There's a lot that can be done on a neighbourhood level to clean up stormwater before it enters the stormwater pits and ends up in the Yarra. And one of the bonuses of treating and capturing stormwater is that one of the best ways to do it is to create nice lush green garden beds.
A lot of developers building new subdivisions out in Doreen or on the dry Western Plains, love treating stormwater because it's pretty much the only way they can create green public landscapes with current water restrictions. And really, it is crazy to let all that water drain directly into the Yarra when we could have it soaking into our soil right here.

The image above shows a section of Charlotte Street showing the existing road profile, and stormwater treatment. So basically the water runs over the road, picking up pollutants on the way, and then falls directly into the drain, where it flows on into the Yarra and does significant damage.

There's lots of ways to introduce stormwater treatment, and some of them require very little changes to the existing kerb and road layout - but the solution I've drawn up here is a little more elaborate.

What we could do is remove the kerbs altogether and allow the road and footpath surface to slope gently down to a vegetated swale (or mini wetland) on one side of the road . The green strappy leaved plants in the swale act to clean and filter the water before it reaches the drains (click here to see plan showing possible location of swale). We could store our stormwater in underground tanks so that we can use it for watering public landscapes. And the whole system can be designed so that in a storm event any overflow will be carried away by the existing stormwater infrastructure.

image of a stormwater treatment swale in the docklands from WSUD an organisation dealing with water sensitive urban design in Sydney, which provides lots of useful practical information.

At the moment all the fresh drinking water we use to shower in and to do our laundry is going straight down the drain after a single use. On top of that, most of us are using more fresh drinking water to water our gardens.

This is a shame - because treating greywater on a neighbourhood scale is pretty straightforward - in principle at least.

Here's a plan showing a possible integrated blackwater, greywater and stormwater treatment system. I’ll run over the possibilities for greywater now, and cover blackwater and stormwater in later posts.

There's a lot of greywater capturing & storage devices out there which individual households can use for their own gardens. Because the greywater isn't processed, each household would have to manage their choice of laundry and toiletry products so that the water was suitable for their garden, or else use the unprocessed greywater on ornament plants which are tolerant of the salts and chemicals it contains. Subsurface delivery systems are recommended (less health risk).

But if we think on a larger scale we can do a lot more with our greywater. We could divert the water we use for washing from entering the main sewerage system and have it carried from our laundry and showers by underground pipes to a series of reed beds housed in a greenhouse located in the existing community garden area.

This reed bed will be capable of processing our greywater, regardless of products used in it, to a level where it is safe for use on all plants (including edible plants). Strictly speaking it would be potable, but the recommendation is that you use this kind of water for everything except drinking.

This wouldn't be a cheap intervention, and I imagine the main cost would be in upgrading the existing sewage infrastructure. Of course it depends on who is paying the bill. If we cover the cost as residents, then it will probably take a long time before it pays for itself (assuming water stays as cheap as it is) - but if state government decided to invest in the local treatment and recycling of our water then it would have the benefit of helping to relieve the pressure and cost of maintaining and upgrading our major centralised infrastructure, and maybe then it's not such a bad deal.

In terms of infrastucture the most complicated aspect would probably be setting up the plumbing to capture the greywater in individual houses - some houses in our neighbourhood have suspended timber floors and would be pretty straightforward, but others would be quite difficult. Digging down to the existing sewage and running an greywater pipe alongside wouldn't be technically difficult, but would require a significant amount of earth works.

So what are the benefits of having a greywater treatment system? Well, we'd reduce the amount of drinking water we use for watering the garden (and possibly, for flushing our toilets) which would in turn reduce the pressure on the existing infrastructure, and it would be easier to keep our gardens and street tree's alive in summer. And we'd also reduce the amount of water entering the sewage system, with flow on benefits to existing treatment systems, and the amount of water entering the bay.

It's a rainy Sunday morning and it's pouring down outside as I write this - everything is getting a really good soaking.

This is great news for our gardens and street trees - but not so good for the poor old Yarra River. Tomorrow, when Yarra Watch measure the contamination in the river, they'll find higher levels of toxins and bacteria than before the rain.

Everyone knows that the Yarra is sick, we've all heard about the kayakers with leptospirosis and the dead eels, but why? No doubt part of the problem is fertilizers and animal poo from farms in the Upper Yarra, or more disturbingly; businesses like Amcor Packaging in Abbotsford who illegally wash toxins into the river, but I can't just blame other people for the problem. The sad fact is that a large part of the pollution is from neighbourhoods like ours, on nice wet days like today.

As I write this, all that rainwater is running over the road, and the footpaths, and down the gutter to the stormwater pits. On the way the rainwater is picking up pollutants from the surface - including petrochemicals, oils, rubbish, dog poo, detergents and organic matter, which are washed into the drains by the water. By this afternoon, all of that water and pollution is going to end up in the Yarra River. (For a more comprehensive listof pollutants and their effects click here).

So what can we do? On an individual level - not a hell of a lot. We can pick up litter, wash the car in a carwash, and report anyone putting anything nasty where it will end up in the drains. As a neighbourhood however, we can do a lot.

Basically, the best thing we can do is retain and use as much of the water here in our neighbourhood as possible, and then make sure the water that ends up in the stormwater system is clean before it gets to the Yarra.

I've got a couple of ideas on how we could apply some water sensitive urban design measure here in our neighbourhood, I'll draw them up and post them shortly.

