[5] Colin has been heavily involved in governmental policy including leading the geomorphology work package in the UK's Foresight flood and coastal defence project.

[12][13] This is achieved by combining and protecting the hydrological and ecological values of the urban landscape while providing resilient and adaptive measures to address future changes in climate, land use, water management, and socio-economic activity in the city.

A Blue-Green City is more than the blue and green infrastructure that it comprises; it is a holistic concept that requires collaboration between government, industry and public stakeholders and partnerships working to be fully implemented.

[14] Blue-Green Cities generate a multitude of environmental, ecological, socio-cultural and economic benefits through integrated planning and management[15] and may be key to future resilience and sustainability of urban environments and processes.

In addition to making the urban environment more resilient to flood and drought events, a Blue-Green City is designed to maximise the use of water as a resource, e.g. through rainwater harvesting, irrigation of river channels, groundwater recharge and as a local amenity.

[16] Water is preferentially attenuated and stored on the surface to maximise the potential environmental and social benefits, and reduce stress on the subsurface piped sewer system.

Blue-Green Cities aim to reintroduce the natural water cycle[11] into urban environments and provide effective measures to manage fluvial (river), coastal, and pluvial (urban runoff or surface water) flooding[17] while championing the concept of multi-functional green space and land use to generate multiple benefits for the environment, society, and the economy.

[20] The concept of Blue-Green Cities involves working with green and blue infrastructure components to secure a sustainable future and generate multiple benefits for the environmental, ecological, social and cultural spheres.

This requires a coordinated approach to water resource and green space management from institutional organisations, industry, academia and local communities and neighbourhoods.

[17] This typically occurs in rural areas with abundant permeable surfaces (soils, green space), trees and vegetation, and natural meandering water courses.

[citation needed] In urban environments water is quickly transported over the impermeable concrete, spending little time on the surface before being redirected underground into a network of pipes and sewers.

[23][24] Land planning and engineering design approaches in Blue-Green Cities aim to be cost effective, resilient, adaptable, and help mitigate against future climate change, while minimising environmental degradation and improving aesthetic and recreational appeal.

[26] Blue-Green Cities favour the holistic approach and aim for interdisciplinary cooperation in water management, urban design, and landscape planning.

DEFRA note, however, that flood risk reduction benefits provided by ecosystems are not well understood[44] and this is an area where more systematic research is needed such as the SWITCH project.

The research consortium led by Colin intends to lead a shift in urban developments to reach the potential shown in these case studies.

A combination of the surface water management plan and community led Learning and Action Alliance[27] was used to select detailed areas to study.

[54] On top of the ecosystem services benefit to carbon sequestration and habitat size, and reduce air pollution, noise and flood risk the Blue-Green city concept was shown to have successfully created resident approval.

[55][56] Multi-benefit analysis was carried out for Wingrove and Newcastle's urban core using the Multiple benefit tool box created by the research consortium.

Evaluation showed that potentially Blue-Green infrastructure in Wingrove would reduce noise and air pollution, increase carbon sequestration and habitat size, and improve access to greenspace for residents.

[64] A variety of innovative solutions have been used in Rotterdam to maximise water management whilst reducing the impacts of developments, which with traditional hard engineering could be costly both economically and spatially.

These include increasing the multi-functionality of dykes, which are needed to reinforce the city against sea level rise, and now have amenities built into their return face.

[68][69][70] The Workshops are designed to present an authoritative review of recent progress in understanding the morphology and processes in gravel bed rivers and each has an accompanying book or special issue journal.

[81] Thorne has been part of a team which suggested a phased sediment management plan to help downstream communities cope with the long lasting impacts which have resulted from the eruption.

[84] Thorne has led field trips for physical geography students from the University of Nottingham to measure channel responses in the North Fork Toutle River.

[85] Thorne was the principal investigator for an analysis of suspended sediment transport data compiled by the US Army Corps of Engineers (USGS).

Colin Thorne provide Expert support on geomorphic and sediment aspects of designing intake and control structures through the Mississippi River for the Coastal Protection and Restoration Authority of Louisiana.

The results of the study have also been presented and are available on the River Restoration Centre website[94] Colin used the iSIS hydrodynamic model to construct a sediment management plan for the Hawkcombe Stream.

The qualitative[101] and quantitative analyses provided a comprehensive vision of possible future flood risk to inform policy development and decision making.

Prof. Colin Thorne attended and moderated panel discussions on ‘The uncertainties and questions regarding restoration to achieve a Stage Zero condition’ and ‘Monitoring approaches and challenges’.

Along with the Upper Deschutes Watershed Council, Thorne has been involved in the Stage Zero restoration of Whychus creek which has created an anastomosing channel in an effort to support increased numbers of anadromous and resident fish, improve stream habitat and expanded biodiversity.