Basic Information
A storm drain is an artificial watercourse attached to an built up area and designed to divert, contain and remove high levels of rainwater (although areas that have to deal with copious snow-melt often have similar structures). Some cultures connect these drains to the sewerage system - others separate the two. Given the quantity of water to be disposed storm drains are usually large - usually much larger than the average sewer - and given the more presentable nature of the contents, being open to the surface is more acceptable.
In many cases, storm drains spend most of the year dry - the storm drains of California, for example, well known internationally due to the local cinema industry are in a desert climate and are mostly dry except for brief periods of violent rainstorms during which they flow very full indeed. The combination of size, limited hazards and accessibility makes these drains highly prone to being occupied by various species - not least humans. The fact that they will also tend to open into accessible places (river banks, local wetlands etc.) also makes occupation - or infiltration - easier. The absurdly spacious sewers beloved of filmmakers will often turn out to be storm drains.
Sources
Game and Story Use
- A traditional way of sneaking into a secure city or other area: break into a storm drain outlet outside the perimeter and simply stroll along to your destination. Your mileage may vary and a good suit of plot armour is very helpful in these circumstances.
- When determining whether or not this part of your setting has storm drains, look at an equivalent part of the real world: if it has large drains and/or floods a lot during the rainy season, then the in-universe people will probably want storm drains as well (assuming they have the technology to build them). Small storm drains and/or those linked to the sewer system would suggest a more even pattern of rainfall.
- Again, compare the storm drains of Los Angeles (those concrete sided dry canal like things that people drive along in action movies) with those of London (that you never see and are mostly tied into the Bazalgette sewer system). London has a climate of frequent rain, but rarely in torrential amounts, so the drainage system is designed for more or less continuous low volume work, whereas LA is dry most of the year but prone to the occasional violent deluge that needs to be disposed of in a great hurry.
- Derry, Maine, famously had its sewers and storm drains linked together pretty promiscuously, but then there were external influences on their design and construction that made things less than entirely practical on that front.
- Most of the year, a storm drain is relatively safe, which tends to attract people (and other things) in need of shelter … the rest of the year, those occupants need to move quickly to avoid being drowned and/or swept away.
- So, for example, a hobo jungle in the storm drains might suddenly become a place of desperate activity as the storm starts to break on the surface. PCs on a mission in the area now have to balance getting the job done and surviving - and possibly trying to save the lives of the homeless people around them. Quite likely, by the time the water has started to flow - thus providing incontrovertible evidence of the coming flood - it is already more or less too late for anyone not close to an exit.
- Also, a storm surge may drive … things … that had been living quite comfortably in those drains out onto the surface. Rats are the traditional opener for this.
- Equally, once the water subsides, interesting things may be washed up on the strainer grates and the strand lines of the drainage system.
- We all float down here…