Failures of Betts Hydro Flood Assessment

Background To This Article

The Rossett Focus Group and local residents have continuing concerns regarding the Castle Green Homes Development in Rossett. We are alarmed by the proposals to raise site levels and to introduce bunds around the existing site. This article has been produced as a result of the multiple concerns being expressed by local residents who live adjacent to both parcels of land and their general view is that Betts Hydro have totally failed to understand how and whence the Rossett flooding emanates. There is great concern that flooding to local properties will be drastically increased by Betts proposals, and the down-stream flooding already being experienced in Darland & Lavister will be made much worse by the  plan to export flood exceedance into the Darland School ditch. We have been in direct contact with Betts Hydro regarding historical information and they have paid as much heed to our communication as they have paid to NRW’s comments on the FCA (Flood Consequences Assessment) and Hydraulic modelling.

The current FCA is Betts Hydro fifth attempt at producing a solution to the flooding issues for Castle Green Homes. Bellis Brothers the former owners of the land previously commissioned Waterco back in 2018 to produce an FCA, but following their infiltration tests on the fields they clearly failed to provide a suitable SuDs solution.

This article refers to the Reserved Matters Planning Applications P/2021/0110 & P/2021/0111 for Residential Development of Two Parcels of Land Located North & South of Lane Farm Rossett Road Rossett Wrexham LL12 0DS. Outline Planning permission was given on appeal to P/2018/0560. There are 16 Conditions (Reserved Matters) placed on this planning permission by the Welsh Government Inspector and the Minister.

Increased Flooding Risk

The proposal to increase the topographic levels adjacent to the properties in Moss Green, Trevalyn Way, Trevalyn Hall View and Darland View will result in flooding to those properties if the Flood Flow Route is that predicted in Figure 5 (see below) of Betts Hydro FCA (see Hydraulic Modelling Assessment – Appendix I) . The existing topographic level of a property in Trevalyn Way is 13.09mAOD. The Castle Green site level is to be raised at a point running alongside this property and the other properties in Moss Green to at least 13.50mAOD.

At present should the River Alyn flood from the direction being suggested by Betts, the flood water can flow in the locations as suggested in Betts Hydro Figure 5 below but if the topographic (site) level is raised by the levels recommended by Betts the Bungalows in Trevalyn Way and Moss Green will be flooded, e.g., a typical Trevalyn Way bungalow has a Finished Floor Level of 13.24mAOD and can expect internal flooding to a depth of 260mm before the Castle Green raised site levels experience any flooding runoff from the predicted direction.

In addition to the bungalows referred to above, there will be a greater risk of flooding to the lower even number properties in Trevalyn Way and those odd numbered properties back towards Eaton Close as the topographic levels of the gardens are lower than the increased site levels being proposed by Betts Hydro. This worsening of the flood risk situation on the properties adjacent to the Southern Parcel of Land is completely unacceptable and contravenes the provisions of TAN15 Section 8.3 by potentially worsening the existing situation. 

Hydraulic Modelling Assessment (Appendix I) – Figure 5

Hydraulic Modelling Failures

It is quite clear from even the limited hydraulic modelling work undertaken by Betts that the whole area from the proposed development site back to the Alyn Road Bridge B5445 is at risk from flooding. The modelling undertaken by Betts does not include any constraint of the River Dee flood waters on the River Alyn upstream of Cooks Bridge. In the last two major flooding events 1976 and 2000 the River Dee was at an extremely high level resulting in flooding of Trevalyn Meadows from Almere to a considerable distance above Cooks Bridge towards Trevalyn.

In addition, no recognition has been given in the Hydraulic Modelling to the influence of the River Dee on the flood direction from the Farm Track south of the Development Site into Harwoods Lane. In the last major river flooding event in Nov 2000 the runoff from the development site was from the southern parcel of land into Trevalyn Way and Moss Green. In the January 2021 storm event the runoff was from the northern parcel of land into Trevalyn Hall View and Darland View with flooding experienced all around Darland View with actual internal flooding to a property in Darland View. 

Betts Hydro Appendix D gives rise to question the adequacy or reliability of any of the Hydraulic Modelling and the scenarios put forward in support of the Castle Green Development Plans. Not one of the suggested scenarios listed in Appendix D reconciles with the EA Evidence Photograph No 6 (see copy below) presented to the UDP Inquiry in 2002. In the EA photograph the River Alyn flooding quite clearly enters Alyn Drive Rossett from the adjacent land not from Station Road & Alyn Road Bridge with a known flood line in the photograph of 14.53m AOD by the far lamp column on the right. 

