MAUREEN SMITH PROPOSED RESIDENTIAL DEVELOPMENT: 121 NESS ROAD, SHOEBURYNESS, SOUTHEND ON SEA FLOOD RISK ASSESSMENT

Transcription

1 WARD MAUREEN SMITH PROPOSED RESIDENTIAL DEVELOPMENT: 121 NESS ROAD, SHOEBURYNESS, SOUTHEND ON SEA HOMES FLOOD RISK ASSESSMENT REPORT REF PROJECT NO APRIL 2017

2 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT Ardent Consulting Engineers Suite 207 One Alie Street LONDON E1 8DE Tel: Fax: REPORT REF PROJECT NO APRIL 2017

3 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 CONTENTS Page 1. INTRODUCTION 1 Scope 1 Site Location 2 Existing and Proposed Development 2 Waterbodies in the Vicinity of the Site 3 Ground Conditions 4 Site Levels 4 Access and Egress 5 2. POLICY CONTEXT 6 National Planning Policy Framework 6 Flood and Water Management Act 7 Sustainable Drainage Systems Non-statutory technical standards for sustainable drainage systems March Southend-on-Sea Borough Council Strategic Flood Risk Assessment Level 1 8 Southend-on-Sea Borough Council Strategic Flood Risk Assessment Level 2 9 Southend-on-Sea Local Flood Risk Management Strategy 10 Southend-on-Sea Surface Water Management Plan 11 Southend-on-Sea Borough Council Core Strategy DPD 12 Development Management DPD REVIEW OF FLOOD RISK 14 Introduction 14 Review of Flood Risk 14 Flood Zone Designation 14 Environment Agency Flood Map for Planning 15 Sequential Test 16 Historic Flooding 16 Tidal Flood Risk Thames Estuary 17 JE/slh21666/170090/Reports/ (i)

4 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Overtopping / Breach Analysis 18 Overtopping Analysis 19 Breach Analysis 19 Fluvial Flood Risk C-X Ditch / River Shoe 21 Pluvial & Sewer Flooding 21 Groundwater 23 Artificial Sources FLOOD RISK MANAGEMENT 25 Flood Risk Mitigation - Tidal 25 Flood Resistance and Resilience 25 Flood Response Plan 26 Mitigation Finished Floor Levels 28 Mitigation Living and Sleeping Accommodation SURFACE WATER MANAGEMENT & FOUL DRAINAGE 30 Existing Flow Regimes 30 Existing Runoff Rates 30 Disposal of Surface Water 30 Post Development Runoff 31 Proposed Sustainable Drainage Systems (SuDS) 31 Water Quality Management 34 Maintenance and Management of System CONCLUSIONS 37 Recommendations 38 FIGURES Figure 1-1: Site Location Plan... 2 Figure 1-2: Location of Waterbodies... 4 Figure 1-3: Digital Elevation Model... 5 Figure 3-1: Environment Agency Flood Map for Planning Figure 3-2: Maximum flood depth, 1 in 200 AEP event plus CC breach scenario Figure 3-3: Environment Agency Risk of Flooding from Surface Water JE/slh21666/170090/Reports/ (ii)

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6 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL INTRODUCTION 1.1. Ardent Consulting Engineers (ACE) has been commissioned by Maureen Smith to undertake a Flood Risk Assessment (FRA) and surface water drainage strategy for the proposed redevelopment of a site for residential use at 121 Ness Road, Shoeburyness, Southend-on-Sea A planning application for the development (16/01469/FUL) has been withdrawn following a Planning Committee recommendation that the application be refused on a number of grounds including flood risk and drainage This Flood Risk Assessment considers the current policy relating to flood risk, including the National Planning Policy Framework and the Strategic Flood Risk Assessment A glossary of common Flood Risk Engineering terms is provided in Appendix A, to assist non-technical readers This document has been informed by consultation with the Environment Agency (EA), Anglian Water and Southend Borough Council. Scope 1.6. In accordance with the assessment criteria found in NPPF, this report and associated surface water drainage strategy seeks to; Ensure that flood mitigation is provided within the Site to avoid detrimental flood risk impacts to third parties; Ensure that the impact of climate change is adequately accounted for; Ensure impermeable areas within the development are minimised where practicable; and JE/slh21666/170090/Reports/

7 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Ensure the use of sustainable drainage systems (SuDS) is optimised in line with current best practice. Site Location 1.7. The proposed development (hereafter referred to as the Site) is located at 121 Ness Road, Shoeburyness, Southend-on-Sea centred approximately at National Grid Reference TQ (Figure 1-1). The Site comprises a total area of approximately 0.09 ha. Legend Development site outline Ness Road Crown Copyright and database rights 2017 Ordnance Survey Figure 1-1: Site Location Plan Existing and Proposed Development 1.8. The Site is currently occupied by a locally listed building in poor structural condition which is not currently in use and should therefore be regarded as brown field The Site is bound by neighbouring residential properties to the north, south and west. Land to the rear of the property is currently greenfield however is understood to have been granted planning permission for a mixed use development. Gunners Park is located to the south east of the Site. JE/slh21666/170090/Reports/

8 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL As part of the development proposals, the existing building will be demolished and replaced with two residential dwellings each providing four bedrooms as well as amenity space and car parking. Development plans are provided in Appendix B The National Planning Policy Framework (NPPF) Planning Practice Guidance classifies residential development as More Vulnerable. Waterbodies in the Vicinity of the Site Waterbodies in the vicinity of the Site are shown in Figure 1-2 below. A flood alleviation ditch known as the C-X Ditch (also known as the River Shoe) flows in a southerly direction approximately 40 m from the eastern boundary of the Site, parallel to Ness Road. This Ditch was constructed as part of the Shoebury Garrison development which re-routed surface water runoff from the urban catchment from Barge Pier Ditch to C-X Ditch/River Shoe. Ditch C- X/River Shoe is also fed by the Anglian Water sewer system which conveys runoff from the urban catchment to the north west of the Site. The C-X Ditch then discharges into Barge Pier Ditch approximately 450 m downstream of the site. Barge Pier Ditch is then discharged into the Thames Estuary approximately 950 m to the south of the Site via a tidal outfall. During high tide, the outfall is tide locked with surface water runoff temporarily stored in the wetland area before being released into the Thames Estuary when the tide level falls. There are a network of ditches, ponds and culverts linking the two watercourses in Gunners Park A pond is situated approximately 140 m to the south of the site on Ness Road. It is unknown whether this pond has hydraulic connectivity with the C-X Ditch Both the C-X Ditch/River Shoe and Barge Pier Ditch are classified as ordinary watercourse. There are no main rivers in the vicinity of the site. JE/slh21666/170090/Reports/

9 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Pond Legend Development site location C-X Ditch / River Shoe Barge Pier Ditch Tidal Outfall Thames Estuary Crown Copyright and database rights 2017 Ordnance Survey Figure 1-2: Location of Waterbodies Ground Conditions In the absence of a detailed site investigation, a review of British Geological Survey (BGS) mapping indicates that the Site lies at a boundary between superficial deposits of fluvial sands and gravels towards the western half of the site with tidal clay and silt deposits towards the east The superficial deposits are underlain by the impermeable London Clay Formation This is supported by BGS borehole records 1 in the vicinity of the site which show deposits of clay down to approximately 7 m below ground level (bgl). Water strikes were recorded between approximately 1.05 and 1.90 m bgl. Refer to Appendix C for BGS borehole records. Site Levels A topographic survey of the Site has been undertaken by Interlock Surveys (February 2017) and is provided in Appendix C. The 1 BGS Borehole Record Reference: TQ98SW5/A, TQ98SW5/B, TQ98SW5/C JE/slh21666/170090/Reports/

10 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 information has been used to develop a Digital Elevation Model (DEM) as illustrated in Figure 1-3 below The survey data shows that the Site slopes downwards quite steeply from west to east with elevations in the order of 5.00 m AOD at the front of the property falling to approximately 3.50 m AOD at the rear of the property. Legend Elevation (m AOD) Crown Copyright and database rights 2017 Ordnance Survey Figure 1-3: Digital Elevation Model Access and Egress The only access to the property is provided via Ness Road to the front of the property. The topographic survey indicates that elevations are in the order of 5.50 m AOD. JE/slh21666/170090/Reports/

11 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL POLICY CONTEXT National Planning Policy Framework 2.1. The National Planning Policy Framework (NPPF) and its Technical Guide was enacted on 27 March 2012; paragraph 100 to 108 inclusive establishes Planning Policy relating to flood risk management The main focus of the policy is to direct development towards areas of the lowest practicable flood risk and to ensure that all development is safe, without increasing flood risk elsewhere. The main considerations are: Applying the Sequential Test, and if necessary, apply the Exception Test; Safeguarding land from development that is required for current and future flood management; Using opportunities offered by new development to reduce the causes and impacts of flooding; and, Where climate change is expected to increase flood risk so that some existing development may not be sustainable in the longterm, seeking opportunities to facilitate the relocation of development, including housing, to more sustainable locations The NPPF states that a Flood Risk Assessment is required for proposals of 1 hectare or greater in Flood Zone 1; all proposals for new development (including minor development and change of use) in Flood Zones 2 and 3, or in an area within Flood Zone 1 where proposed development or a change of use to a more vulnerable class may be subject to other sources of flooding. JE/slh21666/170090/Reports/

12 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL For the NPPF Exception Test to be passed: it must be demonstrated that the development provides wider sustainability benefits to the community that outweigh flood risk, informed by a Strategic Flood Risk Assessment where one has been prepared; and, A site-specific flood risk assessment must demonstrate that the development will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere, and, where possible, will reduce flood risk overall The first point of the Exception Test is for the LPA to consider the supporting information provided as part of the Planning Submission and considers the proposals as a whole. The second element should be demonstrated by a suitably detailed Flood Risk Assessment The Planning Practice Guidance (PPG) 2 to the NPPF provides the methodology required to undertake the Sequential and Exception Tests. Flood and Water Management Act 2.7. The Flood and Water Management Act 2010 defines clearer roles and responsibilities for the implementation of sustainable drainage systems (SuDS) in developments, by requiring drainage systems to be approved against a set of national standards. The Act also requires the Lead Local Flood Authority to develop, maintain, apply and monitor a strategy for local flood risk management in its area Once enacted, Schedule 3 of the Act advocates that the Lead Local Flood Authority (established at the county or unitary local authority level) will be required to establish SuDS Approving Bodies (SABs). The date for enactment is pending supplementary legislative guidance (current timescale for implementation is April 2014). 2 DCLG 2014, Planning Practice Guidance Flood Risk and Coastal Change JE/slh21666/170090/Reports/

13 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Sustainable Drainage Systems Non-statutory technical standards for sustainable drainage systems March The Non-statutory technical standards for sustainable drainage systems were published in March This document sets out nonstatutory technical standards for sustainable drainage systems. They should be used in conjunction with the NPPF and associated Planning Practice Guidance (PPG). In addition, Best Practice Guidance for the Non-statutory technical standards was published in July The Local Planning Authority (LPA) may set local requirements for planning permission that have the effect of more stringent requirements than these non-statutory technical standards In addition, SuDS should be designed in accordance with CIRIA 753 SuDS Manual, which represents current best practice. Southend-on-Sea Borough Council Strategic Flood Risk Assessment Level A Level 1 Strategic Flood Risk Assessment (SFRA) was completed by Scott Wilson in September The primary objective of the study is to enable Southend-on-Sea Borough Council (SBC) to undertake the Sequential Test in line with PPS25 (now the NPPF) and to inform the development of their Local Development Framework (LDF) documents The study area is defined by the administrative boundary of SBC in southeast Essex. This is a total study area of 42km 2. The Thames Estuary forms the southern boundary of the borough and meets the North Sea at Southend. To the north is Rochford District and to the west is Castle Point Borough The Thames Estuary and North Sea pose the greatest flood risk to Southend. Extreme water levels can be generated in the Thames Estuary by intense low pressure systems over the North Sea. JE/slh21666/170090/Reports/

