A long-term flood discharge record derived from slackwater flood deposits of the Llobregat River, NE Spain

Slackwater palaeoflood deposits were identified along two bedrock gorge study reaches of the Llobregat River, at Pont de Vilomara and Monistrol de Montserrat. The compiled palaeoflood record consists of two principal flood series: (a) a relatively complete record of low to high magnitude flood events from the last ca. 100 years and (b) evidence of the largest palaeoflood events that have occurred over the last ca. 2700 years. The longer term extreme palaeoflood record indicates that the discharge of the 1971 flood, the largest on record, was exceeded on at least eight occasions, with two periods of high magnitude flooding identified: (a) the Late Bronze Age (2500-2700 years ago) and (b) the Little Ice Age (AD 1500-1700). At Pont de Vilomara, palaeodischarge estimates of 3700-4300 m3/s compare to a discharge of 2300 m3/s for the 1971 event. Downstream at Monistrol, an estimate of 4680 m3/s for flood deposits dated as AD 1516-1642, and believed to be those of the AD 1617 flood, compared to 2500 m3/s for the 1971 flood.