Thanks for the comments all and for the link George. It led me to
this link and prompts a couple of corrections/Additions. It wasn't the Olympics but Expo 92. It's not (now) across the river but a canal. However, looking at the satellite image, it looks like the canal has been created by blocking off one end of what was one river arm. Finally, the bridge has a name - Puente del Alamillo.
George, don't let this put you off Seville. As a tourist destination for a medium break, it was both interesting and compact. Everything in the city is within walking distance. We loved it.