EA Evidence Photo 6

The photograph above depicts the real event of flooding mid-afternoon on the 6th November 2000. The modelling proffered by Betts Hydro supposedly includes climate change but the predicted flood water levels do not reach, in any scenario, the flood levels recorded in this 2000 photograph which was entered as EA evidence to the UDP Inquiry.

River Dee and River Alyn Combined Effects

The hydraulic modelling  has not included any blockage at Cooks Bridge (Hydraulic modelling node Alr02d). History has shown that with the River Dee breaking its banks and flooding Trevalyn Meadows the flood levels of the Dee and the Alyn have combined at a point up stream of Cooks Bridge. This fact was confirmed at the 2002 UDP Inquiry by Mr David Goodson the EA Officer responsible for this stretch of River Alyn at that time. At no point does the FCA recognise the NRW Development Advice Map which shows the C2 floodplain actually abutting the southern parcel boundary in Harwoods Lane. 

In view of the modelling failing to reach the areas depicted above which were flooded in 2000 no reliance can be placed on any of the flooding predictions made by Betts Hydro in their FCA or in their modelling Appendices.

In view of the perceived inadequacies of the hydraulic modelling it is considered that the FCA does not properly inform the flood risks being presented by the Castle Green Development and must result in the proposed drainage strategy failing to satisfy the Discharge of Condition 7 of the Outline Planning Consent granted by the Welsh Minister.  

Unsubstantiated Assumptions

In the base data a steady state River Flow has been assumed in the modelling  above and below Cooks Bridge but this is far from the case as the flood water levels of the River Dee on Trevalyn Meadows have under extreme flooding, impeded any steady state outfall conditions on that stretch of River and places further doubts as to the Hydraulic Modelling suitability or accuracy. There have been so many unsubstantiated assumptions in the base data of the hydraulic modelling between Pont-y-Capel and Cooks Bridge that its conclusions on flood risk appear meaningless as they continue to defy comparison with reality.

This omission to carry out risk assessment of any blockages at Cooks Bridge is a failure to accord with the provisions of TAN15(2004) Paragraph A1.17.17 and should require further hydraulic modelling to be undertaken using the known flood outlines in Alyn Drive and Harwoods Lane as an absolute minimum. 

Earthwork Bunds Presents More Risk

The proposals to build earthwork bunds to protect the Northern Parcel of land will place existing properties adjacent to the development site at further risk of flooding as well as some of the new proposed adjacent terraced houses. The imposition of  bunds to the NW and E boundaries as shown in Betts Figure 5 above together with the raising of site levels along the remainder of the NW boundary will effectively create a bund with the inherent problems of restricting surface water flow on or off the site as presently occurs.

The whole essence of Betts Hydro proposal appears to be to raise the site levels above the present ground water levels to facilitate some form of SUDs ground infiltration. It is noted that the earlier infiltration tests undertaken by Waterco have been repeated in part and again there are substantial areas of the site that will not support infiltration drainage.

Sustainable Drainage (SuDs)

In paragraph 5.6.3 of Betts FCA reference is made to encountering of groundwater during infiltration testing and has the remarks that “Should groundwater be encountered during any future construction phase(s) then suitable land drainage will need to be installed to intercept groundwater flows”.  The suggested provision of suitable land drainage is unlikely to prove successful as the  southern parcel of land apparently has a system of land drainage in the areas of poor test infiltration but this has not prevented the flooding pictured during recent major storm events.

The FCA fails to acknowledge the existence of an Aquifer on the site and the required SPZ1 protection required. Proposals to raise the ground levels to artificially high levels to create some degree of infiltration should be rejected as this process is totally in contravention of WCBC Policy EC12 and EC13 and the provisions of TAN15(2004) Paragraph A1.17.13.

Landscape and Layout Errors

At no time has it been acknowledged by Betts Hydro or Castle Green Homes that the LVIA (Landscape and Visual Appraisal) produced by Ark Company Landscape Architects for Bellis Brothers, that was approved on appeal (Document APP76), limits the ridge height of all dwellings on the new development to 7.30m above topographic level to ridge.

The whole suite of houses and flats are indicated on average to be well above 8.40m from FFL (Finished Floor Level) to ridge thus the proposals to raise a number of properties by over 1.50m will compound the problem further.  The average increase in site level to FFL is 660mm, in addition to impeding flood water flow it will create a situation of significant overshadowing and overlooking when compared to the approved LVIA of 7.30m to ridge.  

