Week 12: Case Studies

Question 1

What was the initial urban form of Detroit?

Answer 1

Impervious (road transport, grid, etc.)

Dense downtown. Large-scale centralised attractions, etc.

Question 2

Detroit’s local climate can be described as having very cold winters, hot summers, precipitation & snowfall, and frequent thunderstorms in spring and summer.

What effect would these climate characteristics have on SW management?

Answer 2

• Plant growth/biological process rates swing between seasons
• Deicing chemicals. Thawing of ice in spring –> large flows
• Intense thunder storms. intense pulses of rain.

Question 3

What is the local topography and soils of Detroit?

Answer 3

• Clay soils
• Largely flat, low-lying topography

This leads to ineffective natural infiltration and ponding/surface flooding.

Question 4

What kind of issues were there in Detroit?

Answer 4

• Gasoline crises, auto industry struggling (job losses, plants closed)
• Decreasing population
• Social inequality
• Urban blight

Question 5

What is urban blight?

Answer 5

• Urban decay
• Urban rot
• Where a previously functioning urban area falls into disrepair and neglect

Question 6

What are the drivers of urban blight?

Answer 6

• De-industrialisation
• Changes in population
• High local unemployment
• Crime
• Abandonment of buildings and urban infrastructure
• Social instability
• Urban planing decisions
• Mobility and accessibility

1/5th of properties are blighted.

Question 7

What stormwater issues were there in Detroit?

Answer 7

• > 500 km of streams buried in pipes within the city
• Combined sewer systems overloaded (combined sewer overflows to river, significant investment required to upgrade, 30 Mm^3 of untreated WW discharge to Great Lakes)
• Problems such as pollution of local waterways via CS overflows, flooding of basements, roads

Question 8

What were Detroit’s stormwater solutions?

Answer 8

• US$50 million committed to be spent over next 25 years in green infrastructure
• Downpipe disconnections, bioretention gardens in vacant lots, tree planting, bioswales, permeable paving, wetlands
• Availability of unused urban space (frequest, small SW management systems, protect downstream catchments)
• Engaging with local community (flyers, workshops, school demonstrations)
• Research opportunity

Question 9

What was some of the land damage caused by the Canterbury Earthquakes?

(OARC)

Answer 9

• Liquefaction
• Lateral spread
• Ground cracking
• Settlement

Question 10

What can cause liquefaction?

(OARC)

Answer 10

• Area with loose sands or silts
• High GW table
• EQ

Question 11

What can cause lateral spreading?

(OARC)

Answer 11

• Can occur following liquefaction
• Sloping ground
• Near rivers and streams
• Movement towards free face

Question 12

In the Residential Red Zone, ____ is not suitable.

(OARC)

Answer 12

Long term housing

Question 13

The OARC Regeneration Plan outlines 3 Chapters:

(OARC)

Answer 13

1. Vision and Objectives
2. A view for the Future
3. Transformation over Time

Question 14

The OARC Regeneration Plan aims to:

(OARC)

Answer 14

• Create a restored native habitat with good WQ –> abundant source of mahinga kai, birdlife, native species.
• Support safe, strong & healthy communities
• Community participation, recreation and leisure
• Sustainable economic activity and connections that enhance our well-being and prosperity now and into the future.

Question 15

What were the Wainoni site challenges?

(OARC)

Answer 15

• Tidally influenced river levels
• Rising sea levels
• High groundwater
• Loose sandy and silty soils
• Free face of river bank
• Conaminated land
• Integration with other projects (City to Sea, etc.)