14 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL Although defences are present along the River Thames and North Sea frontages, the crest height of these defences in some areas is lower than the extreme water levels, so flood risk from this source is through potential overtopping whereby still water levels are higher than crest heights resulting in an overtopping event as well as the residual risk of a failure in the flood defences Any windfall sites or sites outside of the AAP areas would need to be assessed against the whole local authority study area. Southend-on-Sea Borough Council Strategic Flood Risk Assessment Level A Level 2 Strategic Flood Risk Assessment (SFRA) was completed by Scott Wilson in November PPS25 (now superseded by the NPPF) outlines a two staged approach to the completion of a SFRA as follows: Level 1 SFRA Enables the application of the Sequential Test Level 2 SFRA Increased scope of the SFRA for sites where the Exception Test is required The Level 1 SFRA has confirmed that the two main sources of flooding within the study area are tidal flooding from the Thames Estuary (resulting from a failure of a flood defence or overtopping of a defence) and fluvial flooding from the Prittle Brook, Eastwood Brook and Willingale watercourse Detailed hydrodynamic breach and overtopping modelling has been completed as part of the Level 2 SFRA to provide a greater level of detail regarding the variation of residual flood risk within Flood Zones across Southend-on-Sea BC area. Results show that the Southend-on-Sea seafront and the southern extent of the Central Area are at residual risk of flooding in the event of a breach in the flood defences and via overtopping of the existing defences. JE/slh21666/170090/Reports/

15 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL The defences along the SBC frontage offer a varying standard of protection ranging from less than the 1% annual probability event (1 in 100 year) present day to protection up to the 0.1% annual probability flood (1 in 1000 year) including an allowance for climate change The range in the protection afforded by the defences is due to varying defence types, from formal walls and flood defence barriers in urban areas to earth embankments in the more rural eastern and western extents of the borough The NPPF requires that safe access and egress is provided to enable the evacuation of people from the development, at or above the 1 in 100 year (1%) fluvial and the 1 in 200 year (0.5%) tidal flood event, and also up to the 1 in 1000 year (0.1%) flood event. This also provides emergency services with access during a flood event and would enable flood defence authorities to carry out essential duties during periods of flood Where development in flood risk areas is unavoidable, which in Southend-on-Sea BC includes parts of the seafront, the most common method of mitigating flood risk to people is to ensure habitable floor levels are raised above the maximum flood water level with an allowance of 300mm freeboard. Southend-on-Sea Local Flood Risk Management Strategy The SBC Local Flood Risk Management Strategy (LFRMS) 2015 outlines the long term plan for managing local sources of flood risk across the Borough. The LFRMS states in Section 4.5 that: No modelling of the flood risk from ordinary watercourses has been undertaken to date across Southend-on-Sea. Therefore future flood risk is based on the potential risk that might arise based on knowledge of known flooding hotspots and potential mechanisms for flooding. Often flooding from ordinary watercourses can combine with other sources of flooding, such JE/slh21666/170090/Reports/

16 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 as surface water or main river flooding to exacerbate flood risk. Therefore it is important to consider all these sources in combination The SBC LFRMS also states in Section 4.7 that: Surface water, sewer and tidal flooding: The influence of surface water, sewer and tidal flooding is most predominant in the southern extent of the Borough around the areas of Chalkwell, Eastern Esplanade, Marine Parade and Shoeburyness. This interaction occurs when heavy rainfall coincides with high tides. Heavy rainfall causes the sewer network to fill rapidly and high tide levels restrict the discharge from gravity drained surface water sewers. This causes the surface water sewer to reach capacity rapidly, resulting in flooding where surface water is either unable to enter the sewer network, or where the surface water sewers surcharge. In some areas, flooding is relieved by surface water pumping stations, located along the sea front. This mechanism of flooding is further exacerbated where flap valves on the sewer outfalls fail to close, allowing the ingress of tidal water into the sewer network, further reducing the storage capacity. The Prittle Brook Flood Relief Tunnel, C-X Ditch (River Shoe) and Barge Pier Ditch all discharge to the Thames Estuary. During times of high tide or storm surges, there is the potential for the discharge from the rivers to be restricted by tide levels Southend-on-Sea Surface Water Management Plan The SBC Surface Water Management Plan (SWMP) 2015 provides a detailed assessment of surface water flood risk across the Borough of Southend-on-Sea. The SWMP indicates that the Site is situated within a Critical Drainage Area (CDA5: Shoeburyness) and is therefore more susceptible to surface water flooding and at risk of groundwater flooding. JE/slh21666/170090/Reports/

17 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL The SWMP goes on to state that Ness Road is a main sewer flooding hotspot with surcharging manholes associated with restricted discharges to the ordinary watercourses within Gunners Park The SWMP describes modifications to the C-X Ditch/River Shoe stating: Gunners Park is located in the south-east corner of the Borough and the C-X Ditch and Barge Pier Ditch (formally known as the River Shoe) flow through this area. The course of the C-X Ditch and Barge Pier Ditch have recently been altered by development in this and the adjacent area. Gunners Park is located at a low elevation, with some areas lying below sea level. Surface water modelling demonstrates that this area is a hotspot for surface water flooding in severe storm events. Southend-on-Sea Borough Council Core Strategy DPD The SBC Core Strategy (December 2007) provides a comprehensive land use planning framework for the Borough and replaces the previously adopted Local Plan (1994) Policy KP2 (Development Principles) of the SBC Core Strategy states that: All new development should contribute to economic social physical and environmental regeneration in a sustainable way. This should be achieved by applying a sequential approach to the location and siting of development, particularly having regard to the need to avoid or appropriately mitigate flood risk Policy KP2 also states that: All new development should include appropriate measures in design, layout, operation and materials to achieve avoidance of flood risk, or where, having regard to other sustainability considerations a residual risk remains, the provision of measures to appropriately and adequately mitigate that risk. All development proposals should demonstrate how they incorporate sustainable JE/slh21666/170090/Reports/

18 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 urban drainage systems (SUDS) to mitigate the increase in surface water run-off, and, where relevant, how they will avoid or mitigate tidal or fluvial flood risk Development Management DPD The SBC Development Management DPD (July 2015) forms part of the SBC Local Planning Framework Policy DM6 (The Seafront) of the Development Management DPD states that: All development proposals within the Seafront Area must take account of flood risk and coastal change. This will include, where appropriate, developing, agreeing and then incorporating: i) Appropriate flood defence and engineering solutions; and/or ii) iii) Flood resistant and resilient design that provides safe refuge to occupants in the event of a flood and is easily restored after the event. Design solutions which do not prevent or restrict future maintenance and improvement of flood defences and the Borough Council s ability to manage coastal change This document has also been informed by: PFRA, 2010; Essex and South Suffolk Shoreline Management Plan, 2010; and Thames Estuary 2100 Plan. JE/slh21666/170090/Reports/

19 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL REVIEW OF FLOOD RISK Introduction 3.1. The NPPF requires flood risk from the following sources to be assessed, each of which are assessed separately below: Fluvial sources (river flooding); Tidal sources (flooding from the sea); Groundwater sources; Pluvial sources (flooding resulting from overland flows); Sewer Flooding; Artificial sources, canals, reservoirs etc; and, It also requires the risk from increases in surface water discharge to be assessed (surface water management). Review of Flood Risk Flood Zone Designation 3.2. Flood Zones refer to the probability of river and sea flooding, ignoring the presence of defences. The NPPF Planning Practice Guidance defines Flood Zones as follows: Flood Zone 1: Low Probability. Land having a less than 1 in 1,000 annual probability of river or sea flooding. Flood Zone 2: Medium Probability. Land having between a 1 in 100 and 1 in 1,000 annual probability of river flooding; or Land having between a 1 in 200 and 1 in 1,000 annual probability of sea flooding. JE/slh21666/170090/Reports/

20 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Flood Zone 3a: High Probability. Land having a 1 in 100 or greater annual probability of river flooding; or Land having a 1 in 200 or greater annual probability of sea flooding. Flood Zone 3b: The Functional Floodplain. This zone comprises land where water has to flow or be stored in times of flood. Local planning authorities should identify in their Strategic Flood Risk Assessments areas of functional floodplain and its boundaries accordingly, in agreement with the Environment Agency (EA) The Flood Zones are shown on the EA Flood Map for Planning (Rivers and Sea). The Planning Practice Guidance states that the zones shown on the EA Flood Map do not take account of the possible impacts of climate change and consequent changes in the future probability of flooding. Environment Agency Flood Map for Planning 3.4. The EA Flood Map for Planning is presented in Figure 3-1 below. It can be seen that a large portion of the site falls within Flood Zone 2 with a portion at the eastern end of the site (to the rear of the property) within Flood Zone 3 and a small portion of the western end of the site (front of the property) is within Flood Zone 1. JE/slh21666/170090/Reports/

21 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Legend Development site location Main Rivers Areas Benefiting from Defence Flood Storage Area Flood Zone 3 Flood Zone 2 Flood Zone 1 Environment Agency copyright and database rights Ordnance Survey Crown copyright. All rights reserved. Environment Agency, Figure 3-1: Environment Agency Flood Map for Planning 3.5. It should be noted that the EA Flood Map for Planning does not take into account the presence of flood defences, nor does it take into account the possible impacts of climate change and consequent changes in the furfure probability of flooding As the site is partially located within Flood Zones 2 and 3, it is classified as being at high probability of flooding. Consequently, under the NPPF, it will need to be demonstrated that the Site passes the NPPF Sequential Test and the Exception Test. Sequential Test 3.7. As the Site is located in Flood Zone 3, it should therefore pass the Sequential Test. A report by Phase 2 Planning and Development Limited (February, 2017) has demonstrated that there are no other alternative windfall sites in Shoebury on which to locate the proposed development. The report also demonstrates that the first part of the Exception Test has also been satisfactorily addressed. Historic Flooding 3.8. EA historic flooding records show that the general area of Shoeburyness was flooded in 1953 though the Site itself was not JE/slh21666/170090/Reports/

22 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 directly affected (Appendix D). This flooding was associated with an extreme tidal/storm surge event that affected large parts of the east coast of England In relation to historic flooding on the C-X Ditch/River Shoe, the LFRMS states: As identified within the PFRA, this watercourse and the Barge Pier Ditch, have previously been associated with groundwater flooding. In addition, flooding has been observed from these watercourses on the 24th of August 2013, 11th October 2013 and 20th July In respect of historic flooding on Campfield Road and Ness Road the SWMP states the following: Flooding in 2013 and 2014 has highlighted the susceptibility of the roads adjacent to Gunners Park to flooding. Within these areas, there is the potential for surface water sewers to surcharge, if the sewer outlets, within Gunners Park, are restricted. Tidal Flood Risk Thames Estuary As described above, the development site is partially situated in Flood Zone 2 and 3. Consultation with the EA has shown that the Flood Zones in this location are based on extreme still water tidal levels derived from the National Coastal Flood Boundary data set (Royal Haskonig/JBA, 2008) The peak levels for the Site are as follows: 1 in 200 annual probability 4.61 m AOD 1 in 1000 annual probability 5.01 m AOD Given the elevations on Site described in Section 1.18, the majority of the site would be expected to flood during the 1 in 200 annual probability event. However, consultation with the EA and JE/slh21666/170090/Reports/

