Annex L
Construction Method
Statement
RWE npower renewables
Clocaenog Forest Wind Farm
Draft Construction Method Statement
November 2010
1
Introduction
This document is a draft Construction Method Statement (CMS) for the
proposed Clocaenog Forest Wind Farm. In the event of planning consent, a
finalised Construction Method Statement will be drawn up, post-consent but
pre-construction, between RWE npower renewables (RWE NRL) and their
appointed contractors(s), in consultation with, and for approval by;
Denbighshire County Council (DCC) and Conwy County Borough Council
(CCBC), Environment Agency Wales (EAW), Forestry Commission Wales
(FCW) and the Countryside Council for Wales (CCW).
2
Project Description
The proposed Clocaenog Forest Wind Farm scheme is located approximately
13km south of Denbigh and 10km west of Ruthin, Denbighshire. The
northern site boundary is located 1km south of the B4501. The site extends
8km south of this, 1.5km beyond the summit of Craig Bron–Banog hill in the
south. The eastern and western site boundaries are located just west of the
River Clwyd and east of Llyn Brenig reservoir respectively. The wind farm site
covers an area of approximately 1584.5ha.
The development area comprises an upland plateau with an altitude of
between 380 and 502m. Craig Bron-Banog is the highest point in the
development area with an altitude of 502m. The majority of the land within
the development area is predominantly conifer forest with some open areas of
heather moorland. There are no sizable settlements within the proposed
development area, however, there are a number of settlement clusters which
comprise a number of properties (refer to the Environmental Statement,
Chapter 11 Noise).
The Llyn Brenig Reservoir lies approximately 3km to the west of the
development area. The Afon Clywedog, Afon Alwen and a number of
unnamed tributary streams flow through the north-east and south-west of the
development area.
The main components of the proposed wind farm include:
•
installation of 32 wind turbines (each height to blade tip of 145m);
•
a permanent access route to the site and between wind turbines
consisting of approximately 3.95km of existing public road, 31.89km of
existing forestry track and 6.11km of new track;
•
construction of ancillary development comprising an onsite substation,
hard-standing areas, transformers, connecting cabling and two permanent
wind monitoring masts;
•
creation of two temporary civils construction compounds and one
temporary electrical construction compound;
•
potential working of up to four borrow pits for the extraction of stone.
•
an overhead line from the site to the 132 kV electricity distribution network
The most favoured access route for abnormal loads will be: Ellesmere Port;
• M53 and A55 around the south of Chester;
• A483 past Wrexham;
• West along the A5 to Pentrefoelas;
• A543 to Llyn Bran; and
• B4501 beyond the crossroads with the B5435 where it turns back on itself
onto the unclassified road to the site.
This preferred route is consistent with the route outlined in the WAG Strategic
Route Report.
Construction of the wind farm is expected to take about 24 months.
3
Access Track Construction
Description
Excavation, construction and maintenance of access roads to the wind
turbines (WTGs) with minimal disturbance to vegetation and hydrology at the
site. The tracks need to be sufficient to allow the delivery of large and heavy
turbine components and transformers.
Procedure
The roads within the wind farm site will take the routes agreed in the
Environmental Statement. The tracks will be surfaced and designed to
standards that ensure control of water and integrity of the road surface.
The design requirements are for a road capable of carrying large vehicles
approximately 50m long with axle weights of up to 20t. The surface will be of
water-bound gravel or crushed rock.
Geometric parameters for the site roads are: maximum gradient of 10%, although short lengths (< 200m) of steeper
gradient (up to 12.5%) can be accommodated on water-bound surfaces
in good conditions.;
minimum running surface width of approximately 5m on straight sections
with widening on curves; and
minimum inside radius on bends 20m.
The road width will be increased proportionately for bends and
passing/turning places.
Roadside drains shall have a depth of not less than 250 mm below the
formation edge and a longitudinal gradient of not less than 2%. Catchpits,
settlement ponds and filters will be provided in and adjacent to the drains to
avoid pollution and sedimentation of watercourses. Roadside drains will not
be led directly into watercourses. Further description of track drainage
appears in Section 11 (Control of Water) below.
