Upload
others
View
2
Download
0
Embed Size (px)
Citation preview
Client: F.D Attwood & Partners Surface Water Drainage Strategy for the Proposed Development at Gibraltar Way, Chatham, Kent
January 2019
Canterbury Office Unit 6 & 7 Barham Business Park Elham Valley Road Barham Canterbury Kent CT4 6DQ
Tel 01227 833855 London Office 6-8 Bonhill Street London EC2A 4BX www.herringtonconsulting.co.uk
This report has been prepared by Herrington Consulting Ltd in accordance with the instructions of their client, F.D Attwood & Partners for their sole and specific use. Any other persons who use any information contained herein do so at their own risk.
© Herrington Consulting Limited 2019
Client: F.D Attwood & Partners Surface Water Management Strategy for the Proposed Development at Gibraltar Way, Chatham, Kent
Contents Amendment Record This report has been issued and amended as follows:
Issue Revision Description Date
1 0 Draft report issued by email. 28 December 2018
2 1 Draft report reissued by email. Plans and appendices updated
18 January 2019
3 1 Final report issued by email 25 January 2019
4 2 Final report updated with minor text changes
28 January 2019
Document Verification
Issue Revision Date: 28 December 2018
1 0 Author(s): Sebastian Bures Sean Robinson
Director Sign Off: Simon Maiden-Brooks
Issue Revision Date: 18 January 2019
2 1 Author(s) Lee Adderley
Checked By: Sebastian Bures
Issue Revision Date: 25 January 2019
3 1 Author (s) Sebastian Bures
Checked By: Lee Adderley
Issue Revision Date: 28 January 2019
4 2 Author (s) Sebastian Bures
Checked By: Lee Adderley
Contents Page
1 Scope of Appraisal 1
2 Background Information 2 2.1 Site Location and Existing Use 2 2.2 Site Geology and Topography 2 2.3 Proposed Development 3 2.4 Planning Policy and Context 3 2.5 Climate Change 4
3 Potential Sources of Flooding 6
4 Existing Drainage 8 4.1 Existing Surface Water Drainage 8
5 Management of existing overland flow 9 5.1 Surface Water Flooding 9 5.2 Topographical Survey and Ground Investigations 9 5.3 Catchment Areas 10 5.4 Deluge Model 12 5.5 Flow Path Swale 13
6 Sustainable Drainage Assessment 15 6.1 Opportunities to Discharge Surface Water Runoff 15 6.2 Proposed Surface Water Management Strategy 16 6.3 Management and Maintenance 21 6.4 Sensitivity Testing and Residual Risk 22 6.5 Foul Water Management 23
7 Conclusions and Recommendations 24
8 Appendices
Land at Gibraltar Way, Chatham Surface Water Management Strategy
1
1 Scope of Appraisal
Herrington Consulting Ltd. has been commissioned by F.D Attwood & Partners to prepare a
Surface Water Management Strategy for the proposed development at the following location:
Gibraltar Way, North Dane Way, Chatham ME5 8YE
The objective of this Surface Water Management Strategy is to outline the options for the disposal
of surface water runoff from the proposed development.
This report has been prepared to supplement a full planning application and has been prepared in
accordance with the requirements of both national and local planning policy. To ensure that due
account is taken of industry best practice, reference has also been made to, CIRIA Report C753
‘The SuDS Manual’ and any relevant local planning policy guidance. The surface water
management strategy included within this report is not intended to constitute a detailed drainage
design.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
2
2 Background Information
2.1 Site Location and Existing Use The site is located at OS coordinates 578052, 162983 at Gibraltar Way in Chatham and covers an
area of approximately 27 hectares. The location of the site in relation to the surrounding area is
shown in Figure 2.1.
Figure 2.1 – Location map (Contains Ordnance Survey data © Crown copyright and database right
2019).
The site currently comprises mostly of greenfield space, with a farm located to the north west of the
site.
2.2 Site Geology and Topography Reference to the British Geological Survey (BGS) data identifies that the geology at the site
comprises two bedrock and two superficial formations. The north corner of the site has a Lewes
Nodular Chalk Formation bedrock, overlaid with a Head superficial deposit. Whereas, the rest of
the site has a Seaford Chalk Formation bedrock, overlaid with a Clay-with-flints Formation
superficial deposits.
Reference to a site-specific topographic survey indicates that land levels at the site vary between
103.9m AODN in the north western part of the site and 131.4m AODN in the southern part of the
site.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
3
2.3 Proposed Development The development is an outline application and comprise the construction of up to 450 residential
units, a nursery and associated open space and landscaping. Figure 2.2 below shows the proposed
site plan.
Figure 2.2 – Proposed Development Plan.
Further drawings of the proposed scheme are included in Appendix A.1 of this report.
2.4 Planning Policy and Context The general requirement for all new development is to ensure that the runoff from the development
is managed sustainably and that the drainage solution does not increase the risk of flooding at the
site, or within the surrounding area.
For undeveloped greenfield sites, the impact of the proposed development will therefore require
mitigation to ensure that the runoff from the site replicates the natural drainage characteristics of
the pre-developed site. In the case of brownfield sites, drainage proposals are typically measured
against the existing performance of the site, although it is preferable (where practicable) to provide
runoff characteristics that are similar to greenfield behaviour.
In accordance with the Town and Country Planning (Development Management Procedure) Order
2010, the proposals for this site are classified as ‘major’ development and therefore the (non-
statutory) Technical Standards for SuDS (NTSS) will apply and have been referenced to throughout
this report.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
4
In addition to the NTSS, Chatham is located within the Medway constituency and therefore,
Medway Council is the Lead Local Flood Authority (LLFA). The site is also subject to local
requirements set out within the Medway Strategic Flood Risk Assessment (SFRA), specifically
requiring Sustainable Drainage Systems (SuDS) to be incorporated into all local development.
2.5 Climate Change The global climate is constantly changing, but it is widely recognised that we are now entering a
period of accelerating change. Over the last few decades there have been numerous studies into
the impact of potential futures changes in the climate and there is now an increasing body of
scientific evidence which supports the fact that the global climate is changing as a result of human
activity. Past, present, and future emissions of greenhouse gases are expected to cause significant
global climate change during this century.
The nature of climate change at a regional level will vary: for the UK, projections of future climate
change indicate that more frequent short-duration, high-intensity rainfall, and more frequent periods
of long-duration rainfall (of the type responsible for the recent UK flooding) could be expected.
