Rethinking fundamentals of urban water systems

To provoke senior water resources engineering students into reassessing fundamental precepts about how we expect to use and dispose of water, I posed some rather ill-considered notions (which I would be pleased to share).

My question now is: are there websites for innovative approaches to urban water management? For example: recycling water in the home, collecting stormwater filtered through permeable paving for non-potable use, distributing untreated water for firefighting, garden watering, etc. (The students are wrestling with concepts for making their designs as close to long-term sustainable as possible e.g. using renewable energy, and zero ecosystem impact). Or is there really little scope for innovative, holistic, sustainable but safe design in new urban developments, other than fine tuning what we have, in countries like Canada? A long question.

You asked about WEB sites:
http://www.jade-mtm.com
http://www.homepower.com

Above that there is a dicussion forum:
e-mail address to the list:
dev-habitat@ihnet.it

possibly also:
http:/www.sifat.org

There seems to be little interest in this topic, on the part of regulators, at least in Alberta and BC. Systems can be designed but they need more input than the typical civil engineer can supply and are true multidisciplnary projects requiring innovative thinking and design processes. This limits progress when most projects will go to the lowest bidder for engineering services.

On the bright side there are projects quietly being undertaken by a wide number of people for progressive clients. I would like to hear about success stories as it would make my life as a consultant easier if I could point to successful projects.

I will pass on a couple of my successes and people can contact me directly if they want more information. I have the pleasure of seeing one 'Zero' discharge stormwater system in operation and another where there is 'zero' sanitary discharge. Both use golf course irrigation as the ultimate disposal system to reduce;

1) the make up water required and
2) the impact on the downstream receiving systems.

Each was designed with the soils (agricultural) impacts taken into account as well as the issues of water quality and treatment.

Some suggestions as you explore this area.

Don't forget the legal issues involved. Plumbing codes in at least some areas of the U.S. prevent the collection and re-use of gray water even for irrigation. Students might want to examine the prevalance of such restrictions, what legitimate objectives they serve, and what changes might be made.

Perhaps a more difficult problem in the western U.S. is our system of water law. The prior appropriation system, used in one form or another in most of the western states, recognizes that some water users depend on the return flows from others. A water user is restricted from expanding his or her use if that expansion would harm another water user. Expansion of the use is relative to historical use.

Collecting and applying to irrigation gray water that has historically run to the sanitary sewer and, for the most part, found its way back to the stream would increase the consumptive use of the water supply and would constitute an expansion of the use.

At first blush, one would argue that the use of gray water for irrigation would reduce the need for a similar quantity of potable water. As long as the saved water is left in the stream there would be no problem. But, the city (the holder of the water right) might be prohibited from delivering the saved water to new users,

The bottom line is that a city might have to enter into a formal "change of use" action and formulate an "augmentation plan" to insure that the stream is made whole. Or, it might not, depending on the local variant of water law.

Variants of the prior appropriation system are in use in arid areas throughout the world, so this might be a fruitful area of study.