ANALYSIS: There's an eerie feeling walking down Castle St, North Dunedin, on a Sunday morning.

Beneath a grey sky, chilling winds blow empty cans and beer boxes along an empty footpath. The century-old houses and unkempt lawns add to the scene. 

The city is not abandoned, of course, the residents are just battling a collective hangover and will not rise for another few hours. They'll eventually stumble out of bed, and some will ask a flatmate "what happened last night?" 

Most weekends, the question is about whether they said something embarrassing or made out with someone they shouldn't have. In the wake of the tragic death of Sophie Crestani at an overcrowded party at The Manor, that question has taken on a much darker tone. 

Much has changed in Dunedin's student quarter: the couch fires are gone, the pubs have closed. A student population which was just recently considered politically apathetic is once again at the forefront of protest movements.

But the one thing that hasn't changed is the undeniable impact alcohol has on the culture of the community.

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Heavy drinking at Otago is nothing new. In the 1890s, the university cancelled public graduations for four years because students kept showing up extremely drunk and yelling abuse at guest speakers. 

Records from the 1940s show intense hazing rituals at Knox College, where first year students were made to dig their own shallow 'grave' and drink hard liquor in it until they vomited, and a trophy at Selwyn College for the student who can scull two pints the fastest dates back to 1937 (it's still awarded to this day, though no longer for drinking).

It is perhaps a natural consequence of the environment. Young adults, away from home for the first time and free of the constraints of parental supervision go a bit nuts exploring their new-found freedom. In North Dunedin, the entire suburb is made up of thousands of people in the exact same situation, egging each other on and taking things to extremes. 

The combination of huge crowds and heavy drinking inevitably leads to things going wrong. This is only the latest in a string of accidents arising from overcrowded parties in North Dunedin. In 2016 a balcony collapsed at a Castle St Six60 concert, and in 2012 a roof gave way at a Hyde St Keg Party. 

For the university and local police, it's a constant struggle to control the more extreme elements of the drinking culture without stirring a backlash. 

The Undie 500, a car rally where Canterbury University students would decorate cars and drive down to Dunedin for a rugby game, caused chaos for years before its cancellation in 2010.

Parties at the finish line on Castle St would regularly turn into riots, with couches and cars burned. Police took a heavy-handed approach, with as many as 100 officers in full riot gear forcing revellers out of the road. Grainy Youtube footage showed dramatic confrontations between revellers and officers continuing even as police managed to push the crowd back to university grounds, more than a kilometre away. 

69 people were arrested in one night in 2007, 22 were convicted.

The riots triggered a reaction that would change the landscape of student life. The University introduced a strict Code of Conduct for students and launched its own security force, Campus Watch. 

Students can now be suspended or expelled for breaking rules, even if it's off-campus and unrelated to their university work. 

Campus Watch was initially met with opposition. It was seen to be focusing on petty infringements like marijuana possession rather than student safety. In 2008, it became clear that Campus Watch had been focusing on NORML, a cannabis activism student group, to the point of helping plain-clothes police officers infiltrate the group. 

That news led to hundreds of students protesting outside the Campus Watch office, and the university promised to reform the organisation to be caretakers rather than cops. 

Campus Watch has stoked a couple of controversies since, most notably the removal of the Critic Menstruation Issue in 2018, but for the most part is quite popular among students. 

At night, the team wanders the streets of the student quarter, keeping an eye on parties but mostly staying out of the way. Students can call them for help if a someone needs to be taken home or to the hospital, or if uninvited troublemakers start causing chaos. 

The presence of Campus Watch has also meant less police - and when police are called, crowd management tactics seem to have helped prevent more large parties from turning into riots. 

Crowds of over 1000 people still turn up to major events on Castle St and Hyde St, especially around O Week (Orientation Week), but instead of physically forcing people to move on, police now tend to let the parties continue while blocking off street entrances to prevent newcomers from joining. 

The most famous of Dunedin student parties is the Hyde St Keg Party. It began in 1995 as a keg-drinking race between flats on the street and is now an all-day costumed drink-a-thon. 

The 2012 event hit disaster point with 10,000 people cramming into the tiny street and forcing many onto roofs to escape the throng. One roof collapsed due to the weight. In total, 80 people were hospitalised and 10 were arrested (though only one of those arrested was a student). 

It was clear the party had grown into a monster and was no longer safe. However, authorities worried that forcefully shutting it down the next year would only turn it into a riot, and pushed OUSA to take over the event. The Hyde St Party is now a professionally-run, ticketed event with strict security around the perimeter and a crowd limit of 3500. 

But just as Hyde St has been brought under control, more events keep popping up. The Agnew St Party has arisen as a free-range alternative, with no tickets, and has quickly started to rival Hyde St for crowd size. 

Anecdotally, students say the drinking culture is less extreme than it was 10 years ago. A decade-long study released last year also found a reduction in the number of students getting drunk.

Couch fires, once considered basically synonymous with the university, are almost entirely extinguished from memory. The university's disciplinary reports show fire-related incidents have fallen from 278 in 2011 to just 13 in 2018. 

But major flat parties, which combine together and spill outwards onto the streets, still happen.

Many point to the closure of student pubs as the reason. The two most popular, Gardies and The Cook, closed down in 2010 and 2013 respectively. OUSA, which purchased Starters Bar in 2018, has argued the lack of affordable spaces to drink has pushed students away from licensed venues and into unsupervised flat parties. 

O Week has bloomed into two weeks, with students dubbing the week before it as 'Flat O Week' or 'Flo Week'. There's also Re-O Week, for the first week of the second semester, St Patrick's Day, Castle St Initiations, the Debacle party, and the Stafford St Party.

All it takes it one public Facebook event to go viral and the crowds will descend. 

Big nights used to be predictable, now they could be any weekend. 

Stuff reporter Joel MacManus was previously the editor of Critic magazine at Otago University.