These effects will tend to increase the size of flood zones associated with rivers, and the amount
of flooding experienced from other inland sources. Consequently, the following section of this report
takes into consideration the impacts of climate change and references the most contemporary
guidance which is applicable to the development site.
To ensure that any recommended mitigation measures are sustainable and effective throughout
the lifetime of the development, it is necessary to base the appraisal on climate change predictions
which are commensurate with the planning horizon for the proposed development. The NPPF and
supporting Planning Practice Guidance Suite state that residential development should be
considered for a minimum of 100 years, but that the lifetime of a non-residential development
depends on the characteristics of the development. The development that is the subject of this
SWMS is classified as residential, and therefore a design life of 100 years has been assumed.
Potential Changes in Climate
The recommended allowances for increases in peak rainfall intensity were updated by the
Environment Agency in February 2016 and are applicable nationally. These allowances, shown in
Table 2.2 below, provides a range of values which correspond with the Central and Upper End
percentiles (i.e. the 50th and 90th percentile respectively) over three-time epochs.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
5
Allowance Category (applicable nationwide)
Total potential change anticipated for each epoch
2015 to 2039 2040 to 2069 2070 to 2115
Upper End +10% +20% +40%
Central +5% +10% +20%
Table 2.2 – Recommended peak rainfall intensity allowance for small and urban catchments (1961
to 1990 baseline).
For development sites located within Medway, which are particularly vulnerable to flooding as a
result of changes in peak rainfall intensity, the LLFA require the Upper End climate change
allowance to be applied. For developments which are less sensitive (i.e. commercial development)
the lower central allowance may be referenced.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
6
3 Potential Sources of Flooding
In determining whether the proposals for development are compliant with the NPPF, it is necessary
to determine whether the development will be sustainable in terms of flood risk. A Flood Risk
Assessment has previously been completed (by Others) and this report has been referenced in the
below section. As such, the main sources of flooding have been assessed and are discussed in
Table 3.1 below.
Source of Flooding Evidence
Risk of Flooding from Rivers
The site is situated in Flood Zone 1 and is not located within an area identified by the Environment Agency’s Flood Zone mapping as being at risk of flooding from a fluvial source. Consequently, the risk of flooding from rivers is low.
Risk of Flooding from Sea/Estuaries
The site is located a significant distance inland and is elevated above the predicted extreme tide levels. Consequently, the risk of flooding from this source is low.
Risk of Flooding from Ordinary and man-made watercourses
Inspection of OS mapping of the site and surrounding area reveals that there are no non-main rivers or artificial watercourses within close proximity to the site. Therefore, the risk of flooding from this source is low.
Risk of Flooding from Overland flow
Inspection of the Environment Agency ‘Flood Risk from Surface Water’ mapping identifies that the majority of the site is at ‘very low’ risk of flooding from surface water. The mapping does, however, indicate a surface water flow path crosses the western part of the site from south to north. This flow path is marked as ‘low’ to ‘high’ risk. The risk of flooding to the development from this surface water flow path will be mitigated through the use of SuDS (see Section 5 below). As such, following the implementation of the mitigation measures outlined in this report, the risk of flooding to the development site from surface water is considered to be low.
Risk of Flooding from Groundwater
Groundwater flooding is most likely to occur in low lying areas underlain by permeable rock (aquifers). The underlying geology in this area is Seaford Chalk Formation and Lewes Nodular Chalk Formation. A review of mapping provided as part of the Defra Groundwater Flood Scoping Study (May 2004) shows that no groundwater flooding events were recorded near the site during the very wet periods of 2000/01 or 2002/03. The mapping also identifies that the site itself is not located within an area where groundwater emergence is predicted. Furthermore, reference to the results of site-specific ground investigations (completed by others) identifies that no ground water was encountered within the five 20m deep boreholes carried out at the site. Therefore, taking the above into consideration the risk of flooding to the site from groundwater is considered to be low.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
7
Table 3.1 – Assessment of the risk of flooding from all sources.
From the analysis in Table 3.1, it can be seen that, following the mitigation measures set out within
this report, the site will not be exposed to any significant risk of flooding.
Source of Flooding Evidence
Risk of Flooding from Sewers
Inspection of the asset location mapping provided by Southern Water identifies that there is a foul water sewer located to the southwest of the site along North Dane Way. The same mapping also identifies that there is a surface water sewer to the west of the site along North Dane Way. Both of these sewers flow away from the site to the northwest following the gradient of the highway and the absence of combined sewers significantly reduces the risk of the network surcharging. This is supported by the historic records within the SFRA which indicate that there have been no recorded incidents of sewer flooding in this location previously. Notwithstanding this, in the unlikely event that water was to exit these sewers (i.e. as a result of a blockage or extreme pluvial event), floodwater is unlikely to be directed towards the site. Instead, floodwater will flow to the northwest within the highway, following the natural topography of the area. Consequently, there is a low risk of flooding to the site from sewers.
Risk of Flooding from Artificial Sources
Inspection of the OS mapping for the area shows that there are no artificial sources of flooding within close proximity to the site. In addition, the Environment Agency’s ‘Flood Risk from Reservoirs’ website shows that the site is not within an area considered to be at risk of flooding from reservoirs. Consequently, the risk of flooding from this source is low.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
8
4 Existing Drainage
4.1 Existing Surface Water Drainage The existing site is agricultural land and as such, drains informally to the surrounding areas and
infiltrates into the ground. Greenfield runoff rates have been calculated for the existing site using
FEH statistical method and the Wallingford online tool, and have been summarised in Table 4.1
below based on a site area of 27ha.
Return period (years) Peak runoff from the existing site (l/s)
1 43.3
30 117.1
100 162.4
Table 4.1 - Summary of greenfield runoff rates for the existing site.
4.2 Southern Water Assets
An existing foul sewer and surface water sewer is located along North Dane Way, to the south of
the site. Figure 4.1 below is a plan showing the nearest sewers.
Figure 4.1 – Southern Water asset plan.
Site Boundary
Foul Sewer
Surface Water Sewer
Land at Gibraltar Way, Chatham Surface Water Management Strategy
9
5 Management of Existing Overland Flow
Inspection of the Environment Agency ‘Risk of Flooding from Surface Water’ mapping show that
the site is located within an area identified to be at moderate-high risk of flooding from surface
water. The mapping shows a surface water flow path running through the centre of the proposed
development site from south to north. This section looks at how the existing overland flow path has
been quantified and how it has been incorporated into the final design layout
5.1 Surface Water Flooding A screenshot of the Environment Agency mapping is shown in Figure 5.1 below.
Probability of flooding
High – Extent of flooding from surface water that has a 3.3% (1 in 30) or greater chance of happening each year.
