Urban ecology and the design of a green infrastructure network based on catchments for urban Auckland, New Zealand : the Oakley Creek Catchment case study

Abstract

RESEARCH QUESTIONS:

Main question: How can a catchment-based green infrastructure network better achieve low-impact storm water attenuation goals for urban and community development in Auckland in the context of climate change?

Sub-questions: How well does existing green infrastructure deal with flooding and seconding pollution issues via existing overland flows and stormwater management?

How can Low-Impact Design (LID) and stormwater management methods better utilize a range of values (i.e., ecological, economic and social) to accomplish urban design objectives for Auckland city?

Within the boundaries of unitary plan, is it possible to create a Green Infrastructure Network (GIN) that provides positive environmental change for urban development?

The pressures of global population growth, migration and increasing urban densities present significant issues which can negatively impact on the health of cities. These pressures are more evident in midsize global cities (Allen et al., 2016) where there are often significant conflicts between the development of human infrastructure and the maintenance of natural ecosystems. The conflict leads many times to major environmental degradation.

Urban studies tend to describe development patterns negatively, and often point to environmental problems that stem from development, such as landscape fragmentation (Forman, 2014), degrading water quality (Marjorie van Roon et al., 2004), flooding and increasing water-borne pollution (Pickett et al., 2013; Pickett & Cadenasso, 2007), reduction of green space and biodiversity (Wu, 2014). However, many of these authors reflect on the values and opportunities that arise from urban development to link ecology and urban development through green space networks as described by Borrett (2014), Derbyshire and Wright (2014), Li et al. (2015) and Niemelä (1999).

This project explores a new, valuable and sustainable urban development paradigm through creating a new Green Infrastructure Network (GIN) model based on hydrological catchment in urban Auckland. This GIN connects current LID and WSD stormwater management practices, as is already in use at present, with a new sustainable spatial mode for intensified urban area.

The Oakley Creek catchment is used as a case study to show the details and functions of the GIN. Through classifying Oakley Creek catchment into four scales: 1 block scale; 2 neighbourhood scale; 3 community scale and 4 urban stream scale to form a ‘nested catchment’.

Then manage the catchment by designed GIN nodes and corridors to deal with multiple urban environmental and hydrological issues.

Additionally, design a local area network (LAN) model and shared infrastructures in the GIN to create social and economic benefits to the local community. The new GIN and LAN models show the interrelated character of ecological, social and economic conditions in a local community design.