Habitat reinstatement, restoration and creation on … · Habitat reinstatement, restoration and...

Habitat reinstatement, restoration and creation on the Corrib Gas Onshore Pipeline in Co Mayo,

Ireland - challenges and solutions

Jenny Neff CEcol CEnv FCIEEM

EACS - Ecological Advisory and Consultancy Services

Location and project elements

EACS - Ecological Advisory and Consultancy Services 2

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Corrib Field

Onshore pipeline

• Total Length: 9.2km from landfall at Glengad to the gas terminal at Bellanaboy

• 4.9 km tunnel (4.5m diameter) made by a manned TBM under Sruwaddacon Bay - part of Blacksod Bay/Broadhaven SPA and Glenamoy Bog Complex SAC (mitigation by design).

• Habitat reinstatement except for the Landfall Valve Installation (LVI) at Glengad, in accordance with requirements and commitments made - as enshrined in statutory consents; approved EMP and R&A Plan; Project BAP and LMP etc.

• Opportunities for restoration and biodiversity enhancement

• NNL/NPI Pilot Study 2011 / predicted outcome



Gas Terminal

Leenamore

Aughoose

Glengad

Pipeline Route

Landfall Valve Facility

Project commitment to reinstate to the benefit of wildlife and habitat – the aims

• Landfall reinstatement of semi-improved grassland Allow the site to re-vegetate naturally.

• Leenamore inlet (Annex I Habitats) Salt marsh protection: excavate and store in the intertidal zone but with protection,

avoid prolonged storage of salt marsh vegetation before reinstatement. Intertidal: lift epiphyte - covered cobbles and 300mm benthic layer – store

separately• Atlantic Blanket bog habitats

Using stone road concept – peat stone matrix at the base and regulation layer and peat turves/peat vegetation on top

Retain hydrological function of the peatland (avoid vertical/horizontal drainage paths)

Underlying requirements in order to achieve successful reinstatement.• ‘Forested wayleave’

Plant native deciduous woodland along the sides of the wayleave and create wetland habitat.


Timelines for reinstatement

LOCATION ROUTE SECTION INDICATIVE TIMELINE FOR

REINSTATEMENT†

Glengad Installation of the surface

water outfall pipe at the LVI

Cliff reinstatement :

completed Q3 2013

Remedial repairs completed

Q3 2014

From the LVI to approximately

50m west of the Tunnel

Reception shaft

2015

SC2 compound and eastern

section

2015

Aughoose Compound (SC3) 2015 - 2016

Leenamore Inlet crossing Completed Q3 2013

Fields on either side of the

Leenamore

Completed Q4 2013

The 190m section, recovering

blanket bog

Completed Q4 2013

190m to Terminal Forested Area 190m to RDX1 completed Q3

2014

RDX1 to DL6 completed Q3

2014

DL6 to Terminal Q4 2014



Leenamore inlet – habitats

• Annex I Atlantic salt meadows (Glauco-Puccinellietalia maritimae)” (1330) Upper Salt marsh dominated by

the Juncus maritimus; Lower Salt Marsh with low grassy

sward dominated by Puccinelliamaritima, with Glaux and Armeria.

• Annex I estuarine habitat “Mudflats and sand flats not covered by sea water at low tide” (1140)

Epiphytic flora and epifauna attached to cobbles on the surface. Brown fucoid seaweeds being dominant.

Benthic species occur in the shallow top layer (300mm) of sediments.


Leenamore - challenges

• Successful reinstatement dependent upon:

• The necessary habitat mitigation measures being correctly implemented during construction, including:

• Management of temporary translocation and- of salt marsh, cobbles and the top benthic layer (300mm) of intertidal sediments.

• Storage of the habitats at the correct height in the intertidal zone for as short a period as possible

• Challenges: • Client and contractor buy-in: consultation, education and guidance

• Construction - imposed constraints including duration and extent

• How to maintain the correct salt marsh zones

• Salt marsh substrate


Solutions

• Contractor buy-in : explanation, education (preconstruction workshops and tool box talks), ecological support and guidance throughout

• Duration – ensured design included suitable storage of habitat elements

• Salt marsh, cobbles with epiphytes, and benthic layer all stored separately in the intertidal zone during construction

• Salt marsh substrate:

Vital that salt marsh was reinstated at the correct elevation to ensure the correct vegetation type was maintained

Re-worked peat would not have supported the salt marsh turves and

Ecologists, geotechnical engineers and contractor agreed to use a peat – stone mix to support the reinstated salt marsh and a semi-permeable Geotextile to control sediment seepage post-construction - held in place by cobbles. In time the cobbles will provide additional niche habitats for crustaceans etc. and one year on the cobbles are being colonised by epiphytes .


