Selecting Appropriate Actions
The variability and complexity of our biophysical environment – soils, subsoils, bedrock, ecosystems and weather – makes assessing and determining water movement in the Irish landscape difficult. Allied and related to this is the heterogeneity of farm systems and practices. Deciding on the Actions needed to either protect water resources, whether it is surface water or groundwater, or mitigate impacts is therefore, on the face of it, challenging. However, once a farm advisor or catchment scientist has an understanding of the landscape setting in their area, then the possible optimum Actions can be decided on and established.
Decisions on the most appropriate, effective and efficient Actions undertaken on farmland to protect from impacts on water quality or to mitigate existing impacts are based on the understanding the catchment scientist, farm advisor, farmer or others have of the situation. This is founded on a straightforward scientific understanding of the common situations present on farmland. With this understanding, most potential protection/mitigation actions are ‘basic’, ‘common sense’ decisions; in
fact, many advisors and farmers have much of this understanding intuitively already.
So, what factors are relevant and need a scientific understanding? These are outlined in the questions below.
- What is the receptor? For instance, is it a drinking water source (surface water or groundwater from a well or spring), a watercourse or groundwater in an aquifer?
- What is the receptor water quality requirement (e.g. high status, good status, drinking water standard)?
- Is the objective to protect water quality where it is satisfactory or improve/restore it where it is unsatisfactory?
- What is the environmental stressor or pollutant (e.g. phosphate, nitrate, microbial pathogens, MCPA) that is either posing a threat or is causing pollution?
- What are the water quality metrics (e.g. EQSs, guide values, threshold values, drinking water standards) that indicate whether the receptor water is satisfactory or unsatisfactory?
- What is the potential or actual pressure – is it a point pressure (e.g. farmyard) or diffuse (e.g. slurry spreading, grazing animals, herbicide spraying) or both? (There are often non-farming pressures contributing to the impacts as well.)
- If the pollutant is either phosphate or nitrate, can you estimate the approximate reduction in the quantity (in kgs) in the water that is needed to give satisfactory water quality. This can provide a target that needs to be achieved by mitigation Actions.
- Where it is a diffuse or widespread pressure, what are the land/landscape characteristics? Is the land freely draining or poorly draining? Is it a karst limestone landscape?
- Where exactly might pollutants arise from, where the water quality is satisfactory? Or, where are the pollutants (or most of them) arising from (i.e. the critical source areas), where they are already causing impacts?
Questions 1-6 and 8 can usually be answered readily from existing information, such as that provided by the EPA and LAWPRO. Question 7 requires some extra information on nutrient concentrations (from sampling and analyses) and average stream flows (from EPA and OPW data), but with these data the calculation is straight forward. Question 9 is being answered ‘on the ground’ by LAWPRO catchment scientists, ASSAP advisors, local authority Environment Section staff, NFGWS scientists and consultants, and the EPA Catchments Unit.
So, then the critical question – what Action? There are a multitude of options. But the answer must be based on the ‘right measure in the right place’ principle; otherwise the effort and resources will have limited benefits and, essentially, will often be wasted. In addition, it undermines efforts and reputations in the opinion of farmers. A recommended approach to selecting mitigation Actions is outlined in the Image.
The ‘right’ Action (not taking account of costs and incentives) depends primarily on: i) the requirements of the receptor; ii) whether the objective is to protect or improve/restore; iii) the properties of the pollutant or pollutants causing either a threat or an impact; iv) the farming activity that it relevant; v) the landscape and farm setting; and vi) the input of and acceptability to the farmer.
The aim of this course is to consider all these factors (some only briefly). The overall approach in arriving at the most appropriate and effective Actions derives from the work and experiences of the EPA Catchments Unit and LAWPRO. Descriptions of the Actions themselves are described in the NFGWS Handbook of Source Protection and Mitigation Actions for Farming, which is available at this link: https://nfgws.ie/nfgws-source-protection-publications/.
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