Medium - Extent of flooding from surface water that has between a 3.3% (1 in 30) and 1% (1 in 100) chance of happening each year.
Low - Extent of flooding from surface water that has between a 1% (1 in 100) and 0.1% (1 in 1000) chance of happening each year.
Location of development site
Figure 5.1 – Surface water flood map showing the location of the development site (©
Environment Agency)
The mapping provided by the EA is based on relatively coarse information, designed to provide a
high-level indication of the risk of flooding to a site on a national scale. The mapping does not take
into consideration the localised site-specific topography or geology, and the maps do not include
an allowance for climate change, as is required by the NPPF. Consequently, to more accurately
quantify the potential depth and extent of flooding following an extreme pluvial event, a deluge
model of the catchment has been constructed. The methodology for constructing the model and
the results predicted by the model for the design rainfall event, are discussed further in this section.
5.2 Topographical Survey and Ground Investigations The site-specific topographical survey identifies a dry valley running through the north eastern
section of the site. Figure 5.2 below identifies the current topography and land contours.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
10
Table 5.2 – Site topography with the dry valley indicated by red shape.
When comparing Figure 5.1 to the image above, it is evident that the dry valley closely represents
the geographical shape shown in Figure 5.2.
Although the feature appears sizable, there are no indications of any wet features on site, such as
ditches and wetlands. Site specific investigations for the site indicate that the groundwater levels
are below 20m BGL, which suggests that this feature is historic.
Site investigations also indicate that the ground is relatively permeable due to the underlying
Seaford chalk. This would suggest significant ground saturation would need to occur for above
ground surface water flooding to be present. Nonetheless, a deluge model has been built to quantify
surface water flooding in the event that the ground is fully saturated.
5.3 Catchment Areas The full catchment area for the site has been obtained from the Flood Estimation Handbook (FEH)
catchment web-service, and this indicates the full extent of the catchment covering most of the
Lords Woods estate up to the A2045
Land at Gibraltar Way, Chatham Surface Water Management Strategy
11
Figure 5.3 – Full FEH catchment.
From site visits of the urban extent, it is acknowledged that the impermeable areas are drained
separately and directed away from the total catchment in a dedicated drainage network.
Consequently, the total contributing catchment area has been adjusted taking into consideration
the (drained) urbanised extent.
Taking the above into consideration, the amended catchment area has been adjusted and is shown
in Figure 5.4 below. LiDAR data has been overlaid on top of the catchment and surrounding area
to establish the ground contours.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
12
Figure 5.4 – Adjusted contributing catchment area.
5.4 Deluge Model A deluge model has been constructed by exporting the level data from the contributing catchment
area (shown in Figure 5.4) and applying 61mm of rainfall over the entire catchment. The depth of
61mm has been calculated using the growth chart for a pluvial event with a 1 in 100 year return
period.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
13
Figure 5.5 – Deluge model of rainfall applied over catchment area.
The deluge model indicates 3 areas on site which have the potential to allow surface water runoff
to pond, should the ground become fully saturated. Area A indicates a flow path within the dry
valley, and the maximum flow rate at this location is estimated to be approximately 1,500 l/s (running
directly through the site). Area B indicates an area ponding adjacent to Gibraltar Cottages, and
Area C indicates an area of ponding located just outside of the site area to the north east of the
site.
In order to mitigate the risk of surface water flooding, these areas have been incorporated into the
development layout. The dry valley running through the site (Area A) has been incorporated into a
proposed swale and is discussed further below.
5.5 Flow Path Swale To ensure that the identified flow path is incorporated into the development site, a green corridor is
proposed to run through the site. This area will not contain any residential units. The green corridor
will provide allow a minimum of 1,500 l/s to pass through the site unimpeded, thus maintaining the
natural flow path through the site. Given the permeability of area it is considered unlikely that this
flow path will be visible even during the design event. Notwithstanding this, by adopting this
A B
C
Land at Gibraltar Way, Chatham Surface Water Management Strategy
14
conservative approach when developing the site layout it is possible to minimise the risk to the
development of above ground flooding and it will help to maintain any natural overland flow path.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
15
6 Sustainable Drainage Assessment
6.1 Opportunities to Discharge Surface Water Runoff Part H of the Building Regulations summarises a hierarchy of options for discharging surface water
runoff from developments. The most preferential option is to infiltrate water into the ground, as this
deals with the water at source and serves to replenish groundwater. If this option is not viable, the
next option of preference is for the runoff to be discharged into a watercourse. Only if neither of
these options are possible, the water should be conducted into the public sewer system.
For some sites it is recognised that under periods of high rainfall intensity, or long duration rainfall
events, the saturated ground can lead to insufficient porosity, thus preventing surface water runoff
from infiltrating into the ground. In these cases, a joint solution termed by CIRIA C753 as ‘Type B
SuDS’ is often used. This approach combines infiltration with attenuation to maximise discharge at
source, whilst simultaneously ensuring any runoff which is not infiltrated into the ground can instead
be restricted to greenfield runoff rates.
The following opportunities for managing the surface water runoff discharged from the development
site are listed in order of preference:
Water Re-use – Water re-use systems can rarely manage 100% of the surface water runoff
discharged from a development, as this requires the yield from the building and hardstanding area
to balance perfectly with the demand from the proposed development. Consequently, whilst
rainwater recycling systems can be considered for inclusion within the scheme, an alternative
solution for attenuating storm water will still be required.
Infiltration – Geotechnical Investigations produced by Ground Technology Services (included
within Appendix A.2), indicate that the site is located within the Seaford Chalk Formation and the
Lewes Nodular Chalk Formation. BRE 365 infiltration testing has been undertaken across the site
and the results show good soakage rates (between 0.256 and 3.78m/hr). Consequently, on this
basis, infiltration will be a suitable method for discharging surface water runoff from the site.
Discharge to Watercourses – There are no watercourses located within close proximity to the site
which show onward connectivity to a main river, the sea, or any other large surface water body. As
a result, there is no opportunity to discharge surface water runoff from the development to an
existing watercourse.
Discharge to Public Sewer System – With a preferable solution available to manage the surface
water discharged from the development, a connection to the public sewer system is unlikely to be
required.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
16
Nevertheless, in the event that the option to use infiltration is found to be restricted at the detailed
design stage, there is a Southern Water (surface water) sewer located along North Dane Way which
could be considered as a viable alternative.
