Post on 14-Dec-2015
Biodiversity and the Thames Tunnel
Stephanie McGibbon, EIA Manager12 May 2011
Contents
Overview of the Thames Tunnel project
Thames Tunnel EIA and Biodiversity
– Data gathering
– Initial findings
– Engaging with stakeholders
Questions
Project overview
Victorian infrastructure
Combined sewer system
57 Combined sewer overflows (CSOs)
Headline news
Thames Tunnel to intercept combined sewer overflows
Capturing the overflows
Environmental Impact Assessment (EIA) and Biodiversity
Stakeholder C
onsultation
EIA & reporting stages
Terrestrial ecology data gathering
Desk Study: GIGL data search and consultation
Use of Satellite/Geo-viewer Imagery
Phase 1 Habitat Surveys and Plans (completed)
Detailed Surveys for Protected/Notable Species (underway)
Terrestrial ecology: protected / notable species surveys
Bats
Birds (Breeding & Wintering)
Reptiles
Amphibians
Invertebrates
Otter and water vole
Botanical
Phase 1 terrestrial ecology surveys - extract
Site Habitats Species Potential
Abbey Mills Mature treesScrubSemi-improved grassland Disused buildings
BirdsBatsReptilesInvertebratesWater Voles and otterInvasive Plants
Acton Storm Tanks Amenity grasslandTall ruderal vegetationScattered trees
Wintering birdsBatsReptiles
Barn Elms Amenity grasslandSemi-improved grassland Tall ruderal vegetationScrubScattered treesRunning water
Breeding and wintering birdsBadgersBatsReptilesInvertebratesWater Voles and otter
Beckton STW ScrubScattered treesPlantation woodlandStanding water
Breeding and wintering birdsBlack redstartBatsReptiles
Aquatic ecology data gathering Desk study
– Environment Agency fish and invertebrate databases
– Mammal data
– Local Habitat Action Plan’s (HAPs)
Field surveys
– Construction and ‘Improvement’ sites
– Range of sites and spatial scope of survey
Fish surveys (autumn 2010)
Total fish
Invertebrates surveys (Autumn 2010)
Invertebrate diversity
Mean Diversity
0
2
4
6
8
10
12
14
Borth
wic
k W
hf
Kg E
dw
ard
Mem
Pk
Bla
ckfria
rs B
r
Vic
toria
Em
bkt
Alb
ert E
mbkt
Tid
ew
ay W
k
W P
um
pin
g S
tn
Chels
ea E
mbk
Cre
morn
e W
hf
Jew
s R
ow
Bell L
a C
rk
Putn
ey B
r
Barn
Elm
s
Ham
mers
mith
PS
t
No
Taxa
Subtidal sample
Intertidal sample
Mitigation hierarchy
REDUCE IMPACT
ABATE IMPACTS AT SOURCE
ABATE IMPACTS ELSEWHERE (as close to impact as possible)
COMPENSATE IN KIND
COMPENSATE BY OTHER MEANS
ENHANCE Enhancement
Compensation
Mitigation
AVOID IMPACT
Balance sheet
A B C D E F G
HabitatPermanent landtake for built footprint
Mitigation landtake
Total landtake Habitat creationHabitat enhancement
Total creation/ enhancement
Net loss/gain
Woodland Ha
Scattered Trees No.
Hedgerow M
Scrub Ha
Tall Ruderal Ha
Ornamental Planting/Introduced Shrub
Ha
Semi-improved Grassland
Ha
Amenity Grassland Ha
Short Perennial/Disused Ha
Standing Water/Wetland Ha
TOTAL (Semi-natural habitats)
Hard-standing (buildings and roads/tracks)
Ha
TOTAL (All habitats)
Engaging with stakeholders
A Thames Tunnel Biodiversity Forum has been established
– November 2010
– March 2011
Stakeholders
– 14 local planning authorities
– Environment Agency
– Natural England
– London Biodiversity Partnership
– Thames21
Background Information Slides
For reference
Bazalgette’s intercepting sewers
Thames Tideway Strategic Study
Two problems:
Overloaded sewage treatment works; discharging directly into the river after heavy rainfall
Overloaded sewer network; discharging into the river via CSOs.
Three solutions:
River
Brent
River Lee
River
Roding River Beam
River Ingrebourne
Sewage treatment works discharging to the tidal River Thames
Thames Estuary
Southend
Gravesend
Long Reach
Riverside
Crossness
Mogden
Beckton
The Lee Tunnel
Four mile tunnel from Abbey Mills to Beckton. To start and end on land we already own; requires no intermediate construction sites.
To intercept 16 million cubic metres of untreated sewage currently discharged into the River Thames each year on average, via the River Lee.
Planning consent granted, subject to planning conditions.
£600 million project – largest contract TWUL has ever awarded. Construction started in June 2010 and is scheduled to finish in 2014.
Birds
Objectives:
To obtain survey data on wintering birds and breeding birds at and adjacent to preferred work sites.
Approach:
A huge amount of data and local knowledge already exists on bird populations across London.
Proposed work sites will first be screened for inclusion in the survey.
Sites will then be further screened on the basis of current knowledge.
Methodology:
Survey methodologies would be developed.
Methodologies will be agreed in consultation with statutory agencies.
Bats Objectives: To obtain information on the following,
which could be affected by development works
i) roost sites, and
ii) any significant foraging or commuting routes
Gather and collate existing data
Phase 1 surveys will include a site evaluation
Initial use of remote monitoring equipment
Site surveys.
Surveys methodologies
Approach/Methodology:
There is a large pool of existing data on sites used by bats. The approach will be to: