fairport house, bursledon, river hamble · 2017. 1. 3. · fairport house, bursledon, river hamble...
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Fairport House, Bursledon, River Hamble
Proposed Pontoon and Associated Mitigation
Supporting Statement and Water Framework
Directive Assessment
Compiled by Dr P Tosswell, Lymington Technical Services Ltd
Document 10549 Rpt2 Dec 2016
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Contents
1. Site Location and Works 2
2. Required Consents 3
3. Proposed Use 3
4. Navigation 4
5. Method Statement 4
6. Protected Areas 5
7. Impacts on Protected Areas 5
8. Background to Water Framework Directive Assessment 6
9. WFD Assessment 7
9.1 Screening & Scoping Stage 9
10. WFD Impact Assessment & Mitigation 14
11. Summary 15
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1. Site Location & Works
The proposed jetty and pontoon is located at Fairport House Hamble and shown in red on the
following image:
The proposed works consist of a package which includes mitigation work to improve the nearby
habitat conservation. The land where the jetty starts is used for dinghy storage and regular
usage. This area is indicated (approximately) by the magenta area and is in line with an
agreement between Natural England and the current owner.
The agreed use of this area is for boating activities associated with the River Hamble. This
includes the storage of craft and associated trailers and vehicles. Maintenance and access to all
of the existing slipways, boardwalks and boathouse are also permitted within this agreement.
The jetty is designed to have minimal impact (details follow) and the mitigation consists of
removal of an existing pontoon. This existing pontoon provides berthing for a vessel with access
over high water periods.
The green circle in the above image shows the existing pontoon to be removed. Removal of this
pontoon will reduce the usage of the access channels to an insignificant level. The green line
shows a channel that will have no practical use. Whilst an existing boathouse is also nearby the
practical need for this is negligible with the proposed pontoon.
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The pontoon location is such that it will remain floating at all tidal levels of MLWS and above.
Access to the pontoon will be by an elevated jetty structure with a brow to the pontoon.
At this time no hydrographic data is available but that will be supplied in the near future (Jan
2017).
The access jetty is elevated to prevent flooding and to minimise impact on inter tidal habitat.
The jetty is supported on 4 pairs of tubular steel piles driven into the bed. The seaward end of
the jetty is supported by a cross beam on a larger tubular steel pile which also supports the
hinge of the brow. The bottom of the brow rests on a landing pontoon forming part of the main
pontoon. The pontoon is restrained by two tubular steel piles. This is all in accordance with
normal practice.
The access jetty structure will be formed from steel frames connected to the piles and decked
with an open grid grp decking. This has the additional advantage that there is very little
shadowing of the inter tidal habitat.
Drawing 10549/4 shows the proposed works.
2. Required Consents
These works require the following consents:
Marine Licence from the Marine Management Organisation (MMO)
Planning consent from Eastleigh Borough Council (EBC) (as works cross the MLW mark)
Harbour Works Consent from River Hamble Harbour Authority (RHHA)
Landowner consent – applicant and Crown Estates
Flood Defence Consent – excluded activity by virtue of MMO application
In order to meet application deadlines, the sequence will be RHHA, EBC, MMO.
3. Proposed Use
The pontoon is intended for the personal use of the land owner and is for leisure purposes. At
this stage, no vessel has been specified but the relatively shallow water at low tide would
preclude vessels larger than those on nearby moorings. This will replace the existing berth so
there is no increase in vessel numbers.
The frequency of use is difficult to estimate but it is likely to be similar to vessels on nearby
moorings.
For the avoidance of doubt no dredging is proposed as part of these works.
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4. Navigation
The pontoon is located just seawards of the MLWS contour so that it will remain floating at all
states of tide.
As is clear from the earlier image and drawing the distance between the pontoon (and any
moored vessel) to the existing river moorings is no smaller than the existing gaps downstream
and upstream.
No rafting of vessels is proposed and there is no increase in moorings as this is balanced by the
removal of the existing pontoon.
Whilst the requirement for navigation lighting is determined by Trinity House as part of the
Marine Licence application it is not considered that any such lighting will be necessary or
required.
5. Method Statement
The works are in two distinct phases, marine and land.
Marine -
The pontoon and access brow will be installed from a spud legged crane barge using a vibro
hammer in accordance with usual practice.
The works will be undertaken at high water with the brow support pile being driven first. The top
of this pile will be fitted with a cross piece to support the upper end of the brow.
The pontoon will be floated into position and the two remaining piles driven.
The brow will then be craned into position.
These works will be undertaken over high water periods to minimise any impacts on navigation.
