(Despite that, turnout is low - because while 70% of Catalans want a vote, they want a proper, binding one, where the outcome legally matters - not a non-binding "participation process").
Which shows the futility of the Spanish approach. You can't just legislate against people's desire for self-determination. And in this era of democracy, the idea of trying to retain a region that clearly wants to leave, let alone refusing to let them even vote on it, is simply untenable. Worse, by doing so, and refusing to permit any legal avenue for Catalans to decide their future, the Spanish government will force Catalans to pursue extra-legal ones instead. Hopefully, that will merely take the form of a unilateral declaration of independence by the Catalan parliament. But terrorism and even civil war aren't out of the question here if the Spanish government keeps being so pig-headed.