The Lost River fair and brisk
Updated: Mar 10, 2018
The River Frome - a 'little but useful river'
You may be forgiven for not knowing (given the state and general disappearance of the Frome from the city today), but the Frome (formerly Froom meaning ‘fair and brisk’) was one of the main river systems upon which Bristol was built and formed the foundation of its history. In the 6th edition of Matthew’s Guide to Bristol (published over 200 years ago) it says “over this little but useful river there are thirteen bridges in the city and suburbs”.
20 miles long (rising in Donnington Park in South Gloucestershire) the Frome flows through North East Bristol into the centre of the City. It is also known as the Danny (for reasons that no-one is now certain).
The Frome of the Middle Ages
The Bristol area has been settled since the Stone Age and the original course of Bristol Frome flowed parallel to the M32, round the top of Castle Park, past Pithay, past the old Bridewell Police Station (then Bridewell Bridge) to Froom Bridge (Stone Bridge - now underground between St John’s Gate and Christmas Steps), along St Stephen’s Street and Baldwin Street joining the Avon (on it’s own original course) near Bristol Bridge. Here is a map of Bristol in the Middle Ages showing the original course of the Frome.
Building the city's defences in the Anglo-Saxon period
It was at the point just before the Frome and the Avon converged that the Frome became part of the City’s defences as a castle moat around the Saxon town Brigstow (‘Place of the Bridge’ or ‘Bridge Town’) that had grown up (where Castle Park is now). William the Conqueror quickly recognised the strategic importance of Bristol, and sent Geoffrey of Mowbray to take charge of the town. He built a simple fortification which his successor, Robert of Gloucester, transformed into a huge castle that grew to be twice the size of Caernarvon Castle and one of the grandest in the kingdom. By diverting the Frome a moat was created around the Castle which allowed access by land only. This remained the walled heart of the city for centuries.
To form the moat the Frome was fed from the North side of Castle Park (Broad Weir) where the castle mill stood (its marks can still be seen in the walls). The Frome then went through a series of weirs around the castle walls and then out into the Avon via a great Water Gate.Even though Bristol Castle was dismantled in 1654, underground (as it was covered in 1847) the moat remains almost intact and still forms part of the Frome system which is navigable by boat and emerges from a brick arch next to Castle Park into the Floating Harbour.
This is a modern drawing showing the path of the underground River Frome as it skirts Castle Park and the path of the Castle moat which can still be navigated (carefully) in small boats (but avoid those giant fish as you enter back onto the docks)!
The Great Ditch under the Centre!
By the 13th century Bristol had become a busy port and the harbour facilities around the castle were no longer adequate. There had been a great expansion in trade, and boats now travelled to and from France and Spain, bringing cargoes of wine and fine leather. So in 1239 it was decided to develop a new harbour, by diverting the last stretch of the river Frome at the vast cost of £5,000!
After negotiations with the Abbot, the Great Ditch, Deep Ditch or St Augustine’s Trench (as it’s variously known) was excavated through the marshlands belonging to the Abbey of St Augustine (now Bristol Cathedral).
The great harbour diverted the wide, shallow meandering post ice age Frome from its original course into a new straight trench. It was a mammoth task as the trench was nearly half a mile long, over 36 metres wide and its bed was over 7 and a half metres below ground, carrying the Frome out to join the Avon at Canons Marsh (where the Lloyds Amphitheatre and Arnolfini are now).
The oddest and most surprising thing imaginable
This view from Stone Bridge of 1755 shows the second drawbridge, which when opened allowed ‘traffic’ to pass across from Clare Street to the Hippodrome. On the left is St Stephen's Church and on the right is St Augustine’s Parade. The single 38 metre tower of the Cathedral rises in the background.
The work was completed around 1248. Alexander Pope wrote of the trench in 1739 “in the middle of the street as far as you can see, are hundreds of ships, their masts thick as they can stand by one another, which is the oddest and most surprising thing imaginable”.
The Frome as it joins the Avon in 1750s and 1831
The Frome on the move once again!
As the Frome had long been used as a dumping ground for sewerage and rubbish, now that it had been entirely cut off from the tide (as it now only entered the Floating Harbour and not the tidal Avon), the waste just festered causing a horrible stink and creating a huge increase in deaths! This was when, in 1825, it was decided to once again divert the Frome.
A new culvert known as Mylnes Culvert was created running from Stone Bridge (near Electricity House) where new lock gates were constructed, along Marsh Street, Prince Street and Wapping Road, and enters a syphon below the Floating Harbour to discharge to the Avon just upstream of Gaol Ferry Bridge (opposite what is now Asda and near the Malago culvert). It emerges from the bottom of the River Avon in the New Cut!
On its entrance into the Bristol from South Gloucestershire, the Danny passes through Eastville Park before disappearing at the Eastville Sluices (just by the old Rovers Ground, now Ikea, which often flooded up until 1968) and then runs beneath Baptist Mills, which was probably where the Roman Via Julia, from Sea Mills to Bath, crossed. The name ‘Baptist’, has nothing to do with the church but it is thought to be derived from a local family of mill owners called Bagpath, or a cloth made there called baptiste. It was here that the Bristol Roman Wire Company, the most important in Europe, was established and waste-slag was used in the walls of the Greek church there. Baptist Mills was also the site of White’s Pottery where Egyptian Black teapots were made and the White brothers jealously guarded the secret process for making green and yellow Mr Punch pipes. The Pottery and mill were demolished in the nineteenth century so the river could be widened and deepened to stop flooding.
The river stayed open along its whole length until 1858, when a culvert was built sending the Frome underground from Wade Street (between Staples and the new Cabot Circus multi-storey car park) in St Judes. Wade Street is named after Major Nathaniel Wade who was wounded fighting for the Duke of Monmouth. Wade was sent to Bristol in 1687 by King James, anxious to win the good opinion of his dissenters, to ‘remodel’ the cooperation. The bridge over the Frome in Wade Street (built in 1711 with the help of Wade himself) was long known as Traitor’s Bridge because Wade backed the wrong side. Wade was later pardoned, witnessed William Penn’s marriage and became Town Clerk of Bristol.
St Augustine’s Trench from Stone Bridge to Draw Bridge (near the northern end of Baldwin Street) was covered over to make a site for the 1893 Industrial and Fine Art Exhibition (latterly the Tramway Centre) and the rest of the Trench (from Draw Bridge to what is now cascade steps) was covered in 1938 making the Bristol Frome an underground river. The Floating Harbour between Cascade Steps to the Arnolfini is the last stretch of St Augustine’s Trench that remains open.
What's Father Christmas go to do with Bristol's flood risk?
St Augustine’s Trench is still accessible to the Environment Agency in front of Electricity House on the Centre. For many years the entrance was marked by a green pillar-box which children posted their Christmas letters into for Father Christmas! Although now only marked with a metal pavement cover (the pillar box is now on display at the M Shed) the spot where contractors still disappear into the ground (into a cavern spanned by the ancient Stone Bridge), to routinely check and clear a large screen that prevents debris from flowing further down into the culvert system is. Without this being cleared on a regular basis blockages would occur which could lead to manholes coming up and the flooding of basements throughout the Centre.
When the river is in flood, overflow will still pass into the Floating Harbour over the concrete dam (although the old bridgehead that can clearly be seen in the picture below has not been replaced by Cascade Steps at right as part of the Millennium changes made to the Centre. Ideas for Millennium changes also included a plan to uncover the rest of St Augustine’s Trench to reveal the Frome as it flows through the centre, but this lost out to other design ideas.