sentence: it rises at a spring near the village of rauric , just west of the town of santa coloma de queralt in central catalonia , flows westwards past the villages of llorac , vallfogona de riucorb , guimerà , ciutadilla , nalec , rocafort de vallbona , sant martí de maldà , maldà , belianes , then veers northwards across the plain where it disappears into a network of irrigation canals .