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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Studying at Cambridge

 

Oliver John Marr

The Role of Green Infrastructure in Habitat Connectivity for Future Cities

Biodiversity is highly dependent on the presence of open, natural space. However, urbanisation has led to the rapid decline of such areas.  This is exacerbated by grey solutions that attempt to mitigate the increasing flood risk posed by climate breakdown.  As such, alternative methods of promoting biodiversity must be employed. One such method involves increasing the connectivity between existing patches of natural habitat, thereby creating networks of green space within the urban matrix.   

This dissertation examines the extent to which green infrastructure (GI) such as Sustainable Drainage Systems (SuDS) can contribute to these networks. To better understand the role of SuDS in functional habitat connectivity between natural spaces in an urban environment and to identify how SuDS design and planning might be leveraged to enhance this, the study uses data from Sentinel 2B, SuDS master plans, and Geographic Imaging Software (GIS) to model the connectivity of several areas around London, including Sutton and Ebbsfleet.   

The model combines the SuDS master plans with pre-existing green space and uses a graph theory approach to assess the influence of different SuDS elements on habitat connectivity.   

The following study addresses challenges and opportunities that exist for biodiversity within an urban context, and uses the findings to suggest strategies for urban connectivity at a macro, systems level (e.g., the integration of ecological corridors and steppingstones into urban infrastructure) and at a micro, local level (e.g., the physical design of the structures that form these components).  

The dissertation highlights that functional habitat connectivity can be increased most significantly with a combination of SuDS elements such as green roofs, swales, retention ponds, rain gardens, and street trees, and by focussing on structure and vegetation heterogeneity in SuDS design. The study demonstrates that of all SuDS elements, green roofs have the greatest potential to increase connectivity, particularly in areas with limited space. In areas with pre-existing natural space, it was seen that retention ponds play a valuable role in connectivity and that care should be taken when converting natural land to retention ponds that this value is not reduced or lost due to a reduction in structure and vegetation heterogeneity. Ultimately, this research demonstrates that urban planning centred around green solutions can significantly enhance functional habitat connectivity within the urban matrix.