These activities compensate for the effects of hard defences, dredging, tidal barrages, impoundments, and disruption to the tidal and estuarine environment that results in habitat loss. This involves creating new habitats to compensate for impacted habitat and ensure that biological communities are able to relocate to a suitable nearby location.

These activities can also compensate for any habitat lossed as a  resulting of a changing climate.

Habitat compensation must be undertaken in the same water body as where the impact(s) took place. This ensures that the water body receives the benefits of any offsetting that will contribute to the overall health of the ecosystem.

Techniques

There are a wide range of techniques that can be used to implement this environmental improvement, depending upon the type and characteristics of the water body in which it is going to be applied. These include:

• Coastal and estuarine water bodies: beach recharge, foreshore placement, creation of saltmarsh, intertidal habitats or vegetated shingle, planting of suitable vegetation
• River water bodies: creation of in-channel and marginal features, gravel augmentation, planting of suitable vegetation, creation of backwaters and other online wetland features, creation of offline (floodplain) wetlands

Benefits

The creation of compensatory habitats can deliver a wide range of direct and indirect benefits, including:

• Direct ecosystem benefits associated with the creation of new habiats including maintenance of, and improvements to, biodiversity.
• Climate change adaptation, allowing habitats and species to adapt to changing conditions
• Natural erosion protection
• Natural storage of surface waters
• The provision of opportunities for commercial use of new land (including fishing and agriculture)
• The provision of opportunities for increased amenity value of the area

Case Study Benefits

This diagram displays a comparison of benefits scores (using a high-level ecosystem service assessment methodology) associated with the techniques used in each case study. More details on the methodology can be found here. 

• Trimley and Shotley Intertidal Habitat Creation
• Greatham North Managed Realignment Scheme
• Lower Lea Project - Moselle Brook Deculverting

Cost bandings are as follows:

• £ = £1k-£10k
• ££ = £10k-£50k
• £££ = £50k-£100k
• ££££ = £100k-£500k
• £££££ = £500k+

An explanation of the headings in the case studies and the ecosystem services compass diagrams can be found: HERE

Other relevant case studies:

• Trimley, Suffolk

Alternative examples:

• Alkborough Tidal Defence Scheme

• Environment Agency (2010) Fluvial Design Guide
• Environment Agency (2010) Working With Natural Processes
• Environment Agency (2011) Estuary Edges: Ecological Design Guidance

Throughout this best practice, 'environmental improvements' refer to WFD 'mitigation measures'. The names of some mitigation measures are different in England, Scotland and Northern Ireland.

This mitigation measure is named:

• Indirect / offsite mitigation (offsetting measures) (England)

• Healthy Catchments - managing water for flood risk and the Water Framework Directive

• Environmental improvements & case studies

• What is the WFD?

• Glossary