Drawing Board: Disasters

As you might expect, recent events here in Japan have had me thinking a great deal on the subject of disasters, and with the immediate crisis receding I thought I'd take the opportunity to talk about the role of disasters in the game. Disasters have been a part of city builders since the very first Sim City (Cities XL was a notable exception to this trend). While at first glance they might seem like something of a tacked-on feature, a way to experience the perverse enjoyment of tearing down what we just built, disasters, if executed properly, play a larger role than is immediately apparent in shaping city development. In fact, allowing disasters requires a good deal of forethought in almost every area of the simulation, and is probably one of the trickiest things in the game to model.

There are a lot of possible disaster-related topics to cover, but before we begin let's pause for the Disclaimer:

IMPORTANT DISCLAIMER

This series of posts are not to be read as "official" ideas for the Metropolis Project, they are simply my personal thoughts about what some cool game features might be. The final feature set for the game will be decided by the community and the development team contracted to build the game, and may not include any of these things. More details about the purpose of the Drawing Board articles can be found here.

It's actually a bit sloppy to lump all disasters together, as the term represents such a wide variety of events and phenomena; So to begin I simply want to outline some of the most common disasters. With those in mind, we can split up disasters into three phases (conditions/preparation, actual event, and aftermath) and see how they apply specifically to the things we've listed. One point to take note of here is the distinction between the type of disaster and it's effects, and that the effects may or may not represent unique disasters of their own. For example, a flood is one type of disaster, but is also a possible element of a larger-scope disaster, like a hurricane.

Types of Disaster

The Fukushima Dai-Ichi Nuclear Plant

The disasters themselves can be roughly divided into two categories: natural and man-made, man-made consisting of things caused by human agency or technology. Some typical natural disasters, in no particular order, are:

• Wildfires
• Floods
• Tornadoes
• Hurricanes
• Earthquakes
• Volcanic Eruptions
• Mudslides
• Tsunamis
• Hailstorms
• Blizzards
• Landslides

Man-made disasters, on the other hand, would consist of things like:

• Building Fires
• Dambursts
• Bridge Collapses
• Plane Crashes
• Industrial Accidents
• Meltdowns
• Toxic Spills
• Oil Spills

Some other possibly controversial additions to this category would be disasters resulting from war, including:

• Bombings (whether from planes or artillery)
• Invasions

There are a few more marginal cases that could potentially be considered disasters but might be more appropriately handled by other parts of the simulation, for example:

• Disease Outbreaks: A plague could be handled either as a disaster, or a modifier to the health simulation; There are good cases to be made for both approaches.
• Pest Infestations: Something like a locust swarm, for example; These can be serious, but it's questionable whether they should be modeled as a disaster in the game, or folded into the agriculture model.
• Terrorist Attacks: As we're all aware, terrorist actions can cause a major disaster, but the vast majority of this kind of activity would be considered more simply as crime, and as such would be part of the crime simulation.

Disaster Conditions

The type of disasters which might occur, and the extent of their effects, depends largely on what conditions exist in the city prior to the event itself. There are three rough categories of condition that determine what can happen and how serious it becomes: Topography, Infrastructure, and Situation.

Topography: Topography actually has two elements: The first is topography proper, the "lay of the land" which includes elevation, contour, and water flow. This factor acts to immediately make the city vulnerable or (essentially) invulnerable to certain types of disaster: Coastal cities might suffer hurricanes, tsunamis, or floods; Cities on flat inland plains would be vulnerable to tornadoes and wildfires (although obviously safe from tsunamis). The secondpart of this category is climate: obviously, cities in a rainy, tropical area will be far more likely to suffer from hurricanes than blizzards, and vice versa. Climate also affects the kind of vegetation present in the city, which can be a factor in things like wildfires.

Infrastructure: Infrastructure is a catchall term to describe the general preparedness of the city for a disaster. Some of these things would relate to physical infrastructure, like the presence of seawalls, and the efficiency of the road system (higher traffic density would mean a harder time evacuating). Others would more likely take the form of ordinances: earthquake-safe building codes, civil emergerncy planning, school disaster drills, well-funded emergency response services, etc. The difference these things can make is starkly apparent if you compare the recent real-life earthquakes in Japan and Haiti: while both earthquakes were devastating, a much higher level of building standards and greater civil preparedness made the Japanese earthquake far less destructive in relative terms (discounting the subsequent tsunami effects, of course). Which leads us into:

Situation: By "situation", I refer to the city's place in the larger world. Part of this ties in to topography: is the city close to other major population centers which can provide support, or is it remote? And more significantly, what kind of nation does the city belong to? Is it wealthy, with a strong military that can provide immediate emergency relief? Or is it a third-world nation that can do little but let the city fend for itself? To return to the example of Japan and Haiti: Japan's earthquake was a major disaster, but the central goverment in Tokyo was able to provide emergency support immediately, and the population in the rest of the country provided a large amount of donations and money. In Haiti, on the other hand, the central government was far less able to provide relief (a fact exacerbated by the fact that Haiti's earthquake crippled the national capital,) and the general population was too poor to provide much internal charity support.

The Event

Given the conditions above, when disasters occur they will have immediate effects of various types. These might be very different depending on the disaster, or they might be combinations of other types of disaster effeects. Before discussing the specifics though, I'd like to note an important distinction between damage and destruction. A structure might suffer damage during a disaster (whether its represented graphically or not) but still be standing. For example, an earthquake can cause cracks in foundations, damaged roofs, and broken possessions; All these would require the owner to pay for repairs, and thus have an economic impact. Destruction, on the other hand, means that structures are completely demolished and must be rebuilt from scratch. With that in mind, let's look at the examples listed above in turn.

