The red line diagram you draw for your Biodiversity Net Gain (BNG) assessment is exactly the same as the red line boundary on your planning application diagram.
Sometimes it might be unclear whether you should include your whole site or just the part where development is happening. Here's how to determine what to include:
Red Line Diagram: This is the part of the site that will be developed. It includes the area where the works are taking place, any extra space needed for those works, and access to a road or pathway. This is the area you need to draw into the Joe's Blooms tool.
Blue Line Diagram: This indicates the rest of your site, beyond the area of development.
By the time you’re using the Joe's Blooms tool, you should already have created a site plan with these boundaries. Please check any diagrams you've already drawn and make sure what you draw in the Joe's Blooms tool aligns with them.
It’s crucial to draw the red line carefully to ensure it accurately reflects the area being developed. While you can adjust it later, doing so will mean redrawing the pre- and post-development habitats.
If you think that your red line is too large, you can ask for it to be rejigged so that it only represents the are being developed (and a pathway to the access point) with the rest of the site mapped in a blue line. But, if you decide to do this, you need to make sure that the red line changes in the same way in all your other documents - including those that are not being mapped with Joe's Blooms. The red line must always be the same in all your submitted documentation.