Case study:Nigg Bay Managed Realignment Scheme - Revision history

Alexrrc at 14:50, 8 November 2018

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	The site is owned and managed by the Royal Society for the Protection of Birds (RSPB), and forms part of its wider Nigg Bay reserve. This reserve incorporates extensive areas of mudflat, saltmarsh and wet grassland (RSPB website, 2011).		The site is owned and managed by the Royal Society for the Protection of Birds (RSPB), and forms part of its wider Nigg Bay reserve. This reserve incorporates extensive areas of mudflat, saltmarsh and wet grassland (RSPB website, 2011).
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	https://www.therrc.co.uk/sites/default/files/projects/48_niggbay.pdf		https://www.therrc.co.uk/sites/default/files/projects/48_niggbay.pdf

Alexrrc at 14:36, 8 November 2018

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	This was the first planned realignment in Scotland and involved making two 20m-wide breaches in existing sea defences to allow the top of the tide to flood a 25ha field. This field was the last area of Nigg Bay to be land claimed (in the 1950s) and a secondary sea wall was already in place; this needed repairing and raising to a 1 in 50 year standard in advance of tidal inundation. The soils adjacent to the wall were suitable for use to build up the wall where required (on average by 10-20cm, over a length of 860m). The site was prepared by culverting drains which linked to adjacent fields, topping and grazing to reduce the amount of terrestrial vegetation, and the removal of trees. No internal earthworks were needed to create a creek system as a relict creek was still present. Approximately 2/3 of field is inundated at spring high water.		This was the first planned realignment in Scotland and involved making two 20m-wide breaches in existing sea defences to allow the top of the tide to flood a 25ha field. This field was the last area of Nigg Bay to be land claimed (in the 1950s) and a secondary sea wall was already in place; this needed repairing and raising to a 1 in 50 year standard in advance of tidal inundation. The soils adjacent to the wall were suitable for use to build up the wall where required (on average by 10-20cm, over a length of 860m). The site was prepared by culverting drains which linked to adjacent fields, topping and grazing to reduce the amount of terrestrial vegetation, and the removal of trees. No internal earthworks were needed to create a creek system as a relict creek was still present. Approximately 2/3 of field is inundated at spring high water.

	The site is owned and managed by the Royal Society for the Protection of Birds (RSPB), and forms part of its wider Nigg Bay reserve. This reserve incorporates extensive areas of mudflat, saltmarsh and wet grassland (RSPB website, 2011).		The site is owned and managed by the Royal Society for the Protection of Birds (RSPB), and forms part of its wider Nigg Bay reserve. This reserve incorporates extensive areas of mudflat, saltmarsh and wet grassland (RSPB website, 2011).
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			https://www.therrc.co.uk/sites/default/files/projects/48_niggbay.pdf
	\|Monitoring surveys and results=A range of monitoring studies were undertaken to describe ecological development of site (i.e. surveys of overwintering waterbirds, benthic invertebrates, vegetation and sedimentation/erosion patterns) as well as impacts to saltmarsh habitats and benthic invertebrate communities outside the breached area.		\|Monitoring surveys and results=A range of monitoring studies were undertaken to describe ecological development of site (i.e. surveys of overwintering waterbirds, benthic invertebrates, vegetation and sedimentation/erosion patterns) as well as impacts to saltmarsh habitats and benthic invertebrate communities outside the breached area.

Alexrrc at 14:35, 8 November 2018

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	\|Project started=2001/03/01		\|Project started=2001/03/01
	\|Project completed=2004/03/01		\|Project completed=2004/03/01
			\|Total1 cost=£47k
	\|Funding sources=Heritage Lottery Fund (HLF), Scottish Natural Heritage, Scottish Environment Protection Agency, Miss EMP Scott Will Trust		\|Funding sources=Heritage Lottery Fund (HLF), Scottish Natural Heritage, Scottish Environment Protection Agency, Miss EMP Scott Will Trust
	\|Supplementary funding information=Land purchased by RSPB in 2001, project part funded by HLF, SNH and SEPA grants as well as a legacy from Miss EMP Scott Will Trust. Excluding staff costs and land purchase, the whole scheme cost £53,840 to complete. Of this, £22,400 were spent on the design and impact study; £2,100 on strengthening existing landward defences; £1,470 on culvert blocking and breach digging; £1,100 on tree removal from the sea wall; £8,450 on fencing to retain stock on site; £1,350 on topping; £8,500 on surveys and		\|Supplementary funding information=Land purchased by RSPB in 2001, project part funded by HLF, SNH and SEPA grants as well as a legacy from Miss EMP Scott Will Trust. Excluding staff costs and land purchase, the whole scheme cost £53,840 to complete. Of this, £22,400 were spent on the design and impact study; £2,100 on strengthening existing landward defences; £1,470 on culvert blocking and breach digging; £1,100 on tree removal from the sea wall; £8,450 on fencing to retain stock on site; £1,350 on topping; £8,500 on surveys and