6.2 Proposed Surface Water Management Strategy The drainage strategy set out below discusses each element of the proposed scheme, along with
calculations that have been undertaken to demonstrate how the overall objectives can be achieved.
This does not represent a detailed surface water drainage design; it is simply an assessment to
demonstrate that the objectives and requirements of the NPPF can be met at the planning stage.
Due to the scale of the development, the drainage systems have been split between 6 discrete
catchment areas, defined using the existing site topography. These sub-catchments can be seen
in Figure 6.1 below.
Figure 6.1 – Plan showing drainage sub-catchment areas for the properties.
A B
C D
E
E
F
DB1
DB2
DB3
DB4
DB6
DB5
B
Land at Gibraltar Way, Chatham Surface Water Management Strategy
17
Water Butts
To reduce the developments reliance on potable water supplies for external use there is the
potential to incorporate water butts within the communal garden area. Typical sizes and dimensions
of water butts are outlined below.
Typical house water butt options Dimensions of a typical house water butt
Volume of storage provided (litres)
Type 1 (wall mounted – Small) 1.22m high x 0.46m x 0.23m 100
Type 2 (Standard house water butt) 0.9m high x 0.68m diameter 210
Type 3 (Large house water butt) 1.26m high x 1.24m x 0.8m 510
Type 4 (Column tank – Very large) 2.23m high x 1.28m diameter 2000
Table 6.1 – Estimated storage capacity of available water butts.
Most of the properties have gardens and therefore, present the option to include a water butt. It is
recognised that each of the water butts will need to overflow into the main drainage system for the
site, to ensure that in the event the water butt is full prior to the onset of the design rainfall event,
water can be discharged away from the properties without increasing the risk of flooding.
Permeable Paving Driveways
Surface water falling on the driveways of the residential units will be directed into the permeable
paving systems, located on each driveway. The underlying granular sub-base of each driveway will
be used to attenuate surface water runoff and infiltrate water into the ground. It is recommended
that the depth of sub-base beneath the permeable paving is specified to be a minimum of 450mm
deep, which will help to enhance the water quality benefits.
An overflow from each property will need to be installed with onward connectivity to the drainage
basins. The overflow will be connected into the combined residential drainage system which will
include surface water runoff from the units without driveways. The system will discharge into the
series of drainage basins located across the site (discussed further below).
Highway Drainage and Permeable Surface
Surface water runoff from the main through roads will be drained into a series of road gullies with
catch pits, designed to collect sediment. Water will be conveyed across the site and discharged
into the residential roads. The residential roads and car park areas will be constructed of a
permeable surface with an open graded sub-base layer. The sub-base layer will provide water
quality treatment benefits and subsurface attenuation storage, before infiltrating into the underlying
ground.
It is recognised that it will be necessary to ensure that the sub-base is constructed within the chalk
layer to ensure appropriate infiltration. Where the roads are sloped across the site, it will also be
necessary to install a series of check-dams to maximise the storage capacity within the sub-base.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
18
Figure 6.2 below shows where there is potential to install permeable surfacing within the residential
roads and car parking areas. The plan also indicates approximate sub-catchment areas which have
been used within the calculations below.
Figure 6.2 – Plan showing areas suitable for permeable surfacing. The design parameters for the permeable surfacing system is summarised in the table below. The
calculations have been referenced based on approximate positions of the permeable surfacing and
are referenced to in Figure 6.2 above.
Parameter Value (1:100yr+30%cc event)
SuDS Permeable Paving
Sub-base depth 500 mm
Infiltration 0.256 m/hr
Sub-grade porosity 0.3
Table 6.2 – Summary of the permeable surfacing design.
A summary of the Micro Drainage analysis for permeable surfacing is shown in Table 6.2 below.
1
2
5
4
3
Land at Gibraltar Way, Chatham Surface Water Management Strategy
19
Catchment Total area draining to catchment
Total area of permeable surface Half Drain time
Catchment 1 (PP1) 5,540m2 3,861m2 79 minutes
Catchment 2 (PP2) 2,990m2 2,652m2 57 minutes
Catchment 3 (PP3) 8,300m2 4,800m2 89 minutes
Catchment 4 (PP4) 4,400m2 1,800m2 145 minutes
Catchment 5 (PP5) 6,370m2 3,465m2 97 minutes
Table 6.3 – Summary of Micro Drainage calculations for 1:100 yr + 30% climate change.
It is evident that, with the inclusion of the proposed SuDS, there is the potential to accommodate
all the surface water runoff from the highway and car park areas up to, and including, the design
rainfall event.
Landscaped Swales
Catchments C and D will have landscaped areas which will be used to convey surface water runoff
towards the proposed detention basins. Surface water runoff from the residential roofs will be
diverted into the landscaped areas, maximising potential for water to be absorbed and treated,
before discharging to the drainage basins.
Figure 6.3 below shows the location of these areas, highlighted in dark green.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
20
Figure 6.3 – Landscaped areas suitable for conveying surface water. Drainage Basins
Surface water runoff discharged from the roof areas will drain into a number of detention basins,
located across the site. These drainage basins will consist of vegetated depressions in the
landscape, which will be used to attenuate and infiltrate storm water. The location of the proposed
drainage basins can be seen in Figure 6.3 above. The attenuated volumes have been estimated to
provide 300mm float from each feature and assuming infiltration through the base only, into the
underlying chalk.
The design parameters for the drainage basins is summarised in Table 6.4 below.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
21
Parameter Value (1:100yr+30%cc event)
SuDS method Drainage Basin
Proposed depth of basin 1.5m BGL
Infiltration rate 0.256 m/hr
Basin Identity DB 1 DB 2 DB 3 DB 4 DB 5 DB 6
Estimated impermeable area draining to basin 8,950m² 7,120m² 3,040m² 7,650m² 7,800m² 3,540m²
Total storage volume 1,032 m³ 803 m³ 350 m³ 882 m³ 990 m³ 412 m³
Half drain times (minutes) 1,354 1,371 1,362 1,343 1,414 1,351
Table 6.4 – Summary of the Micro Drainage Results for the Drainage Basins.
From the table above and Table 6.3, it can be seen that the proposed drainage system can manage
the runoff from the entire development through infiltration, thereby limiting the amount of surface
water runoff discharged offsite.
Indicative Drainage Layout Plans
The proposed plans showing the indicative drainage layout and delineating how the proposed SuDS
can be incorporated into the proposed scheme is included within Appendix A.3 of this report.
