Designed for Water

The sound of the rain on your roof, lovely umbrellas, the gorgeous smell, going out looking for puddles in your wellie boots…

Traditionally when we develop new urban areas we put a whole series of pipes under the ground to capture all of the stormwater running off from the new surfaces (houses, carparks, roads etc.) , which takes all the water away somewhere else to be managed.

Stormwater is water flowing over ground surfaces in natural streams and drains as a direct result of rainfall over a catchment.

This comes from the fundamental idea that humans must control the environment in order to make it comfortable for civalised society. So we put massive pipes which supposed to be designed to capture the HUGE rain events, the kind we get once every 100 years or so and fair enough, I don’t want my house being flooded, even if its once a century. The problem is that these systems capture the water from all rain events even the little ones we get somewhat frequently in winter. It was believed that all rainfall events posed a flooding risk due to the dregree of imperviousness of the built environment. Why is that a problem? Surely that is a good thing, design for worse case scenario and everything smaller is neligible.

Well the problems occur when you consider where all this water ends up. Down the stromwater drains on the side of the road, into a pipe and off to some drainage sump, constructed compensation basin, bushland or watercourse. Sometimes this is far away from where it fell, mostly it is not treated to get rid of contaminants (like hydrocarbons from the road), often you get very pretty pipes jutting out over the water, and sometimes it causes erosion because all the water is hitting one spot. To be honest, they don’t seem to be doing a fantastic job, given the unbelievable amount of chaos and flooding of roads that happens everytime we get a heavy rain in Perth.

The idea behind ‘Water Sensitive Urban Design’ is to design developments so that the rains which happen most often are dealt with on site, as close as possible to where they fell through either infiltration or water capture and reuse leaving only high intensity rainfall evenst to be managed in the old way (making it a bit less stressful on them).

Need a quick brush up on the water cycle? High school too long ago? Agreed.

Nice things about Water Sensitive Urban Design;

– Water can infiltrate into the ground close to the source (recharging local groundwater aquifers)

– It results in better water quality as water is filtered by plants (less contaminants reaching the groundwater). Plants are really great at pulling yucky stuff out of water, a bit like artifical kidneys.

– No more fenced-off-ugly-weed-infested drainage areas (can you tell I dont like them?), you know the ones I mean.

– Pretty public open space areas with lovely vegetated swale, emphemeral (dry in summer, wet in winter) creek beds with lovely rocks, living streams, wetlands etc.

– It can encourage and supports the growth of large trees which keep the water table down, which means less salt and other nastiest like Acid Sulfate Soils, provide shade, and habitat for animals, children and children-like-adults.

Here are some examples to demonstrate;

These are drainage areas in a public open space development (wet in winter, dry in summer).These are biofilters, which are designed to capture run off from hard surfaces like roads and such.There are other things included in Water Sensitive Urban Design like rainwater tanks, permeable paving (which allows water to infiltrate it) and more hard engineering like underground litter traps and soak wells.

Most importantly its about designing urban spaces to work with water rather than against it. Use it rather than collect it and get it as far away as possible.

Have a look at the New Waterways website, its full an fantastic info on the subject.

Thoughts? Would you like some bigger scale examples? Let me know.


Our water suplies are running out.

This figure is from the Water Corporations document ‘Water Forever – Towards Climate Resiliance’, 2009:

Experts are predicting the next world war will be over water….. a war over water within my lifetime (lets be generous and give me another 65 years). We could look back and say that we didnt know, but it wouldnt be true.

I am a firm believer in human ingenuity and its very likely that technology will come to the rescue yet again and dirvert us from the path of disaster. However, this doesnt mean that we should all just sit around twiddling our thumbs and waiting for all those incredible scientists and engineers to work it out on our behalf. Our excessive water use is causing a problem right now, just look at the Murray Darling Basin as just one of thousands of examples. Plus, I think it would be pretty great of us to give these great people a bit more time to work the problem out, this will undoubtably give us a better solution.

We are already looking at alternative supplies; pipes from wetter neighbours, recycling, desalination etc.

“Over the next 50 years, it is expected that existing surface water and groundwater sources will comprise an increasingly smaller portion of public water supply. As the climate dries the focus of new source development will continue to favour rainfall independent sources such as recycling and desalination.” (Water Corporation, 2009)

Climate change is a major consideration. Through a process being dubbed “future proofing” organisations are planning how to adapt to the changing climatic conditions. I find it so interesting that we have moved the focus from stopping climate change to adapting to it. So new “rainfall independant” sources are appearing more often in strategic planning documents for water supply.

A hugely popular one both in the Australia and internationally is desalination.

Wiki ->

In my opinion desalination is not the most elegant of solutions.I believe that sustainable solutions work with the existing natural cycles. Are we solving a problem by creating another?  How will its greenhouse gas emissions be managed? (an issue which caused climatic change and the reduced rainfall which led to the need for desalination.. )

Pwer supply (peak oil, coal industry decline etc) have been a pressing issue for quite some time and research and development focussed on this issue is far more advanced than the industry for water supply. So it is possible that it is far enough ahead to be able to solve this issue pretty quickly once desalination and the like kick off. Although the economic considerations seem to drag and holds back great technology because they are not cost effective (a very valid concern).

Perth’s Kwinana desalination plant is wind powered, although they could have easily gone with non renewable power and i’m guessing it probably would have been cheaper. Great work though :)

The EPA (Environmental Protection Agency of Western Australia) did some very extensive investigations into the environmental impact of the proposed desalination plants in Perth. The EPA’s document “Southern Seawater Desalination Project – Water Corporation, Report and Recommendations of the Environmental Protection Authority” of October 2008 states:

“The EPA has concluded that Environmental Quality Objectives can be met subject to the proponent complying with the recommended conditions which provide for the identification of trigger levels, monitoring, reporting and contingency measures. The EPA considers the effects on biota including marine mammals and benthic habitat relating to the construction of the intake and outfall structures should be limited in area and duration, and best practice design and management measures should minimise impacts.”

The EPA also supported the Water Corporations proposal to offset the native vegetation removed to built the plant and the damage to a conservation catergory wetland, and bestowed on them a long list of regulatory conditions.

The social impact which was not considered by the EPA of the location on a pristine beach which has high community value was mentioned a lot in the public consultation. I don’t know how much that was considered, I will atempt to find the planning decision (either the Town of Kwinana or the Western Australian Planning Commission). However either way, a desalination, no matter how urgent, will be placed on a beach close to a city – this will always cause the community some loss.

It seems unnecessarily ugly and disruptive in my opinion.

People need water (of course) so I’m not disputing the fact that we need to face this issue. I believe that we shouldn’t give up on being able to make real changes in the way we use the water we have!

We can use water as close to possible to its source (to avoid treatment, infrastructure and evaporation) by installing water tanks on all houses, developing using awesome water sensitive urban design techniques (follow up post to come on this!), standard water efficiency for our stuff, developing water recycling technology etc.

We can make it beautiful, elegant, and engaging instead of grey, damaging and boring. The solution for the long term has got to be something that mimics nature.