Alexrrc at 14:34, 8 November 2018

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	\|Specific mitigation=Flood and coastal erosion protection,		\|Specific mitigation=Flood and coastal erosion protection,
	}}		}}
	{{Measures}}		{{Measures
			\|Other technical measure=Salt marsh and mudflat restoration,
			}}
	{{Hydromorphological quality elements header}}		{{Hydromorphological quality elements header}}
	{{Hydromorphological quality element table row		{{Hydromorphological quality element table row

Alexrrc at 14:34, 8 November 2018

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	monitoring; £1,400 on a video, £600 on the launch event; and £110 on the FEPA licence. In terms of staff cost, the RSPB estimated that for the duration of the project (March 2001 – March 2003), total staff time was equivalent to 70-75% of one full time employee (Chisholm et al., 2004).		monitoring; £1,400 on a video, £600 on the launch event; and £110 on the FEPA licence. In terms of staff cost, the RSPB estimated that for the duration of the project (March 2001 – March 2003), total staff time was equivalent to 70-75% of one full time employee (Chisholm et al., 2004).
	}}		}}
	{{Motivations}}		{{Motivations
			\|Specific mitigation=Flood and coastal erosion protection,
			}}
	{{Measures}}		{{Measures}}
	{{Hydromorphological quality elements header}}		{{Hydromorphological quality elements header}}

Alexrrc at 13:28, 1 November 2018

2018-11-01T13:28:33Z

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	\|Project started=2001/03/01		\|Project started=2001/03/01
	\|Project completed=2004/03/01		\|Project completed=2004/03/01
	\|Funding sources=HLF, ~~SNH and SEPA grants;~~ Miss EMP Scott Will Trust		\|Funding sources=Heritage Lottery Fund (HLF), Scottish Natural Heritage, Scottish Environment Protection Agency, Miss EMP Scott Will Trust
	\|Supplementary funding information=Land purchased by RSPB in 2001, project part funded by HLF, SNH and SEPA grants as well as a legacy from Miss EMP Scott Will Trust. Excluding staff costs and land purchase, the whole scheme cost £53,840 to complete. Of this, £22,400 were spent on the design and impact study; £2,100 on strengthening existing landward defences; £1,470 on culvert blocking and breach digging; £1,100 on tree removal from the sea wall; £8,450 on fencing to retain stock on site; £1,350 on topping; £8,500 on surveys and		\|Supplementary funding information=Land purchased by RSPB in 2001, project part funded by HLF, SNH and SEPA grants as well as a legacy from Miss EMP Scott Will Trust. Excluding staff costs and land purchase, the whole scheme cost £53,840 to complete. Of this, £22,400 were spent on the design and impact study; £2,100 on strengthening existing landward defences; £1,470 on culvert blocking and breach digging; £1,100 on tree removal from the sea wall; £8,450 on fencing to retain stock on site; £1,350 on topping; £8,500 on surveys and
	monitoring; £1,400 on a video, £600 on the launch event; and £110 on the FEPA licence. In terms of staff cost, the RSPB estimated that for the duration of the project (March 2001 – March 2003), total staff time was equivalent to 70-75% of one full time employee (Chisholm et al., 2004).		monitoring; £1,400 on a video, £600 on the launch event; and £110 on the FEPA licence. In terms of staff cost, the RSPB estimated that for the duration of the project (March 2001 – March 2003), total staff time was equivalent to 70-75% of one full time employee (Chisholm et al., 2004).

