Managing phosphorus water pollution in an uncertain future
An Oxford-led study suggests that multiple strategies may be needed to manage phosphorus in rivers. Sources of phosphorus pollution vary depending on future changes in rainfall and runoff under different scenarios of climate, land use and water resource management.
Phosphorus causes eutrophication or over-fertilisation of rivers, a serious problem that leads to excessive growth of algae, having a harmful effect on plant and animal life. Managing phosphorus levels in rivers is therefore a major global, national and European concern. Phosphorus can come from diffuse sources such as agricultural fertilisers or point sources such as sewage treatment works.
The study, led by Dr. Jill Crossman and Prof. Paul Whitehead, assesses how the water quality and hydrology of the Thames River system respond to future changes in climate, agricultural land use and water resource allocations. It then evaluates the effectiveness of phosphorus management strategies under these scenarios of future change.
The authors of the study found that the relative contribution of phosphorus from diffuse and point sources vary according to future rainfall and runoff. During high flow periods, agricultural diffuse sources are the main problem, and during low flow periods point sources dominate.
The study suggests that the best approach to phosphorus management may be to adopt multiple strategies for use at different times and locations in order to target the dominant source.