Step 3: Identify environmental risks and assess their significance

You need to identify the risks of environmental harm that might arise from nutrient management activities (e.g. fertiliser use, dairy effluent irrigation and cropping) and to decide which of these are important enough to need management to avoid, reduce, or mitigate them.

There are several different approaches to assessing environmental risks. Most land managers can use a simple system of assessing risks themselves but some may need more formal risk assessment if their industry organisation or Regional Council requires this.

The approach provided here will help you recognise and understand the inherent environmental risks associated with the main nutrient management activities. In some situations you may need a higher standard of proof that you have assessed risks more scientifically – e.g. regulatory authorities may require a more detailed assessment if nutrient management activities do not fit within the ‘permitted activity’ category and require resource consent.

Identifying ‘inherent risks’

For each land management unit you must assess the inherent environmental risks associated with the main nutrient management activities. Inherent risk means any risk that arises because of the activity and the location. If you have not divided the property into its respective LMUs then assess the inherent environmental risk for the property as a whole. Do not ignore an environmental risk because the land manager already uses good management to reduce it. This does not remove the inherent risk, it only shows that they have recognised it and responded to it.

Some land managers may need to consider environmental risk in special detail – e.g. when applying for resource consent to apply fertiliser in a way that is not a ‘permitted activity’ in their region. Such detailed risk assessments should usually be prepared by a consultant with specialist knowledge of nutrient management and environmental risks.

Inherent risks are largely governed by site factors and the amount of nutrient applied (i.e. risks increase as the level of nutrient inputs increases). A list of site factors to consider in evaluating inherent risk is provided in Table 1 below:

Table1: Site features that affect inherent environmental risks from nutrient use/application:

Assessing significance

Having identified the environmental risks on the land, you need to decide on the significance of these risks.

In many cases the significance will be fairly obvious. For example, land managers applying nitrogen fertiliser regularly on highly permeable soils with a high water table are likely to be well aware that there is a significant risk of groundwater contamination. Land managers applying similar rates of nitrogen to impermeable soils with little groundwater do not need to be so concerned with groundwater contamination but may need to be aware of the risk of surface water contamination if heavy rain falls soon after fertiliser application.

For each risk identified on the property, think about the potential adverse effects and the likelihood that they will occur in the short (up to 1 year) to medium (3-5 years) term given the conditions on each of the LMUs. Are the adverse effects highly likely or quite unlikely? You could think about it like this:

Think also about the environmental consequences in the context of Regional Council and/or local community expectations. If the adverse effect happens, will the effects be major or minor? Will they be very localised or widespread? Will neighbours be affected? Will the effects be easy to fix or irreversible? You could think about it like this:

At this stage, think only of the overall practice of the activities proposed – e.g. nitrogen or phosphate fertiliser use. Do not downplay the likelihood or consequence because the land manager will practice good management. You will allow for good management and risk mitigating measures, such as applying split dressings of nitrogen, at a later stage in the planning process.

Now you can decide whether the overall risks of nutrient management activities are highly significant or less important. Figure 3 below combines likelihood and consequence to decide the overall significance of any environmental risk.

Figure 3: Assessing environmental risk

In other words, if the likelihood, consequences or both are low, then the risk is generally low. As the likelihood of adverse effects and/or the seriousness of these effects increases, the risk becomes more significant.

Any environmental risk with a combination of high or medium likelihood and high or medium consequences must be addressed in the NMP with best management practices chosen to minimise the risk.

Getting advice on activities and their risks

In many cases, you will already be aware of the environmental risks associated with production activities. If you are making major changes to production operations and you are not sure about the inherent risks, seek further advice. Sources of information and advice include:

• Regional Council staff (or equivalent)
• industry organisations – these may have their own standards, separate to any set or recommended by Regional Council
• fertiliser company staff
• other agribusiness consultants (e.g. agricultural, horticultural or forestry professionals)
• other land managers – look for experience with similar production systems to the management under consideration