NickRRC at 14:47, 9 April 2014

2014-04-09T14:47:14Z

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	}}		}}
	{{Project background		{{Project background
			\|Project started=2001/03/01
			\|Project completed=2004/03/01
	\|Funding sources=HLF, SNH and SEPA grants; Miss EMP Scott Will Trust		\|Funding sources=HLF, SNH and SEPA grants; Miss EMP Scott Will Trust
	\|Supplementary funding information=Land purchased by RSPB in 2001, project part funded by HLF, SNH and SEPA grants as well as a legacy from Miss EMP Scott Will Trust. Excluding staff costs and land purchase, the whole scheme cost £53,840 to complete. Of this, £22,400 were spent on the design and impact study; £2,100 on strengthening existing landward defences; £1,470 on culvert blocking and breach digging; £1,100 on tree removal from the sea wall; £8,450 on fencing to retain stock on site; £1,350 on topping; £8,500 on surveys and		\|Supplementary funding information=Land purchased by RSPB in 2001, project part funded by HLF, SNH and SEPA grants as well as a legacy from Miss EMP Scott Will Trust. Excluding staff costs and land purchase, the whole scheme cost £53,840 to complete. Of this, £22,400 were spent on the design and impact study; £2,100 on strengthening existing landward defences; £1,470 on culvert blocking and breach digging; £1,100 on tree removal from the sea wall; £8,450 on fencing to retain stock on site; £1,350 on topping; £8,500 on surveys and

Ascarr at 10:31, 3 January 2014

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	{{Site		{{Site
	\|Name=Cromarty Firth, Highland Region		\|Name=Cromarty Firth, Highland Region
			\|WFD (national) typology=Intertidal,
	\|WFD water body name=Cromarty Firth		\|WFD water body name=Cromarty Firth
	\|Desired post project morphology=Estuary (tidal),		\|Desired post project morphology=Estuary (tidal),
	\|Heavily modified water body=No		\|Heavily modified water body=No
	\|Protected species present=Yes		\|Protected species present=Yes
	\|Invasive species present=No		\|Invasive species present=No
	\|Species=Wading birds (e.g. Lapwing), wigeon, oyster catchers, pintail,		\|Species=Wading birds (e.g. Lapwing), wigeon, oyster catchers, pintail,
	\|Dominant hydrology=Estuary,		\|Dominant hydrology=Estuary,
	\|Dominant substrate=Estuarine mud,		\|Dominant substrate=Estuarine mud,
	\|River corridor land use=Arable;		\|River corridor land use=Arable;
	}}		}}

Ascarr at 10:30, 3 January 2014

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	\|Main contact surname=Armstrong		\|Main contact surname=Armstrong
	\|Contact organisation=ABPmer		\|Contact organisation=ABPmer
	\|Partner organisations=RSPB, SEPA,		\|Partner organisations=RSPB, SEPA,
	\|Multi-site=No		\|Multi-site=No
	\|Project picture=Nigg bay managed realignment scheme.jpg		\|Project picture=Nigg bay managed realignment scheme.jpg
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	A PhD study investigating sediment characteristics and invertebrate colonisation reported the following results from monitoring the site during the first three winters post implementation (with the caveat that the realignment sampling points were higher in the tidal frame than those on the reference intertidal flats) (Crowther, 2007):		A PhD study investigating sediment characteristics and invertebrate colonisation reported the following results from monitoring the site during the first three winters post implementation (with the caveat that the realignment sampling points were higher in the tidal frame than those on the reference intertidal flats) (Crowther, 2007):
	(1) The particle size of the sediments in Nigg Bay realignment site was significantly smaller than that of the (fronting) reference intertidal flats (mostly silts compared to mostly fine sands) – this was attributed to the sheltered environment and limited wave exposure within the site.
	(2) The organic matter content of the sediments on the reference intertidal flats was less than 1%, whereas within the site, it was 46.6% in the first winter, and 27.2% in the second. The author highlighted that ‘organic matter is usually associated with fine grained sediments (…), so the sediments in [the site] are likely to have provided a large surface area for colonisation by		(1) The '''particle size''' of the '''sediments''' in Nigg Bay realignment site was significantly smaller than that of the (fronting) reference intertidal flats (mostly silts compared to mostly fine sands) – this was attributed to the sheltered environment and limited wave exposure within the site.

