Is time-lag a drag for your nutrient neutrality assessment?

We can help developers achieve nutrient neutrality, by assessing the timelag between reducing nutrient loading and the impact reaching the water environment. Development achieves nutrient neutrality when the nutrient load created through additional wastewater (including surface water) from the development is mitigated. By designing development alongside suitable mitigation measures, additional nutrient loads can often be avoided or mitigated. This approach is called ‘nutrient neutrality’ or ‘nutrient offsetting’. It essentially allows developments to be permitted without impacting on the condition of protected sites.

There are many options for mitigation, including upgrading of sewage treatment works and stopping fertiliser application to farmland (i.e. rewilding). However, it can take many years, decades even, for water from the mitigation land (or ‘offset site’) to reach the water table and rivers, depending on the geology of the mitigation land. Authorities often question the suitability of mitigation land due to this timelag.

The good news is that we can quantify the timelag between reducing nutrient loading and the impact reaching the water table and river. We have undertaken many nutrient neutrality assessments throughout the UK. These include mitigation land on Chalk geology, where the timelag is more complicated to assess (due to the dual porosity of the Chalk aquifer). Our assessments provide confidence to the authorities that the nutrient neutrality goals are achievable – thereby delivering a successful planning application.

Please contact us for advice – or 01743 352797.


H Fraser Consulting Ltd
The Pump House
Coton Hill

01743 352797

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