Blue space

In urban planning and design, blue space or blue infrastructure refers to all the areas which have bodies of water or water courses (that is lakes, rivers, and bays). Together with greenspace (parks, gardens and the like), it allows to lower the temperature in the city (called urban heat island).^[1]

Many cities have waterbodies. Very often, these waterbodies have been important in the history of the city. One such example is the River Thames in London.^[2]

Accessible blue spaces can help revitalize neighborhoods. It can also promote the people feeling like they belong together.^[3] Examples of such project are the Chattanooga Waterfront (Chattanooga, Tennessee), the CityDeck in Green Bay, Wisconsin, or the Brooklyn Bridge Park in New York City.^[4] Festivals at the waterfront also help promote this feeling.

Neighborhoods with access to attractive natural features often have the problem of gentrification, people with more money, a better education or a higher social class will move in, and lead to a price increase. For this reason, the social benefits associated with waterbodies are often not distributed equally. Normal neighborhoods and poorer ones often do not have access to good quality blue spaces.^[5]

Living close to water bodies carriessome risks, such as water-borne diseases in drinking water,^[6] flooding risks,^[7] or drowning. Scientific evidence shows that exposure to blue spaces is also associated with different health benefits to those near water bodies.^[8][9] One of the mechanisms by which this phenomenon can be explained is by the Biophilia hypothesis developed by Edward O. Wilson. This theory states that humans have developed a strong connection with nature throughout their evolution: This leads them to subconsciously seek natural environments, including green and blue spaces.Recent research has identified three main way that can help explain why living close to green and blue spaces can be beneficial to health.

• Mitigation addresses these health benefits and looks at the physical improvements that natural environments bring to the built environment, such as reduction of urban heat island, traffic air pollution or traffic noise.
• Instoration focuses on the promotion of physical activity and other positive outcomes associated with people being more active and on social connectivity promoted by natural spaces.
• Restoration explains how the non-threatening characteristics of the natural environments reduce negative feelings and increase cognitive restoration.^[10]

Different studies have found that people who live near coastal areas are more likely to practice a form of physical activity that is healthy.^[11] This has been explained by the fact that there are walking paths along the coast, that can be used. Another explanation is that blue spaces have aestethical attributes (they 'look good') which may motivate people to practice a physical activity near or on the water.^[12] Having a body of water close by is not enough to motivate people to be physically active: These bodies of water need to be accessible. A study that focused on teenagers found that those living near beaches that had a major road between their homes and the water body had lower levels of physical activity than those with a direct access to the beach.^[13]

As outlined above, the presence of blue spaces may lead to people being physically more active. A study found that people who lived far from green spaces or a waterfront in an urban area have a higher risk of developing obesity.^[14]

People who have conditions that affect breathing (such as asthma) can improve their quality of life when they move closer to a body of water. This could be explained by the mists and sprays generated by the water movement.^[15] Another study that measured the impact in health of green and blue spaces for those with chronic obstructive pulmonary disease (COPD) had similar findings.^[16]

Researchers found a reduction of psychiatric cases on people living near green or coastal areas.^[17] Some of the studies found that ocean exposure or running along river helped war veterans suffering from PTSD. Others found that practising water-related activities such as surfing can help coping with mental health issues and help develop self-confidence and self-reliance skills.

Exposure to blue spaces is also linked to increased happiness. A group of researchers studying the effect of green and blue spaces on happiness used a mobile app to track feelings of people when they were near water landscapes. The researchers found that people were happier near water bodies.^[18] Consistently with the findings focusing on physical health, the positive effects on mood associated to blue spaces seem to diminish as the distance between the residence and the water increases.^[19]

It was shown that pratising a common activity in blue spaces, for example sailing, had a positive effect on people doing drug and alcohol rehabilitation.

A group of researches has developed a set of tools, to be able to measure the quality and potential health benefits of these blue spaces. The BlueHealth Environmental Assessment Tool (BEAT) - enables comparable assessment of environmental aspects and attributes that influence access to, use of and health-promoting activities in blue spaces. The tool has been developed to be used by communities and urban/landscape designers.^[20][21]

• Green belt
• Public health