			(2) The '''organic matter''' content of the '''sediments''' on the reference intertidal flats was less than 1%, whereas within the site, it was 46.6% in the first winter, and 27.2% in the second. The author highlighted that ‘organic matter is usually associated with fine grained sediments (…), so the sediments in [the site] are likely to have provided a large surface area for colonisation by
	micro-algae’. Furthermore, the higher organic content during the first winter was described as ‘not surprising given the large quantity of vegetation that had been killed following the re-establishment of tidal conditions’. A significant positive relationship with elevation in the tidal frame was found for the percentage organic matter in the sediments during the second winter. The author theorised that such high organic matter content of the sediments ‘may have caused hypoxic conditions due to the increased biological oxygen demand of the sediments’, however oxygen content was not measured (and the presence of hypoxia hence not determined).		micro-algae’. Furthermore, the higher organic content during the first winter was described as ‘not surprising given the large quantity of vegetation that had been killed following the re-establishment of tidal conditions’. A significant positive relationship with elevation in the tidal frame was found for the percentage organic matter in the sediments during the second winter. The author theorised that such high organic matter content of the sediments ‘may have caused hypoxic conditions due to the increased biological oxygen demand of the sediments’, however oxygen content was not measured (and the presence of hypoxia hence not determined).
	(3) The following four invertebrate species were found to be most abundant within the site three years after the re-establishment of tidal conditions: Corophium volutator, Hediste diversicolor, Hydrobia ulvae and Macoma balthica. All of these were also noted as colonists in the first year, and also found to be the most abundant species on the adjacent reference marshes. The presence of M. balthica during the 1st winter was considered unusual, as it is usually considered to be relatively immobile. It was theorised that this could have resulted, at least in part, from wind or wave-driven immigration. The presence of C. volutator and H. diversicolor was (amongst others) attributed to the high organic content of the sediments. Intertidal invertebrate densities within the site were generally lower than the reference intertidal flats; which was mostly related to the higher elevations of the realignment site.s well as impacts to saltmarsh habitats and benthic invertebrate communities outside the breached area.
	\|Lessons learn=By 2005 the area had developed into three distinct zones: (i) an upper zone, which is rarely inundated and retains terrestrial grassland; (ii) an intermediate zone, which has been colonised by salt marsh species; and (iii) a lower zone, which experiences regular inundation and in which terrestrial grassland has been replaced by fine sediments. Nineteen species of waders and wildfowl were recorded using the site during winter 2004/05, the commonest of which were redshank (RSPB, 2005).

			(3) The following four '''invertebrate species''' were found to be most abundant within the site three years after the re-establishment of tidal conditions: ''Corophium volutator'', ''Hediste diversicolor'', ''Hydrobia ulvae'' and ''Macoma balthica''. All of these were also noted as colonists in the first year, and also found to be the most abundant species on the adjacent reference marshes. The presence of M. balthica during the 1st winter was considered unusual, as it is usually considered to be relatively immobile. It was theorised that this could have resulted, at least in part, from wind or wave-driven immigration. The presence of ''C. volutator'' and ''H. diversicolor'' was (amongst others) attributed to the high organic content of the sediments. Intertidal invertebrate densities within the site were generally lower than the reference intertidal flats; which was mostly related to the higher elevations of the realignment site.s well as impacts to saltmarsh habitats and benthic invertebrate communities outside the breached area.
			\|Lessons learn=By 2005 the area had developed into three distinct zones:

			(i) an upper zone, which is rarely inundated and retains terrestrial grassland;

			(ii) an intermediate zone, which has been colonised by salt marsh species; and

			(iii) a lower zone, which experiences regular inundation and in which terrestrial grassland has been replaced by fine sediments. Nineteen species of waders and wildfowl were recorded using the site during winter 2004/05, the commonest of which were redshank (RSPB, 2005).
	}}		}}
	{{Image gallery}}		{{Image gallery}}

Ascarr at 18:05, 2 January 2014

2014-01-02T18:05:55Z

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	{{Site		{{Site
	\|Name=Cromarty Firth, Highland Region		\|Name=Cromarty Firth, Highland Region
			\|WFD water body name=Cromarty Firth
			\|Desired post project morphology=Estuary (tidal),
	\|Heavily modified water body=No		\|Heavily modified water body=No
	\|Protected species present=No		\|Protected species present=Yes
	\|Invasive species present=No		\|Invasive species present=No
	\|River corridor land use=Arable		\|Species=Wading birds (e.g. Lapwing), wigeon, oyster catchers, pintail,
			\|Dominant hydrology=Estuary,
			\|Dominant substrate=Estuarine mud,
			\|River corridor land use=Arable;
	}}		}}
	{{Project background		{{Project background