The plans being used by Betts Hydro obviously follow closely those created by Castle Green Homes but the plans do not accord with the determined access plans approved by the Inspector and Welsh Minister, and the housing layout should be amended to accord with those plans and should result in a revision of the drainage layout and possible re-siting of infiltration ponds into other areas. This failure to accord with the determined plans has been communicated to the Planning Case Officer and the Developers.

History of Flooding

The Betts Hydro proposals continue to extol the virtues of discharging any exceedance from both parts of the development site into the distant ditch in the grounds of Darland High School. The existing ditch has a history of flooding to substantial areas of Darland and Lavister and the proposal to discharge exceedance from 132 dwellings into an existing flood risk area is totally unsatisfactory.

The proposal to construct simple earthwork bunds in an attempt to stem the exceedance flow or flooding to neighbouring properties is also unacceptable. The outline planning consent was given following claims by the speculator’s agent that the community claims of flooding were mischievous and that no risks from flooding existed; the recent FCA by Betts Hydro has failed to uphold these claims, it acknowledges that the development is at risk of flooding and has proposed unreasonable site level changes in mitigation bearing in mind the inadequate modelling indicated above.

Suitable SuDs Scheme Not Forthcoming

The Speculator was advised by WCBC Flood Officer prior to appeal that failure to provide a suitable SUDs scheme may result in the proposed development being changed or reduced to meet SAB requirements. To date no suitable SUDs scheme has been tabled by Betts for Castle Green Homes and the planning consent is conditional on an approved SUDs scheme. Local residents have always contended that the development site is not sustainable or deliverable on drainage & flooding grounds but this has always been dismissed by the Speculators Agent.

To date nothing that Betts Hydro has produced has altered local perceptions and evidence that the development site results in runoff flooding to the surrounding area and will if built out make the situation worse. Under the circumstances it would not be appropriate to discharge Conditions or Reserved Matters as a suitable SUDs scheme has not been approved or proposals demonstrated that long term flood risks have been properly addressed.

Flooding Evidence Ignored

In the FCA it is clear that inadequate research was undertaken regarding the flooding incidents in Rossett since 1976 leading to wrong assumptions on where and when pluvial & fluvial flooding occurs. Had a proper internet search been undertaken by this company the Rossett Focus Group (RFG) website would have shown the level of flooding that has been evident over the last 45 years.

There have been two major flood events in 1976 and 2000 with a number of lesser but important river flooding events in the 1980s, 1990s and 2020s. A video link to the 2000 event is and was provided on the website. Examination of the flooding photo gallery should have alerted the company to the inherent flood risks in the area. Any close examination of the photographs show that the company have continued with a dismissive attitude towards pluvial and fluvial flood risks and have deliberately cropped Development Advice Maps to conceal directions of flood risk or have deliberately underplayed the flooding that occurred during the January 2021 storms as evidenced by Appendix G compared with the photographic details displayed on the RFG website.

Summary of Failures

In conclusion, the aspects and comments on the FCA and drainage strategy documents have considerable discrepancies between the text and the graphical content, diagrams or figures.

The proposals do not alleviate local concerns that the flooding risks both on and off site have been properly or adequately addressed.

The overall proposal to regrade the site from Harwoods Lane down to Darland View is both unacceptable and irresponsible as it will place existing residents at greater risk of flooding, it will impede natural water flows to and from the land.

The wisdom and permanency of earth bunds to impede or to attempt to contain exceedance in both the short and longer term must be questioned as there can be no guarantee in the proposals that existing properties will not be flooded along with a number of the new houses.

The issue of the lifetime expectancy of the earth bunds and how these can be guaranteed to survive intact for the anticipated lifetime of some 80 years for the development must be considered along with the issues of climate change.

Hydraulic modelling has always included a number of assumptions regarding inflow rates, run-off  and flow between gauging points etc. but this set of modelling parameters has more unknowns than knowns and downstream estimates are all guesswork as there is no downstream monitoring below the Alyn Road Bridge or the Castle Green Development site.

Confidence that the FCA properly informs on the flooding risks to the Castle Green Development site(s) has not been demonstrated by the latest version and that the Drainage Strategy built upon a deficient FCA should be rejected.