6.3 Management and Maintenance For any surface water drainage system to operate as originally designed, it is necessary to ensure
that it is adequately maintained throughout its lifetime.
The key requirements of any management regime are routine inspection and maintenance, when
the development is taken forward to the detailed design stage an ‘owner’s manual’ will need to be
prepared. This should include:
• A description of the drainage scheme,
• A location plan showing all of the SuDS features and equipment such as flow control
devices etc.
• Maintenance requirements for each element, including any manufacturer specific
requirements
• An explanation of the consequences of not carrying out the specified maintenance
• Details of who will be responsible for the ongoing maintenance of the drainage system.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
22
For the SuDS recommended by this assessment, the most obvious maintenance tasks will be the
regular brushing and cleaning of the permeable surfacing and the pruning of vegetation across the
site. Typical maintenance requirements of each of the proposed SuDS is included within Appendix
A.5.
For developments such as this that rely to some extent on the ongoing inspection and maintenance
of SuDS, it will be necessary to ensure that measures are in place to maintain the system for the
lifetime of the development.
For the communal SuDS including the permeable surfacing system and drainage basins, it is likely
that the management company responsible for maintaining the rest of the site will be tasked with
the inspection and maintenance of these features. In addition, the regular inspection and desilting
of the manholes will need to be carried out.
For the SuDS located within the private garden areas, it is likely that maintenance will be the
responsibility of the individual property owners / occupants. In this case maintenance tasks are
likely to include desilting of the water butts.
Further details of the maintenance and management strategy should be confirmed following the
completion of a detailed drainage design for the development.
6.4 Sensitivity Testing and Residual Risk When considering residual risk, it is necessary to consider the impact of a flood event that exceeds
the design event, or the implications if the proposed drainage system becomes blocked.
The proposed drainage system has been designed for an extreme rainfall event with a return period
of 1 in 100 years, including a 30% increase in peak rainfall intensity (to account for the impacts of
climate change). Nonetheless, based on the EA’s most contemporary climate change guidance an
Upper End climate change allowance of 40% has been used to test the proposed drainage system
to reflect further increases in peak rainfall intensity.
Calculations have been undertaken to assess the performance of the drainage system under the
design rainfall event, including a 40% increase in peak rainfall intensity due to climate change.
These calculations can be found within Appendix A.4.
The calculations for the permeable paving and drainage basin show that the proposed drainage
systems are not susceptible to increases in peak rainfall intensity and as such, the system does not
flood. This is due to the storage features having additional (spare) capacity.
Inspection of the topography across the site suggests that if the permeable paving was to block, or
become overwhelmed following an extreme rainfall event, water could exit the permeable paving
and flow northwards. Where this is not possible, local ponding may occur. It is recommended that
kerbs are installed on the road network to contain any flood water resulting in a blockage, or as the
result of an exceedance event.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
23
It should be recognised that the drainage proposals will incorporate a significant volume of
additional storage for storm water, which is not currently provided for on the existing site. As a
result, when compared to the existing site, it is evident that the volume of water discharged from
the site during an extreme rainfall event is likely to be reduced, thus minimising the potential impact
of flooding to the surrounding area.
6.5 Foul Water Management Southern Water has been consulted (by others) under a level 2 enquiry. A copy of the Southern
Water response has been provided in Appendix A.6 of this report.
It will be necessary to install a foul pumping station at the site in the north western corner of the
development, with a direct connection to the Southern Water network.
Southern Water have advised that additional sewer network upgrades will be required if a local
connection is required, or alternatively a direct connection could be made approximately 1,800m
Northwest of the proposed development site.
The response indicates that there is potential to accommodate foul water from the proposed
development providing adequate network infrastructure is put in place as part of the development.
It is recommended Southern Water are consulted further at detailed design to agree the route of
discharge.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
24
7 Conclusions and Recommendations
The overarching objective of this report is to appraise the proposals for the development at Gibraltar
Way, Chatham to ensure that the risk of flooding to the occupants of the proposed residential units
is acceptable and that the risk of flooding offsite will not increase as a result of the development
proposals. This report has therefore been prepared to appraise the risk of flooding from all sources
and to provide a sustainable solution for managing the surface water runoff discharged from the
development site, in accordance with the NPPF and local planning policy.
The risk of flooding has been considered for a wide range of sources and it has been identified that
the risk of flooding to the proposed development is low, with the exception to surface water. Where
there is an increased risk of surface water flooding, this risk has been quantified and measures
have been included as part of the development to mitigate the risk. The mitigation measures
comprise a ‘green corridor’ through the residential units, allowing surface water to follow its natural
route through the site.
In order to minimise the impact that the buildings could have with respect to an increase is surface
water runoff, the opportunities for managing surface water at the site have been further analysed.
It is concluded that the most viable solution for managing all of the surface water runoff discharged
from the proposed development will be via infiltration into the ground.
To restrict the rate at which surface water runoff is discharged offsite, various SuDS have been
proposed, including; water butts, swales, permeable paving and drainage basins. These SuDS will
be used to store water onsite and maximise the water which can be adsorbed by vegetation and
infiltrated into the ground. The permeable paving and drainage basins provide storage on site,
allowing water to be stored during rainfall events with longer return periods. This approach
replicates the greenfield conditions and is in accordance with the NTSS.
Details of the typical maintenance and management requirements for each element of the drainage
system have been provided to ensure that the proposed drainage solution can be maintained and
will continue to operate in perpetuity. It is, however, recommended that an “owner’s manual”
containing additional product specific maintenance requirements is produced as part of the detailed
design for the site.
In conclusion, it is evident that the development is at low risk of flooding and a sustainable solution
for managing the surface water runoff discharged from the proposed development at Gibraltar Way
is available. Consequently, the proposals will meet the requirements of the NPPF and local planning
policy.
