Blackweir Bridge across the River Taff, Cardiff A nearby information board states that the weir's present location dates from the early 19th century when water was taken from the Taff to feed the new docks in Cardiff. The suspension bridge, built in the 1980s by engineering students from Cardiff University, gives a well-used route between Bute Park and Pontcanna Fields. Replacing a smaller version, the fish pass on the right was opened in 2010 by rugby legend and keen angler Gareth Edwards. The numbers of migratory salmon and other fish have increased upstream since then.