This also has the advantage that any feeding wildfowl will be some distance away as the mudflats
will be covered.
Land -
The land work comprises the driving of the jetty support piles and the construction of the elevated
walkway. In terms of plant this is a much smaller operation than the marine phase and the works
will have to be conducted when tidal access is possible.
The works will be undertaken using small tracked plant operating over crawler mats to protect the
inter tidal areas.
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Mitigation –
The existing pontoon will be removed at high water with a small launch. The pontoon may form
part of the new structure or will be sold.
6. Protected Areas
Hackett’s Marsh LNR (1009285) – this is south of the site and primarily a saltmarsh habit. It is an
important feeding area for waders and wildfowl.
Ramsar Site – Solent & Southampton Water (UK11063). Ramsar sites are wetlands of international
importance. This particular site is designated for the habitats that support wintering wildfowl and
breeding gull and tern populations (JNCC). Overlays SPA & SSSI. The works above MLW are within
this area.
Site of Special Scientific Interest (SSSI) – Lincegrove and Hackett’s Marshes (1080734). The
condition is unfavourable recovering. There is a wider concern (Natural England) regarding erosion
of the saltmarsh. Overlays SPA & Ramsar. The works above MLW are within this area.
Special Protection Area (SPA) – Solent and Southampton Water (UK9011061). SPAs are sites of
importance for rare and vulnerable birds as well as migratory birds. For this SPA the main threats
are pollution, fishing, water quality, leisure (JNCC). Overlays SSSI & Ramsar. This covers the works
above MLW.
The Special Area of Conservation (SAC) – Solent Maritime (UK0030059). SACs are sites designated
areas to ensure the conservation of important habits and species. This area is of importance for
estuaries, Spartina swards and Atlantic sea meadows. For this SAC the main threats are pollution,
fishing, water quality, leisure (JNCC). Overlays all the above sites.
WFD Estuarine and Coastal Water Bodies Cycle 2 GB520704202800 Southampton Water
Coastal Sensitive Areas – Eutrophic – Hamble Estuary UKENCA123 (Nitrate sensitivity).
WFD Habitats – higher sensitivity – saltmarsh
7. Impacts on Protected Areas
This section summarises the key points, details of the mitigation are provided as part of the WFD
assessment. In order to meet RHHA submission deadlines we have not yet been able to discuss
these details with Natural England but this is intended.
LNR – The works are outside of this area but the proposed mitigation has the potential to offer
improvement due to a lowering of human activity nearby.
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Ramsar – Whilst the works are within this protected area the proposed mitigation offers a direct
improvement to the habitat.
SSSI – Whilst the works are within this protected area the proposed mitigation offers a direct
improvement to the habitat.
SPA – Whilst the works are within this protected area the proposed mitigation offers a direct
improvement to the habitat. There will be no increase in threat from pollution, fishing or water
quality. The threat from leisure (human activity) is lessened by removal of the existing pontoon.
SAC – Whilst the works are within this protected area the proposed mitigation offers a direct
improvement to the habitat. There will be no increase in threat from pollution, fishing or water
quality. The threat from leisure (human activity) is lessened by removal of the existing pontoon.
WFD – Covered in WFD assessment
8. Background to Water Framework Directive Assessment
The purpose of a Water Framework Directive (WFD) assessment is to determine whether the
proposed works will compromise the attainment of a WFD objective or result in the deterioration
of the current ecological status of the relevant waterbodies.
The EA have released (Dec 2016) a new version of ‘Clearing the Waters for All’ and this version is
followed here.
The process consists of 3 stages –
Stage 1 – The Screening Stage
This stage is used to identify activities which need to be considered further (i.e. excludes those
which do not require further assessment). Activities conducted between 2009-2014 are excluded
as they would have been covered by the River Basin Management Plan (RBMP) evidence collection
process. This typically applies to maintenance activities including dredging.
Stage 2 – The Scoping Stage
This stage identifies the potential risks to the following receptors:
Hydromorphology
Biology – fish habitats
Biology – fish
Water quality
Protected areas
Stage 3 – Impact Assessment
This stage examines whether the activity will have a significant non-temporary effect on each
receptor.
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9. WFD Assessment
The assessment uses the new (Dec 2016) online EA tables which are reproduced in the following
pages.
In order to improve clarity the water body data from Catchment Data Explorer is reproduced
below.
The Catchment Data Explorer provides data updated 31:03:16.