The road alignment and gradients will be set out to fit existing landforms as
far as possible and shall be marked out prior to commencement of the works.
Cut–and-fill operations will be designed to achieve a good balance where
possible and will be designed to cause the minimum amount of impact to the
area. Surface soils will be used to dress the slopes and verges if required.
Sections of track through soft or peaty ground will be assessed by first trial
pitting to establish the depth to suitable formation. The appropriate course of
action will be determined based on the results of these trial pits.
Widening of Existing Roads
A walk-over would be conducted and any soft or rutted areas identified and
dealt with prior to any large construction plant arriving. Sections of track
requiring minor widening will be excavated to a suitable formation. The
arisings will be either stockpiled in bunds adjacent to the tracks or transported
to the borrow pit areas to be used for final reinstatement. Rock will be
transported from the borrow pit to the point of deposition and widening
undertaken in line with the specification set out in the Forestry Civil
Engineering Handbook.
Selected smaller material from the crushing operations will be used to finish
off the tracks to the required profiles and to provide a smooth watertight
running surface. Several sections of track will require widening in areas with
steep cross falls. Areas requiring fill to be placed to comply with longitudinal
gradients will be designed to minimise the overall footprint of the
embankment. Site-won material will be placed and compacted in layers to
the required profiles. Areas in cuttings will be designed to cut more into the
high side to minimise the impact of the road widening.
New Access Track Construction
The new access track construction will follow the same design principle as the
road widening. Areas of cut-and-fill will be designed to achieve a suitable
balance. Floating roads are not considered necessary as it is not anticipated
that peat of any significant depth will be encountered. The track footprint will
be designed to cause the minimum of disruption.
Where the removal of trees is required the area will be felled according to the
felling plan and in line with Forestry Commission Wales standard procedures,
and where appropriate, the stumps will be removed. The top soil will be stock
piled for use during reinstatement. In areas clear of trees the area will be
cleared of all vegetation and surface soils and set aside for reinstatement.
Material removed from cuttings will be hauled to fill areas where suitable.
Suitable rock from either cut-and-fill or quarry/borrow pit will be spread and
compacted in layers. Final profiles will be completed with crushed material
and graded to form the required profile. Selected smaller material from the
crushing operations will be used to finish off the tracks to the required profiles
and to provide a smooth watertight running surface.
Drainage ditches will be provided on either side of the tracks, if required (see
also Section 11) and cross culverts will be used where necessary to minimise
flow.
Ten watercrossings have been identified from 1:25,000 scale OS mapping.
and site reconnaissance.
Culverts will either be upgraded or replaced at these locations, and any other
locations along existing access tracks where existing culverts are found, in
the event that the tracks at the culverts need upgrading. On new tracks,
culverts will be installed on any additional channels that are not large enough
to be shown on 1:25,000 scale OS mapping. However, these additional
culverts will only be installed where there is a need to prevent significant
disruption to the natural drainage pattern.
The principal means of minimising scour and silt run-off from steep roads lies
in choice of surfacing material and crossfall, as well as limiting the gradient of
the road to 10%. The stone specification will be as set out in the Forestry
Civil Engineering Handbook and will have a fine content to bind the surface.
Where the bed of the ditch is not on rock, small rock “arrester” dams will be
placed at regular intervals to slow down flow and retain granular material.
Cross-carriageway drains will be provided during track construction and,
where necessary, culverts extended or replaced. Ditches will be designed
around the existing layout to minimise the effect on the existing site
hydrology. In areas of cuttings with high batters, cut-off ditches will be formed
where required. Where steep gradients are present then the ditches will be
designed to prevent erosion, including the provision of check dams.
The location of cable tracks and crossings will be considered and sections of
ditch piped where required. During the construction period, the road drainage
will be planned in such a way so as to minimize the production of silty run-off
water. Check dams and/or filtration fences will be erected as and when
required.
Reinstatement
Where applicable turf cut from the surface of the access track routes will be
stored during construction and reinstatement undertaken as soon as each
section of track is finished to minimise turf storage time and potential for
erosion.