Wildfires: Forest or brush fires, these would begin at a random point and spread as an area of conflagration depending on conditions in the surrounding terrain. Buildings or other infrastructure caught up in the area would be damaged or destroyed.

Different disasters can be modeled different ways. Some examples: A wildfire is created as a vector area based on a series of points. The points continue moving as long as there is fuel in their radius, expanding the conflagration area.

A flood, on the other hand, is based on elevation: Anything in the area below the waterline suffers damage.

A tornado creates heavy damage in a small radius, which moves randomly across the landscape, leaving a trail of destruction.

Floods: Floods would generally consist of a temporary rise in water level from rivers, lakes, or the ocean. Damage in this case would be based on elevation, as anything under the water level would suffer damage or be washed away.

Tornadoes: A vortex of high-velocity wind, tornadoes would touch down on a relatively small area and cause destruction and heavy damage; The affected point would move randomly until the tornado dispersed.

Hurricanes: A hurricane would combine several effects, the most significant two being high winds, which would cause random damage in the entire area, and floods.

Earthquakes: Earthquakes would also cause random damage and collapse from shaking across the entire area. They would also be very likely to cause secondary effects like fires and tsunamis, as discussed below.

Volcanic Eruptions: Volcanoes could have several possible effects: The effect from a smaller event might be limited to an ash cloud, which would cause relatively light damage and disruption, especially to agriculture. A severe eruption, on the other hand, could cause magma flows which would destroy anything in their path, as well as raining debris which would cause widespread damage.

Landslides, Mudslides: These would both have a similar mechanic: they would affect an area with a downward gradient, creating a moving zone that would destroy most buildings in its path.

Tsunamis: Tsunamis would have the same mechanics as floods, but with a slightly more destructive effect.

Hailstorms: A weather event that would cause light damage in a wide area.

Blizzards: Although perhaps not causing much direct damage, blizzards would hamper the effect of everything depending on the transportation network, like police, fire, and ambulance services, as well as causing a temporary economic slowdown.

Building Fires: The effect would be similar to a wildfire, but would be initially contained in a single building, leaving a window for the emergency services to put it out before it creates a wider conflagration area.

Dambursts: These would simply trigger a flood disaster, as well as disabling any hydroelectric generation from the dam.

Bridge Collapses: A one-point structure collapse that could occur if a city skimps on maintenace.

Plane Crashes: A random smaller-scale disaster which would cause heavy damage to the impact area.

Toxic Spills: An accidental release of dangerous chemicals, this would make the affected area unusable, and might even have an effect on the groundwater (thus having negative health consequences for the whole city) depending on its location.

Oil Spills: Similar to toxic spills, but affecting an area of water rather than land; this would contaminate coastlines and adversely affect both transporation and the fishing industry.

Industrial Accidents: These could take several forms, be it a simple building fire, a toxic spill, or even a large explosion, which would cause severe damage inside the blast radius.

Meltdowns: A more severe version of the toxic spill, this would make a large area around the meltdown uninhabitable indefinitely, as well as having widespread public health consequences. It could also potentially cause a large-scale explosion.

Clearly, there are a large number of very different mechanics that need to be taken into account when calculating the effects of these disasters. Another point to note is that, depending on the exact nature of the disasters, various secondary effects should be possible: An earthquake, (to turn yet again to a recent example), has a specific effect of its own, but should also have a high probability of causing subsequent effects: fires, tsunamis, even meltdowns.

Aftermath

Even after the immediate effects of these disasters recede, they should still have short and long-term effects on the simulation, depending on the type of event. Some of the most obvious examples would be:

Outages: In the wake of some kinds of disasters, utilities could be disrupted, potentially for a long period. Electricity is a good example: a minor disaster, resulting in some downed power lines, could cause blackouts for a few hours or days; A major event, on the other hand, might damage or destroy generating capacity and force the city to deal with a long-term electricity shortage. Especially if something like the realistic building speed slider was implemented, this would present quite a challenge for the player: not only would it have the usual effects of a power shortage, like hindering growth and decreasing satisfaction, but would act as a multiplier on other kinds of after-effects, as described below. The same could be said for water, sewage, communications, etc., and could even apply to municipal services like hospitals and police.

Shortages: Depending on existing infrastructure, the level of damage sustained, and the city's situation in terms of sourcing basic necessities (like food,) the city could experience shortages in the immediate aftermath of a disasters. This would act as a strong negative to the population's satisfaction which would increase as the situation went unresolved. The duration of the shortage would depend on the availabilitly of internal and external relief, and the speed with which infrastructure could be restored.

Cleanup: Cleanup takes two forms, public and private. The player would have to coordinate the public cleanup, such as clearing debris and rebuilding roads and infrastructure (the level of micromanagement that should be required here is a topic for further discussion). Private cleanup, on the other hand, would be going on behind the scenes: households and businesses in the city would take an economic hit as they are forced to repair more or less severe damage; These kinds of repairs should go on outside the player's control, and would take more or less time depending on factors like the wealth of the population and the speed with which the government is able to restore vital services. In fact, given a poor population and scanty government response, some households might simply abandon their properties.

In addition to short-term effects like the above, there would naturally be long-term fallout from a disaster. These would primarily be economic and demographic effects. For example, a chemical spill could have a negative impact on agriculture-based industries, but could also create a negative modifier to health for the population. Other long-term impacts might not be so obvious at first: since the death toll in disasters tends to be higher among the elderly, the demographics of the city would shift towards a younger population, with all that that implies. Similarly, if the immediate challenges of rebuilding are overcome, the city will benefit from newer infrastructure and better-constructed buildings.

As you can see, disasters can have far-reaching effects for a city sim, and implementing each type will present different challenges. However, if they are done well, disasters have the potential to be one of Metropolis's best features.