23 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 SBC has confirmed that their coastal flood defences along Gunner s Park and Shoebury Common serve to protect the proposed development site. SBC have confirmed that the minimum elevation of flood defences adjacent to Shoebury Common is 5.04 m AOD. It should also be noted that SBC have confirmed that there are currently plans in place to improve the standard of protection of the defences along Shoebury Common by raising them, however no timescale for delivery of this scheme is currently available The existing defences therefore afford the Site protection from an extreme tidal scenario up to the 1 in 1000 annual probability event. However, a residual risk of flooding remains in the event that these defences breach or are overtopped. Overtopping / Breach Analysis Ardent have previously carried out detailed breach and overtopping modelling for the Shoeburyness area in support of a planning application for an adjacent development situated at Gunner s Park in As part of this assessment, a hydraulic model has been prepared in order to assess the impact of a breach or overtopping scenario at the site incorporating the latest peak still water levels and climate change allowances Environment Agency guidance published in April states that the cumulative rise in sea levels for the south-east of England can be expected to be 1.21 m Therefore, for the purposes of this assessment, an additional 1.21 m has been added to the 1 in 200 year peak tidal level resulting in 1 in 200 annual probability event plus climate change value of: 3 ss14217, H , FRA, Ardent Consulting Engineers, JE/slh21666/170090/Reports/

24 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL m AOD Overtopping Analysis The hydraulic model has been developed using industry standard software, Tuflow. Further details regarding the modelling approach are provided in the accompanying hydraulic modelling technical note (Ref ) During the 1 in 200 year annual probability event plus climate change overtopping scenario, sea levels overtop the defences at Shoebury Common at approximately 24.0 hours into the simulation and rapidly inundate this area. The flood waters then propagate eastwards along Ness Road and into Gunners Park and then northwards through the CX Ditch and Barge Pier Ditch and their associated floodplain. Flood water then rises and spills westwards onto Ness Road and impacting properties here, including the Site The Site becomes flooded at approximately into the simulation, approximately 1.25 hours from when overtopping begins Examination of modelling outputs shows that the anticipated peak flood level at the site during the 1 in 200 year plus climate change overtopping scenario is 5.62 m AOD. Given the elevations described in Section 1.18, this would result in a flood depth on site of approximately 0.92 m at the location of the proposed dwellings. Breach Analysis In order to simulate the impact of a breach of the flood defences, the Tuflow model was updated by incorporating a 2d_bc file at the location of the slipway at Shoebury Common (Grid Reference: , ). Specifically, the breach has been situated at this location as this is the meeting point of two lines of defences to the east and west and is considered to be the most likely point for a breach to occur. The width of the breach is 20 m and the sill level is JE/slh21666/170090/Reports/

25 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 set at 4.0 m AOD. These details are consistent with the Environment Agency approved Ardent model for the Garrison Development mixed use site Analysis of the modelling outputs shows that flood water begins to flow through the breach at approximately hours into the simulation. As in the overtopping scenario, the Shoebury Common area is inundated first before flood waters propagate east and northwards towards the development site The development site becomes flooded at approximately hours, approximately 1.5 hours from when the defences are first breached Examination of modelling outputs shows that the anticipated peak flood level at the site during the 1 in 200 year plus climate change breach scenario is 5.66 m AOD. Given the elevations described in Section 1.18, this would result in a flood depth on site of approximately 0.96 m at the location of the proposed dwellings Model outputs for all modelled scenarios are included within the appendices of the accompanying hydraulic modelling technical note (Ref ), however an extract showing anticipated flood depths at the site during the 1 in 200 plus climate change breach scenario is included in Figure 3-2 below. Flood risk from this source will be mitigated against through the proposed measures described in Section 4. JE/slh21666/170090/Reports/

26 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Legend Flood Depth (m) Crown copyright and database right 2017 OS Figure 3-2: Maximum flood depth, 1 in 200 AEP event plus CC breach scenario Fluvial Flood Risk C-X Ditch / River Shoe There are no main rivers in the vicinity of the Site. The Site is situated adjacently to the C-X Ditch / River Shoe which is classified as ordinary watercourse and therefore flood risk from this source is the responsibility of SBC. No hydraulic modelling data is available for this watercourse. In addition, the SWMP has highlighted that hydraulic regime of the watercourse is intrinsically linked to the surrounding surface water sewer system. As such, flood risk from the C-X Ditch / River Shoe is addressed in the Pluvial Flooding section below. Pluvial & Sewer Flooding The C-X Ditch / River Shoe ordinary watercourse flows to the rear of the property and is hydraulically connected to the Barge Pier Ditch. The SWMP indicated that the hydraulic regime of the Ditches is dictated by the urbanised upstream catchment and adjoining surface water sewer system. This is supported by Anglian Water sewer plans (Appendix E) for the area obtained as part of the previously submitted FRA for the neighbouring Shoebury Garrison Site. The JE/slh21666/170090/Reports/

27 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 plans show that the River Shoe is fed by both a 1.3 m diameter surface water sewer and a 375 mm diameter surface water sewer that outlet underneath Campfield Road approximately 100 m to the north east of the site A review of LiDAR data for the area suggests that the west bank of the C-X Ditch (adjacent the Site) is sufficiently elevated above the flood plain on the eastern bank (by approximately 1.5 m) and that therefore any significant volumes of surface water within the channel would be directed away from the site. This is supported by the flooding extents shown in the Risk of Flooding from Surface Water map in Figure As stated previously, the Site is situated within the Shoeburyness CDA as identified by the SBC SWMP. In particular, Ness Road is identified as a main sewer flooding hotspot with surcharging manholes associated with restricted discharges to the ordinary watercourses within Gunners Park This is supported by historical accounts of flooding in 2013 and 2014 which highlighted the susceptibility of the roads adjacent to Gunners Park to flooding. Within these areas, there is the potential for surface water sewers to surcharge if the sewer outlets within Gunners Park are restricted This is also supported by hydraulic modelling as identified by the EA Risk of Flood from Surface Water Map in Figure 3-3 below. However as can be seen in Figure 3-3, it is the southern end of Ness Road which is identified at high risk of surface water flooding with the Site itself being classified as at very low risk. This is as a consequence of the northern end of Ness Road being at a slightly higher elevation than the Gunner s Park area to the south In addition, the steeply sloping nature of the Site should also direct surface water runoff towards the C-X Ditch / River Shoe and away from the development. JE/slh21666/170090/Reports/

28 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Legend Risk of Flooding from Surface Water High (> 1 in 30 AEP) Medium (1 in 100 to 1 in 30 AEP) Low (1 in 1000 to 1 in 100 AEP) Very Low (<1 in 1000 AEP) Crown copyright and database right 2017 OS Figure 3-3: Environment Agency Risk of Flooding from Surface Water The site is therefore considered to be at low risk of flooding from pluvial and sewer sources. Any residual risk of flooding from these sources will be mitigated against through the measures described in Sections 5 and 6 of this report. Groundwater The Level 2 SFRA states that groundwater flooding is not a major issue in this area. There have been no groundwater flooding incidents reported to the Environment Agency within the Southendon-Sea BC boundary and there is only one record of groundwater flooding reported to the Council between 1998 and This was related to the flooding of a basement in the south seafront area Conversely however, the SBC SWMP (2015) states the following in regards to the Shoeburyness Critical Drainage Area (CDA) which the Site resides in: There is evidence of high groundwater levels within this CDA, both from borehole level analysis and site observations of high groundwater levels. This area is also identified as being highly susceptible to groundwater flooding in the BGS dataset JE/slh21666/170090/Reports/

29 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL However, given the impermeable nature of the ground conditions described in Section 1.15, it is considered that ground water emergence at the Site is unlikely In the unlikely event that ground water emergence does occur on site, the steeply sloping nature of the Site would direct flood water towards the C-X ditch and away from the Site The risk of flooding from ground water is therefore assessed as being low however any residual risk of flooding from this source will be mitigated against by the measures described in Section 4. Artificial Sources Artificial sources of flooding refers to the potential flood risk posed by reservoirs or canals in the event that they become overwhelmed and / or fail There are no canals in close proximity to the site. A review of the Environment Agency s online Risk of Flooding from Reservoirs Map shows that the Site is not in an at risk area. As the Site is not in the vicinity of any canals or at risk of reservoir flooding, the Site is not considered to be at risk of flooding from artificial sources. JE/slh21666/170090/Reports/

30 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL FLOOD RISK MANAGEMENT 4.1. This site-specific flood risk assessment aims to demonstrate that the development will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere, and, where possible, will reduce flood risk overall. Flood Risk Mitigation - Tidal 4.2. As identified in Section 3, there is a residual risk of flooding to the site in the event that flood defences are breached or overtopped. Flood Resistance and Resilience 4.3. It is recommended any levels below the flood level should incorporate flood resistance and/or resilience construction to minimise the potential damage that could be caused by flooding of the Site Possible resistance measures that could be incorporated into the design of the building are listed below: Using materials and construction with low permeability. Raising thresholds and finished floor levels e.g. porches with higher thresholds than main entrance. Flood gates with waterproof seals Measures to ensure the Site remains resilient to the impacts of flooding include the following: Use materials with either, good drying and cleaning properties, or, sacrificial materials that can easily be replaced post-flood. Design for water to drain away after flooding. Design access to all spaces to permit drying and cleaning. JE/slh21666/170090/Reports/

31 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Raise the level of electrical wiring, appliances and utility metres. Coat walls with internal cement based renders; apply tanking on the inside of all internal walls. Ground supported floors with concrete slabs coated with impermeable membrane. Use plastic water resistant internal doors In addition to the above, it is also recommended that in order to further mitigate against the impact of overtopping or breach affecting the site, a Structural Assessment should be undertaken to ensure that proposed buildings are constructed to withstand the predicted hydrostatic and hydrodynamic loadings exerted by breach flood flows. Flood Response Plan 4.7. The Site is located in an EA Flood Alert / Warning area (Figure 4-1). The EA provide Flood Alerts to subscribers of the service when flooding is possible. Flood Warnings are issued when flooding is likely. JE/slh21666/170090/Reports/

32 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Legend Flood Alert Area Flood Warning Area Environment Agency copyright and database rights Ordnance Survey Crown copyright. All rights reserved. Environment Agency, Figure 4-1: Environment Agency Flood Alert / Warning Areas 4.8. The occupants of the Site should register with the Environment Agency s floodline. This is a free service provided by the Environment Agency, which gives advanced notice of potential flooding. Registration is either through the Environment Agency s website ( or by calling the Environment Agency on In the event that a Flood Alert or Warning is issued, and only if it is safe to do so, it is recommended that residents evacuate the Site via the front access to Ness Road, before proceeding north for 20 m and then west onto St Andrews Road for approximately 200 m to ground sufficiently elevated above the anticipated peak flood level. This is illustrated in Figure 4-2 below Flood Warnings for extreme tidal events would likely be issued with sufficient time to allow for safe evacuation of the site or for appropriate action to be made. If however it is not safe to evacuate the property, safe refuge can be sought in the upper floors of the dwellings which are sufficiently elevated above the anticipated extreme flood levels A Flood Response Plan (FRP) has been developed and is included in Appendix F. Southend-on-Sea Borough Council Emergency JE/slh21666/170090/Reports/

33 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Planners have been approached regarding the suitability of the FRP and have confirmed it is acceptable. Legend Development site outline Proposed Evacuation Route Crown copyright and database right 2017 OS Figure 4-2: Proposed Evacuation Route However, instructions issued by the emergency services either prior to or during a flood event should be adhered to and will supersede the advice provided within the FRP. Mitigation Finished Floor Levels From the modelling undertaken, the depth of flooding on Site at the location of the proposed properties equates to approximately 0.96 m (Ground and Breach/overtopping levels equate to 4.7 m AOD and 5.66 m AOD / 5.62 m AOD respectively) It is recommended that Finished Floor Levels (FFL) at the Site should be raised to 300 mm above adjacent ground levels post development which will provide a FFL of 5.0 m AOD at the location of the proposed dwellings There is a residual risk of surface water flooding and ground water flooding at the Site. In the unlikely event that ground water emergence does occur on site or there is a failure of the surface water drainage system, the raising of FFLs will enable any potential JE/slh21666/170090/Reports/

34 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 overland flows to be conveyed safely across the site without affecting the property in accordance with the approach promoted by government policy The measures described in the following Surface Water Management section demonstrate how surface water falling directly onto the site can be appropriately managed in accordance with both local and national planning policy. Mitigation Living and Sleeping Accommodation It is proposed that all living accommodation for the residential units be set at a minimum level of 5.0 m AOD. accommodation to be at first floor level or above. All sleeping JE/slh21666/170090/Reports/

35 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL SURFACE WATER MANAGEMENT & FOUL DRAINAGE Existing Flow Regimes 5.1. The sloping topography of the Site would be expected to direct any surface water runoff generated at the Site eastwards towards the C- X Ditch / River Shoe The existing site has a total area of 0.09 ha of which 0.01 ha comprises impermeable surfaces. No details have been provided regarding whether the existing impermeable services are positively drained however it is assumed that there is an existing connection to the Anglian Water sewer system to the front of the property. Existing Runoff Rates 5.3. The runoff rates for the existing site have been calculated adopting the Modified Rational Method. The peak runoff rates for the Site are presented below. The full calculation record is presented in Appendix F. Q1 = 1.41 l/s Q30 = 3.14 l/s Q100 = 4.00 l/s Disposal of Surface Water 5.4. In accordance with the NPPF Planning Practice Guidance, surface water runoff should be disposed of according to the following hierarchy: 1. Into the ground (infiltration); 2. To a surface water body; 3. To a surface water sewer, highway drain, or another drainage system; or 4. To a combined sewer As discussed in Section 1.15, ground conditions at the site suggest that disposal of surface water via infiltration will not be feasible. JE/slh21666/170090/Reports/

36 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL In addition, there are no suitable surface water bodies located within the vicinity of the site in which to dispose to without the necessity to cross third party land It is therefore proposed to dispose of surface water via the surface water sewer on Ness Road at a restricted discharge rate. As mentioned, no details are currently available regarding the existing drainage network serving the site however it is assumed that an existing connection is in place. Post Development Runoff 5.8. Post development it is anticipated that approximately 0.05 ha of the Site will comprise impermeable surfaces. This represents a 400% increase from existing conditions on site as shown in Table 5-1 below. Table 5-1: Existing and Proposed Impermeable Surfaces Total Area (ha) Impermeable Surfaces (ha) Impermeable Surfaces (%) Existing Site Post Development Proposed Sustainable Drainage Systems (SuDS) 5.9. Table 5-2 appraises the constraints and opportunities for the use of SuDS techniques within the site and it adopts the management train approach outlined in CIRIA C753 The SuDS Manual. JE/slh21666/170090/Reports/

37 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Table 5-2: C753 SuDS Management Train Approach Type: Infiltration Devices (Source Control) Constraints: The site is underlain by London Clay formation which has a limited infiltration rate. Therefore, infiltration would not be a practical option for discharge. Opportunities: None, infiltration devices would not be feasible. Type: Lined Permeable Paving (Source Control) Constraints: Because it is not possible to provide infiltrating permeable paving/permavoid, it could be wrapped in geo-membrane to provide surface water attenuation and a stage of treatment before discharging into existing Anglian Water sewers. Opportunities: Opportunities to utilise lined permeable paving/permavoid should be maximised as this would improve the water quality of the surface water discharge. Type: Rainwater Harvesting (Source Control) Constraints: The benefits of rainwater harvesting on a specific design storm event cannot be quantified, due to the seasonal availability of storage within the structure. Opportunities: Not considered as part of the surface water management strategy Type: Swales, etc. (Permeable Conveyance) Constraints: In order to provide practicable attenuation benefits 1:3 side-slope swales tend to require a significant land requirement and no outfall. Opportunities: None, no space or outfall available to utilise swales. Type: Living Roofs Constraints: Could be implemented as extensive/intensive which provide some attenuation of surface water and delay the time at which rain water will runoff the roofs. Opportunities: Rooftops can be utilised and can provide some surface water treatment but not generally suitable on residential properties. Type: Attenuation Tanks (end of pipe treatment) Constraints: None. Opportunities: Volume of crates required and shallow gradient of surrounding Anglian Water sewer network mean unlikely this option would be feasible from a design perspective After consideration of the CIRIA C753 approach, it is considered that the most viable SuDS option for the Site is permeable paving/permavoid. It is therefore proposed to restrict surface water discharge rates from the site to 1.4 l/s through provision of 100 m² of permavoid across the driveways of each proposed dwelling connected by lateral drains to a hydrobrake with a 64 mm diameter orifice. It should be noted that any further reduction in the discharge rate would require a reduction in the size of the orifice and would thereby constitute a significant increase in the chance of blockage. JE/slh21666/170090/Reports/

38 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL A pre-development enquiry has been submitted to Anglian Water as sewerage provider and have confirmed that the above discharge rate would be acceptable. The response from Anglian Water is included alongside the sewer plans for the area in Appendix E As a conservative approach, an additional 10% has been added to the impermeable areas on Site post development to represent urban creep i.e. possible extensions to the property at a later date. The total impermeable area was therefore ha The results of the MicroDrainage Source Control calculations are shown in Table 5-3 below. The full calculation record is provided in Appendix H. Table 5-3: Existing and Proposed Discharge Rates and Storage Volumes Return Period Discharge Rate 1 in 1 year 1 in 30 Year 1 in 100 year 1:100 year + 40% CC Pre Development 1.41 l/s 3.14 l/s 4.0 l/s - Post Development 1.4 l/s 1.4l/s 1.4 l/s 1.4 l/s % Difference -1% -55% -65% - Max Attenuation Storage Requirements 22.1 m³ The permavoid solution would be capable of providing a maximum storage volume of 22.1 m³ during the 1 in 100 annual probability event plus 40% climate change, including an allowance for urban creep Any surcharged volume would be expected to flow eastwards towards the C-X Ditch / River Shoe. As stated in Section 4, it is recommended that Finished Floor Levels of the dwellings are raised to 5.0 m AOD (approximately 300 mm above adjacent ground JE/slh21666/170090/Reports/

39 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 levels). It is considered that this would be sufficiently elevated so as to prevent any ingress of surface water into the property The SuDS system would connect to the Anglian Water network either via the existing drainage connection serving the site (if confirmed) or alternatively via a new connection immediately adjacent to the property under Section 106 of the Water Industry Act. An indicative drainage layout is presented in Drawing No in Appendix I. Water Quality Management The recommended stage of treatment in terms of water quality would be provided through the aforementioned lined permeable/permavoid paving Therefore in line with Tables 26.2 and 26.3 of the CIRIA C753 SuDS Manual, the pollution hazards indices associated with a residential development are mitigated by the proposed SuDS features. Maintenance and Management of System The maintenance of all SuDS components will be in accord with the best practices and the CIRIA C753 SuDS Manual. The recommended Operation and Maintenance requirements for the proposed permeable paving is outlined in Table 5-4 below. It is recommended that maintenance of the proposed SuDS feature and drainage network will be carried out by a private management company. The management company will be financed by a yearly maintenance fee chargeable to the residential development. name of the Management Company to be advised. The JE/slh21666/170090/Reports/

40 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Table 5-4: SuDS Operation and Maintenance Maintenance schedule Regular maintenance Occasional maintenance Remedial Actions Required action Brushing and vacuuming (standard cosmetic sweep over whole surface) Stabilise and mow contributing and adjacent areas Removal of weeds or management using glyphosate applied directly into the weeds by an applicator rather than spraying. Remediate any landscaping which, slip, has been raised to within 50 mm of the level of the paving through vegetation maintenance or soil Remedial work to any depressions, rutting cracked of broken blocks Typical frequency Once a year, after autumn leaf fall, or reduced frequency as required, based on sitespecific observations of clogging or manufacturer s recommendations pay particular attention to areas where water runs onto pervious surface from adjacent impermeable areas as this area is most likely to collect the most sediment. As required As required once per year on less frequently used pavements As required As required JE/slh21666/170090/Reports/

41 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 considered detrimental to the structural performance or a hazard to users, and replace lost jointing material Rehabilitation of surface and upper substructure by remedial sweeping Initial inspection Every 10 to 15 years or as required (if infiltration performance is reduced due to significant clogging) Monthly for three months after installation Monitoring Inspect for evidence of poor operation and/or weed growth if required, take remedial action Inspect silt accumulation rates and establish appropriate brushing frequencies Monitor inspection chambers Three-monthly, 48 h after large storms in first six months Annually Annually JE/slh21666/170090/Reports/

42 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL CONCLUSIONS 6.1. According to the EA s Flood Map for Planning the Site is partially located in Flood Zone 3. However, the site is afforded protection from tidal flooding by the presence of coastal flood defences at Shoebury Common and Gunner s Park. There is a residual risk of flooding in the event these defences are breached or are overtopped The maximum anticipated flood level at the site during the 1 in 200 annual probability event plus climate change breach scenario is 5.66 m AOD A flood modelling report has been developed that examines the breach scenarios in detail There is a residual risk of ground water and surface water flooding at the site A report by Phase 2 Planning and Development Limited (February, 2017) has demonstrated that there are no other alternative windfall sites in Shoebury on which to locate the proposed development. The report also demonstrates that the first part of the Exception Test has also been satisfactorily addressed This flood risk assessment aims to satisfy the second part of the Exception Test and demonstrate that the development will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere, and, where possible, will reduce flood risk overall In conclusion, this FRA demonstrates that the proposals are consistent with the aims of the NPPF and the Technical Guidance to the NPPF along with the aims of the Strategic Flood Risk Assessment (including the application of the Sequential and Exceptions Tests). The Site is protected by defences and defence improvements will further decrease the flood risk to Site in the future. The residual flood risk for the Site is appropriately mitigated and managed. JE/slh21666/170090/Reports/

43 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL 2017 Recommendations 6.8. It is recommended that flood resilient and resistant materials are implemented into the design of the building at ground floor level Finished floor levels to be set at 5.0 m AOD and sleeping accommodation to be at first floor level. This will mitigate against the residual risk of overland, groundwater flooding or failure of the surface water drainage system In order to mitigate against overtopping and / or breach of the flood defences affecting the site, it is recommended that a Structural Assessment should be undertaken to ensure that proposed buildings are constructed to withstand the predicted hydrostatic and hydrodynamic loadings exerted by breach flood flows The Flood Response Plan to be followed unless instructed otherwise by the emergency services on the day whose instruction supersedes the FRP The occupants of the Site should register with the Environment Agency s floodline. This is a free service provided by the Environment Agency, which gives advanced notice of potential flooding. Registration is either through the Environment Agency s website ( or by calling the Environment Agency on The surface water drainage strategy to comprise of permeable paving and permavoid construction. This will attenuate surface water runoff up to the 100 year climate change event This report has demonstrated that surface water runoff generated on site can be sustainably managed in accordance with the principles set out in the NPPF as well as local planning policy and provide betterment over the current situation. JE/slh21666/170090/Reports/

44 121 NESS ROAD, SHOEBURYNESS FLOOD RISK ASSESSMENT APRIL The information in this report should be made available to prospective buyers and their property insurers to reassure them of the low flood risk status of the development A copy of this report should be submitted to the Environment Agency to demonstrate that the FRA has been completed and the development complies with requirements of NPPF. JE/slh21666/170090/Reports/

45 Appendix A Glossary of Flood Risk Engineering terms

46 Glossary AEP: Annual Exceedance Probability The estimated probability of a flood of given magnitude occurring or being exceeded in any year. Expressed as, for example, 1 in 100 chance or 1 per cent. Attenuation (surface water) The reduction of a peak flow by restricting the rate at which water discharges. Attenuation usually refers to a design volume associated with a specific AEP event. Compensatory Floodplain Storage In order to maintain a similar flood flow profile post development, it is usual to offset any land raising within the 1% AEP + Climate Change floodplain, by lowering land elsewhere. The land lowered has to provide the same volume of floodplain and at the same vertical level. Climate Change Under NPPF the predicted impacts of climate change need to be considered as part of an FRA, this is to protect the development over the lifetime of the development. Design flood level The maximum estimated water level during the design event, relates to a specific AEP i.e. 0.5% for tidal or 1% for fluvial Flood Zone 3. Flood Defences Flood defence infrastructure, intended to protect an area against flooding to a specified standard of protection, through the use of engineered embankments or walls. Flood Defence Level The level required to be achieved by flood defences, usually the design flood level with a freeboard allowance, to account for wave action and modelling uncertainty. Floodplain An area of land adjacent to a river or tidal water body that is predicted to become affected by water as the result of a defined flood event. Fluvial Flooding Flooding caused by a river overtopping its banks, as a result of high flows exceeding the rivers capacity. Flood Zone An area defined by the Environment Agency and/or SFRA as being at risk from a specified flood event. The Flood Zone definitions ignore the benefits of flood defence structures. Flood Zone 1: Low Probability An area having a less than 0.1% AEP of flooding for both tidal and fluvial sources. Flood Zone 2: Medium Probability An area having a fluvial AEP of between 1% and 0.1%. Or a tidal AEP of between 0.5% and 0.1%. ~ i ~

47 Flood Zone 3(a): High Probability An area having a fluvial AEP of between 5% and 1%. Or, a tidal AEP of between 5% and 0.5%. Flood Zone 3(b): The Functional Floodplain An area having an AEP of more than 5% for both tidal and fluvial sources. Flood Zone Map A map produced by the Environment Agency, or SFRA which designates the flood zones. Site specific FRA usually refine the detail of these maps to provide a more accurate prediction at the Site level. Freeboard The difference between the Flood Defence level and the Design Flood level, usually 300mm for fluvial sources and 600mm for tidal sources. But local variations do occur. Groundwater Flooding Caused by groundwater rising through permeable soil strata either into basements, or through the ground. Tends to occur at the bottom of a valley in large chalk catchments. Greenfield Rate Two definitions of the greenfield rate are used interchangeably. C697 defines it as The surface water runoff regime from a site before development, or the existing site conditions for brownfield redevelopment sites. However common usage ignores the brownfield status. National Flood Risk Assessment(NaFRA) Through the Environment Agency Flood Mapping website the output from the NaFRA study can be selected for a specific location. This NaFRA study is provided to financial institutions so that they can identify if flood insurance can be provided in the normal way (low or moderate likelihood) or if an increase in premiums is likely (significant likelihood) Pluvial Flooding Caused by overland run-off exceeding the capacity of natural and artificial drainage systems as a result of the volume of rainfall. NPPF Exception Test NPPF identifies a number of vulnerability classes within certain flood zones which will require the Exception Test. The Exception Test can enable development within flood risk areas when taking account of the wider sustainability benefits of the site, i.e. to avoid economic or social blight on previously developed land. NPPF Sequential Test The Flood Zones and Vulnerability Classifications are used Residual Risk The risk which remains following the use of all risk reduction, mitigation and management options. Or the risk beyond the design AEP event. Run-off The flow of water from an area as a result of a rainfall event. ~ ii ~

48 Tidal Flooding Caused by sea or estuarine levels rising beyond the level of the land or flood defences. Usually associated with significant offshore storm events. SFRA Strategic Flood Risk Assessment, usually undertaken on behalf of Local Authorities to inform their Sequential Tests. SuDS Sustainable Drainage Systems, a sequence of drainage devices which promote a more natural run-off regime from developments. The use of SuDS can result in a reduction in the volume of water discharged to sewers and watercourses, therefore reducing the risk of Pluvial Flooding. ~ iii ~

49 Appendix B Development Proposals

50 LOUNGE 22sqm 3.4 m DINING 18sqm UTILITY 3sqm LOUNGE 15sqm WC 2sqm DINING 21sqm 4.2 m GARAGE 19sqm ~ 6.7 m UTILITY 6sqm WC 3.5sqm GARAGE 20sqm HALL STUDY 6sqm KITCHEN ~ 5.2 m MORNING SUN GARDEN GARDEN 10.6 m TOTAL GIA PLOT 1 GROUND FLOOR: 110SQM TOTAL GIA PLOT 2 GROUND FLOOR: 128SQM TOTAL GIA PLOT 1 FIRST FLOOR: 111SQM PATIO PATIO 4.0 m TOTAL GIA PLOT 2 FIRST FLOOR: 138SQM BIN STORE BIN STORE 3.0 m KITCHEN / BREAKFAST 31sqm BEDROOM 1 21sqm 7.4 m 1.8 m 4.1 m 4.2 m BEDROOM 3 22sqm 3.4 m 1.8M HIGH FEMCE 119A 1.0 m 14.8 m 3.2 m 4.7 m ALL DOORS MIN 838MM CLEAR LEVEL THRESHOLD TO LANDING AND FRONT DOOR RAMP 9.2 m A 3.0 m 1.0 m 1.0 m 3.0 m A 1.5 m ALL DOORS MIN 838MM CLEAR LEVEL THRESHOLD TO LANDING AND FRONT DOOR 3.1 m 5.7 m 2.2 m 1.0 m 7.6 m 16.9 m 1.8M HIGH FEMCE 1.2M HIGH FEMCE 1.8 m 2.1 m ENSUITE 5sqm BATHROOM 6sqm BEDROOM 3 18sqm 4.0 m 3.7 m LANDING BEDROOM 4 18sqm A BEDROOM 2 16sqm ENSUITE 6sqm 2.8 m 3.1 m 3.8 m BATHROOM 9sqm ENSUITE 6sqm BEDROOM 2 16sqm 4.9 m 3.0 m A ~ 1.9 m LANDING BEDROOM 4 19sqm ROOFLIGHT ENSUITE 6sqm 3.1 m 5.7 m BEDROOM 1 18sqm VIEW TO GREEN RAMP PLOT 1 CAR PARKING ON DRIVE 14.7 m OVERHANG ABOVE CAR PARKING ON DRIVE 9.0 m PLOT 2 2 FIRST FLOOR PLAN 1800/01 Scale: 1:100 TURNING TURNING 3.0 m 3.0 m ~ 10.0 m 10.0 m A KEY LOCATION OF FUTURE LIFT TO COMPLY WITH PART M BUILDING REGULATIONS N CAR PARKING ON DRIVE 1 GROUND FLOOR PLAN 1800/01 Scale: 1: m NEW CROSSOVER CAR PARKING ON DRIVE NEW CROSSOVER 11.1 m 1800/01 PROJECT NO REVISION. A DATE JAN '16 SCALE A2 PROJECT PROPOSED DEVELOPMENT 121 NESS ROAD SHOEBURYNESS DESCRIPTION PROPOSED PLANS REVISION A REVISED TO PLANNERS REQUIREMENTS D. J. W ARCHITECTURAL DESIGNS LTD

51 2.5 m 0.25 m 8.4 m 2.5 m 8.4 m PLOT 1 PLOT FRONT / WEST ELEVATION 1800/02 Scale: 1:100 FLOOR LEVEL RAISED TO TAKE INTO ACCOUNT FLOOD RISK ASSESSMENT VERTICAL TIMBER CLADDING OUTLINE OF BUILDING TO PLOT 2 BEYOND 8.4 m 2.5 m 2.5 m BRICKWORK CORBELLING FACING BRICKWORK 2 SIDE / NORTH ELEVATION 1800/02 Scale: 1:100 3 REAR / EAST ELEVATION 1800/02 Scale: 1:100 OUTLINE OF BUILDING TO PLOT 1 BEYOND SIDE / SOUTH ELEVATION 1800/02 Scale: 1: /02 PROJECT NO REVISION. A DATE FEB '16 SCALE A2 PROJECT PROPOSED DEVELOPMENT 121 NESS ROAD SHOEBURYNESS DESCRIPTION PROPOSED ELEVATIONS REVISION A REVISED TO PLANNERS REQUIREMENTS D. J. W ARCHITECTURAL DESIGNS LTD

52 SLATE ROOFTILES TO FALL 1 SKETCH VIEW 1800/03 Scale: NTS PLOT 1 PLOT m 10.6 m 1.0 m 1.0 m 3 ROOF PLAN 1800/03 Scale: 1:200 2 SKETCH VIEW 1800/03 Scale: NTS N /03 PROJECT NO REVISION. A DATE FEB '16 SCALE A2 PROJECT PROPOSED DEVELOPMENT 121 NESS ROAD SHOEBURYNESS DESCRIPTION PROPOSED ROOF PLAN AND PROPOSED 3D SKETCH VIEWS REVISION A REVISED TO PLANNERS REQUIREMENTS D. J. W ARCHITECTURAL DESIGNS LTD

53 Appendix C Topographic Survey and BGS Borehole Records

54 TP E E Symbol & Abbreviation Key. BARBED WIRE FENCE POST & RAIL FENCE CLOSE BOARD FENCE RAILINGS N CHAIN LINK FENCE OTHER FENCE KERB INDICATIVE ONLY DROPPED KERB GULLY CHANNEL TOP / BOTTOM OF BANK FOLIAGE 5.42 DITCH VERGE grass 5.37 ST cl=5.48 bitumen TOW gutter = 7.68 ridge = OVERHEAD CABLES GATE HEDGE TREE - BROAD LEAVED TREE - CONIFEROUS BUSH BUILDING BOREHOLE SURVEY STATION N FH 5.43 paving 5.48 TP grass grass N E S S R O A D LP 5.47 bitumen grass bitumen SV TOF CTV grass TOF 6.63 bitumen 4.77 grass ST shed ST TOF TOF TOF 4.58 TOF DP FL DP roof level= DP DPGU gutter = DP CR TOW 6.58 DP TOW 4.90 TOW ST TOF TOF TOF TOF 4.25 TOF grass grass ST TOF N A/C AV BOL BH BL BM BT CTV CL CR DP ER EP EM FB FH FP FL GV GM GU HM IL General. Notes. AIR CONDITIONING UNIT AIR VALVE BOLLARD BOREHOLE BED LEVEL BENCH MARK BRITISH TELECOM CABLE TV COVER LEVEL CABLE RISER DOWN PIPE EARTH ROD ELECTRICITY POLE ELECTRICITY MARKER FUSE BOX FIRE HYDRANT FENCE POST FLOOR LEVEL GAS VALVE GAS MARKER GULLY HYDRANT MARKER INVERT LEVEL ORDNANCE SURVEY BENCH MARK KO LC LP NP NB PR RP RS SP SV TL TP TOF TOH TOR TOS TOW UTL VM VP WL WM WO KERB OFFLET LIGHTING COLUMN LAMP POST NAME PLATE NOTICE BOARD PIPE RISER RODDING POINT ROAD SIGN SIGN POST STOP VALVE TRAFFIC LIGHT TELEGRAPH POLE TOP OF FENCE TOP OF HEDGE TOP OF RAILINGS SERVICE LEVEL TOP OF WALL UNABLE TO LIFT VALVE MARKER VENT PIPE WATER LEVEL WATER MARKER WASH OUT This survey has been prepared with a scaling accuracy for a plot at a scale of 1:200. All tree heights and spreads are approximate. We have tried to identify tree types, however if tree species are critical specialist advice should be gained. Drainage pipe sizes have been measured from the surface. Chamber access has not been gained for safety reasons, therefore sizes should be regarded as approximate. Some detail may have been omitted due to parked vehicles. Coordinates related to OS National Grid from ST01 by GPS (No scale factor added). Levels related to GPS Rev Details of Revision Drawn Date 5.43 Surveyed Drawn Date Checked Date Approved Date grass 5.42 bitumen grass bitumen TOH 6.85 parapet= ridge= parapet= BO BO 14/02/17 RGT 23/02/17 RGT 23/02/17 Interlock Surveys Limited St. Andrews House Radford Semele Leamington Spa Warwickshire CV31 1TF T: F: E: info@interlocksurveys.co.uk ST Client. ARDENT CONSULTING ENGINEERS 1-2 CRESCENT COURT HIGH STREET, BILLERICAY CM12 9AQ Title. TOPOGRAPHICAL SURVEY CAMBRIDGE HOUSE 121 NESS ROAD SHOEBURYNESS, SOUTHEND-ON-SEA ESSEX, SS3 9ES E E Dwg No. Scale Sheet 1 of 1 1:200 A2 Sheet Rev. -

55 BGS Borehole Records: Reference: TQ98SW5/A-C

56

57

58

59

60 Appendix D Environment Agency Data

61 Georgia Athanasia Ardent Consulting Engineers Our ref EAn/2017/36015 Date 17 February 2017 Dear Georgia Provision of Product 4 for 121 Ness Road Shoebury Essex SS3 9ES Thank you for your request of 25 January 2017 to use Environment Agency data in the development of the above site. The information that we hold can be found below and attached to my . The information on Flood Zones in the area relating to this address is as follows: 1. This area falls within Flood Zone 3, Tidal Please see the attached map showing the Flood Zones (outlines) for the area of the site. If you are obtaining this information for use within a Flood Risk Assessment (FRA) required for a planning application, please include our unaltered Product 4 data (flood map, flood levels and flood level node points) within an appendix of the FRA. Flood Zone 1, (i.e. a less than 0.1% annual probability of flooding). The Flood Zone 2 outline shows a 1 in 1000 chance of flooding at a location in any one given year (i.e., a 0.1% annual probability of flooding). The Flood Zone 3 fluvial outline shows a 1 in 100 chance of flooding at a location in any one given year (i.e., a 1% annual probability of flooding). The Flood Zone 3 tidal outline shows a 1 in 200 chance of flooding at a location in any one given year (i.e., a 0.5% annual probability of flooding). The flood outlines show areas of potential flooding as a direct result of floodwater coming from rivers or sea. They do not show the risk of flooding to individual properties, because we do not hold this data. East Anglia Area Ipswich Office, Iceni House, Cobham Road, Ipswich, Suffolk, IP3 9JD Brampton Office, Bromholme Lane, Brampton, Huntingdon, PE28 4NE General Enquiries: Calls to 03 numbers cost no more than a national rate call to an 01 or 02 number and must count towards any inclusive minutes in the same way as 01 and 02 calls. These rules apply to calls from any type of line including mobile, BT, other fixed line or payphone. enquiries@environment-agency.gov.uk Website:

62 Flood risk data requests including an allowance for climate change will be based on the 1% annual probability flood including an additional 20% increase on peak flows to account for climate change impacts, unless otherwise stated. You should refer to 'Flood risk assessments: climate change allowances' to check if this allowance is still appropriate for the type of development you are proposing and its location. You may need to undertake further assessment of future flood risk using different allowances to ensure your assessment of future flood risk is based on best available evidence. Please be aware that in recent years, there has been an increase in flood damage caused by surface water flooding or drainage systems that have been overwhelmed. We have worked with Lead local Flood Authorities (LLFAs) to develop a map which incorporates the best local and national scale information on surface water flood risk. These maps can be viewed on our website at the following:- 2a. Examinations of our records of historic flooding show that the general area of Shoeburyness, Essex was flooded in January to February The historic flood event records are based on a combination of anecdotal evidence, Environment Agency staff observations and surveys. Please note that these records show flooding to the land and do not necessarily indicate that properties within the historic flood events were flooded internally. It is also possible that the pattern of flooding in this area has changed and that this area would now flood under different circumstances. 4. For more information regarding the open coast modelled flood levels, please read the guidance regarding design sea levels on the link below. We have produced a map which shows the extent of flooding if a reservoir was to fail and release the water that it holds. The map shows the worst case scenario. These can be viewed on our website at the following:- This information is provided subject to the Open Government Licence available here: which you should read. We respond to requests under the Freedom of Information Act 2000 and Environmental Information Regulations Please get in touch if you have any further queries or contact us within two months if you would like us to review the information we have sent. Further guidance If you have requested this information to help inform a development planning proposal, then you should view the government guidance on whether a Flood Risk Assessment is required using the FRA Guidance Note, the Flood Risk and Coastal Change planning guidance and read our attached guidance on the requirements for a Flood Risk Assessment entitled Flood Zone 3 Factsheet. TEAM2100 is delivering the first 10 years of capital investment in tidal flood defences in London and East Anglia Area Ipswich Office, Iceni House, Cobham Road, Ipswich, Suffolk, IP3 9JD Brampton Office, Bromholme Lane, Brampton, Huntingdon, PE28 4NE General Enquiries: Calls to 03 numbers cost no more than a national rate call to an 01 or 02 number and must count towards any inclusive minutes in the same way as 01 and 02 calls. These rules apply to calls from any type of line including mobile, BT, other fixed line or payphone. enquiries@environment-agency.gov.uk Website:

63 the Thames estuary, as recommended by the TE2100 plan. For more information, visit the TEAM2100 website or Please be aware that we now charge for planning advice provided to developers, agents and landowners. If you would like advice to inform a future planning application for this site then please complete our pre-application enquiry form and it to our Sustainable Places team. We will initially provide you with a free response identifying the following: the environmental constraints affecting the proposal; the environmental issues raised by the proposal; the information we need for the subsequent planning application to address the issues identified and demonstrate an acceptable development; any required environmental permits. If you require any further information from us (for example, a meeting or the detailed review of a technical document) we will need to set up a charging agreement. Further information can be found on our website. Please note we have published revised climate change allowances, which are available online. These new allowances will need to be reflected in your Flood Risk Assessment. If you want to discuss this please call our Sustainable Places team on (East) Yours sincerely Gavin Rumsey Customers and Engagement Officer Environment Agency Direct dial: East Anglia Area Ipswich Office, Iceni House, Cobham Road, Ipswich, Suffolk, IP3 9JD Brampton Office, Bromholme Lane, Brampton, Huntingdon, PE28 4NE General Enquiries: Calls to 03 numbers cost no more than a national rate call to an 01 or 02 number and must count towards any inclusive minutes in the same way as 01 and 02 calls. These rules apply to calls from any type of line including mobile, BT, other fixed line or payphone. enquiries@environment-agency.gov.uk Website:

64 Flood Map for Planning centred on Shoeburyness, Essex Created on 06/02/17 - Ref: EAn/2017/36015 Environment Agency Iceni House Cobham Road Ipswich Suffolk IP3 9JD ± Kilometers Scale 1:10,000 Legend Site outline Main Rivers Areas Benefiting from Defence Flood Storage Area Flood Zone 3 Flood Zone 2 Flood Map for Planning (assuming no defences) Flood Zone 3 shows the area that could be affected by flooding: - from the sea with a 1 in 200 or greater chance of happening each year - or from a river with a 1 in 100 or greater chance of happening each year. Flood Zone 2 shows the extent of an extreme flood from rivers or the sea with up to a 1 in 1000 chance of occurring each year. Crown copyright and database rights 2016 Ordnance Survey Environment Agency Contact Us: National Customer Contact Centre, PO Box 544, Rotherham, S60 1BY. Tel: (Mon-Fri 8-6). enquiries@environment-agency.gov.uk Produced by: Flood Risk Management Team Partnership & Strategic Overview Essex, Norfolk & Suffolk

65 Flood Model Levels Map centred on Shoeburyness, Essex Created on 06/02/17 - Ref: EAn/2017/36015 Environment Agency Iceni House Cobham Road Ipswich Suffolk IP3 9JD ± Kilometers Scale 1:24,000 Legend 4304!( Site outline Main Rivers!( CFB Extreme Sea Levels nodes 4310!( 4308!( Crown copyright and database rights 2016 Ordnance Survey Environment Agency Contact Us: National Customer Contact Centre, PO Box 544, Rotherham, S60 1BY. Tel: (Mon-Fri 8-6). enquiries@environment-agency.gov.uk 4306!( Extreme Sea Level data (Royal Haskoning et al. 2008) The data in this map has been extracted from the model above. This model has been designed for catchment wide flood risk mapping. It should be noted that it was not created to produce flood levels for specific development sites within the catchment. Modelled outlines take into account catchment wide defences if present. Produced by: Flood Risk Management Team Partnership & Strategic Overview Essex, Norfolk & Suffolk

66 Datasheet Reference ENS/2017/36015 Tidal flood levels (maodn) Extreme Sea Level data Annual Exceedance Probability Maximum water levels (maodn) Node 100% 20% 5% 50% (1:2) 10% (1:10) (1:1) (1:5) (1:20) 4% (1:25) 2% 1.3% 1% 0.6% 0.5% 0.4% 0.3% 0.2% 0.1% 0.01% (1:50) (1:75) (1:100) (1:150) (1:200) (1:250) (1:300) (1:500) (1:1,000) (1:10,000) CC = Climate Change Source of information: Extreme Sea Level data (2008) by Royal Haskoning, Jeremy Benn Associates Limited and National Tidal and Sea Level Facility for

67 Recorded Flood Events Outlines Map centred on Shoeburyness, Essex Created on 06/02/17 - Ref: EAn/2017/36015 Environment Agency Iceni House Cobham Road Ipswich Suffolk IP3 9JD ± Kilometers Scale 1:24,000 Legend Site outline Main Rivers 1953 Flood Outline Crown copyright and database rights 2016 Ordnance Survey Environment Agency Contact Us: National Customer Contact Centre, PO Box 544, Rotherham, S60 1BY. Tel: (Mon-Fri 8-6). enquiries@environment-agency.gov.uk The historic flood event outlines are based on a combination of anecdotal evidence, Environment Agency staff observations and survey. Our historic flood event outlines do not provide a definitive record of flooding. It is possible that there will be an absence of datain places where we have not been able to record the extent of flooding. It is also possible for errors occur in the digitisation of historic records of flooding. Produced by: Flood Risk Management Team Partnership & Strategic Overview Essex, Norfolk & Suffolk

68 Appendix E Anglian Water Consultation

69 (c) Crown copyright and database rights 2017 Ordnance Survey Date: 31/01/17 Scale: 1:1250 Map Centre: , Data updated: 05/01/17 Our Ref: Wastewater Plan A3 This plan is provided by Anglian Water pursuant its obligations under the Water Industry Act 1991 sections 198 or 199. It must be used in conjunction with any search results attached. The information on this plan is based on data currently recorded but position must be regarded as approximate. Service pipes, private sewers and drains are generally not shown. Users of this map are strongly advised to commission their own survey of the area shown on the plan before carrying out any works. The actual position of all apparatus MUST be established by trial holes. No liability whatsoever, including liability for negligence, is accepted by Anglian Water for any error or inaccuracy or omission, including the failure to accurately record, or record at all, the location of any water main, discharge pipe, sewer or disposal main or any item of apparatus. This information is valid for the date printed. This plan is produced by Anglian Water Services Limited (c) Crown copyright and database rights 2017 Ordnance Survey This map is to be used for the purposes of viewing the location of Anglian Water plant only. Any other uses of the map data or further copies is not permitted. This notice is not intended to exclude or restrict liability for death or personal injury resulting from negligence. Foul Sewer Surface Sewer Combined Sewer Final Effluent Rising Main (Colour denotes effluent type) Private Sewer (Colour denotes effluent type) Decommissioned Sewer (Colour denotes effluent type) Outfall Inlet (Colour denotes effluent type) (Colour denotes effluent type) Manhole (Colour denotes effluent type) Sewage Treatment Works Pumping Station Cambridge House

