Water, buildings and cities

Water is a key element of human survival. So why is it that we haven't made it a priority in our cities? Why is it still illegal in most places to use rainwater or grey water (think used bathroom sink and shower water)?

My understanding of the water issue goes something like this: Water is precious, it forms part of a natural cycle (the water cycle). Although there is an abundance of water in the world, very little of it is potable. The general problem is that we use too much. Things that contribute to this, is the fact that we know very little about the resources used in our buildings. For cars we often want to know what the mpg rating is, but for buildings, do we ever stop to ask what the annual water use (L/year) is or energy use (GJ/year or GJ/year/m^2)? But that is a rant for a future post...

The primary problem in cities, which is increasingly where most of the world lives, is that we have in our infinite engineering wisdom designed cities to take up a lot of room (sprawl), given priority to cars, and in so doing have created a "crust" that deliberately interferes with the water cycle. Water is meant to be held temporarily in the leaves of trees and infiltrated to recharge the aquifer. Some of the water is then released back through plant evapotranspiration and the cycle starts over. Of course nature works rather differently from humans. Nature tries to promote life, while our human solutions don't. This can change!

So, some of the consequences of having all these paved areas are that water speeds up and collects creating flash floods, water is unable to recharge the aquifer, water is unintentionally contaminated with oily car residues and cigarette buds, transferred to a waste water treatment plant where we then use significant amounts of energy to clean it up and then a little more to redistribute it through the use of pumps. This is a problem in my native city, the once prosperous Tenochtitlan, a city surrounded by a lake that now suffers both droughts and floods and is known as Mexico City.

Other bad consequences of paved surfaces are that they contribute to the warming effect of cities, called the urban heat island effect, and they require expensive maintenance which will inevitably disturb you someday when the machines are loudly operating by your front door (and additionally cause you to pay more taxes for what is now called "our aging infrastructure" whereas it could be called "our stupid and short-sighted investment of the past").

OK, so what can we do? Well, we can do better for sure, cause what we are currently doing is wasteful and irresponsible to say the least (we are not securing a bright future for our children). We could use resources better and more consciously. We could design buildings to be sub-metered so that we could understand that our long super-hot showers are perhaps a shameful practice if we claim to be "green" at least giving us the option of making the decision to be wasteful. We could use some rain water and have systems that ensure that we adequately recharge the aquifer. We could plant more trees and have less parking lots.

Similarly, we could begin to try to imitate nature, treat the waste water from our building on site. This is what I believe is the right thing to do, but a lot of this is illegal (depending on where you live) and for a lot of people it means very risky business, so the next thing we have to do is organize and spread the word to help this become legal. We must do research to demonstrate the savings and synergies that exist that will help us reduce our dependence on fossil fuels and live a life that is connected to nature, because nature will then help us heal. Ok, that last part came out a bit spiritual, but it was sincere.

I will conclude this article with a suspicion. I think that overly densified areas are perhaps just as bad as sprawl areas. Is there a balance? I suspect that the balance is NOT more high-rises, specially when we consider other social dimensions of urban life.