GEOG 346: Day 22Chapter 8, etc.

Housekeeping Items Deanna will present today. The article on retail is on my web site. We’ll go through Chapter 8, and if we have time I’ll show you

a student project from last year that Linda brought to my attention.

I put a few pages in the folder of that report on new urbanist vs. conventional subdivisions.

You asked for some pictures of Charleson Park in Vancouver. Here are some:

‘Business as Usual’ Infrastructure Hard infrastructure consists of roads, water mains,

storm sewers, and sanitary sewers. This chapter focuses mainly on storm sewers and alternatives thereto.

Alienates people from nature and is often even more expensive.

The more sprawl there is, the more infrastructure has to be paid for, and typically development cost charges (DCCs) don’t pay for these.

The infrastructure deficit for Canadian municipalities, as noted by Condon and others, exceeds $125 billion.

Condon’s Alternative “Green infrastructure” for roads and stormwater

drainage. He doesn’t focus as much on municipal water and sanitary systems, though others have.

He starts out by arguing that conventional stormwater systems are a disaster because they abuse water, the most important element, he argues, of any ecological system.

Condon’s Alternative As natural drainage systems become urbanized, they

begin to see immediate degradation – even once they reach a point of 10% imperviousness. The greater the percentage, the worse it gets.

Imperviousness has a number of negative effects vis-à-vis the hydrological cycle.

Condon’s Alternative The consequences include: instead of much of the

water being absorbed and infiltrating, and thereby feeding ground-water and interflow to streams and rivers, it runs off into storm sewers loaded with contaminants;

it also increases sediment loading in water bodies and greatly increases streambank erosion

there is a loss of fish habitat – for instance, salmon habitat;

Condon’s Alternative Further consequences

include: people are alienated from

nature and can’t see fish spawning;

the “urban heat island” effect is made worse.

With roofs, parking lots, streets and roads, driveways, sidewalks, and patios, imperviousness can reach close to 100% in urban areas.

Condon’s Alternative In the U.S., the passage of the Clean Water Act in 1972

was a victory for water quality but, as Condon points out, not necessarily for water quantity, which is equally essential to the health of the hydrological system.

In 1999, the U.S. Fish and Wildlife Service made use of provisions in the Endangered Species Act to declare five species of Pacific salmon “endangered” and mandated that they be protected against logging and urbanization activity.

In Canada, the closest comparative piece of legislation is the Fisheries Act under the administration of Department of Fisheries and Oceans. However, apparently, the Conservatives have gutted the Act.

Condon’s Alternative Both cities and

salmon tend to favour the same areas – areas with a low grade (for salmon 1 - 4°). As a result, Vancouver has lost all but two of its sixty salmon-spawning streams over the last century and a half.

Condon’s Alternative Condon wants to emulate, as much as possible, a natural

drainage system where a maximum of 10% of all rainfall runs off, and he cites numerous examples where this has been partly achieved. Key elements would include:

narrow roads, possible with porous shoulders

smaller building footprints,

and riparian buffers with continuous tree cover.

Green roofs could be a part of this, but he emphasizes that green roofs in the absence of a comprehensive stormwater management plan are of limited value.

He feels retention ponds are also of limited value in that they may overflow and only filter 50% or less of pollutants.

Condon’s Alternative A key element is a minimum 30-metre setback

from all streams and watercourses. This has the benefit of shading fish-bearing streams, providing fallen logs – places for fish to hide – and corridors for wildlife to use.

Condon’s Alternative His more detailed ground rules are: infiltrate, infiltrate, infiltrate design for one inch of infiltration per day (Amble Green in

South Surrey manages 4 inches – equivalent to a 100-year flood event)

infiltrate everywhere possible, and don’t neglect that heavy soils can be a part of the solution.

Condon’s Alternative He also notes that soil management practices need to

change. Typically, soil is scraped off a site prior to development.

He advocates stockpiling it, avoiding compaction, covering it so it doesn’t wash off, and then re-applying it.

He also advocates using permeable paving surfaces where load-bearing surfaces are required.

Condon’s Alternative Vancouver has a “country lane” program…

Condon’s Alternative Condon spearheaded an alternative stormwater management

system in East Clayton, Surrey, but the city engineers made the developer put in a back-up conventional system for risk protection which removed all financial incentive for future developers.

In addition to alternative stormwater systems, eliminating combined sewer overflows (CSOs), as still exist in parts of Vancouver, is a must.

Friedrichstrasse Block 6 stormwater system

Bioworks for sewage treatment in Kolding, Denmark