Salt marsh - GIS referencing

Original position Temporary storage area


Salt marsh translocation and storage


Geo-referencing and labelling turves prior to lifting

Depth of peat = up to 2m under upper salt marsh

Dammed inlet floods after Exceptional high spring tide

Salt marsh storage area after 10 days – note colour of vegetation

Leenamore inlet - pipelay


Leenamore inlet: reinstatement


Spreading the base peat/ stone layer

Salt marsh reinstatement


Leenamore inlet

Before construction 9 months post reinstatement


Leenamore - landscape overview

Before construction One year post reinstatement



The big reinstatement challenge for 2015

The aim of reinstatement of the Aughoose compound is to establish a functioning peat-based habitat with created wetlands interspersed in an area which, prior to

construction, comprised modified Atlantic blanket bog habitats.



Aughoose – stored surface vegetation

May 2014: Eriophorum angustifoliumand E. vaginatum

Peat storage area A

Aughoose compound - reinstatement plan


Aughoose reinstatement

• Main challenge: • Stored surface vegetation equates to approximately one-third of the

area to be reinstated

• Planned solutions: • Areas of bare peat:

• Native ericaceous seed (collected autumn 2014)

• Plant plugs – E. angustifolium and Carex panicea (collected locally - 2014)

• Sphagnum moss beads – BeadaMoss®

• Wetland habitat creation

• Populate re-created drains with Sphagnum taken from an old cutover at Aughoose in 2011 prior to construction and temporarily stored locally and grown on in drains at a commercial cut away.


Collection of Sphagnum moss at Aughoose in 2011 for BeadaMoss® production in UK for use in reinstatement 2015/2016

BeadaMoss® trial on 190m - 2014


Ongoing challenges – invasive species


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TO SUMMARISE• Specialists worked closely across disciplines with client management, design

and construction engineers; and assisted in developing methodologies to address ecological requirements in order to achieve mitigation by design.

• Solving problems together on the ground - as they arise.

• Exploring and exploiting opportunities for biodiversity enhancement and habitat creation – using native species and novel methods.

• Opportunity to restore previously overgrazed areas of blanket bog unaffected by construction (now in the ownership of the project) to Annex I quality.

• Development of project Biodiversity Action Plan (Client buy in essential and global group support helps too!).

• BAP commitment for Land Management Plan which enshrines best practice stewardship of habitats and species; and monitoring into the future (Landfall to, and including, the terminal site of 160ha).

• Predicted to have Net Positive Impact /Gain (NPI/NPG) by 2020 (The Biodiversity Consultancy, report 2011) – currently on target!



Links to Corrib:

BAP: http://www.shell.ie/content/dam/shell-new/local/country/irl/downloads/pdf/corrib-development-biodiversity-action-plan-2014-2019.pdf

The Corrib project - environment: http://www.shell.ie/aboutshell/our-business-tpkg/e-and-p/corrib/safety-environment/environment.html

The Corrib project - general: http://www.shell.ie/aboutshell/our-business-tpkg/e-and-p/corrib.html

Further reading and information



ADDITIONAL SLIDES

Glengad landfallThe landfall area at Glengad is in the buffer zone of Glenamoy Bog ComplexSAC on the southern edge of dune complex. Construction areas comprise

semi- improved grassland

• Aim: Reinstate semi-improved grassland by allowing the site to re-vegetate naturally.

• Challenges: • No imported seed permitted – relying on natural regeneration of vegetation from seed and

by vegetative means• Repeated top soil stripping (2002, 2005, 2008, 2009, 2012)• Duration of soil stock piling (currently since 2012 in parts)• Steepness of Landfall Valve Installation (LVI) side slopes

• Outcomes to date:• Despite this the reinstatements to date have been successful – see next slide and 2009 where

some of the soil had been stockpiled since 2002. • LVI side slopes – 2014 with good vegetation cover within weeks of top soil spreading

• Precaution (belt and braces): this year have collected seed from the adjacent semi-improved and fixed dune grassland to have in hand in case needed.


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Glengad – landfall and tunnel reception


Offshore works – 2009Reinstated landfall site September 2009

Reinstated landfall site in June 2010 2013/2014

Glengad – LVI side slopes


Top soil spreading on LVI side slopes(19 June 2014)

Vegetation regeneration on side slopes (18 September 2014)

The “190m” blanket bog recovering from previous overgrazing


190m Atlantic Blanket bog habitat recovering to Annex I status (not yet Active*)

Aims and methods

Using stone road concept – peat stone matrix at the base and regulation layer and peat turves/peat vegetation on top

Retain hydrological function of the peatland (avoid vertical/horizontal drainage paths)

Underlying requirements in order to achieve successful reinstatement.


“190m” construction and challenges

Nesting Skylark caused 3 week delay

in lifting blanket bog turves in the

exclusion zone and construction programme to be prolonged.


Bog mats placed ready to receive blanket bog turves

Blanket bog turves stored on bog mats with central bog mat ‘road’ for access by bowserfor watering in dry weather

Stone Road Construction / Mitigation hydrology and ecology


Peat plugs Regulation layer

Peat turves placed on top

The 190m – during reinstatement


190m post reinstatement


Reinstated turves

Overview of 190m (2014)


“Forested wayleave”: construction, habitat creation and biodiversity enhancement (north of RDX1)

Planted deciduous native species

Wetland number 3

“Forested wayleave” (south of RDX1)


Wetland number 6

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