70 Pre-Planning Assessment Report Ness Road, SOUTHEND ON SEA - Shoeburyness Pre-Planning Report Wednesday, 05 April 2017

71 Section 1: Proposed Development Thank you for submitting a pre-planning enquiry. This has been produced for Ardent Consulting Engineers. Your reference number is If you have any questions upon receipt of this report, please contact Sandra Olim on or planningliaison@anglianwater.co.uk. The response within this report has been based on the following information which was submitted as part of your application: List of Planned Developments Type of Development No. Of Units C3 Dwellings 2 The anticipated residential build rate is: Year 2017 Build Rate 2 The grid reference for the site is TQ The site currently does not have planning permission and is located on a brownfield site. Pre-Planning Report 1 Wednesday, 05 April 2017

72 Section 2: Assets Affected Our records indicate that there are no public water mains or public sewers or other assets owned by Anglian Water within the boundary or overlapping your development site. However, it is recommended that you carry out a thorough investigation of your proposed working area to establish whether any unmapped public or private sewers and lateral drains are in existence. Due to the private sewer transfer in October 2011 many newly adopted public used water assets and their history are not indicated on our records. You also need to be aware that your development site may contain private water mains, drains or other assets not shown on our records. These are private assets and not the responsibility of Anglian Water but that of the landowner. Pre-Planning Report 2 Wednesday, 05 April 2017

73 Section 3: Water Recycling Services In examining the used water system we assess the ability for your site to connect to the public sewerage network without causing a detriment to the operation of the system. We also assess the receiving water recycling centre and determine whether the water recycling centre can cope with the increased flow and influent quality arising from your development. Water Recycling Centre The foul drainage from the proposed development is in the catchment of Southend Water Recycling Centre, which currently has capacity to treat the flows from your development site. Anglian Water cannot reserve capacity and the available capacity at the water recycling centre can be reduced at any time due to growth, environmental and regulation driven changes. Used Water Network Anglian Water has assessed the impact of gravity flows from the planned development to the public foul sewerage network. We can confirm that this is acceptable as the foul sewerage system, at present, has available capacity for your site. The connection point will be to manhole 1802 in Ness Road at National Grid Reference (NGR) TQ Existing foul water connection may be re used, subject to confirmation that discharge is to the public foul sewer in Ness Road. Surface Water Disposal In principle, your proposed method of surface water disposal is acceptable to Anglian Water. It is our understanding that the evidence to confirm compliance with the surface water hierarchy is not available. Once the evidence has been confirmed, then a connection point may be made to manhole 1852 in Ness road at NGR TQ at a rate of 5l/s. It is your responsibility to provide the evidence to confirm that all alternative methods of surface water disposal have been explored and these will be required before your connection can be agreed. This is subject to satisfactory evidence which shows the surface water management hierarchy as outlined in Building Regulations Part H has been explored. This would encompass the results from the site specific infiltration testing and/or confirmation that the flows cannot be discharged to a watercourse. Anglian Water's surface water policy follows the Surface Water hierarchy, outlined in Part H of the Building Regulations. Should your assumptions or evidence change then an alternative solution, connection point or flow rate may be required. You are therefore advised to update Anglian Water with the key supporting evidence at your earliest convenience. Pre-Planning Report 3 Wednesday, 05 April 2017

74 As you may be aware, Anglian Water will consider the adoption of SuDs provided that they meet the criteria outline in our SuDs adoption manual. This can be found on our website at We will adopt features located in public open space that are designed and constructed, in conjunction with the Local Authority and Lead Local Flood Authority (LLFA), to the criteria within our SuDs adoption manual. Specifically, developers must be able to demonstrate: 1. Effective upstream source control, 2. Effective exceedance design, and 3. Effective maintenance schedule demonstrating than the assets can be maintained both now and in the future with adequate access. If you wish to look at the adoption of any SuDs then an expression of interest form can be found on our website at: Trade Effluent We note that you do not have any trade effluent requirements. Should this be required in the future you will need our written formal consent. This is in accordance with Section 118 of the Water Industry Act (1991). Used Water Budget Costs It has been assumed that the onsite used water network will be provided under a section 104 Water Industry Act application. It is recommended that you also budget for both infrastructure charges and connection costs. The 2016/17 charges are: Infrastructure Charge per connection Please note that we offer alternative types of connections depending on your needs and these costs are available in our annual charges booklet, which can be downloaded from Pre-Planning Report 4 Wednesday, 05 April 2017

75 Section 4: Map of Proposed Connection Points Connection point to manhole 1802 Figure 1: Showing your used water point of connection at manhole Connection point to manhole 1852 Figure 2: Showing your surface water point of connection at manhole Pre-Planning Report 5 Wednesday, 05 April 2017

76 Section 5: Useful Information Water Water Industry Act Key Water Sections: Section 41: This provides you with the right to requisition a new water main for domestic purposes to connect your site to the public water network. Section 45: This provides you with the right to have a connection for domestic purposes from a building or part of a building to the public water main. Section 51A: This provides you with the right to provide the water main or service connection yourself and for us to vest them into our company. Section 55: This applies where you request a supply of water for non domestic premises. Section 185: This provides you with the right to make a reasonable request to have a public water main, sewer or public lateral drain removed or altered, at your expense. Details on how to make an application and the s185 form is available on our website at or via our Developer Services team on Details on how you can make a formal application for a new water main, new connection or diversion are available on from our Developer Services team on or via our website at If you have any other queries on the rights to requisition or connect your housing to the public water and sewerage infrastructure then please contact our developer services team at: Developer Services, Anglian Water, PO Box 495, Huntingdon, PE29 6YY or Telephone: or developerservices@anglianwater.co.uk Water pressure and flow rate: The water pressure and consistency that we must meet for your site is laid out in the Water Industry Act (1991). This states that we must supply a flow rate of 9 litres per minute at a pressure of 10 metres of head to the external stop tap. If your water pressure requirements exceed this then you will need to provide and maintain any booster requirements to the development site. Self Lay of Water Mains: A list of accredited Self Lay Organisations can be found at Pre-Planning Report 6 Wednesday, 05 April 2017

77 Used Water Water Industry Act Key Used Water Sections: Section 98: This provides you with the right to requisition a new public sewer. The new public sewer can be constructed by Anglian Water on your behalf. Alternatively, you can construct the sewer yourself under section 30 of the Anglian Water Authority Act Section 102: This provides you with the right to have an existing sewerage asset vested by us. It is your responsibility to bring the infrastructure to an adoptable condition ahead of the asset being vested. Section 104: This provides you with the right to have a design technically vetted and an agreement reached that will see us adopt your assets following their satisfactory construction and connection to the public sewer. Section 106: This provides you with the right to have your constructed sewer connected to the public sewer. Section 185: This provides you with the right to have a public sewerage asset diverted. Details on how to make a formal application for a new sewer, new connection or diversion are available on our website at or via our Developer Services team on Sustainable Drainage Systems: Many existing urban drainage systems can cause problems of flooding, pollution or damage to the environment and are not resilient to climate change in the long term. Therefore our preferred method of surface water disposal is through the use of Sustainable Drainage Systems (SuDS). SuDS are a range of techniques that aim to mimic the way surface water drains in natural systems within urban areas. For more information on SuDS, please visit our website at We also recommend that you contact the Local Authority and Lead Local Flood Authority (LLFA) for the area to discuss your application. Private Sewer Transfers: Sewers and lateral drains connected to the public sewer on the 1 July 2011 transferred into Water Company ownership on the 1 October This follows the implementation of the Floods and Water Management Act (FWMA). This included sewers and lateral drains that were subject to an existing Section 104 Adoption Agreement and those that were not. There were exemptions and the main nontransferable assets were as follows: Surface water sewers and lateral drains that did not discharge to the public sewer, e.g. those that discharged to a watercourse. Foul sewers and lateral drains that discharged to a privately owned sewage treatment/collection facility. Pre-Planning Report 7 Wednesday, 05 April 2017

78 Pumping stations and rising mains will transfer between 1 October 2011 and 1 October The implementation of Section 42 of the FWMA will ensure that future private sewers will not be created. It is anticipated that all new sewer applications will need to have an approved section 104 application ahead of a section 106 connection. Encroachment: Anglian Water operates a risk based approach to development encroaching close to our used water infrastructure. We assess the issue of encroachment if you are planning to build within 400 metres of a water recycling centre or, within 15 metres to 100 metres of a pumping station. We have more information available on our website at Locating our assets: Maps detailing the location of our water and used water infrastructure including both underground assets and above ground assets such as pumping stations and recycling centres are available from All requests from members of the public or non-statutory bodies for maps showing the location of our assets will be subject to an appropriate administrative charge. We have more information on our website at: Summary of charges: A summary of this year s water and used water connection and infrastructure charges can be found at Disclaimer: The information provided within this report is based on the best data currently recorded, recorded within the last 12 months or provided by a third party. The position must be regarded as approximate. If there is further development in the area or for other reasons the position may change. The accuracy of this report is therefore not guaranteed and does not obviate the need to make additional appropriate searches, inspections and enquiries. You are advised therefore to renew your enquiry should there be a delay in submitting your application for water supply/sewer connection to re-confirm the situation. Any cost calculations provided within the report are estimated only and may be subject to change. The responses made in this report are based on the presumption that your proposed development obtains planning permission. Whilst this report has been prepared to help assess the viability of your proposal, it must not be considered in isolation. Anglian Water supports the plan led approach to sustainable development that is set out in the National Planning Policy Framework (NPPF). As a spatial planning statutory consultee, we assist planning authorities in the preparation of a sustainable local plan on the basis of capacity within our water and water recycling (formerly referred to as wastewater) infrastructure. Consequently, any infrastructure needs identified in this report must only be considered in Pre-Planning Report 8 Wednesday, 05 April 2017

79 the context of up to date, adopted or emerging local plans. Where local plans are absent, silent or out of date these needs should be considered against the definition of sustainability set out in the NPPF as a whole. No liability whatsoever including liability for negligence is accepted by Anglian Water Services Limited for any error or inaccuracy or omission including the failure to accurately record or record at all, the location of any water main, discharge pipe, sewer, or drain or disposal main or any item of apparatus. Pre-Planning Report 9 Wednesday, 05 April 2017

80 Appendix F Flood Response Plan

81 FLOOD RESPONSE PLAN 121 NESS ROAD, SHOEBURYNESS MARCH 2017 SAFE ACCESS AND EGRESS ROUTES The below diagrams outline safe access and egress routes in the event of a flood at 121 Ness Road, Shoeburyness. Details of Environment Agency Flood Warnings and Emergency contact details are provided overleaf. PLEASE NOTE THAT PRIOR TO OR DURING A FLOOD EVENT, THE INFORMATION IN THIS PLAN SHOULD BE SUPERSEDED BY ANY ADVICE OR INSTRUCTIONS DISSEMINATED BY EMERGENCY SERVICES. 121 NESS ROAD - OFF SITE EVACUATION ROUTE Legend Development site outline Proposed Evacuation Route Crown copyright and database right 2017 OS ENVIRONMENT AGENCY FLOOD ZONES & LOCATION OF EMERGENCY SERVICES Legend Development site location Main Rivers Areas Benefiting from Defence Flood Storage Area Flood Zone 3 Flood Zone 2 Flood Zone 1 Environment Agency copyright and database rights Ordnance Survey Crown copyright. All rights reserved. Environment Agency, ENVIRONMENT AGENCY FLOOD WARNING CODES The Environment Agency operates three levels of flood warnings as summarised below: FLOOD ALERT FLOOD WARNING SEVERE FLOOD WARNING Flooding is possible be Flooding is expected. Severe flooding. Danger to life. prepared. Act Now. Action Needed. EMERGENCY KIT This is a useful bag that is packed with essentials in case you need to evacuate your home. It should be stored somewhere you can easily get to. Handy things to keep in your grab bag include: A list of useful telephone numbers (local authority, insurance company, family and friends, Corgi registered gas engineer and trained electrician). Mobile phone charger. Spare home and car keys. Toiletries, sanitary supplies. First-aid kit. Any essential medication, or details of your prescription. A wind-up or battery-operated radio with spare batteries. Torch with spare batteries. Cash and credit cards. Spare clothes and blankets. Sensible flat shoes. Bottled water. A stock of non-perishable snack items. Essential items for babies or pets. If asked by the emergency services to leave your home, please do so as quickly and calmly as possible. If you have time, turn off electricity, gas, and water supplies, unplug appliances, and lock all windows and doors. Take your grab bag with you. An offsite refuge centre will be confirmed by emergency services. ANNUAL REVIEW OF PLAN Check the management team and contacts lists and update details if necessary; Contact the Environment Agency Floodline Service to check that the flood risk to the Site has not changed; Check if the evacuation procedures are still correct; Undertake Flood Evacuation exercise; Check the flood emergency kit.