Land at Gibraltar Way, Chatham Surface Water Management Strategy
Appendices
8 Appendices
Appendix A.1 – Drawings
Appendix A.2 – Site Investigation Results
Appendix A.3 – Indicative Drainage Layout Plans
Appendix A.4 – Surface Water Management Calculations
Appendix A.5 – Maintenance Schedules
Appendix A.6 – Foul Enquiry (Extract from report Ref GL/HB/P14-630/03)
1.1
3.7
3.7
3.7
3.7
VV
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
SWALE
V
V
V
V
V
V
V
V
BUS STOP
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
R
C
2
9
F
o
o
t
P
a
t
h
16
6
14
14
5a
41
1
ROAD
53
14
45
29
25
18
6
5
KIR
KDAL
E C
LOSE
27
WAVERLEY CLOSE
12
40
20
MAYFORD
45
15
1
46
24
Path (um)
42
40
28
14
29
18
51
2a
72
30
Hall Wood Business Park
12
FARLEY CLOSE
MILLFIELDS
70
11
21
3
33
1
56
6
38
12
19
55
WH
EATF
IELD
S
30
76a
FARL
EY C
LOSE
12
47
12
57
23
3
1
18
5
11
15
El Sub Sta
30
7
44
65
HAYFIELDS
43
24
11
118.1m
23
7
Hall Wood
12
20
33
14
17
22
3
29
27
37
29
2
1
35
43
36
32
67
9
7
29
Path (um)
Hall Wood
Gibraltar
The Granary
Track
Tank
Farm
36
NORTH DANE WAY
104.8m
Playground
Path (um)
Co C
onst
& U
A Bd
y
Path (um)
Und
Def
Path (um)
Def
107.0m
CA
PS
TON
E
Elm Court
115.8m
Area
109.7m
2
Play
LB
112.2m
115.5m
Path (um)
113.4m
Co Const & UA Bdy
1
HAM LANE
Bor
o C
onst
Bdy
Elm Court Village
116.1m
Boro Const & UA Bdy
ROADSR
112.2m
HAM LANE
Gibralt
ar Cott
ages
Indoor
Co
Con
st &
War
d B
dy
LIDSING
CR
Co Const Bdy
111.9m
115.1m
114.6m
18
4
7
5
3
4
40
1
FARL
EY C
LOSE
33
3
17
FARLEY CLOSE
23
75
43
9
70
34
CLO
SE
78
76
41
12
28
14
7
11
47
12
12
18
14
10
El Sub Sta
1
37
70
2
17
22
62
64
10
62a
72
8
1
37
14
23
1
50
14
29
85
31
36
30
1
4
30
11
8
21
25
19
2422
14
HAYFIELDS2a
15
WAVERLEY CLOSE
38
2
BENTLEY
57
31
4
1
7
16
6
PIRB
RIG
HT C
LOSE
15
1
49
42
20
30
41
COM
PTO
N CL
OSE
11
29
17
5
19
12
34
24
2
23
12
1
56
26
11
2
9
15
11
3
1
27
12
17
1
45
7
11
33
15
15
33
1
43
LAD
YFIE
LDS
32
11
CLAN
DON
ROAD
6
15
7
31
619
24
59
70a
11
11
9
El
TATLER CLOSE
2
Sub Sta
71
72
2
17
5
39
2
48
7
67
77
27
1
3
14
76a
15
27
25
RUDG
E CL
OSE
36
V
V
V
V
V
V
V
V
V
V
V
V
VV
VV
V
V
V
V
V
V
V
V
V
V
V
VVV
V
VV
VV
V V
V
V
V
V
V
V
V
V V
V
V
V
V
V
V
V
V V
V V V V
V
V
V
V
Nursery
Play areafor nursery
V
V
V
V
V
V
V
Nursery
Play areafor nursery
16
6
14
14
5a
41
1
ROAD
53
14
45
29
25
18
6
5
KIR
KDAL
E C
LOSE
27
WAVERLEY CLOSE
12
40
20
MAYFORD
45
15
1
46
24
Path (um)
42
40
28
14
29
18
51
2a
72
30
Hall Wood Business Park
12
FARLEY CLOSE
MILLFIELDS
70
11
21
3
33
1
56
6
38
12
19
55
WH
EATF
IELD
S
30
76a
FARL
EY C
LOSE
12
47
12
57
23
3
1
18
5
11
15
El Sub Sta
30
7
44
65
HAYFIELDS
43
24
11
118.1m
23
7
Hall Wood
12
20
33
14
17
22
3
29
27
37
29
2
1
35
43
36
32
67
9
7
29
Path (um)
Hall Wood
Gibraltar
The Granary
Track
Tank
Farm
36
NORTH DANE WAY
104.8m
Playground
Path (um)
Co C
onst
& U
A Bd
y
Path (um)
Und
Def
Path (um)
Def
107.0m
CA
PS
TON
E
Elm Court
115.8m
Area
109.7m
2
Play
LB
112.2m
115.5m
Path (um)
113.4m
Co Const & UA Bdy
1
HAM LANE
Bor
o C
onst
Bdy
Elm Court Village
116.1m
Boro Const & UA Bdy
ROADSR
112.2m
HAM LANE
Gibralt
ar Cott
ages
Indoor
Co
Con
st &
War
d B
dy
LIDSING
CR
Co Const Bdy
111.9m
115.1m
114.6m
18
4
7
5
3
4
40
1
FARL
EY C
LOSE
33
3
17
FARLEY CLOSE
23
75
43
9
70
34
CLO
SE
78
76
41
12
28
14
7
11
47
12
12
18
14
10
El Sub Sta
1
37
70
2
17
22
62
64
10
62a
72
8
1
37
14
23
1
50
14
29
85
31
36
30
1
4
30
11
8
21
25
19
2422
14
HAYFIELDS2a
15
WAVERLEY CLOSE
38
2
BENTLEY
57
31
4
1
7
16
6
PIRB
RIG
HT C
LOSE
15
1
49
42
20
30
41
COM
PTO
N CL
OSE
11
29
17
5
19
12
34
24
2
23
12
1
56
26
11
2
9
15
11
3
1
27
12
17
1
45
7
11
33
15
15
33
1
43
LAD
YFIE
LDS
32
11
CLAN
DON
ROAD
6
15
7
31
619
24
59
70a
11
11
9
El
TATLER CLOSE
2
Sub Sta
71
72
2
17
5
39
2
48
7
67
77
27
1
3
14
76a
15
27
25
RUDG
E CL
OSE
36
16
6
14
14
5a
41
1
ROAD
53
14
45
29
25
18
6
5
KIR
KDAL
E C
LOSE
27
WAVERLEY CLOSE
12
40
20
MAYFORD
45
15
1
46
24
Path (um)
42
40
28
14
29
18
51
2a
