Study region: United Kingdom (UK). Study focus: Climate change and urbanization pose significant threats for flooding and water
quality in urban areas. This paper reviews the evidence concerning the combined impacts of
urbanisation and climate on the urban water environment of inland catchments of the United
Kingdom and assesses the degree of confidence in reported directions of change and response. It
also assesses the utility of the evidence for setting environmental legislation and managing the
urban water environment in the future and identifies knowledge gaps that limit effective and
management interventions. New hydrological insights: There is a lack of nationally research focused on the dual impacts of
climate change and urbanisation on flooding and water quality in UK urban areas. This is despite
there being a clear acceptance that flood risk is increasing, water quality is generally not meeting
desirable levels, and that combined population and climate change projections pose a pressing
challenge. The available evidence has been found to be of medium-high confidence that both
pressures will result in (i) an increase in pluvial and fluvial flood risk, and (ii) further reduction in
water quality caused by point source pollution and altered flow regimes. Evidence concerning
urban groundwater flooding, diffuse pollution and water temperature was found to be more
sparse and was ascribed a low-medium confidence that both pressures will further exacerbate
existing issues. The confidence ascribed to evidence was also found to reflect the utility of current
science for setting policy and urban planning. Recurring factors that limit the utility of evidence
for managing the urban environment includes: (i) climate change projection uncertainty and
suitability, (ii) lack of sub-daily projections for storm rainfall, (iii) the complexity of managing
and modelling the urban environment, and (iv) lack of probable national-scale future urban landuse
projections. Suitable climate products are increasingly being developed and their application
in applied urban research is critical in the wake of a series of extreme flooding events across the
UK and timely for providing state-of-the-art evidence on which to base possible future water
quality legislation in a post Brexit-WFD era