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9.1 Screening & Scoping Stage - WFD Tables for activities in estuarine and coastal waters
Works take place in or affect more than one water body, complete a template for each water body – single water body
Works include several different activities or stages as part of a larger project, complete a template for each activity as part of your overall WFD assessment – not significantly different as mitigation is included
Activity Description, notes or more information
Applicant name Mr Mark Keeling
Application reference number (where applicable) n/a
Name of activity Fairport House Jetty and Pontoon
Brief description of activity Installation of tubular steel piles to support jetty and restrain pontoon. Removal of existing pontoon.
Location of activity (central point XY coordinates or national grid reference)
449244,109230
Footprint of activity (ha) 55m2 (0.0055 ha)
Timings of activity (including start and finish dates) Dependent upon licence issue
Extent of activity (for example size, scale frequency, expected volumes of output or discharge)
One off installation along with removal of structure for mitigation
Use or release of chemicals (state which ones) No
Water body1 Description, notes or more information
WFD water body name Southampton Water
Water body ID GB520704202800
River basin district name South East
Water body type (estuarine or coastal) Transitional
Water body total area (ha) 3091.32
Overall water body status (2015) Moderate
Ecological status Moderate
Chemical status Fail
Target water body status and deadline Moderate by 2015
Hydromorphology status of water body Supports good by 2015
Heavily modified water body and for what use Yes
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Higher sensitivity habitats present Yes - saltmarsh
Lower sensitivity habitats present Yes – soft sediment
Phytoplankton status High with good by 2015
History of harmful algae No
WFD protected areas within 2km Yes
Specific risk to receptors -
Section 1: Hydromorphology
Consider if hydromorphology is at risk from your activity.
Use the water body summary table to find out the hydromorphology status of the water body, if it is
classed as heavily modified and for what use.
Consider if your activity: Yes No Hydromorphology risk issue(s)
Could impact on the hydromorphology (for example morphology or tidal patterns) of a water body at high status
Requires impact assessment
Impact assessment not required
No
Could significantly impact the hydromorphology of any water body
Requires impact assessment
Impact assessment not required
No
Is in a water body that is heavily modified for the same use as your activity
Requires impact assessment
Impact assessment not required
No
Record the findings for hydromorphology and go to section 2: biology.
Section 2: Biology
Habitats
Consider if habitats are at risk from your activity.
Use the water body summary table and Magic maps, or other sources of information if available, to
find the location and size of these habitats.
Higher sensitivity habitats 2 Lower sensitivity habitats 3
chalk reef cobbles, gravel and shingle
clam, cockle and oyster beds intertidal soft sediments like sand and mud
intertidal seagrass rocky shore
maerl subtidal boulder fields
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mussel beds, including blue and horse mussel subtidal rocky reef
polychaete reef subtidal soft sediments like sand and mud
saltmarsh
subtidal kelp beds
subtidal seagrass
2 Higher sensitivity habitats have a low resistance to, and recovery rate, from human pressures. 3 Lower sensitivity habitats have a medium to high resistance to, and recovery rate from, human pressures.
Consider if the footprint4 of your activity is:
Yes No Biology habitats
risk issue(s)
0.5km2 or larger
Yes to one or more – requires impact assessment
No to all – impact assessment not required
No
1% or more of the water body’s area No
Within 500m of any higher sensitivity habitat
Yes
1% or more of any lower sensitivity habitat
No
4 Note that a footprint may also be a temperature or sediment plume. For dredging activity, a footprint is 1.5 times the dredge area.
Fish
Consider if fish are at risk from your activity, but only if your activity is in an estuary or could affect
fish in or entering an estuary.
Consider if your activity: Yes No Biology fish risk
issue(s)
Is in an estuary and could affect fish in the estuary, outside the estuary but could delay or prevent fish entering it or could affect fish migrating through the estuary
Continue with questions
Go to next section No
Could impact on normal fish behaviour like movement, migration or spawning (for example creating a physical barrier, noise, chemical change or a change in depth or flow)
Requires impact assessment
Impact assessment not required
No
Could cause entrainment or impingement of fish
Requires impact assessment
Impact assessment not required
No
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Record the findings for biology habitats and fish and go to section 3: water quality.
Section 3: Water quality
Consider if water quality is at risk from your activity.
Use the water body summary table to find information on phytoplankton status and harmful algae.
Consider if your activity: Yes No Water quality
risk issue(s)
Could affect water clarity, temperature, salinity, oxygen levels, nutrients or microbial patterns continuously for longer than a spring neap tidal cycle (about 14 days)
Requires impact assessment
Impact assessment not required
No
Is in a water body with a phytoplankton status of moderate, poor or bad
Requires impact assessment
Impact assessment not required
No
Is in a water body with a history of harmful algae
Requires impact assessment
Impact assessment not required
No
Consider if water quality is at risk from your activity through the use, release or disturbance of
chemicals.
