Chester Canal
In Chester, from the top of the arm leading down to the Dee, the SU follows the old Chester Canal built in 1772 to connect Chester and Nantwich. The canal passes alongside the city walls of Chester in a deep, vertical red sandstone cutting. After Chester, there are only a few locks as the canal crosses the nearly flat Chester Plain, passes Beeston Castle, and the junctions at Barbridge and Hurleston and arrives at Nantwich basin, the original terminus of the Chester Canal.
The two junctions on this stretch are very important links in the English and Welsh connected network.
- At Barbridge, the Middlewich Branch of the SU goes northeast to Middlewich on the Trent and Mersey Canal (via the tiny Wardle Canal). This was the original planned main line of the Chester Canal, but was in fact built much later than the Nantwich stretch.
- At Hurleston, the old Ellesmere canal from Llangollen and Montgomery made a connection from Frankton Junction eastwards to the old Chester Canal after it was realised that the planned main line from Trevor to Chester along the Dee was never going to be built. This canal eventually merged with the Chester Canal and became the Llangollen Branch of the Shropshire Union. These waters are now known as the Llangollen Canal and (south from Frankton Junction, and still being restored) the Montgomery Canal.
Birmingham and Liverpool Junction Canal
The odd angle between Nantwich basin and the next stretch of the SU shows that the journey southwards is on a newer (and narrow) canal originally constructed as the narrow Birmingham and Liverpool Junction Canal to connect Nantwich, at the end of the Chester Canal, to the Staffordshire and Worcestershire Canal at Autherley Junction, near Wolverhampton. An important lost link can be seen at Norbury Junction, where a branch (1841) ran south-west through Newport to connect with the Shrewsbury Canal at Wappenshall Junction.
After Nantwich basin, a long sweeping embankment incorporating an aqueduct carries the canal across the main A534 Nantwich-Chester road. The canal then has to climb out of the Cheshire Plain by means of a flight of 15 locks at Audlem. The canal passes through the eastern suburbs of the town of Market Drayton in Shropshire. Further south there are substantial lengths of embankment through the Staffordshire village of Knighton. There is an aqueduct south of Norbury Junction and deep cuttings at Loynton near Woodseaves (Staffordshire), Grub Street, and at Woodseaves (Shropshire).
The canal then continues as the 1-mile-long (1.6 km) Shelmore Embankment. Repeated soil slippage during construction meant that this was the last part of the B&L Junction Canal to be opened to traffic. The lengthy embankment is equipped with flood gates at both ends to prevent loss of water should the canal be breached in this area. During World War II these locks were kept closed at night because of the risk of bomb damage.
At Gnosall the canal enters the 81-yard (74 m) Cowley Tunnel. Originally the tunnel was planned to be 690 yards (630 m) long, but after the rocky first 81 yards (74 m), the ground was unstable, and the remaining length was opened out to form the present narrow and steep-sided Cowley Cutting.
At Wheaton Aston, the canal climbs its last lock to reach the summit level, fed by the Belvide Reservoir just north of Brewood. North of the reservoir, the canal passes by Stretton Aqueduct over Watling Street (the A5 road).
The SU terminates at Autherley Junction on the Staffs and Worcester Canal. Immediately before the junction is a very shallow stop lock built to prevent the loss of water to the new rival canal from the preexisting Staffordshire and Worcestershire Canal. Unusually, the B&L Junction canal's summit level was designed to be a few inches lower than the older canal, so the newer canal gains a small amount of water each time the lock is cycled (the reverse of the practice usually insisted on by canal companies as a condition for not opposing the construction of a newer one).