Half of the world’s population – over 3.5 billion people – live in cities, a figure that is expected to rise to 60% within the next 20 years. Of this urban growth, 95 % is to take place in the developing world where the provision of clean water and sanitation is often inadequate, leading to outbreaks of disease and other health issues. In addition, even within developed countries, rapid urbanisation will still act as a real threat as natural areas are converted to less permeable surfaces, increasing the speed and volume of surface run-off and heightening the risk of flooding.
Throughout the FreshWater Watch programme, developed in partnership with HSBC and Earthwatch, global water bodies in urban areas were studied by citizen scientists to look at water quality within cities, ultimately unearthing key issues that needed addressing.
Since China’s economic reform in the late 1970s, Shanghai, the country’s largest and most modern city, has expanded rapidly to become one of the world’s megacities with a population of more than 24 million. But such rapid urbanisation can have extensive impacts on local water quality.
Research conducted by FreshWater Watchers in China, led by scientists at the Nanjing Institute of Geography and Limnology, South China Agricultural University and the Open University of Hong Kong, has informed a number of new scientific developments on what drives and reduces poor water quality in rivers across Shanghai, Guangzhou and Hong Kong.
Research within India revealed the scale of urbanisation impacts in Hyderabad, where the number of waterbodies has fallen dramatically. Lakes in Hyderabad were also found to have fluoride concentrations exceeding maximum permissible limits set by the Bureau of Indian Standards and World Health Organization.
FreshWater Watch measurements identified key links between the nutrient concentration and inputs of raw sewage, domestic waste and industrial effluents.
Toronto- Urban ponds are increasingly being used for the retention of storm water and within many of the newer commercial developments in Southern Ontario, Canada, they are now a prominent feature. The Greater Toronto area alone has around 500 ponds which receive and hold storm-generated run-off to reduce downstream flooding. However, little is known about their ecological role in the urban environment.
Therefore, FreshWater Watchers in Toronto surveyed water quality across 22 of the city’s urban ponds. Their results indicate that urban ponds may improve water quality in downstream waterbodies by retaining pollutants, and that in-pond vegetation plays an important role in reducing available nutrients.
Vancouver- The Greater Vancouver area (Metro Vancouver) has the highest population density in Canada. To monitor the effect of rapid urbanisation on the quality of streams, 231 FreshWater Watchers collected 838 water quality samples across Vancouver. The results contributed to important new knowledge about the factors that control stream water quality in a rapidly urbanising environment, in relation to land use and seasonality. This was made possible thanks to efforts of citizen scientists who gathered data at a much finer scale than would have been achievable by professional scientists alone.
As the HSBC Water Programme now embarks on its second phase, urbanisation and the relationship to water will become a much larger focus. With such far reaching and global impacts on the water cycle by a rapid rise in urbanisation, it is vital we continue to work to understand how best to manage this.