Post a comment on the text below

5.4 Future challenges

As measures to reduce point source pollution improve, the significance of diffuse inputs will increase. Such inputs are typically more difficult to address and manage.

Surface water bodies can be affected by intermittent discharges of untreated wastewater from storm overflows in combined sewer systems (combined storm overflow (CSO)). This will occur where there is no or insufficient storm water overflow retention capacity. Often, the nearby watercourse (usually the surface water) receives the wastewater and water quality is affected as a consequence.

CSOs represent a multiple, diffuse and uncontrolled source of pathogens and pollutants and are one of the major threats to good bathing water quality (see chapter 2), and consequently to human health.

The long-term effects of climate change may also influence the degree of environmental impacts caused by intermittent discharges. Higher intensity rainfall may result in some overflows operating more frequently and with greater spilled volumes.

Diffuse pollution from agriculture can affect raw water supplies for drinking water, for example leading to the need for increased treatment or dilution with less contaminated sources. It can also affect water quality, where surface runoff transports nutrients, harmful chemicals and microbiological contaminants from manure into watercourses.

Emerging issues for water quality, which represent potential but as yet poorly understood risks, include newly-identified micropollutants, microplastics and antimicrobial resistance. Improving understanding of these topics, particularly the risk they might present to public health and water quality, represent new challenges.