With all the above unsatisfactory issues the Betts Hydro FCA and Drainage Strategy fails to satisfy both the national and local policies on flood risk and SUDs and will result in increased flooding risks in the surrounding areas.

We place this here as Wrexham Council hide all objection documents from the public, which means no residents can see what other residents are objecting about and how many objections that are being presented, also there is no means to check that your objection has actually been read and placed on file.

Objection Document on Behalf of Rossett Focus Group

Background: The Rossett Focus Group was formed in 2017 by a group of 8 residents to fight any planning application that would harm the sustainability of our village. We have put up strong cases to have the Bellis fields removed from the Wrexham LDP and the subsequent planning applications by the Bellis’. The planning application was rejected by the Council Planning Committee but was subsequently overturned on appeal by Minister Julie James. The decision was made by the Minister Julie James on the 14th February 2020 after considering the report of the Inspector and without herself reviewing any of the evidence neither does it appear did her Chief Planning Officer who certified that these 2 sites were sustainable. We still await a decision by the Inspectors on the drawn out Wrexham LDP submission.

The WG Planning Inspector placed 16 Conditions on the Outline Planning Permission together with recommending the defective pavement; the conditions are known as Reserved Matters. Some of these conditions prevent any construction works taking place until certain reserved matters have been approved. In some cases the Planning Officer in Wrexham has delegated powers to approve reserved matters without consulting the Planning Committee!

Below is a copy of the contents of a recent objection document submitted to the Council by the Rossett Focus Group. We refer to numerous other documents that are too large to display here but can be found on the WCBC planning portal, the LDP portal and WG TANs.

We place this here as Wrexham Council hide all objection documents from the public, which means no residents can see what other residents are objecting about and how many objections that are being presented, also there is no means to check that your objection has actually been read and placed on file.

Objection to Reserved Matters Planning Application P/2021/0110 & P/2021/0111 For Residential Development of Two Parcels of Land Located North & South of Lane Farm Rossett Road Rossett Wrexham LL12 0DS

A. Introduction: The applications P/2021/0110 & P/2021/0111 continue to be inextricably linked in the way the Reserved Matters and Discharge of Conditions have been placed on the WCBC Planning Portal the following Objection is based on both the confusing and repetitive manner the details are displayed. The new suite of plans submitted by or on behalf of Castle Green Homes has not clarified the original position and a number of the documents placed on the Planning Portal show that the development although having the principle of development established at appeal does not satisfy the Conditions imposed on appeal and should be refused. It is considered that due to the intertwining of these two files the whole matter should be referred back for decision in spite of Officer Claims that they have full delegated powers to decide the Application.

A1. It is evidently clear that in purely objective terms, that many of the conditions have not been satisfied by this new suite of plans. The contraventions to the conditions are there for all to see and are incontrovertible. The 14day consultation period along with the proliferation of information may unfortunately have ruled out many who may have wished to object. It is important that the Borough Council and Planning Department acts with transparency and integrity on behalf of its Members and Electorate on this matter.

A2 We will go on to highlight those areas of particular concern in order to assist identification of those matters capable of resolution and those that are not. Attention is drawn to the use of Alphabetic Paragraph Identifiers for the avoidance of confusion as the paragraph content invariably covers Appeal Condition numbers. 

B. General Comment on whether the development can proceed on riverine Special Area of Conservation (SAC)

B1. As advised previously the application site is within the catchment of the River Dee and Bala Lake Special Area of Conservation (SAC). On the 21st January 2021, NRW published an evidence package outlining phosphate levels for all river SACs across Wales as well As part of this package, they issued a planning position statement – River SAC Compliance. It is clear that no HRA has yet been undertaken to demonstrate that this and other sites can be accommodated by the Welsh Water Lavister Treatment Works as a result WCBC should not be granting any new development approvals either outline or discharge of drainage under reserved matters until an appropriate HRA is in position and it has agreed by NRW and Welsh Water.

This objection relates to the above Reserved Matters and Discharge of Conditions Application on the following grounds: 

C. Condition 1

C1. The access points on the recently submitted suite of plans still do not accord with the determined plans. The whole of the housing types do not meet the scale in relation to height as approved in the Landscape Visual Impact Assessment (LVIA). The approved LVIA set the maximum height to ridge at 7.30m above the existing topographic levels. The situation regarding the height of ridges has increased substantially with the submission of the new suite of drawings. The latest set of proposals include the uplift of the site topographic levels by an average of 600mm according to Betts Hydro and then to construct roadways and buildings another 450mm above that just to avoid conflict with the high ground water levels experienced on this farmland. This proposal if implemented will result in a development that exceeds the approved and endorsed LVIA by a considerable margin and will exceed the approved scale and overshadow the adjacent existing properties. It will be visible in the countryside for an even greater distance than claimed in the LVIA or in the Appeal.  None of the house or apartment types satisfy the limited height criteria and condition discharge should be refused on the grounds of scale.

