Objectives To understand the perceptions and motivations of hikers who approached a swift river at locations that have been associated with drowning in the past.

Methods A survey was completed by 399 adults who had been observed getting ‘too close’ to the Merced River. The questionnaire covered trail familiarity, information sources, timing and motivation of their decision, perceived safety, knowledge and opinion of park rules.

Results Sixty-eight per cent of invited hikers agreed to participate. Almost all had received advance information about their hike, but most often that did not include a river warning. Most respondents were observed in the risk zone by the footbridge, and their most frequent motivation was to ‘cool off’. Ninety-two per cent of hikers reported feeling very or somewhat safe by the river. Their risk perceptions did not correlate with expert ratings of danger. Males, younger subjects and those who had hiked the trail before were more likely to enter the most hazardous parts of the risk zone. Eleven per cent of people at the footbridge and 43% at the top of the waterfall thought that the park should not allow visitors to go where they had been. The most common reason they gave for this view was that the location was unsafe.

Conclusions While this needs assessment identified channels for informing hikers of drowning risk, there are indications that they might not personalise such warnings. Another option would be to explore cooling alternatives that could compete with the swift water that runs along many hiking trails.