Biodiversity Net Gain

Biodiversity Net Gain is likely to have an enourmous impact upon new developments and its impacts should not be underestimated.


The Environment Bill is passing through the necessary phases required for it to become law.


Once this has happened all local authorities will be required to ensure that all new developments produce a 'Biodiversity Net Gain (BNG)' post development. The minimum requirement is a 10% gain on developments considered as 'major'. The exact figure for smaller developments is still being thrashed out. 


As a headline figure 10% does not seem so bad, does it? Until that is you realise that the 10% figure is based on the whole site and therefore if you are building on 50% of the site, the remaining 50% has to produce a 110% gain.


So how do you calculate the BNG of a site?


Initially, we undertake a site survey and establish the biodiversity baseline. The baseline is composed of various components: area, linear and water courses. This data is entered into the DEFRA metric calculator and a baseline 'Unit' value is established. 


The DEFRA metric is then used to establish the 'losses' caused as a result of the development proposal and the target required to achieve the BNG is calculated.


The mitigation hierarchy for BNG assumes that the BNG is achieved on site, only if this is not possible is it permitted to provide 'offsite mitigation' (enhancing land not part of the development to achieve the 10% BNG) and finally, if there is not offsite land available to pay compensation to a local authority to fund enhancement works elsewhere.


Quite clearly, developing on land which has a low initial biodiversity value, makes it easier to achieve BNG. Arable land is amongst the lowest biodiversity value land, whilst an area containing ancient woodland would make achieving a BNG impossible due to the irreplacable nature of this habitat.


Artificial 'deflating' biodiversity value by destroying a site pre-survey, will not work as local authorities are able to use websites such as Google Earth Pro, to establish the true value of a site by simply using historic information, which might infact result in a higher BNG calculation than would have been the case had a legitmate survey been undertaken at the outset.


We strongly suggest that you discuss your proposal with us as early as possible, even prior to land purchase and engage us to undertake a BNG calculation. This might well save you buying land at a development land price, only to discover that you can only build on a portion of it -


Before you invest money on land purchase and possibly rue your decision, contact us and see if we are able to help clarify matters.



Contact us today!

Office - 0800 888 6846

Mobile- 07736 458609 (Paul - MD)

Mobile- 07491 998866 (Phin - Office Manager)

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