Safety considerations during operation of the wind farm mean that it is not
feasible to develop vegetation cover over the width of the track. Tracks on
land managed by Forestry Commission Wales will be maintained to forestry
standards.
4
Site Compound Construction
Description
During the construction period, two civils construction compounds and one
electrical construction compound will be required; these will include a laydown
and storage area for components of the wind farm awaiting installation and for
equipment required for that installation.
Procedure
The construction compound areas will be felled and stumps removed.
Surface soils will be excavated and set aside in storage bunds for
reinstatement on completion of the project. These soils will be separated
following best practice for re-use. Any existing drainage ditches will be
diverted around the extent of the compound where necessary. Unsuitable
soils will be excavated and stockpiled until a suitable formation is reached.
The two civils compounds are located as follows with one in the north at
approx. 300940, 358340 and one in the south at approx. 301810, 351123).
Depending on the final grid connection route selected by the distribution
network operator, SP Manweb, then the electrical construction compound will
be located either in the north of site at approx. 301345, 358795, or the south
of site at 302180, 350450. Dependent upon civil contractor design, geotextile
or geogrids may be placed where required to ensure optimal weight
distribution. Rock excavated from the on-site borrow pits and/or the cut–andfill operations will be spread and compacted in layers. Finer crushed rock will
be used in the final layers to provide an adequately smooth running surface.
Appropriate pollution control measures will be used as determined by the civil
contractor.
Welfare facilities will be provided in accordance with the Construction (Design
and Management) Regulations 2007. Facilities for waste management,
refuelling, power, water supply and chemical storage will be provided. All
welfare facilities will be provided for the duration of the construction, during
the operational phase of the project welfare facilities will be provided in the
permanent control building at either 301345, 358795, or 302180, 350450
depending on the final grid connection and hence substation location.
Reinstatement
Material used to construct the compound, and aggregate won to ensure a
level surface, will be excavated and both used to restore the area to its
original form and any excess used for the reinstatement of the borrow pit
Stockpiled subsoil and topsoil will then be replaced and turfs, removed during
installation, will be relaid.
5
Culverts and Watercourses
A detailed statement for work in and around watercourses will be provided by
the contractor to EAW prior to works being undertaken and the method
included in the finalised CMS. Detailed environmental procedures will be
incorporated within the design and construction to minimise soil erosion,
siltation and their effects on water quality and ecology.
Ten watercrossings have been identified (see Table in Section 3 above).
Culverts will either be upgraded or replaced at these locations, and any other
locations along existing access tracks where existing culverts are found, in
the event that the tracks at the culverts need upgrading. On new tracks,
culverts will be installed on any additional channels that are not large enough
to be shown on 1:25,000 scale OS mapping. However, these additional
culverts will only be installed where there is a need to prevent significant
disruption to the natural drainage pattern.
6
Borrow Pit
Description
Excavation and operation of the site borrow pit with minimal disturbance to
vegetation and hydrology at the site.
Procedure
The potential borrow pits are located as below:
BP A (301880, 357550)
BP B (302470, 354100)
BP C (301850, 351500)
BP D (300780, 350630)
The borrow pits shall be worked in strips, to ensure that only enough
aggregate for the project is obtained, and to limit the impacts of the borrow pit
to as small an area as possible. A borrow pit design and restoration plan will
be produced prior to commencement of the work. Any top soils and sub-soils
will be separated and progressively stored in a temporary storage area. The
storage mound should also be terraced, where possible, to ensure stability.
All temporarily stored materials shall be utilised in the restoration of the
borrow pit.
Rock shall be ripped using an excavator. The borrow pit floor level shall be at
the entrance level and shall have a very shallow gradient down to the
entrance to allow for free drainage out of the borrow pit, both during active
extraction and after final restoration. This overall gradient shall not exceed 1in-100 to ensure that run-off is not too rapid, which would result in erosion and
excessive particulate transmission out of the borrow pit excavation.
Excess run-off from the borrow pit floor shall be directed to a sump area
located in the floor level, towards the access. After restoration, drainage from
the borrow pit will continue to infiltrate into the borrow pit floor, but in addition
a soakaway should be constructed using single-size aggregate across the
borrow pit entrance.
