We know that people are more likely to experience mental health disorders in areas with greater population density. Overcrowding, pollution, urban violence and less social support may all be contributing factors, and this is becoming more of a challenge as more people around the world move into towns and cities.
Natural settings have long been seen as a potential solution, since many studies have shown that when people are closer to nature they are less stressed, and their mood and general mental health improve. There has been much research into using therapeutic landscapes in cities to bring the benefits of being in nature to more people.
So far, studies show that people living near water have a lower risk of premature death, a lower risk of obesity, and generally report better mental health and wellbeing. These blue spaces also reduce the gap between less and more affluent areas in the risk of dying prematurely.
But while being close to water enhances people’s wellbeing, no research has yet shown that it reduces the incidence of mental health disorders. Most studies have also focused on coastal towns rather than cities.
Given that even landlocked cities are built around water features like canals, rivers and lakes, our research aimed to uncover their health benefits, and how they could be repurposed to improve the mental health of people living in cities.
Mental health connection
We conducted a systematic review and meta-analysis of all the evidence about how blue space positively impacts health. This showed that living closer to and having more blue space within your neighbourhood could significantly increase your physical activity levels.
Researchers studying the effects of blue space delivered through virtual reality have also found that people see it as restorative, fascinating, and preferable to a built-up environment. This shows how technology could be used as a way of studying how being near water affects people.
Our next area of research will be to understand how blue spaces benefit people in these ways. We also think that having more stretches of water in cities could improve the population’s health in other ways, such as reducing heat and lowering air pollution. But more research will be needed to effectively understand whether this is true.
Creating blue spaces
But if the early evidence points to lots of health benefits from living near water, the problem many cities encounter is finding ways to bring them to residents. During the Victorian era, canals in the UK were tremendously important to the economy.
Canals allowed trade to happen and helped workers to move around. There’s still a huge network of these waterways in many UK cities, but very few of them are in use.
For example, there are more canals in Birmingham than in Venice. But access to them is often blocked by tall buildings or fences, and their potential is far from being exploited. Derelict canals can sometimes even cause environmental problems, such as plastic litter pollution, which can reduce biodiversity and harms wildlife.
Numerous projects in the last few years have sought to regenerate canal networks in the UK, though mainly with a view to improving the local economy creating valuable real estate.
But even aside from the potential mental health effects, regenerating these networks can bring other benefits, such as controlling water levels, preventing floods and making cities more resilient to climate change.
With this in mind, some municipalities are starting to use canals to mitigate flood risks and to provide greener transport options, This is creating a win-win-win that combines economic, environmental and health benefits.
Efforts in Scotland to regenerate canals are a good example. Land that was previously flooded by rainwater has seen new homes and businesses built. Walking paths along the canals have also been created, allowing people to visit the canals, even while further development is underway.
While further research is needed to better understand the true benefits that blue spaces have on residents, it is clear that finding ways to repurpose derelict canals in cities could have other benefits to the environment and economy too.
The world’s urban population has grown by approximately 460% between 1950 and 2018, increasing the number of people living in urban areas from 751 million in 1950 to 4.2 billion in 2018 . This tremendous increase in the urban population has raised several environmental, social and health concerns .
Urbanisation is linked to increased risk of non-communicable diseases, premature mortality , as well as a higher risk of mental illnesses  and social isolation . Urban growth is projected to continue and bring an additional 2.5 billion people to urban areas by 2050 . It is therefore of paramount importance for city-planners to create sustainable and healthy urban environments, which promote mental and physical wellbeing.
Natural environments bring several benefits to public health and social wellbeing in urban settings. Studies have shown that exposure to natural environments contributes to reduced mortality rates and increased wellbeing among urban dwellers . Most of the research has concentrated on the impact of green spaces (e.g., parks), but in recent years it has emerged that blue spaces such as coasts, lakes, rivers and canals can bring similar ben- efits [7–9].
To date, few studies differentiate between green and blue spaces, as blue space is often treated as an inherent component of parks and natural environments . However, blue spaces are independent entities and there is a need to be considered separately and not solely as a subcategory of green spaces . Over the years, research has focused on the negative effects of blue spaces and the understanding of such effects is well devel- oped .
Health hazards, such as an increased risk of flooding and higher levels of disease transmission, through exposure to several microbes and contact of humans with a wide range of hazardous chemicals, have often been linked to blue spaces . However, recent epidemiological studies have shown that blue spaces also have a positive effect on public health , including the reduction of mortality rate with the greatest rate of decline seen in areas closest to blue space , better physical health , and better mental health .
In fact, a recent meta-analysis quantified the health impact of blue spaces and concluded that it is as strong as that of green spaces . Therefore, it logically derives that the existence of such benefits from blue spaces also enables discussion of environmental justice around their accessibility and availability to some groups of the population. Simultaneously, blue spaces are considered valuable ecosystem services, have both an aesthetic and ecological role in urban environments and can be used for urban microclimate regulation [10,13].
In order to leverage these salutogenic effects and improve the health of the urban population, it is important to understand the linking mechanisms between exposure to blue space and health. Four mechanisms have been proposed to mediate the relationship between blue spaces and health (Figure 1): (1) Access to blue spaces may promote physical activity which is the fourth most important risk factor for poor health ; (2) Exposure to blue spaces may improve restoration .
This follows the definition by  and therefore considers markers of restoration, including, but not limited to, stress, anxiety, depressed mood and psychological wellbeing, which have been linked with risk of cardiovascular diseases  and mental health issues ; (3) Blue spaces may contribute to a healthier environment and reduce air pollution, heat island effect, risk of flooding ; and finally (4) Blue spaces may promote social interactions which have been found to benefit mental and physical health, among others, through a sense of community, mutual support between people, quicker emergency reaction and sense of coherence .
To date there has been no review synthesising evidence about these potential mechanisms. The purpose of this systematic review and meta-analysis is to summarise current evidence and quantify the effect of blue space on physical activity, restoration, environmental factors and social interaction.
Source: The Conversation