C2. As pointed out before, the commissioned original Kingdom Ecology Report (2016) now adopted by Castle Green Homes is long expired and the earlier report also by Kingdom Ecology is now about two years old. An up to-date Ecology Report is now required to demonstrate that the Ecology changes that have occurred over the last 2 years have been properly taken into account as required by WCBC LPG 32 Bio-diversity and Development.

C3. Notwithstanding the age of the first Ecology Report now being entered by Castle Green it is clear that the requirements to protect all of the Trees are still not being observed and that tree No 2 in the centre of the Northern parcel is not shown protected on the latest Castle Green Layout Plan. The Kingdom Report identifies the value of Tree No 2 to the invertebrates, birds, mammals and other associated ecological groups but this 70year-old alder tree is not retained on the latest submitted layout plan.

C4. In addition, the Ecology Report identifies the existing hedgerows act as wildlife corridors, these are being removed in great sections although their value was recorded in the Ecology Report. From the submitted proposals it is clear that the Ecology Reports are being ignored and that the Reserved Matter Application should be refused as the revised layout still does not accord with the Applicants Ecology advice nor the requirements of WCBC LPG 32 Bio-diversity and Development.

D. Condition 2

D1. Affordable Housing, a formal objection was lodged to the earlier layout and the new suite of plans are no better in this regard.  The revised layout and affordable property types still conflicts with WCBC Local Planning Guidance Note 28 on the grounds that the affordable houses which are terraced properties are in blocks of between 3 and 4 and not visually integrated into the development in terms of design and site layout. In addition, they should be  distributed throughout a development and not result in all of the affordable housing being concentrated in substantial parts of the site. In this latter context although the affordable houses have been split into a number of groups it is evident that they are the affordable houses and they will not satisfy the design requirement to be visually integrated into the development and the Discharge of this Condition should therefore be refused.

D2. Questions are also raised as to whether the parking provisions in the context of affordable housing actually complies with LPG 16 for C3 dwellings. A number of 2-person 1 bed flats are shown on the revised plans and several of these do not accord with LPG16 parking provision as 1.5 parking spaces have not been provided throughout. Many other properties are at least 2 bedrooms and some are 3 bedrooms, the layout Plan does not show adequate provision in many locations for what appears necessary for the designated types of houses. Turning now to the remainder of the larger house types there would still not appear to be adequate provision of parking as all the larger properties are 3/4 bed houses which require 3 parking spaces per property. Following through the numbered parking spaces the provision of spaces does not accord with LPG 16 and should be accordingly refused as an unacceptable layout plan. As there appears to be a shortfall of 73 parking spaces on a development requiring 365 or thereabouts then there is a 20% shortfall in provision. As parking spaces are an essential  spatial planning element the layouts being offered should be refused as they are unsatisfactory in this parking requirement, correction of which will impact on the layout of numerous properties so the scheme cannot be discharged in relation to Condition 1. The issue of ridge heights needs  to be addressed as part of the layout of types, location and height revisions.

D3. As far as the provision of any affordable homes is concerned there is a major question if any will actually be provided on this development bearing in mind the  £10,600,000 paid for the site thus the viability of the development to provide 35 affordable dwellings is questioned. It would be expected that upon discharge of Conditions or Reserved Matters the Developer will apply for a change of consents to remove any affordable houses from the scheme on grounds of viability. It is evident from the DVS Report LDP Ref EBH02b that the site cannot  be deemed viable and cannot provide the level of affordable houses set out in the planning approval bearing in mind that the developer has paid over 5.7 times the DVS viability guidance for Rural East Wrexham.  The situation regarding 0% affordable houses at the Air Products Site at Acrefair is cited as an example together recent application from Glyndwr University to vary 410 apartments to 90  detached Houses reducing the affordable houses from 102 to 22. Much play has been made of the LDP to the justification of this site against multiple WCBC UDP policies but the viability of this site does not accord with the DVS Viability Guidance (September 2019) in the LDP placing any affordable development on the site in doubt. The viability of this site appears to conflict substantially with LDP Policy SP1 paragraphs a) and b) and certainly does not accord with EBH02b on the viability of Wrexham Rural East.

