Avoid-Reduce-Offset sequence
The core of a defensible ecological file
The Avoid-Reduce-Offset (ARO) sequence is the backbone of any ecological file: first avoid impacts, then reduce them, and only offset what remains.
Avoid-Reduce-Offset sequence
The Avoid-Reduce-Offset (ARO) sequence is the backbone of any ecological file: first avoid impacts, then reduce them, and only offset what remains. ARKENOR structures a defensible ARO sequence to secure permits and authorisations.
The principle
A hierarchy, not a menu.
French law requires impacts on nature to be addressed in a fixed order: avoid first, reduce what cannot be avoided, and offset only what remains. The order is binding. Offsetting is not an alternative that a project may choose because it is simpler or cheaper, it is what is left once avoidance and reduction have been examined and shown to be impossible or insufficient.
This is the single most common reason for a negative opinion from the environmental authority. A file that opens with a generous compensation package, without demonstrating what was avoided and what was reduced, reads as a project that never considered changing its design. The demonstration matters as much as the outcome.
In practice
Avoidance is a design decision, and it is dated.
Avoidance happens at layout stage: moving a building envelope off a wetland, keeping a hedgerow, changing an access route. Once the design is frozen, avoidance is no longer available, which is why the sequence has to start while options are still open, and why the file records when each decision was taken.
Reduction covers what remains: works phasing outside breeding periods, lighting design that limits disturbance, protective measures during construction supervised by a site ecologist. Offsetting comes last and carries the heaviest evidence burden, because it has to be demonstrated equivalent, additional and durable.
Going further
Related pages.
The sequence structures the whole environmental file.
- Offsetting measures — equivalence, additionality, duration
- Site ecologist — how reduction measures are enforced on site
- Four-season surveys — the evidence the sequence rests on
- Natural component of the impact assessment — where the sequence is set out
- Protected-species derogation — requires the sequence to be exhausted first
- Environmental impact assessment — the containing procedure
- Working with land developers — where avoidance is decided
- Working on infrastructure projects — linear projects and cumulative effects
Discuss your project
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