Related Experiment Videos
The problem of agricultural 'diffuse' pollution: Getting to the point
Simon Harrison1, Cassandra McAree1, William Mulville1
1School of Biological, Earth and Environmental Sciences, University College Cork, Ireland.
The Science of the Total Environment
|May 10, 2019
Summary
Farmyard drainage ditches significantly impact water quality in agricultural catchments, contributing to nutrient and organic pollution. Improving these drains could be a cost-effective way to mitigate agricultural impacts on water bodies.
Area of Science:
- Environmental Science
- Agricultural Science
- Water Quality Management
Background:
- Agricultural practices are a significant contributor to poor water quality in EU member states, despite existing legislation like the EU Nitrates Directive and Water Framework Directive.
- Elevated nutrient, organic matter, and agro-chemical inputs from agricultural lands, including diffuse sources and intermediate sources like farmyards, are recognized causes of water quality deterioration.
- The precise contribution of intermediate sources, such as farmyards, to catchment-wide water quality at high temporal or spatial resolution remains largely unknown.
Purpose of the Study:
- To investigate the impact of farmyard drainage on water quality within a single agricultural drainage network at high spatial resolution.
- To assess the contribution of farmyard drains to nutrient, organic matter, and sediment loads in receiving watercourses.
- To evaluate the ecological impact of farmyard drainage on aquatic invertebrate communities.
Main Methods:
- Conducted a high spatial resolution water chemistry survey across natural and artificial watercourses in a dairy farming area in Southern Ireland.
- Analyzed water samples for key parameters including ammonium, phosphorus, potassium, suspended sediment, and biochemical oxygen demand.
- Assessed macro-invertebrate communities to evaluate the ecological quality of headwaters impacted by farmyard inputs.
Main Results:
- Most headwaters were impacted by organic inputs from drainage ditches originating near farmyards.
- Farmyard drains exhibited elevated concentrations of ammonium, phosphorus, potassium, suspended sediment, and biochemical oxygen demand compared to background levels.
- Macro-invertebrate assessments indicated impaired ecological quality in headwaters affected by these farmyard inputs.
Conclusions:
- Farmyard drains represent a major source of 'diffuse' agricultural inputs at the catchment scale, despite being intermediate point sources.
- The individual and aggregate contributions of farmyard drains significantly impact water quality within agricultural catchments.
- Engineering farmyard drains to enhance retention and attenuation functions offers a potentially cost-effective strategy for mitigating agricultural water pollution.