82 FLOOD RESPONSE PLAN SHOEBURY GARRISON, SHOEBURYNESS AUGUST 2013 DRAFT ISSUE. Agency EMERGENCY CONTACT NUMBERS: Number Environment Agency Flood Warnings Direct Southend-on-Sea Borough Council Customer Service Centre (24 hours) Police, Fire Brigade, Ambulance 999 or 112 National Grid Gas Emergency Service UK Power Networks Essex and Suffolk Water * Contacts provided need to be updated regularly by residents, management team and Emergency Planning Manager. Tune into a local radio station. Visit the Environment Agency flood warnings website (Flood warning (RSS) feeds are also available that show national and regional flood warnings in force and are updated every 15 minutes). Monitor local television broadcasts (You can also view the latest warnings on Digital Ceefax page 405) IF THERE IS A DANGER TO LIFE ALWAYS DIAL 999 OR 112 AND ASK FOR THE APPROPRIATE EMERGENCY SERVICE.

83 Appendix G Existing Runoff Rate Calculations

84 Ness Road, Shoebury 27 February 2017 Existing Surface Water Runoff - Modified Rational Method Existing site information: Site Boundary Area (Ha): 0.09 Impermeable Area (Ha): 0.01 Modified Rational Method Equation: Q n = 2.78 CiA where: C i n A Q n Runoff Coefficients (in this case 1 as using impermeable area) Rainfall Intensity for n return period (mm/hr) Impermeable Area (Ha) Runoff for n return period (l/s) Rainfall Intensity: The rainfall intensities for various return periods were extracted from Table 1(a) of the Transport and Road Research Laboratory Report - Estimated rainfall for drainage calculations in the United Kingdom (TRRL Report LR 595) by C. P. Young. for the 5 min duration. i 1 i 30 i mm/hr mm/hr mm/hr Existing Surface Water Runoff: Therefore: Q 1 = 2.78 x 1 x 50.8 x 0.226= Q 30 = 2.78 x 1 x x = Q 100 = 2.78 x 1 x x = 1.41 l/s 3.14 l/s 4.00 l/s

85 Appendix H Post Development Runoff Calculations

86 Ardent Consulting Engineers Page 1 Suite 207 One Alie Street London E1 8DE Date 30/03/ :44 Designed by JEaston File Ness Road - P... Checked by Micro Drainage Source Control Summary of Results for 100 year Return Period (+40%) Half Drain Time : 148 minutes. Storm Event Max Level (m) Max Depth (m) Max Infiltration (l/s) Max Control (l/s) Max Σ Outflow (l/s) Max Volume (m³) Status 15 min Summer Flood Risk 30 min Summer Flood Risk 60 min Summer Flood Risk 120 min Summer Flood Risk 180 min Summer Flood Risk 240 min Summer Flood Risk 360 min Summer Flood Risk 480 min Summer Flood Risk 600 min Summer Flood Risk 720 min Summer Flood Risk 960 min Summer Flood Risk 1440 min Summer Flood Risk 2160 min Summer Flood Risk 2880 min Summer Flood Risk 4320 min Summer O K 5760 min Summer O K 7200 min Summer O K 8640 min Summer O K Storm Event Rain (mm/hr) Flooded Volume (m³) Discharge Volume (m³) Time-Peak (mins) 15 min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer min Summer XP Solutions

87 Ardent Consulting Engineers Page 2 Suite 207 One Alie Street London E1 8DE Date 30/03/ :44 Designed by JEaston File Ness Road - P... Checked by Micro Drainage Source Control Summary of Results for 100 year Return Period (+40%) Storm Event Max Level (m) Max Depth (m) Max Infiltration (l/s) Max Control (l/s) Max Σ Outflow (l/s) Max Volume (m³) Status min Summer O K 15 min Winter Flood Risk 30 min Winter Flood Risk 60 min Winter Flood Risk 120 min Winter Flood Risk 180 min Winter Flood Risk 240 min Winter Flood Risk 360 min Winter Flood Risk 480 min Winter Flood Risk 600 min Winter Flood Risk 720 min Winter Flood Risk 960 min Winter Flood Risk 1440 min Winter Flood Risk 2160 min Winter O K 2880 min Winter O K 4320 min Winter O K 5760 min Winter O K 7200 min Winter O K 8640 min Winter O K Storm Event Rain (mm/hr) Flooded Volume (m³) Discharge Volume (m³) Time-Peak (mins) min Summer min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter min Winter XP Solutions

88 Ardent Consulting Engineers Page 3 Suite 207 One Alie Street London E1 8DE Date 30/03/ :44 Designed by JEaston File Ness Road - P... Checked by Micro Drainage Source Control Summary of Results for 100 year Return Period (+40%) Storm Event Max Level (m) Max Depth (m) Max Infiltration (l/s) Max Control (l/s) Max Σ Outflow (l/s) Max Volume (m³) Status min Winter O K Storm Event Rain (mm/hr) Flooded Volume (m³) Discharge Volume (m³) Time-Peak (mins) min Winter XP Solutions

89 Ardent Consulting Engineers Page 4 Suite 207 One Alie Street London E1 8DE Date 30/03/ :44 Designed by JEaston File Ness Road - P... Checked by Micro Drainage Source Control Rainfall Details Rainfall Model FSR Winter Storms Yes Return Period (years) 100 Cv (Summer) Region England and Wales Cv (Winter) M5-60 (mm) Shortest Storm (mins) 15 Ratio R Longest Storm (mins) Summer Storms Yes Climate Change % +40 Time Area Diagram Total Area (ha) Time From: (mins) To: Area (ha) XP Solutions

90 Ardent Consulting Engineers Page 5 Suite 207 One Alie Street London E1 8DE Date 30/03/ :44 Designed by JEaston File Ness Road - P... Checked by Micro Drainage Source Control Model Details Storage is Online Cover Level (m) Porous Car Park Structure Infiltration Coefficient Base (m/hr) Width (m) 10.0 Membrane Percolation (mm/hr) 1000 Length (m) 10.0 Max Percolation (l/s) 27.8 Slope (1:X) 40.0 Safety Factor 2.0 Depression Storage (mm) 5 Porosity 0.95 Evaporation (mm/day) 3 Invert Level (m) Membrane Depth (m) 0 Hydro-Brake Optimum Outflow Control Unit Reference MD-SHE Design Head (m) Design Flow (l/s) 1.4 Flush-Flo Calculated Objective Minimise upstream storage Application Surface Sump Available Yes Diameter (mm) 64 Invert Level (m) Minimum Outlet Pipe Diameter (mm) 100 Suggested Manhole Diameter (mm) 1200 Control Points Head (m) Flow (l/s) Control Points Head (m) Flow (l/s) Design Point (Calculated) Kick-Flo Flush-Flo Mean Flow over Head Range The hydrological calculations have been based on the Head/Discharge relationship for the Hydro-Brake Optimum as specified. Should another type of control device other than a Hydro-Brake Optimum be utilised then these storage routing calculations will be invalidated Depth (m) Flow (l/s) Depth (m) Flow (l/s) Depth (m) Flow (l/s) Depth (m) Flow (l/s) XP Solutions

91 Appendix I Indicative Drainage Layout

92 N grass paving 5.37 ST cl= ANGLIAN WATER 5.30 MANHOLE REF CL 5.49 IL TOW gutter = 7.68 ridge = NOTES : 1. PROPOSED LAYOUT IS BASED ON DRAWING REF: 1800/01 REV A, DATED RECEIVED FROM D.J.W ARCHITECTURAL DESIGNS LTD. 2. DRAWING BASED ON TOPOGRAPHICAL SURVEY REF: BY INTERLOCK SURVEYS LTD DATED ALL LEVELS ARE IN METRES ABOVE ORDNANCE DATUM AND DIAMETERS ARE IN MILLIMETRES UNLESS OTHERWISE STATED. 4. THE SURFACE WATER DISCHARGE RATE FROM THE SITE HAS BEEN RESTRICTED TO 2.0 L/S UP TO THE 1 IN 100 YEAR EVENT + 40% FOR CLIMATE CHANGE grass FH grass TP mm Ø N E S S R O A D LP bitumen LINED PERMAVOID PAVING WITH 0.15m DEEP SUB-BASE bitumen grass 1:113 SV CTV TOF CL 5.00 IL 4.33 PROPOSED SADDLE CONNECTION IL 4.25 TBC grass TOF 6.63 bitumen 1: grass ST shed ST : CL 5.00 IL CL IL 4.50 TOF TOF TOF 4.58 TOF DP FL DP roof level= DP DPGU 4.40 FFL: gutter = DP FFL: 5.00 CR TOW 6.58 DP TOW 4.90 TOW ST TOF TOF TOF TOF 4.25 TOF grass grass ST TOF THE LOCATIONS OF EXISTING CONNECTIONS TO SURFACE WATER SEWERS SHOULD BE CONFIRMED ON SITE BY CCTV DRAINAGE SURVEY. 6. ALL EXISTING LEVELS TO BE CONFIRMED ON SITE. LEGEND SURFACE WATER SEWER SURFACE WATER MANHOLE / INSPECTION CHAMBER SURFACE WATER FLOW CONTROL CHAMBER LINED PERMAVOID PAVING (95% VOID RATIO) ANGLIAN WATER SURFACE WATER SEWER ANGLIAN WATER FOUL WATER SEWER FOR INFORMATION ONLY 5.45 Rev Description Drn Chk App Date ARDENT CONSULTING ENGINEERS Suite 207 One Alie Street London E1 8DE Tel: Fax: Web: enquiries@ardent-ce.co.uk Client MAUREEN SMITH abcdee Project Title: Drawing Title: 121 NESS ROAD, SHOEBURY SOUTHEND-ON-SEA INDICATIVE DRAINAGE STRATEGY TYPICAL LINED PERMAVOID PAVING CROSS-SECTION DETAIL (POLYPIPE PRODUCT) Reproduced from/based upon Ordnance Survey material with the permission of the Controller of Her Majesty's Stationary Office, Crown Copyright Reserved. License No user name: dominic ramdeen A3 Scale Date Designed by 1: JE Drawn by Checked by Approved by JE CC JD Drawing Number File Location: y:\ardent projects\ ness road, shoebury\technical\acad\drawings\ indicative drainage strategy.dwg Rev