7
Crane Hardstandings
Description
Crane pads are required to provide a suitably robust and level area, upon
which cranes are used to lift turbine components into place.
Procedure
The location of the crane pads will be optimised to make best use of the
existing topography, prevailing wind conditions (to enable safe lifting) and
chosen erection procedure. As with access tracks, areas will be felled where
necessary and stumps removed. The subsequent topsoil and subsoils will
then be excavated and stored in separate bunds for later reinstatement.
The area will be set out to the required dimensions and excavated to a
suitable formation. Plate bearing tests will be conducted at regular intervals
across the excavation to prove the bearing capacity of the underlying strata.
Coarse rock fill will then be placed and compacted in layers using compaction
equipment. Gradings are likely to be carried out to determine the compaction
methodology. Geotextile matting, to facilitate better distribution of weight,
may be used depending on the suitability of the underlying strata.
The final surface will be formed from selected granular material and trimmed
to allow surface water run-off, to either drainage ditches or soakaways (see
also Section 11).
Crane pads will be formed as the construction of site tracks progress.
However the pads may be formed initially to provide lay-down areas for
materials associated with WTG foundation materials and finalised closer to
the lifting operations.
Reinstatement
On completion of the lifting operations and following successful
commissioning of the turbine, the area around the crane pads will be
topsoiled.
8
Cable Laying
Description
Cables are required between the turbines and the substation (at either
301345, 358795, or 302180, 350450 depending on the final grid connection
and hence substation location), and will be located alongside the access
tracks. The cables will be laid with minimal disturbance to vegetation and
hydrology at the site.
Procedure
The trench will fall within the envelope of felling for the access track. The
position of trenches will be marked out and the line stripped of surface soils
and set aside for reinstatement. The trench will be excavated to the required
dimensions and the spoil set aside for backfill if suitable. Trenches will be
excavated to follow the profile of the existing ground where practical.
Typically, sand bedding will be placed and levelled following insertion of earth
conductors (if required). The cable will be laid onto the sand bedding and a
further layer of sand installed to provide suitable protection to the cable.
Following testing by the electrical works contractor, the trench will be
backfilled and compacted in layers with suitable material and reinstated with
previously excavated surface soils.
Cable ducts will be used over water crossings, under sections of track and
hardstandings.
Cable markers will be used to mark the route of cables.
9
Turbine Foundations
Description
Large reinforced concrete foundations are required to support the large
turbine structures.
The bases need to be constructed with minimal
disturbance to the vegetation and surrounding hydrology.
Procedure
The position of each WTG will be set out to the agreed co-ordinates. The
extent of the foundation will be marked on the ground and an allowance made
for working space and shuttering. Any adjacent ditches which would convey
surface water towards the area will be diverted in advance of any
excavations. The required area will have been felled and stumps removed
where necessary, then topsoil and subsoils and set aside for reinstatement.
The area will be excavated to a suitable formation and cleared of all loose,
fractured rock.
Drainage ditches will be excavated around the perimeter to keep the
excavation dry. An outfall ditch will be created where possible or a sump
formed for pumping out of the excavations. Batters will be formed where
appropriate and in cases where these are adjacent to site tracks, bunds will
be formed along the top edge. In some instances, it may be the case that site
tracks need to be widened to allow safe passage of construction plant and
vehicles.
A plate bearing test will be carried out to prove the bearing capacity of the
strata below and work only allowed to continue on a successful result. Failure
of the test will result in either further excavation or placement of rock fill and
retesting of the bearing capacity.
Blinding concrete will be placed and levelled to the required dimensions and
level and finished with a vibrating power screed. The base will be set out to
the required dimensions and offered for inspection prior to steel fixing.
Reinforcement bar will be delivered to site and stored adjacent to the
excavation. A telehandler will deposit the largest bundles of bars onto the
blinding concrete to cut down on manual handling. Steel fixers form the
reinforcement cage to the required dimensions and levels as indicated on the
design drawings and schedules. All steel will be adequately supported on
chairs, cover blocks and tied securely. The area will be cleared of all debris
prior to edge formwork being inserted.