E. Condition 5

E1. Southern Parcel of Land: The access proposed does not comply with Approved Plans Pinc-100 -37 SMPA-01 and should be rejected. The latest Castle Green Plan on the southern parcel of land again shows two access points into Trevalyn Way contrary to the requirements of approved Plan Pinc-100 -37 SMPA-01. (Master Plan Access). Neither of these access points can be allowed as the land that Castle Green wishes to cross is in private ownership and permission is not being granted to gain access to Trevalyn Way.
This item will be dealt with further in Condition 9 below.

E2. Northern Parcel of Land: As advised previously, the access point shown on approved Plan Pinc-100 -37 SMPA01 (Master Plan Access) cannot be developed as the triangle of land showing the entrance adjacent to No 1 Trevalyn hall View is not in the ownership of Castle Green Homes. The location of this access and the proposed parking layout will if developed infringe the access rights and impede the access to the garage of No 1 Trevalyn Hall View. In view of this triangle of land not being in the ownership of Castle Green Homes this access cannot be built without infringing the rights of adjacent occupiers it results in the objection to this access condition being discharged. This item will be dealt with further in Condition 9 below. It is noted that the latest plans show an electricity substation located immediately adjacent to the front of Number 1 & 2 Trevalyn Hall View, the placement of the substation at this location within a close distance of the footway fronting these two residential properties is an unacceptable location and must be resited if development is to proceed.

F. Condition 6

F1.Turning now to Ascerta Arboricultural Plan P.1416.20.03 Rev B Tree reference H4 – A mature Holly Hedge which  is not in the ownership of the developer nor is the land upon which it stands. Other than pruning to the proposed side of the Development the hedging cannot be interfered with or cut through to provide any form of access (See Ref to planned work to H4 on Page 12) . The Arboricultural Plan does not accord with the determined plans regarding access, neither do any of the layout plans submitted by Castle Green, Eddison’s or Betts Hydro.

F2. The layout plan again submitted by Ascerta is still wrong in that the 3 trees shown in Trevalyn Way are still in the wrong place not located in the rear garden of 21 Trevalyn Way as shown on plan P.1416.20.03 Rev B but actually in Trevalyn Way itself on privately owned land. It does not inspire confidence in the ability of the “Arboricultural Expert” when a simple routine of plotting the location of large existing trees cannot be carried out correctly. Other than pruning to the development side of the boundary these trees should not be interfered with. Should any attempt be made to cut through this privately owned boundary hedging this will be treated as an act of vandalism and reported to the Police. This hedging is located on land over which the developer has no control and is outside the determined red line plan Pinc-100-37-RLP-01 and the determined access plan Pinc100-37-SMPA-01. No approval has been or will be given to anyone to interfere with this hedging or trees in Trevalyn Way.

F3. Tree Reference H5 – Holly Hedge again is not in the ownership of the developer nor is the land upon which it stands. Other than pruning to the side of the proposed Development the hedging cannot be interfered with.

G. Condition 7

G1. The Flood Consequence Analysis is flawed and cannot be accepted as representing a satisfactory position for the Application. The layout plan on which the FCA is based bears no relation to the determined plan on the southern site. NRW have criticised the FCA and the proposal to flood areas off site in contravention and advised that this Discharge of this Condition be refused. The conclusions that the development site has little or no risk of flooding based on Tan 15 Development Advice Maps is totally wrong. The most recent site flooding event occurred in January 2021 resulting in substantial run-off into the areas of Trevalyn Hall View and Darland View in addition to considerable standing water in both southern and northern parcels of land. Betts Hydro and NRW have been advised of the flaws in the submitted Hydraulic Modelling based on earlier Environmental Agency Wales evidence. This objection to the latest proposed Drainage Strategy builds upon the previous objections submitted regarding the Preliminary Drainage Proposals. 

G2. The information submitted by Betts Hydro continues to base its proposals on building up the general site levels to attempt to use the uplift of levels to permit some form of SUDs infiltration. The ground  water table on both the northern & southern parcels has always been very high and the Water infiltration trial pits were excavated in October 2020 at the end of a long dry spell giving a false representation of typical water table levels. In order to avoid the high water tables the drainage proposal requires a site uplift on average of 600mm on top of which will be constructed roads and foundations that will be uplifted by a further 450mm resulting in a ground level over 1.0m higher than the existing topographic levels. The drainage strategy proposal although marked preliminary contravenes WCBC Policy EC12 and EC13 and will increase runoff into the surrounding areas.  