72
30
Hall Wood Business Park
12
FARLEY CLOSE
MILLFIELDS
70
11
21
3
33
1
56
6
38
12
19
55
WH
EATF
IELD
S
30
76a
FARL
EY C
LOSE
12
47
12
57
23
3
1
18
5
11
15
El Sub Sta
30
7
44
65
HAYFIELDS
43
24
11
118.1m
23
7
Hall Wood
12
20
33
14
17
22
3
29
27
37
29
2
1
35
43
36
32
67
9
7
29
Path (um)
Hall Wood
Gibraltar
The Granary
Track
Tank
Farm
36
NORTH DANE WAY
104.8m
Playground
Path (um)
Co C
onst
& U
A Bd
y
Path (um)
Und
Def
Path (um)
Def
107.0m
CA
PS
TON
E
Elm Court
115.8m
Area
109.7m
2
Play
LB
112.2m
115.5m
Path (um)
113.4m
Co Const & UA Bdy
1
HAM LANE
Bor
o C
onst
Bdy
Elm Court Village
116.1m
Boro Const & UA Bdy
ROADSR
112.2m
HAM LANE
Gibralt
ar Cott
ages
Indoor
Co
Con
st &
War
d B
dy
LIDSING
CR
Co Const Bdy
111.9m
115.1m
114.6m
18
4
7
5
3
4
40
1
FARL
EY C
LOSE
33
3
17
FARLEY CLOSE
23
75
43
9
70
34
CLO
SE
78
76
41
12
28
14
7
11
47
12
12
18
14
10
El Sub Sta
1
37
70
2
17
22
62
64
10
62a
72
8
1
37
14
23
1
50
14
29
85
31
36
30
1
4
30
11
8
21
25
19
2422
14
HAYFIELDS2a
15
WAVERLEY CLOSE
38
2
BENTLEY
57
31
4
1
7
16
6
PIRB
RIG
HT C
LOSE
15
1
49
42
20
30
41
COM
PTO
N CL
OSE
11
29
17
5
19
12
34
24
2
23
12
1
56
26
11
2
9
15
11
3
1
27
12
17
1
45
7
11
33
15
15
33
1
43
LAD
YFIE
LDS
32
11
CLAN
DON
ROAD
6
15
7
31
619
24
59
70a
11
11
9
El
TATLER CLOSE
2
Sub Sta
71
72
2
17
5
39
2
48
7
67
77
27
1
3
14
76a
15
27
25
RUDG
E CL
OSE
36
1.1
3.7
3.7
3.7
3.7
VV
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
SWALE
V
V
V
V
V
V
V
V
BUS STOP
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
R
C
2
9
F
o
o
t
P
a
t
h
16
6
14
14
5a
41
1
ROAD
53
14
45
29
25
18
6
5
KIR
KDAL
E C
LOSE
27
WAVERLEY CLOSE
12
40
20
MAYFORD
45
15
1
46
24
Path (um)
42
40
28
14
29
18
51
2a
72
30
Hall Wood Business Park
12
FARLEY CLOSE
MILLFIELDS
70
11
21
3
33
1
56
6
38
12
19
55
WH
EATF
IELD
S
30
76a
FARL
EY C
LOSE
12
47
12
57
23
3
1
18
5
11
15
El Sub Sta
30
7
44
65
HAYFIELDS
43
24
11
118.1m
23
7
Hall Wood
12
20
33
14
17
22
3
29
27
37
29
2
1
35
43
36
32
67
9
7
29
Path (um)
Hall Wood
Gibraltar
The Granary
Track
Tank
Farm
36
NORTH DANE WAY
104.8m
Playground
Path (um)
Co C
onst
& U
A Bd
y
Path (um)
Und
Def
Path (um)
Def
107.0m
CA
PS
TON
E
Elm Court
115.8m
Area
109.7m
2
Play
LB
112.2m
115.5m
Path (um)
113.4m
Co Const & UA Bdy
1
HAM LANE
Bor
o C
onst
Bdy
Elm Court Village
116.1m
Boro Const & UA Bdy
ROADSR
112.2m
HAM LANE
Gibralt
ar Cott
ages
Indoor
Co
Con
st &
War
d B
dy
LIDSING
CR
Co Const Bdy
111.9m
115.1m
114.6m
18
4
7
5
3
4
40
1
FARL
EY C
LOSE
33
3
17
FARLEY CLOSE
23
75
43
9
70
34
CLO
SE
78
76
41
12
28
14
7
11
47
12
12
18
14
10
El Sub Sta
1
37
70
2
17
22
62
64
10
62a
72
8
1
37
14
23
1
50
14
29
85
31
36
30
1
4
30
11
8
21
25
19
2422
14
HAYFIELDS2a
15
WAVERLEY CLOSE
38
2
BENTLEY
57
31
4
1
7
16
6
PIRB
RIG
HT C
LOSE
15
1
49
42
20
30
41
COM
PTO
N CL
OSE
11
29
17
5
19
12
34
24
2
23
12
1
56
26
11
2
9
15
11
3
1
27
12
17
1
45
7
11
33
15
15
33
1
43
LAD
YFIE
LDS
32
11
CLAN
DON
ROAD
6
15
7
31
619
24
59
70a
11
11
9
El
TATLER CLOSE
2
Sub Sta
71
72
2
17
5
39
2
48
7
67
77
27
1
3
14
76a
15
27
25
RUDG
E CL
OSE
36
V
V
V
V
V
V
V
V
V
V
V
V
VV
VV
V
V
V
V
V
V
V
V
V
V
V
VVV
V
VV
VV
V V
V
V
V
V
V
V
V
V V
V
V
V
V
V
V
V
V V
V V V V
V
V
V
V
Nursery
Play areafor nursery
V
V
V
V
V
V
V
Nursery
Play areafor nursery
16
6
14
14
5a
41
1
ROAD
53
14
45
29
25
18
6
5
KIR
KDAL
E C
LOSE
27
WAVERLEY CLOSE
12
40
20
MAYFORD
45
15
1
46
24
Path (um)
42
40
28
14
29
18
51
2a
72
30
Hall Wood Business Park
12
FARLEY CLOSE
MILLFIELDS
70
11
21
3
33
1
56
6
38
12
19
55
WH
EATF
IELD
S
30
76a
FARL
EY C
LOSE
12
47
12
57
23
3
1
18
5
11
15
El Sub Sta
30
7
44
65
HAYFIELDS
43
24
11
118.1m
23
7
Hall Wood
12
20
33
14
17
22
3
29
27
37
29
2
1
35
43
36
32
67
9
7
29
Path (um)
Hall Wood
Gibraltar
The Granary
Track
Tank
Farm
36
NORTH DANE WAY
104.8m
Playground
Path (um)
Co C
onst
& U
A Bd
y
Path (um)
Und
Def
Path (um)
Def
107.0m
CA
PS
TON
E
Elm Court
115.8m
Area
109.7m
2
Play
LB
112.2m
115.5m