The photo above left is one of the stormwater pits in our neighbourhood, taken today during a brief hiatus in the rainfall. Click image to see larger

I've been writing a post on possible strategies for dealing with stormwater in our neighbourhood (inspired by the wet wet day we've had today). But I thought I might post a quick roundup on the weeks water news...

Water costs tipped to more than double
Because of the cost of new infrastructure, and the fact that the water supplies are at 30.6%, down about 5% from this time last year. So maybe, contrary to my earlier suggestion, an investment in water infrastructure could end up paying for itself afterall...

and...

Bizarre solutions to water crisis
Apparently someone in the Queenland government said something about shipping water from Japan.

and...

Rainwater tanks could save public $600m
Taxpayers could save big money if all new houses installed tanks and raingardens - apparently a lot of that saving is from reducing the amount of water which enters the stormwater system.

One of the key jobs to do if we to make our neighbourhood sustainable, or our home, is to reduce our reliance on large scale centralised infrastructure and maximise our use of local resources. In other words; become more 'self-sufficient'. And harvesting our own rainwater is a relatively easy place for us to start.

Each time we turn on the tap, fresh clean water is there for us to drink, wash our clothes in or rinse out the left-over weet-bix from breakfast. It's so easy, and so available, that it's easy to forget the massive engineering feat, and ongoing maintenance, that makes it possible. And easy to forget that each drop of water in my kitchen tap has traveled about 80 odd km from the to top of the Yarra River to reach it.


I've been reading a little about Melbourne's water system - and it really is a massive piece of infrastructure. The system as it stands really started in the 1920's, and eight or nine new reservoirs have been created through the decades to supply Melbourne's increasing demands up until the completion of Sugarloaf Reservoir in the early 80's. Along with new reservoirs, huge systems of pipes have been constructed to transport the water from the hills to the city. Areas of the conduit have diameters of 2.1m - you could walk upright inside!

So it makes sense to harvest water locally to reduce the pressure on all that infrastructure.

If self-sufficiency is our goal, does that mean we need to go all the way and sever ourselves from the existing water infrastructure? I don't think so. Surely there's a good point of balance between total self-sufficiency and a centralised system? If we do everything we can to reduce our demands on the existing water system, then we can use still it as a 'back-up' or booster for our local water harvesting systems, but because we're relying on local water supplies we could relieve the water crisis without expanding the centralised system, which we could only really do by finding new valleys to flood and turn into reservoirs.

The other reason it might be better to remain connected to the system is that it may not be such good idea to try and produce our own drinking water. I'm going to look into that further, but my feeling is that responsibility for ensuring the quality of our drinking water is probably a good thing to centralise, which probably also means centralised harvesting and treatment.

But drinking water is only a small percentage of our water needs. We can certainly collect rain-water from our roofs and use it for gardens, dishwashers, washing machines and maybe showers. For everything really, except drinking.

The easiest way to do this is to install water tanks. There's an ever growing choice of water tanks suitable for individual residences, some of them are surprisingly attractive. But many people who live in our neighborhood with our tiny back yards (if any) don't have a lot of room to spare for a water tank...

If you're trying to make your own individual house sustainable, you would look at 'small space' tank solutions - skinny wall tanks, under deck tanks, underground tanks or under house 'bladders'. But for this hypothetical design project, I'm thinking on a neighbourhood scale, so if the water tanks become part of the 'public' or communal infrastructure why not put them under the roads? Of course I haven't done any kind of detailed costing on this proposal, but it seems likely that the cost may be comparable to the expense of installing individual tanks in each house in the neighbourhood.

Of course one of the 'problems' with installing water sustainability measures is the current artificial cheapness of water. So it takes a long time (if ever) for you to recoup your money. Of course; it does mean you can have nice green plants in summer.

Earlier this week I went to talk about this project to Dominique Hes who gave me some useful feedback, which included pointing me in a new direction in terms of treating and reusing waste.

In earlier plans I had drawn a distributed system of blackwater treatment facilities, but Dominque pointed out that maintenance of several small scale plants would be a major problem, and I mean, you really don’t want your blackwater treatment system to go wrong!

For some more ideas Dominique referred me to a project called EVA Lanxmeer in the Netherlands which she has used as a case study in her recent paper: “Opportunities for Semi-Decentralised Water Reuse and Power Production in High Density Areas.”

EVA Lanxmeer is a small community in Culemborg. In some ways it’s comparable in size to our neighbourhood; there's about 250 homes with a small commercial/education area.


It is designed to not produce dust, odour or noise. And it’s estimated that the system as a whole will save 194 kg/home/yr of CO2 emissions. Not bad.

This system is not completely detached from existing infrastructure for waste treatment, water and energy – it’s not completely self sufficient, but it promises a workable balance between localised management and production and the inefficient centralised systems we use now.

This plant needs a sizeable space, but we do have the room to do this in our neighbourhood! The warehouse on the corner of Wellington and Hotham is currently vacant; developers were trying to turn it into apartments but the proposal appears to have either failed to make it through VCAT (our system for dealing with planning/development conflicts), or lost momentum in some other way.

The warehouse has a large floor area and is located in our proposed neighbourhood activity centre. It would be a great site for a environmentally sustainable six star (or equivalent) mixed use development. And this development could house our community black water treatment plant in its basement. Perfect.