G3. Betts Hydro have already been advised that their Hydraulic Modelling peak flood water predictions do not reflect the evidence submitted by The Environmental Agency Wales (forerunner to NRW) to the UDP Inquiry on 2002 that showed the flood levels way above the current modelling. In addition, the proposal to discharge exceedance to the ditch in the grounds of Darland School is totally irresponsible as the areas of Trevalyn Hall View, Darland View, Darland School and substantial areas of Darland and Lavister are already subject to regular flooding. These proposals will make matters markedly worse. 

G4. The original Betts Hydro FCA is still being displayed and attempts to deliberately mislead as the walk-through photographs displayed in Appendix G were taken on the 22nd January 2021 two days after the River Alyn peaked at 2.337m above normal at the Rossett Alyn Bridge monitoring station. The peak occurred on the 20th January 2021. Photographs showing the actual flooding conditions form part of our earlier objection and are not repeated here. The Betts FCA has introduced the latest NRW 2021 flood mapping but the way in which this is being displayed seeks to marginalise the flooding risks to the whole of the development.  

G5. NRW have advised that the Development is now regarded on the 2021 flood mapping (to be issued shortly) as an undefended Zone 2 area with an anticipated peak flood level of 13.60m AOD. This peak flood level is above the levels of the surrounding fields and the majority of the development site without the present unacceptable metre plus site uplift. It is against this background of flood risk that the FCA still proposes the re-grading of the development site levels and constructing dwellings with a finished ground floor level way above the existing topographic levels. As stated previously If re-grading of the site is undertaken to direct exceedance away from these new properties the run-off will be directed towards existing housing which is contrary to Tan 15, EC12 & EC13.   

G6. The statement in the FCA statement page 29 paragraph 6.6 “underlying ground conditions, which in this case are highly permeable” flies totally in the face of the findings of the Preliminary Drainage Strategy which recognises in the infiltration tests that there were significant areas of underlying clay where soakaway infiltration by SUDs would not work, hence building up the site to build clear of the ground water levels.  

G7. The Preliminary Drainage Strategy indicates that mitigation measures of site regrading and building the properties further out of the ground quite clearly shows that the FCA regards the development at risk from the unprotected Zone 2 flood plain. In addition, the planning proposal to cut an access through the hedgerow onto Harwoods Lane agreed by NRW as part of a C2 floodplain (now Zone 3) will increase the flood risk on the site. Proposals to protect the aquifer to which the Welsh Water condition applies, still contains no mention of this valuable water supply and how it  must be protected from contamination. 

G8. So far there has been no apparent submission of a SUDs application so that this condition cannot be discharged. The Preliminary Drainage Strategy recommends further ground condition  testing before a scheme is finalised. In view of the fact that the scale of the dwellings is limited by the LVIA the BETTS Site Uplift (Regrading) Proposals cannot be accommodated by the limit of the LVIA to 7.30m to ridge. 

G9. It is against this background that Condition 7 Preliminary Drainage Strategy should be rejected and the development Reserved Matters be refused.  

G10. Please Note:  An Appendix was submitted with the earlier objection contains an extract from the flooding evidence document submitted in respect of the Bellis Application P/2018/0560 together with new material that has become available since that Application was made in 2018. The appended information to that objection was submitted as it is extremely relevant as Tan 15 Appendix 1 provides for such evidence to be considered in connection with the Technical Requirements for assessing flood consequences. This document is what NRW describes as anecdotal evidence to defend their admitted lack of evidence on the 2000 and 1976 flood incidents. Since the submission of that Appendix additional original evidence which was provided by the Environmental Agency Wales  has demonstrated that the NRW inspired Betts Hydraulic modelling predicted water levels are flawed and that confidence levels on safe river flood levels have not been satisfactorily illustrated.

H. Condition 8

H1. Reference has already been made above in Condition 5 above that the access adjacent to No I Trevalyn Hall View should not be constructed due to the land being outside the ownership of Castle Green Homes. The requirement for the provision of a pedestrian footway along the south side of Holt Road is a condition that will result in a footway that fails to comply with PPW11 and the section on Active Travel Paragraph 4.1.28 Statutory Design Guidance, the Manual for Streets, the WG Active Travel Guidance 2013 or Active Mobility. This failure to comply with the necessary safety standards has now been confirmed by the Developers Agent Eddison’s who have submitted a Road Safety Audit confirming the footway provision as unsafe on a number of counts. The Welsh Minister required the footway Condition 8.3 to meet the requirements of UDP Policy GDP1(d) GDP1(e) but the road safety audit confirms that this is not likely. This safety failure has long been claimed by residents and a Highways Consultant for the last 2 years and has at last been vindicated by the Developers Road Safety Audit. 

