Healthy Estuaries project 2020

The Healthy Estuaries 2020 Toolbox (HET) is an approach that focuses on the longer-term sustainability of estuary systems to address coastal squeeze in particular, and inform management decisions (please see pdf below for more information). HET will enable more effective and consistent advice to the Environment Agency on intertidal habitat creation needed by 2020 to address coastal squeeze. The aim is to understand the requirements that will move the intertidal habitat and estuary features towards favourable condition within the Special Areas of Conservation (SACs) and Special Protection Areas (SPAs) and their underpinning SSSIs in order to meet national and international obligations for biodiversity.

The science behind the tool is referred to as Regime Theory, which is the empirical relationship between tidal prism (amount of water entering an estuary) and cross section area. The HET will be tested on Chichester Harbour.

Jo Brooksbank reports, “The desk study and collation of historic mapping data and aerial photography is progressing well. We are beginning to review the data collected so far and are seeking advice from our national specialists on survey techniques. We are planning on carrying out saltmarsh surveys in Chichester Harbour during the week commencing 9th September 2019.”

Courtesy of Chichester Harbour Conservancy

Results

The project changed direction when unfortunately it wasn’t possible to apply the HET. Instead a detailed condition assessment was undertaken using historical photography analysis and fieldwork. The SCOPAC funds supported the GIS analysis and detailed investigations in the field which show the Chichester Harbour SSSI to be in unfavourable condition. The work found that:

“552 hectares are required to restore saltmarsh habitat within Chichester Harbour to achieve the SSSI designation. This could begin with climate change safeguarding policies to help protect low lying land around the harbour for future saltmarsh restoration. Opportunities to recreate saltmarsh habitat should then be identified e.g. realigning sea defences. An additional 257 hectares of saltmarsh from the current level is initially needed to restore it back to recovering, and as the habitat structure evolves then to favourable condition.”

The following document summarises the findings:

• The full report can be found at the Natural England website: http://publications.naturalengland.org.uk/publication/5535304204419072

The outputs have provisionally been presented to the Environment Agency and a presentation was given to the Southern Coastal Group and SCOPAC.