Habitats Regulations Assessment (HRA) refers to the process of assessment that is undertaken, to determine whether a proposed plan or project is likely to significantly affect the integrity and designated interest features of a ‘habitats site’[1]; the information from the assessment is then used by the competent authority to decide whether to undertake, permit or authorise the plan or project.

HRA applies to all plans and projects that are not directly connected with, or necessary for, the conservation management of a ‘habitat’ site, which includes Special Areas of Conservation (SACs) and Special Protection Areas (SPAs), in addition to Ramsar sites.

SACs are high-quality conservation sites that make a significant contribution to conserving the habitats and species identified in Annexes I and II of the Habitats Directive. The listed habitat types and species are those considered to be most in need of conservation at a European level (excluding birds). SPAs are designated for their bird interest and together with SACs form the UK’s national site network. Ramsar sites are wetlands of international importance, designated under the Ramsar Convention; they are often of importance to waterbirds and designated as SPAs too.

One aspect of HRA that has been making waves in recent months is the concept of nutrient neutrality in relation to proposed development, which this article focuses on.

What is nutrient neutrality?

Nutrient input relating to wastewater from residential housing (and agriculture) is cited as one of the most significant threats/pressures to the conservation status and functionality of many designated sites of nature conservation importance. Wastewater from water treatment works is released into waterbodies, such as rivers, that in turn can flow into connected habitats and sites of conservation importance such as wetlands, estuaries and marine enviroments.

Increased nutrient inputs (primarily nitrogen and phosphorus) can result in habitat degradation through processes such as eutrophication, which promotes the development of algal blooms by reducing oxygen content in waterbodies. This degradation has negative impacts for habitats and the species that rely on these habitats.

There is currently a requirement in many areas for all new development with wastewater implications to achieve nutrient neutrality, when the proposed development is within the ‘zone of influence’ of an internationally designated site, to ensure that development does not add to existing nutrient burdens and further degradation of the designated site and its qualifying features.

How is nutrient neutrality achieved?

The first step is for a competent practitioner to determine, through the use of appropriate guidance and calculations, whether projected nutrient burdens relating to a proposed development require mitigation. Where mitigation is required in order to achieve nutrient neutrality, this is typically achieved via on-site treatment of wastewater and surface water runoff, and/or through off-site habitat creation such as woodlands or wetlands. 

How can we assist?

The Ecology Co-op has an experienced team of ecological consultants who can take you through the HRA process including advice on achieving nutrient neutrality.



[1] in accordance with the Conservation of Habitats and Species Regulations 2017 (as amended) and the Conservation of Offshore Marine Habitats and Species Regulations 2017 (as amended).