 H2. As advised previously, this footway proposal therefore dis-advantages persons with protected characteristics and it understood that the Equality Commission have again written recently in June 2021 to  WCBC about its Duty of Care under the Equality Act 2010. We re-iterate that under such circumstances prosecution of the Council would be most likely either by the Equality Commission or by private action should this footway be altered in a way that does not meet the Mandatory Conditions of PPW11 and the Manual for Streets. As advised in correspondence forwarded to WCBC Highways Officer the Appeal Inspector or the WG Minister cannot instruct WCBC to ignore the Equalities Act 2010 or break the Equality Law. Only recently WCBC Highways Officer has advised that the footway proposals are not in line with best practice so that there is now universal agreement from the Developers Road Safety Audit and the objectors that this footway proposal is totally unsafe and should be refused under Condition 8.3 & 9.3 in failure to comply with GDP1(d) and GDP1(e). 

H3. As a result of this key item 3) in Condition 8 that cannot or should not be implemented without legal repercussions ensuing is such that the Reserved Matter Condition 8 cannot be fully complied with.

J. Condition 9

J1. Reference has been made above in Condition 5 above that the access points into Trevalyn Way cannot be constructed as these will cross land which is not owned by Castle Green Homes. 

J2. In addition, we reiterate the above comments in Condition 8 regarding the requirement for the provision of a pedestrian footway along the south side of Holt Road, as this is a similar condition that will result in a footway that fails to comply with PPW11 and the section on Active Travel Paragraph 4.1.28 Statutory Design Guidance and has now not surprisingly failed a Road Safety Audit. 

J3. Again, as a result of these two key items 2) and 3) in Condition 9 that cannot or should not be implemented without legal repercussions ensuing. As such the Reserved Matter Condition 9 cannot be fully complied with and the development should be refused notwithstanding the principle of development having being decided by an Inspector and the Welsh Minister. 

K. Condition 10.5

K1. Construction Management Plan : Hours of Working. A formal objection is lodged regarding the working hours being requested for this development especially on a Saturday. It is normal practice to limit Saturday Working until 1300 hours so that in accordance with normal practice, working times until 2-00pm in the afternoon should not be permitted as the construction work can and will often be in close proximity to existing adjacent houses. 
Normal construction industry site work times are as follows.
Monday – Friday 8.00 am – 6.00 pm 
Saturday 8.00 am – 1.00 pm 
Sunday and Bank Holidays – No work activities

K2. The UK Gov special planning guidance on extended working hours such as those that were introduced during the Covid Pandemic were rescinded on the 1st April 2021. The Castle Green Construction Management plan should therefore be amended in line with the normal construction industry working times if this development proceeds in spite of all the objections. 

K3. The reference to Ecological Matters (5.6) in the Construction Management Plan is inadequate. As mentioned above the previously deposited Ecology Reports are out of date and the  CES Ltd report dated June 2021 does not deal with protected species only INNS. This shortfall in both, in up to date Ecological Evaluation should be addressed in accordance with both Local and National Planning Policy and it would be expected that the Development if approved would follow where possible the NHBC Publication NF89: Biodiversity in new Housing Developments: Creating Wildlife Friendly Communities. 

L. Condition 14

L1. Travel Plan – although this plan has been dated 2021 the content regarding local facilities mirrors guidance to some local facilities that have long closed reminiscent of the Bellis Application way back in 2018. We remind you that in view of the fact that the requirement for the provision of a pedestrian footway along the south side of Holt Road is now deemed unsafe by a Road Safety Audit this may now place the LPA in direct conflict with the Equality Commission. Additionally, the reference to the access links is incorrect as they cannot all be delivered so the content of the Travel Plan  cannot be accepted as properly discharging the Travel Plan Condition 14 thus the Reserved Matter Application should be refused.

M. In summary, there are so many unsatisfactory items in this application for Discharge of Conditions and Reserved Matters the whole application across both Files P/2012/0110 and P/2021/0111 should be refused.