tolls were levied from completion in 1844. The work included straightening, dredging and shortening the navigation. Dartford Creek Tidal Flood Barrier On Dartford Creek, close to its junction with the Thames, is the Dartford Creek Tidal Flood Barrier with two drop-leaf gates, which may be lowered if the sea threatens to inundate the land. The barrier is managed by the Environment Agency. Roman Connection Dartford (Domesday Book "Tarentefort") was a major fording place on Watling Street. Research by Woodlands Junior School indicates that the ford existed even before the Roman period. Tarentefort itself flourished through the Roman period AD50 - AD 450. A ferry controlled by a hermit was established c.1235 and survived until 1518, long after the first bridge was constructed during the reign of Henry IV (1399–1413). That bridge survived into the 1700s. Historic and pre-historic Today's river is not much more than a stream apart from in conditions of spate, a surprise given the breadth of the valley it runs through. The "proto-Darent" was much larger than today's trickle but the River Medway, through erosion of the soft chalk and clays of the North Downs/Western Weald, has captured much of the headwaters which once supplied the Darent. Modern neglect In 1989, concerned individuals realised that almost all flow through Dartford had ceased. The River Darent was later recognised officially as the 'lowest flowing' river in the country. Wildlife was decimated but the reason became apparent as soon as the problem was addressed. Increasing quantities of water were being diverted by the then Rivers Authority to supply the growing greeds of adjacent towns and even London Boroughs. Since 1989, much work has been [claimed to have been] carried out to rectify this situation, including the shutting down of a number of boreholes by the Environment Agency. This is documented in Dartford Library by Environment Agency documents lodged there.