I was recently talking to a potential client around EIA’s and renewable energy. We had both studied similar subjects at university and we were comparing notes around my MSc dissertation which looked at flood risk assessments using historical data and comparing that to a standard modelled flood risk. His PhD was in mathematical modelling so there was some overlap. He knows I can be a little cynical on engineered solutions to problems – especially when those ‘solutions’ badly mirror natural processes. So, when he started talking about Blue Green Infrastructure, I was hooked.
The concept is simple – introduce the natural water cycle back into urban spaces to provide effective management of river, coastal, runoff and flood water. By integrating into multi-use spaces which are functionally equivalent to natural spaces, then water is managed in a way which benefits the environment, society and the economy.
Essentially, there are three types of space in an urban place – grey, green and blue referring to buildings, vegetation and water respectively. Often these are designed and managed as separate entities. However, Blue Green Infrastructure designs in vegetation and water as a single, functioning entity tied together visually, systemically and operationally.
The concept mirrors natural processes but does require a close collaborative relationship between water management, urban design and landscape planning.
There is a whole shopping list of components which can be used in Blue Green Infrastructure. Here are some:
- Bioretention systems;
- Bioretention swales;
- Buffer strips;
- Storage ponds, lakes and reservoirs;
- Controlled storage areas in car parks, playing fields, recreational areas, minor roads and school playgrounds;
- Sand filters;
- Permeable paving;
- Rain gardens;
- River restoration;
- Street parks;
- Pocket parks;
- Planted drainage areas such as green roofs;
- Green outflows; and
- Rehabilitated and enhanced urban water courses;
For me, the key thing is that many of these benefits are experienced outwith any flood or high rainfall event. Then, when the event occurs, the water is managed effectively. Key benefits are:
- Climate change adaptation;
- Better management of surface water;
- Improved air quality;
- Improved quality of life;
- Better access to green space;
- Diversity in green space plants;
- Water pollution control;
- Habitat enhancement;
- Community engagement;
- Quality of place;
- River shading;
- Sediment accumulation reduction;
- Stronger ecosystem resilience;
- Ecological corridors; and
- Healthy soils and reduction in erosion;
Globally, some cities are moving towards this concept. Portland, Oregon has begun its ‘grey-to-green’ inititive as has Melbourne, Australia. Other cities embracing this approach and beginning the journey are Copenhagen, Rotterdam, Lodz, Berlin and New York.