Conservation Design - Why and How we do it.

This post is for those of you who don't understand the fuss over Conservation Design, or Open Space Subdivision planning and development. It's not that complicated, but too often the reasons for doing it are overlooked, misunderstood, or held in suspicion by people who simply have not been properly shown what it's about.

In HRM, during the development of the Regional Plan, we took a good look at how this form of development might work, and planners attempted to write policy that would encourage it. Unfortunately, all that has really resulted is a clever, backhanded response by developers and their design consultants, to create the same unsustainable sprawl, with a commensurate lack of open space creation, as had been the rule before the Regional Plan implementation.

So, here, briefly, is a small example that shows the reasons why we should be doing this more. It's not because the result creates a more efficient way to live. It's not because it creates a more attractive place to live in. It's not because it results in better profit margins for the developer. And it's not because the result is a better environmental and public health outcome. It's because, done right, it's all of that and more.

Here is a sample piece of land mapping.

We have many things that are common to developing in Nova Scotia, especially in the areas of HRM under development pressure. Open, bare rock, lakes, wetland, places with some good soil, and land sloping to lakes.

To a developer, or anyone wanting to live here, that lakefront is the main draw. A developer wants to build a road to access that land, create as many lots along the lake as possible, and sell them quickly, with a minimal initial investment. Government, representing the public's desires, wants to limit the amount of road frontage per home to reduce future costs of maintenance, keep the sewage away from the lake, keep the sewage away from drinking water wells, and, where government is moderately enlightened, create open space that is connected to the lake, and other open space - a connectivity of open space that the deer and birds and other wildlife can use to get around without too much trouble from us.

Currently, the figure below shows the reflex reaction to this land by current development practice. Lots are limited in size individually because they will all have both a well and an on-site sewage disposal (septic)system on them. Their size is directly related to how good and deep the soil cover is on them.

Note the lots on the high side of the road have part of them in dirt, part on rock. That part with the dirt is for the septic system.

In this example, there are several septic systems that, although legally OK in terms of their clearance from a downslope well, are still above, and therefore upstream of someone else's well based drinking water supply. The road has to be extended is a long way in order to create the minimum frontage per lot required by the subdivision bylaws, and also to create a minimum width of a lot required by the Provincial Environment Regulations. Note also that there are 15 lots, and 6 have waterfront.

If this same land were treated as a clustered development, sharing water and sewer, it could be done quite differently.

In this layout, there are several major improvements. First, the number of lots is the same, and the number of waterfront lots is one more, but all the lots enjoy a common access to the lake. The road is much shorter, and therefore costs less to build and disrupts less land. Septic systems are not located all along the edge of the lake, but are replaced by a large shared system that can also become a part of a walking trail. There is, in this example, one well, shared among all the homes, and that is located far from the septic system, and in a location where perhaps even a dug well might work.

Most important, however, is the difference in land not taken over for development. The conservation of open space, mostly lands not that suitable for development anyway, and in a connected pattern, is far greater here. It's not logged and turned into lawns. It is available for wildlife, and for play.

This is a form of development that can result in a developer doing as well, or better from their land.  They can create a neighbourhood that, presumably, more people would want to live in.  The outcome should be at least the same number of lots, but with less investment in roads, and hopefully more lots in locations where people want their homes to be. The result, especially if practiced in a planned concerted effort with neighbouring land owners, should be development that maintains the connectivity of the ecosystem.  Servicing would be safer, and more reliable.  The cost of servicing could be less, and no more than 15 individual systems.  And it could be managed by the Municipal unit on a cost recovery basis, so we would know the system is actually working.

I have been a proponent of this approach, with central water supplied by a Municipality, for a long time.  As in: If you build it this way, we will allow access to "city water".  And if you build the sewage treatment to our specifications, we will take it over and pay for it with an area rate.  It's hard to believe how Halifax Water readily takes over huge expensive pumping stations that only add to their existing problems and costs at the waterfront treatment plants, and mean more effluent being discharged to the aquatic environment, but is apparently afraid of having to look after a small treatment plant with no outfall to a watercourse.  

We can and should use our expensive (geosmin laden) water supply as a carrot, or a beneficial tool, to direct development to where it is best for the Municipality, and not just for some quasi-independent water utility.   Shared sewage systems, operated on a cost recovery basis by the Municipality,  is the approach that is now taken in most North American jurisdictions, because it presents a far better environmental solution than simply connecting more people to the big treatment plants, sometimes miles away, that still don't work right, and never will get better.  In this case, the liquid effluent goes into the ground (as already suggested by existing design guidelines for sewage treatment), and the solids go to stabilization and composting.  Ultimately, they should return to the land as fertilizer, being free from the industrial concerns of a "Burnside mix" because this waste doesn't get added to the Big Pipe.  (If you are still afraid of fertilizer made from human waste, look up "Milorganite".)

All that is required is for our Governmental institutions to enter the 21st century and work at managing clusters of development on smaller, in-ground dispersal, sewage treatment systems.  Most other medium scale rural development such as condos, golf clubs, schools, rental cottages, camp grounds, and recreational facilities already rely on the same solutions.  In fact the Halifax Regional School Board is probably better at this that our illustrious Halifax Water utility, who have, apparently, not yet figured out that, in most things, Big is Stupid.  I mean, nothing could ever go wrong with a huge treatment plant serving all the peninsula, right?