Path (um)
113.4m
Co Const & UA Bdy
1
HAM LANE
Bor
o C
onst
Bdy
Elm Court Village
116.1m
Boro Const & UA Bdy
ROADSR
112.2m
HAM LANE
Gibralt
ar Cott
ages
Indoor
Co
Con
st &
War
d B
dy
LIDSING
CR
Co Const Bdy
111.9m
115.1m
114.6m
18
4
7
5
3
4
40
1
FARL
EY C
LOSE
33
3
17
FARLEY CLOSE
23
75
43
9
70
34
CLO
SE
78
76
41
12
28
14
7
11
47
12
12
18
14
10
El Sub Sta
1
37
70
2
17
22
62
64
10
62a
72
8
1
37
14
23
1
50
14
29
85
31
36
30
1
4
30
11
8
21
25
19
2422
14
HAYFIELDS2a
15
WAVERLEY CLOSE
38
2
BENTLEY
57
31
4
1
7
16
6
PIRB
RIG
HT C
LOSE
15
1
49
42
20
30
41
COM
PTO
N CL
OSE
11
29
17
5
19
12
34
24
2
23
12
1
56
26
11
2
9
15
11
3
1
27
12
17
1
45
7
11
33
15
15
33
1
43
LAD
YFIE
LDS
32
11
CLAN
DON
ROAD
6
15
7
31
619
24
59
70a
11
11
9
El
TATLER CLOSE
2
Sub Sta
71
72
2
17
5
39
2
48
7
67
77
27
1
3
14
76a
15
27
25
RUDG
E CL
OSE
36
16
6
14
14
5a
41
1
ROAD
53
14
45
29
25
18
6
5
KIR
KDAL
E C
LOSE
27
WAVERLEY CLOSE
12
40
20
MAYFORD
45
15
1
46
24
Path (um)
42
40
28
14
29
18
51
2a
72
30
Hall Wood Business Park
12
FARLEY CLOSE
MILLFIELDS
70
11
21
3
33
1
56
6
38
12
19
55
WH
EATF
IELD
S
30
76a
FARL
EY C
LOSE
12
47
12
57
23
3
1
18
5
11
15
El Sub Sta
30
7
44
65
HAYFIELDS
43
24
11
118.1m
23
7
Hall Wood
12
20
33
14
17
22
3
29
27
37
29
2
1
35
43
36
32
67
9
7
29
Path (um)
Hall Wood
Gibraltar
The Granary
Track
Tank
Farm
36
NORTH DANE WAY
104.8m
Playground
Path (um)
Co C
onst
& U
A Bd
y
Path (um)
Und
Def
Path (um)
Def
107.0m
CA
PS
TON
E
Elm Court
115.8m
Area
109.7m
2
Play
LB
112.2m
115.5m
Path (um)
113.4m
Co Const & UA Bdy
1
HAM LANE
Bor
o C
onst
Bdy
Elm Court Village
116.1m
Boro Const & UA Bdy
ROADSR
112.2m
HAM LANE
Gibralt
ar Cott
ages
Indoor
Co
Con
st &
War
d B
dy
LIDSING
CR
Co Const Bdy
111.9m
115.1m
114.6m
18
4
7
5
3
4
40
1
FARL
EY C
LOSE
33
3
17
FARLEY CLOSE
23
75
43
9
70
34
CLO
SE
78
76
41
12
28
14
7
11
47
12
12
18
14
10
El Sub Sta
1
37
70
2
17
22
62
64
10
62a
72
8
1
37
14
23
1
50
14
29
85
31
36
30
1
4
30
11
8
21
25
19
2422
14
HAYFIELDS2a
15
WAVERLEY CLOSE
38
2
BENTLEY
57
31
4
1
7
16
6
PIRB
RIG
HT C
LOSE
15
1
49
42
20
30
41
COM
PTO
N CL
OSE
11
29
17
5
19
12
34
24
2
23
12
1
56
26
11
2
9
15
11
3
1
27
12
17
1
45
7
11
33
15
15
33
1
43
LAD
YFIE
LDS
32
11
CLAN
DON
ROAD
6
15
7
31
619
24
59
70a
11
11
9
El
TATLER CLOSE
2
Sub Sta
71
72
2
17
5
39
2
48
7
67
77
27
1
3
14
76a
15
27
25
RUDG
E CL
OSE
36
0 20 40 m20 m
Scale 1:1000
REV. DATE DRN. CKD. NOTES
B 08.05.18 SB NLE Site Plan updated to reflect trackingfrom Civil Engineer
Lee Evans Partnership LLP own the copyright of this and any associated
documents. Such documents may not be used or reproduced for any
purpose other than that for which they were created.
z DO NOT SCALE DRAWING
DRAWING NUMBER
DRAWING TITLE
PROJECT
chartered architects
ISSUE STATUS
REVISION
DRN + CKD
SCALE
DATECLIENT
Lee Evans Partnership LLP,
Canterbury: St Johns Lane, Canterbury, Kent CT1 2QQ Tel: 01227 784444
email: [email protected] website: www.lee-evans.co.uk fax: 01227 819102
and planning consultants
@ A0
London: 31-35 Kirby Street, London EC1N 8TE Tel: 0207 492 1744
08418-A-L-(00)-0203
1:1000
21/01/2019
Proposed Site Plan
Kevin Attwood
Gibraltar Farm, Lordswood, Medway : housing
X
N
F 05.10.18 SB NLE Site Plan updated to reflect trackingfrom Civil Engineer
J 05.11.18 SB NLE Footpaths removed from Ancient Woodland
K 06.11.18 SB NLE Site plan adjusted to 15m bufferzone to Hook Wood Ancient Woodland
L 07.11.18 SB NLE West area adjusted to respect Hook Wood Ancient Woodland
M 15.11.18 SB NLE Outline Planning
N 21.11.18 SB NLE Outline Planning
P 22.11.18 SB NLE Outline Planning
Q 22.11.18 SB NLE Outline Planning
R 22.11.18 SB NLE Outline Planning
S 12.12.18 SB NLE Outline Planning
T 18.12.18 NP NLE Outline Planning
U 20.12.18 NP NLE Red line boundary amended
V 04.01.19 NP NLE Red line boundary amended
W 09.01.19 NP NLE Red line boundary amended
X 21.01.19 NP NLE Planting added to NE junction