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Overall, the monitoring has found an accretionary trend over the survey period between 2007 and 2011, with an average difference between 2007 and 2011 of +14cm. The degree of accretion was found to have decreased over time. The main change in elevation took place in the initial year following the breach, with typical elevations increasing by between 0 and 50cm between 2006 and 2007.
The change in elevation in subsequent years has decreased, although increases of up to 40cm have still been observed at some locations across the site between the 2009 and 2011 surveys. Over the survey period, the majority of change in elevation (accretion) has occurred in lowest (seaward) parts of the site, which were around 1.5 to 1.75mODN in 2007 - with changes in elevation of the order of 10-40cm.
Erosion was initially noted in the creeks, and continually towards the rear of the site within the created saline lagoons. The latter should, however, be viewed with a degree of caution as the presence of standing water can reduce the accuracy of the LiDAR data. The higher elevations (above ca. 2.75mODN) have barely, or not at all, been subject to a net gain in elevation.
Saltmarsh vegetation has generally established in areas above 2.5 to 3mODN (2.5mODN is approximately 50cm above the MHWN level). Most of the mudflat areas below 2mODN remain un-vegetated.
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Welwick
Table of content
- 1. Measure description
- 1a. Description of the issue and measure
- 1b. Monitoring
- 1c. Monitoring results
- 2. Execution of main effectiveness criteria
- 2a. Effectiveness according to development targets of measure
- 2b. Impact on ecosystem services
- 2c. Degree of synergistic effects and conflicts according to uses
- 3. Additional evaluation criteria in view of EU environmental law
- 3a. Degree of synergistic effects and conflicts according to WFD aims
- 3b. Degree of synergistic effects according to Natura 2000 aims
- 4. Crux of the matter
Crux of the matter
The “crux of the matter“ refers to the basic, central or critical point of an issue. For example, in this context, the main issues relating to the development and progression of the specific measure detailed within this FAS Repost represent the crux of the matter.Overall, the monitoring has found an accretionary trend over the survey period between 2007 and 2011, with an average difference between 2007 and 2011 of +14cm. The degree of accretion was found to have decreased over time. The main change in elevation took place in the initial year following the breach, with typical elevations increasing by between 0 and 50cm between 2006 and 2007.
The change in elevation in subsequent years has decreased, although increases of up to 40cm have still been observed at some locations across the site between the 2009 and 2011 surveys. Over the survey period, the majority of change in elevation (accretion) has occurred in lowest (seaward) parts of the site, which were around 1.5 to 1.75mODN in 2007 - with changes in elevation of the order of 10-40cm.
Erosion was initially noted in the creeks, and continually towards the rear of the site within the created saline lagoons. The latter should, however, be viewed with a degree of caution as the presence of standing water can reduce the accuracy of the LiDAR data. The higher elevations (above ca. 2.75mODN) have barely, or not at all, been subject to a net gain in elevation.
Saltmarsh vegetation has generally established in areas above 2.5 to 3mODN (2.5mODN is approximately 50cm above the MHWN level). Most of the mudflat areas below 2mODN remain un-vegetated.