I have been thinking about how we change the land and environment with our projects. Part of my family lives in Calgary Ab Canada. And had their house flooded last year. This house is over 100 years old and this is the first flood it has seen. I grew up in Calgary and it is a sprawling city and still growing... What I see is that water that would normally have an opportunity to soak into the ground are caught by roofs and streets(and sidewalks) and routed to sewers and into the rivers that overflowed. Considering a city lot that is 50x100 feet (yes some are that small) and a 50foot width of road in front and a roof that is 1200sqft, that is a large percentage of rainfall that is being sent to the sewer. Calgary is not a wet city. I moved away because the dry air gave me nose bleeds.
Other places use the ground water so much the level of the land has fallen.
So what about house styles that use an umbrella of sealing material to keep a large chunk of earth dry to use as mass? I think most of these are built outside the city to allow proper siting or less code problems or because the builder who wants something like this is looking to be off grid. But what if someone decided to create a PAHS subdivision? It would seem that the underground umbrellas would tend to interconnect (drainage would be more of a problem too). Would this make runoff problems even worse? What would happen to the ground water level?
On the plus side
interconnected umbrellas would work really well. In fact (assuming the sides are facing the next house) if the sides are connected then probably the front and back parts could be less than 20 feet. A 20ft umbrella increases the house foot print 3 to 4 times (or more).
Would a single floor four-plex need less umbrella? Or to rephrase, does the need for thermal mass go down with inside area? While I do know of a successful small high mass home with seemingly very small umbrella, it is built on a rock ledge (granite I think) and that may have the effect of creating a very large heat mass without an umbrella. Would making the heat storage lower help? are there correct ways of landscaping over top of the heat storage?
I love the idea of staying comfortable without using fuel, but maybe this will not "save the world". I will not even start into the question of how large should a city be? The idea of a PAHS house is lighten the load on earth so it lasts longer, I think we need to be careful in the design to make sure it does.