If your activity uses or releases chemicals (for example through sediment disturbance or building works) consider if:
Yes No Water quality
risk issue(s)
The chemicals are on the Environmental Quality Standards Directive (EQSD) list
Requires impact assessment
Impact assessment not required
No
It disturbs sediment with contaminants above Cefas Action Level 1
Requires impact assessment
Impact assessment not required
No
If your activity has a mixing zone (like a discharge pipeline or outfall) consider if:
Yes No Water quality
risk issue(s)
The chemicals released are on the Environmental Quality Standards Directive (EQSD) list
Requires impact assessment5
Impact assessment not required
No
5 Carry out your impact assessment using the Environment Agency’s surface water pollution risk assessment guidance, part of Environmental Permitting Regulations guidance.
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Record the findings for water quality go on to section 4: WFD protected areas.
Section 4: WFD protected areas
Consider if WFD protected areas are at risk from your activity. These include:
special areas of conservation (SAC) bathing waters
special protection areas (SPA) nutrient sensitive areas
shellfish waters
Use Magic maps to find information on the location of protected areas in your water body (and
adjacent water bodies) within 2km of your activity.
Consider if your activity is: Yes No Protected areas risk issue(s)
Within 2km of any WFD protected area6
Requires impact assessment
Impact assessment not required
Yes
6 Note that a regulator can extend the 2km boundary if your activity has an especially high environmental risk.
Record the findings for WFD protected areas and go to section 5: invasive non-native species.
Section 5: Invasive non-native species (INNS)
Consider if there is a risk your activity could introduce or spread INNS.
Risks of introducing or spreading INNS include:
materials or equipment that have come from, had use in or travelled through other water
bodies
activities that help spread existing INNS, either within the immediate water body or other
water bodies
Consider if your activity could: Yes No INNS risk issue(s)
Introduce or spread INNS Requires impact assessment
Impact assessment not required
No
Summary
Receptor Potential risk to receptor?
Note the risk issue(s) for impact assessment
Hydromorphology No
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Biology: habitats Yes Saltmarsh and Soft sediment
Biology: fish No
Water quality No
Protected areas Yes SPA, SAC, SSSI, Ramsar, LNR
Invasive non-native species No
10. WFD Impact Assessment & Mitigation
The assessment has identified potential risks to protected areas and biological habitats.
The proposed works are minor and of small scale and any such risks are considered to be low.
The installation works are over an intertidal and subtidal area in an area of existing high activity
by leisure vessels. In themselves the works and operation will have no significant impact on the
habitats nor the protected areas.
However, it is good practice to provide mitigation where possible to enhance the receptor areas.
As such the following mitigation measures are proposed:
The access jetty is elevated so no part will rest on the inter tidal habitat. This has the
advantage that light levels will be similar to those at present.
The decking on the access jetty will be of a grp grid style as this affords significantly
increased light penetration to the habitat. This is an approach that has been employed
for these reasons elsewhere.
The actual physical loss of inter tidal habit is from the jetty support piles and represents an
area of approximately 0.25m2 assuming an area of loss of Ø200mm for each support pile.
To provide additional mitigation for this small loss it is proposed to remove an existing
floating pontoon (which dries out) as shown on drawing 10549/4. This pontoon has an
area of 9m2 (excluding any moored vessel) which is far in excess of the loss.
As a result of the pontoon removal there will be a significant reduction in levels of human
activity in the main part of the saltmarsh area as vessel access will be relocated.
Marine piling and works to be undertaken over high water periods. This maximises the
distance to any feeding wildfowl. This is an approach that is widely accepted.
Marine piling to be undertaken using vibro-piling methods and this minimises any impact
and is also accepted good practice.
In the event that the marine piling requires percussion methods to reach design level
(considered unlikely) then the standard soft-start process will be employed.
Marine piling will only be undertaken during daylight hours
The land based works will be undertaken using small plant working on crawler mats to
protect the habitat. This is also standard practice and a widely accepted approach.
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11. Summary
The proposed works are relatively small in scale and the floating pontoon is similar to many
elsewhere in this river.
The works have been designed with minimal environmental impact as a major consideration. The
designed in mitigation and accompanying removal produces a significant net benefit to the
protected areas.
The location of the works is in an already active area and will produce no increase in impact.
By following EA guidance and providing significant mitigation it is concluded that the proposal will
have no negative impact on the water body or any protected area.
In terms of each receptor the proposed mitigation will ensure that there is no deterioration of the
area. For the saltmarsh there is a pathway for the area to be improved as a direct result.
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