How urbanization, climate change affects water quality in UK

There is a lack of national research focusing on the double impact of climate change and urbanization on floods and water quality.

Climate change and urbanization are the main threats to floods and water quality in urban areas. The paper 'The impacts of urbanisation and climate change on urban flooding and urban water quality: A review of the evidence concerning the United Kingdom' published in the Journal of Hydrology: Regional Studies Volume 12, reviews the evidence on the combined impacts of urbanization and climate on the urban water environment of UK watersheds and assesses the degree of confidence in the directions of change and response reported.

It also evaluates the usefulness of the evidence to establish environmental legislation and the management of the urban aquatic environment in the future and identifies gaps in knowledge that limit effective interventions and management. 

New hydrological knowledge

There is a lack of national research focusing on the double impact of climate change and urbanization on floods and water quality in urban areas of the United Kingdom.

This despite the clear acceptance that the risk of flooding is increasing, that water quality generally does not reach desirable levels, and that the combined projections of population and climate change are an urgent challenge.

It was found that the available evidence was moderately high since both pressures would result in

• an increased risk of rain and water floods and
• a greater reduction in water quality caused by point source pollution and altered flow regimes.

It was found that tests of urban groundwater floods, diffuse contamination, and water temperature were rarer and were found to be weak and moderately certain that both pressures would exacerbate existing problems. It was also considered that confidence in the evidence reflects the usefulness of current science for urban planning and policies.

The recurring factors that limit the usefulness of the evidence for urban environmental management include:

• the uncertainty and adequacy of the projection of climate change;
• the lack of sub-daily projections for climate change; stormy rains,
• the complexity of the management and modeling of the urban environment, and
• the absence of probable projections of urban land use at the national level.

Adapted climate products are increasingly being developed and their application in applied urban research is crucial after a series of extreme floods in the UK and it is timely to provide cutting-edge evidence on which to base future climate change legislation in a post-Brexit-WFD era.