All ducts, earth connectors, drainage pipes and bolt assemblies will be
inserted in accordance with the drawings.
Edge formwork will be positioned to the required dimensions and adequately
shored. Height checks will be set where necessary and on completion the
base will be offered for inspection in advance of the concrete pour.
Prior to the concrete pour, accurate local weather forecasts will be obtained
and checked for temperature, wind speed and general outlook. The decision
to pour will be based on this information. This data will also be used to
determine the curing agents and protection measures required for the pour.
The concrete will be delivered to the turbine locations in truck mounted mixers
and discharged through a mobile concrete pump into the formwork until the
required profile and level is achieved. Concrete deliveries will be slump
tested and cubes taken at the required frequency for later testing. The
exposed faces will be finished and an appropriate curing agent applied in
accordance with the manufacturers recommendations. Covers will be applied
when necessary.
Formwork will be removed on satisfactory curing and care taken so as not to
damage any ducts or inserts.
Reinstatement
Voids around the turbine foundations will be backfilled as required to facilitate
cabling and earthing works and completed on successful testing. Subsoils
excavated from the existing location will be used and topsoil spread to tie to
existing ground levels.
10 Turbine Erection
Description
Installation of the components of the wind turbines with no significant adverse
ecological effects.
Procedure
The components of the wind turbine (towers, nacelles and blades) will be
delivered directly from the highway network via the access tracks (and
possible storage at the civils construction compounds) to the working area at
the prepared wind turbine bases.
The cranes will be brought to the site in a disassembled condition. The crane
body is expected to be a self-propelled unit when driving to the site. All
counterweights and boom sections will be delivered by articulated lorries.
The tail cranes will be smaller, hydraulic, telescopic, rough-terrain cranes that
may also require one or two articulated lorries to supply the counterweights
and other parts. Before moving on the site the main cranes will require
disassembling to reduce the overall weight and the axle loading to a
maximum of the 20 tonnes.
The towers will be erected from the delivery trailer onto the foundation bolts.
The HGVs and cranes will operate from the track and the hardstanding at
each base location.
The nacelle will be unloaded from its trailer and laid adjacent to the base
within the base working area prior to erection on the tower using the crane.
Some minor work on the nacelle will be required on the ground prior to the lift.
Upon delivery, the blades will be fitted onto the rotor. The rotor assembly will
then be lifted onto the previously erected nacelle by crane. Alternatively the
hub may be lifted and attached to the nacelle followed by a one-at-a-time
installation of the blades.
It is anticipated that the installation of each turbine will take 2 lifting days in
good weather; however, the construction programme will make allowance for
an amount of weather downtime.
Reinstatement
Following the successful completion of the turbine erection, the crane
hardstandings will be cleared and the area reinstated.
11 Control of Water
Description
Control of water is of great importance during construction to prevent exposed
soils eroding and silting up surrounding watercourses. It is essential that the
works have little or no impact on the existing hydrology due to the sensitive
ecology of the surrounding countryside.
Procedure
During the construction phase of the wind farm, measures will be adopted in
order to prevent silt, chemicals and/or other contaminants from being washed
into existing watercourses. Areas exposed due to the removal of vegetation
are more susceptible to erosion during heavy rainfall so areas will be
reinstated as soon as possible to minimise this effect. Where areas are
disturbed, the following measures may be implemented to minimise these
effects:
Ditches shall be provided adjacent to all roads and other operational
areas, where practicable and required, and will primarily be used to hold
water temporarily and to encourage infiltration/discharge into the ground
locally to where the rainfall hits the ground. This will be achieved through
the provision of small check dams at approximately 40m centres along
the swales. The stone used for the construction of the check dams will
be 20mm ‘clean’ graded stone. On steeper slopes the check dams will
be reinforced using larger 100mm stone placed on the downhill side of
the dam to prevent washing away of the small stones. The check dams
will serve dual functions, both removing and settling out silts and reducing
flow velocities, therefore mitigating against the effects of erosion within
the swale.
Under track drainage/pipes will be provided with associated sumps and
check dams. The under track drainage will provide a means for flows to
pass from a ditch on the uphill side of the slope to the downhill side of the
slope.
