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Is it time we adapted to uncertainty?

Why adaptive management is the means to addressing impact uncertainty in consenting decisions.

At the end of 2020, a long and costly marine consenting and monitoring process came to an end. It lasted 14 years and cost in the region of £4 million. Most of that fee, and five years of that process, were spent on the consenting alone. The process concluded when, after nine years of monitoring, an overseeing panel of specialists and stakeholders agreed that the implemented mitigation measures had offset any development impacts.

The story of this project, and its outcome, need to be shared because they demonstrate how to overcome one of the most common and important challenges associated with marine planning and management: the problem of uncertainty.

Uncertainty: a challenge to consenting decisions

The marine environment is a changeable, inter-connected and complex place. It is therefore often difficult to know, and agree, what the outcome of an action in the marine environment will be with a high level of certainty. Yet we do want to be confident about the effects of any changes we make on the coast and in the sea. Certainty is also what legal and planning frameworks demand.

The friction between the need to be certain and the uncertainty of the environment can lead to difficulties and delays with marine consenting. The project mentioned at the start was not a major windfarm or a massive port development. It was a change that Wightlink Ltd. made to their ferries crossing the Solent between Lymington and Yarmouth on the Isle of Wight.

These ferries navigate between coastal mudflats and marshes that are continually changing. And, just like other parts the south and east coast of the UK, the marshes have been rapidly eroding since the early part of the 20th century. It took nearly five years of research, assessment and consultation just to agree that any effects from the new ferries would be small and potentially dwarfed by the natural changes already taking place.

It was also agreed that the effect was uncertain.

It is this uncertainty which presented a major challenge to consenting this project. This was especially because the coastal habitats are all internationally designated; a high degree of certainty was needed that there would be no adverse effect under the Habitats Regulations and associated case law.

The detailed reasons why such a relatively small development (changing a ferry) took so much time, effort and money to permit, probably merits further consideration by someone someday. But today, everyone should definitely be aware of how we solved the uncertainty issue.

The solution was adaptive management.

Solving uncertainty with adaptive management

Adaptive management is essentially a rolling process of ‘learning by doing’; it requires flexibility of approach, effective and focused monitoring, and strong oversight and leadership.

For the Wightlink ferry change, an adaptive mitigation process was enshrined within a S106 legal agreement.

The steps of this process were to:

  1. Undertake marsh and mudflat restoration in a flexible and adaptable manner as mitigation (in this case, using dredge sediment to enhance a very vulnerable part of the eroding marshes)
  2. Monitor the effects of the development (in this case the ferries)
  3. Have an overseeing panel regularly meet to compare the development effects against the mitigation benefits and advise whether more mitigation is needed (e.g. by doing more restoration work using more dredge sediment over more years)

Why the uncertainty with working with uncertainty?

In the marine environment, we have known that adaptive management is the answer for a while.

For more than a decade, it has been advocated as a measure to provide certainty regarding the effects of port developments in Special Areas of Conservation,(1) or to manage dredging activities.(2) It is also the go-to coastal defence strategy for complex, dynamic and unpredictable coastal settings(3) and is a recognised mechanism for evaluating marine developments more generally.

But we still find it difficult, nationally and internationally, to embrace the concept of adaptive mitigation/compensation and embed adaptive management wholeheartedly into our inflexible planning and consenting regimes.(4,5,6)

For some reason, when it comes to development, we cannot fully accept that sometimes we do not know, and that the only way we will know is to act, review, and if necessary, course correct. It is risky, but so are a lot of things worth doing.

Instead we continue to look for fixed and certain solutions (often with burdensome unbending obligations) so we can wash our hands of a project and move on.

But such a practice can lead to protracted and subjective debates about impacts that cannot be resolved through collecting still more evidence.

It also stymies creative thinking and stunts knowledge and understanding.

It is time this changed, and time we learned to lean more into the adaptive option.

All of this is especially true given we have increasing ambitions to work with natural processes and adopt nature-based solutions.(7,8) If we really are going to allow natural processes to have a greater role in marine management, we will need to be braver and start embracing the uncertainties that must come with that.

The Wightlink project shows what can be done.

There were no detectable effects from the ferry, and the mitigation measures worked well.(9) The mitigation also provided its own valuable lessons about how to restore decaying habitats with dredge sediment. Details and results can be found on ABPmer’s habitat restoration website.

Embracing adaptive management and adaptive mitigation / compensation as the answer to uncertainty would help overcome some protracted and painful consenting processes without losing the need for certainty and adherence to the precautionary principle.

It would also help avoid the heart-breaking waste of money that can happen in some instances and, in doing so, could help direct more financial resource towards habitat restoration instead.

We need to find a way to be more flexible in our consenting processes and direct more resources towards sustainable habitat restoration, rather than debating the detail and quantification of impacts.

Adaptive management can be used to do this, and should be a primary tool for delivering net gain and realising our ambitions to leave the environment in better state for the next generation.(10) 

Prepared by Colin Scott, Habitat Creation and Restoration Specialist

ABPmer regularly helps developers through the minefield of marine consents, and is experienced in reaching agreement with regulators on mitigation and compensatory measures. If you have questions about anything raised in this post, please contact Colin Scott.


(1)^ European Commission, 2011. Guidelines on the Implementation of the Birds and Habitats Directives in Estuaries and Coastal Zones with particular attention to port development and dredging.

(2)^ Environment Agency, 2018. Working with natural processes to reduce flood risk.

(3)^ Environment Agency, 2009. Pagham to East Head draft coastal defence strategy summary document. Summary report in partnership with Chichester and Arun District Councils. 

(4)^ Craig., R. K. and Ruhl. J. B., 2010. Governing for Sustainable Coasts: Complexity, Climate Change, and Coastal Ecosystem Protection, Sustainability 2010, 2(5), 1361-1388.

(5)^ Frohlich, M.F., Jacobson, C., Fidelman, P., and Smith, T.F., 2018. The relationship between adaptive management of social-ecological systems and law: a systematic review. Ecology and Society 23(2). doi:10.5751/ES-10060-230223.

(6)^ Scott, C.R., Harris, E. and Townend I.H., 2020. Lessons in applying adaptive management on a dynamic coastline: a case study at the inlet to Pagham Harbour, UK. Anthropocene Coasts. 3(1): 86-115. 

(7)^ Environment Agency, 2018. Working with natural processes to reduce flood risk.

(8)^ MMO (in prep): Regulatory Decision Making to enable marine Nature-Based Solutions. Developing an Action Plan for the Defra Family Project Code: MMO 1246.  

(9)^ ABPmer, 2020. Lymington to Yarmouth Ferries: Mitigation and Monitoring, 2020, Five-year update and 10th Report for the Environment Management Panel, ABPmer Report No. R.3472. A report produced by ABPmer for Wightlink Ltd., December 2020.

(10)^ HM Government, 2018. A Green Future: Our 25 Year Plan to Improve the Environment