The level of silt in run-off during construction shall be monitored and if it is
excessive in any area this can be managed by providing straw bales
locally around the problem areas. These will filter the run-off and trap silt.
During construction of the turbine bases, hardstandings, and inter-turbine
roads drainage will be effected by ditches draining either to mini
settlement ponds (where practicable) or to infiltration trenches. These will
either infiltrate the water to the ground or discharge over open vegetated
areas across the site. Any watercourses where there is a risk of being
contaminated by silty run-off water will be protected by silt fences as a
precautionary measure.
Silt run-off from stockpiles and excavated spoil heaps will be contained
through the placement of geotextile silt fences, mats or straw bales on
the downhill side of the stockpile.
All check dams and mini-settlement ponds will be regularly inspected and
maintained to ensure their effectiveness. All excess silts will be removed
and disposed of within site earthworks. Where check dams have become
fully blocked with silt, they shall be replaced in accordance with the
following procedure:
1.
2.
3.
4.
5.
Silt deposits to be removed from the upstream side of check dams.
Removed silt to be disposed of by spreading in an area of the site
where surface run-off will not convey silt deposits back to a water
course.
The existing 20mm stone check dams are to be removed and
disposed of in the nearest borrow pit. Stone materials removed
from the check dams should not be disposed of over vegetated
areas of the site.
Replacement check dam to be installed using 20mm stone.
Where there are regular incidents of check dam blockage further
check dams to be installed (every 15-20m intervals) within the
swales.
Reinstatement
Ditches will remain in place to convey surface water flows during the
operational life of the wind farm. The ditches will therefore be seeded or
turfed as soon as they have been formed to ensure their maximum
effectiveness. Check dams and any settlement pools will also be retained to
remove silt and reduce the velocity of surface water flows.
12 Reinstatement
A detailed Restoration Plan, either included in the final CMS or as a separate
document, will be:
agreed with the construction contractors for Clocaenog Forest Wind
Farm;
subject to consultation with FCW, CCW, EAW, DCC and CCBC;
provided before the commencement of construction.
For the purposes of this draft CMS, and ahead of the necessary preparation
of the Restoration Plan, the broad restoration measures proposed are
described below and, where they relate to specific elements of the project, in
the preceding and following relevant sections.
General restoration will be required at turbine bases, crane pads and the
construction compound together with the edges of new or widened tracks and
cable routes. Specific restoration will also be required around water
crossings, the control building and borrow pits. This is described in their
respective sections in this draft CMS.
As detailed in the various construction activities, areas will be carefully
cleared and then turfs will be excavated and stored locally. Subsequently
topsoil and subsoil layers will be excavated and stockpiled for use during
reinstatement. The stockpiles will be located away from surface water flows
and their surfaces smoothed or covered to prevent erosion through rainfall.
Excess subsoils will be transported for use at other areas on site, i.e.
reinstatement of borrow pits.
The areas will be restored with the materials previously set aside as soon as
reasonably practical.
Turbine bases will be reinstated once all cables and transformers are
installed. The crane pads will be left in position for future lifting operations
and if required will receive a cover of subsoil and turfs where possible. A
turning head will be left for maintenance vehicles.
Site tracks and access roads will be dressed off once the drainage ditches
and cable trenches are complete. Turfs and soils previously set aside will be
used to reinstate the verges and batters. Soils and vegetation will generally
be kept within their natural habitat and any excess used to cover areas where
available soils are minimal.
The site compound will be removed to the original formation level with all
imported rock, geogrids and geotextile removed. All slabs and drainage
facilities will be removed and backfilled. Previously set-aside materials will be
used to backfill the area.
The works will be carried out to follow progress as much as possible. The
reinstated areas will be protected so as to prevent any erosion while
vegetation re-establishes.
13 Pollution Prevention Measures
Fuel and Oils
All construction plant will be in good condition with no excessive emissions of
exhaust, oil, fuel or coolants. Plant operators will check machines daily for
oil/fuel leaks and take appropriate action. All re-fuelling will be by an
approved mobile fuel bowser using a suitable pump and hose. Absorbent
material (spill kits) will be available on site and will be deployed to contain
drips and small spillages. All other fuels, oils and potential contaminants will
be stored within the site compound in secure, fit for purpose containers within
bunded containment as appropriate and in accordance with EAW guidance.
Concrete
All concrete will be delivered directly to the location of the foundation and
transferred to the formwork by truck mounted concrete pump or by crane and
skip method. Optionally direct discharge from the delivery truck into the
formwork may be used or excavator bucket as appropriate.
Formwork will be constructed to ensure that no concrete loss occurs at joints.
Any concrete loss will be either removed or contained.
All vehicles, tools and buckets will only be cleaned within a designated area.
The wash out water from trucks carrying concrete to construction areas will
be discharged into a lined pit, remote from any watercourses. The wash out
water will be removed from the site for appropriate disposal.
If a concrete spillage occurs during transfer it will be cleared immediately in
accordance with the requirements detailed in the Emergency Response Plan.
Silt
A number of silt- and sediment specific measures are detailed above in the
respective sections, particularly where they refer to tracks or quarrying
activities.
There is to be no discharge or disposal of any material directly into any river,
stream or drainage ditch.
All discharges will be via settling tank or lagoon prior to discharge to the
nearest watercourse. Where silty water is to be pumped out of excavations,
the water will be pumped out from a sump within the excavation in order to
avoid disturbance to sediments.
Settling lagoons will typically be made from straw bales lined with a suitable
textile membrane or follow other best practice guidance (such as CIRIA
Control of Water Pollution from Linear Construction Projects). The settling
lagoons will be constructed to an appropriate size to suit local requirements.
Where necessary a series of settling lagoons will be used to ensure that no
silty water is discharged. Pumps will be small-bore and will operate
continually to prevent large volumes of silty water building up in the
excavation. Settled silt will be emptied into the excavation when the lagoon is
removed.
Water will be prevented from entering excavations by the use of cut-off
ditches where appropriate.
All site roads will be kept free of soil and mud deposits, weather permitting.
Small dams will be placed in roadside ditches to aid silt retention. Fording of
rivers and streams will not be permitted.
Temporary soil/peat mounds will be sited away from watercourses and drains.
Surface water will directed away from construction activity to avoid silty runoff entering watercourses or ecologically sensitive areas. Where there is a
high risk of fines or silt washing off stockpiles their size and the duration for
which they will be in such a location will be minimised as far as is reasonably
practicable
Waste and Litter
Contractors will be required to provide a Site Waste Management plan which
will include details on waste minimisation, recycling and disposal of all waste
streams. The requirements of this plan will be implemented on site as
required.
With respect to the control of ‘litter’ on site, all such waste will be collected
and stored within sealed containers within the site compound and serviced by
a registered waste carrier. No disposal of litter will be permitted at other
locations.
Site Induction and Training
All employees and sub-contractors will undergo a site induction to ensure that
they are familiar with the site rules prior to any work commencing on site. In
addition, the contractor will ensure that all operatives and sub-contractors
responsible for handling fuel, oil, concrete or cement or other potential
pollutants undergo a thorough induction programme with respect to the
proposed pollution control measures. The programme will include, as a
minimum, the following:
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Avian and protected species mitigation measures;
Habitat protection;
Potential sources of pollution and their effects on the environment;
Requirements of the contract and legislation with respect to pollution;
The contractor’s pollution avoidance plan;
Traffic management and routing, including areas where access is not
permitted;
The Emergency Response Plan;
Training in the use of pollution control equipment.
14 Emergency Response Plan
The appointed contractors will implement an Emergency Response Plan in
the event of a pollution incident.
The contractor will provide and maintain on site, suitable oil spill response kits
to deal with pollution emergencies. In addition, individual items of plant
including mobile fuel bowsers will carry an oil spill kit. The contractor will
replenish materials which are removed or expended as soon as possible.
In the event that a spill occurs on site, the following immediate action will be
taken to limit the amount of spill by isolating and controlling/stopping the
source. The spill will be contained by applying absorbent material and, in the
case of spillage to a watercourse, by the use of booms. Action will be taken
to ensure that no ecologically sensitive area can be contaminated.
Clean-up operations can proceed by either excavation and removal of
contaminated ground and mop-up material and removal from the site in a
skip, for controlled disposal of hazardous waste. Consultation with EAW for
further instructions would follow.
The site manager, RWE NRL and EAW will be informed of the incident as
soon as possible. A spill/incident report will be made out and copied to RWE
NRL.
15 Private Water Supplies
A number of properties have been identified which utilise private water
supplies (PWSs) which are potentially at minor risk of deterioration during
construction. Residents with a PWS considered to be ‘At Risk’ will be
consulted prior to commencement of construction to inform them of the works
that will be undertaken and how their water supplies will be safeguarded
during construction. Residents will be provided with a suitable point of
contact through establishment of a Communications Protocol, should they
experience any problems with their PWS. Regular progress updates will be
provided to inform residents when works are likely to be undertaken in their
PWS catchment area.
In the unlikely event that construction works lead to the temporary
deterioration of a PWS, an alternative temporary supply of water will be
provided (eg water tankered to property and provision of temporary drinking
water storage tanks). Damaged filters will be replaced in the unlikely event
that a PWS becomes contaminated with sediments.
16 Prohibited Activities
Description
Ensuring the sympathetic development of the site and restricted practices
which could have a negative effect on the ecology of the site following
construction.
Procedure
The following activities will be prohibited:
Entry of plant to or trampling of marked sensitive zones;
Entry of plant to areas outside of designated working areas;
Unauthorised construction work near protected species sites;
Disposal of waste materials on site;
Spreading of non-recommended seed mixes;
Lighting of fires;
The presence of pets;
Vehicles parking outside of designated parking areas;
Fuelling outside of designated area.
In addition, a set of site rules will be developed based on previous experience
and introduced to all authorised persons working on the site. Visitors will be
escorted. A suitable site passport carrying the site rules and authorising the
person carrying the passport will be available.
In accordance with best practice, disturbance of protected species sites will
be avoided. Areas supporting protected species will be carefully demarcated
during the construction phase. Demarcation will be by the placement of
coloured plastic fencing or tape to mark out areas where protected species
are present and that are not to be disturbed during construction. No
construction work, no vehicles or machinery and no storage of materials or
spoil will be permitted within the marked off area.
17 Environmental Monitoring
Description
Ecological mitigation and associated environmental monitoring will be set out
in a Construction Phase Habitat Management Plan (CPHMP) to be drawn up
by a working group including the developer, FCW and CCW. This will cover
the ecological commitments given in the mitigation sections of Chapters 9 &
10 of the Environmental Statement to be overseen by an Ecological Clerk of
Works.
18 Working Hours
The construction programme will be based on a working week of 5.5 days,
07:00 to 19:00 on weekdays and 07:00 to 13:00 on Saturdays. Generally,
night time or Sunday work will not be permitted. However, working at night,
outside daylight hours and on Sundays may be required to disassemble,
move and re-assemble the main cranes, if for any reason this work is not
completed within normal working hours. It is essential that the crane
movement takes place as programmed in order not to slow down turbine
erection work. Furthermore, critical operations, (eg a foundation concrete
pour that cannot be stopped before completion or the lifting of turbine parts
where the work has to continue to a safe condition) may require working
outside of standard hours.
The work potentially to be carried out outside normal working hours will
involve operation of generators, machines and cranes.
Heavy goods vehicle access to the wind farm site will also be restricted to
these hours where possible.
Floodlighting may be provided during extended working hours or periods of
early darkness to ensure safe working conditions. The floodlights will be
positioned in such a way as to limit light pollution in the direction of local
residents. Lighting will be powered by mobile generators which will have drip
traps and will be re-fuelled by an approved mobile fuel bowser using a
suitable pump and hose.
19 Staff Movements
It is generally necessary for a security guard to be present on the site. Other
than the security guard, there will be no overnight presence on the
construction site. All personnel will meet in the morning and depart after
completing their work. It is assumed that most workers will use minibuses to
travel to the site, although there may be a number of private cars used to
reach the site along with various contractors’ four-wheel-drive vehicles.