AC Line, Connah's Quay to Dolgarrog

CPAT Report No. 1628

AC Line, Connah’s Quay to Dolgarrog

Desk-based Assessment

YMDDIRIEDOLAETH ARCHAEOLEGOL CLWYD-POWYS

CLWYD-POWYS ARCHAEOLOGICAL TRUST

Client name: SP Manweb PLC / SP Energy Networks CPAT Project No: 2339 Project Name: AC Line Grid Reference: SJ 2711 7141 to SH 7702 6776 County/LPA: Flintshire, Denbighshire and Conwy CPAT Report No: 1628 Report status: Final Confidential until: 31 December 2019

Prepared by: Checked by: Approved by:

Nigel Jones Paul Belford Paul Belford Principal Archaeologist Director Director 12 December 2018 13 December 2018 14 December 2018

Bibliographic reference: Jones, N. W., 2018. AC Line, Connah’s Quay to Dolgarrog: Desk-based Assessment. Unpublished report. CPAT Report No. 1628.

YMDDIRIEDOLAETH ARCHAEOLEGOL CLWYD-POWYS CLWYD-POWYS ARCHAEOLOGICAL TRUST

41 Broad Street, Welshpool, Powys, SY21 7RR, United Kingdom +44 (0) 1938 553 670 [email protected] www.cpat.org.uk

©CPAT 2018

The Clwyd-Powys Archaeological Trust is a Registered Organisation with the Chartered Institute for Archaeologists

CONTENTS

SUMMARY ...... II 1 INTRODUCTION ...... 1 2 NATURE OF THE SCHEME ...... 1 3 METHODOLOGY ...... 2 4 SCOPE AND GUIDANCE ...... 2 5 HISTORICAL BACKGROUND ...... 3 6 BASELINE ASSESSMENT ...... 5 7 ASSESSMENT OF IMPACTS ...... 9 8 MITIGATION ...... 11 9 SOURCES ...... 17 10 ARCHIVE DEPOSITION STATEMENT ...... 18 APPENDIX 1: METHODOLOGY FOR ASSESSING THE POTENTIAL IMPACTS OF DEVELOPMENT ON HERITAGE ASSETS ...... 19

Summary A desk-based assessment has been conducted by the Clwyd-Powys Archaeological Trust in connection with proposals to modernise an existing overhead powerline, known as the AC Line, which runs between Connah’s Quay, in Flintshire, and Dolgarrog, in Conwy. The assessment identified a small number of assets where there is the potential for direct impacts as a result of the various elements of the scheme and appropriate mitigation has been recommended. The results will inform the development of the work programme for the scheme and the assessment should be reviewed before the scheme is finalised.

Crynodeb Bu Ymddiriedolaeth Archaeolegol Clwyd-Powys yn cynnal asesiad wrth ddesg mewn cysylltiad â chynigion i foderneiddio llinell drydan uwchben bresennol, o’r enw Llinell AC, sy’n rhedeg rhwng Cei Connah, yn Sir y Fflint, a Dolgarrog, yng Nghonwy. Nododd yr asesiad nifer fach o asedau y gallai elfennau amrywiol y cynllun effeithio’n uniongyrchol arnynt, ac argymhellwyd camau lliniaru priodol. Bydd y canlyniadau’n darparu sail ar gyfer datblygu’r rhaglen waith ar gyfer y cynllun, a dylid adolygu’r asesiad cyn y penderfynir ar fersiwn derfynol y cynllun.

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

1 Introduction 1.1. The Clwyd-Powys Archaeological Trust (CPAT) were invited to undertake and archaeological desk-based assessment on behalf of SP Manweb PLC / SP Energy Networks in connections with the proposed modernisation of an existing 132kV overhead powerline known as the AC Line, which runs between Connah’s Quay in Flintshire and Dolgarrog in Conwy (SJ 2711 7141 to SH 7702 6776). See Figs 1-15 at the rear of the report for location.

1.2. The AC route forms an integral part of the North Wales coast 132kV interconnected network, connecting Connahs Quay Grid Supply Point (GSP) to Pentir GSP, with Bulk Supply Points (BSPs) connected along its entire length at Holywell, St Asaph, Colwyn Bay and Dolgarrog. The remaining sections of this route (AC and AD) between Dolgarrog and Pentir were modernised in 2012/2013 and they are not part of the proposed works.

1.3. It is understood that there are no elements of the scheme which require planning permission, but the works are subject to the Electricity Act of 1989 which makes provision for the supply, generation and transmission of electricity. Schedule 9 of the Act details the preservation of amenity and fisheries, stating that:

‘In formulating any relevant proposals, a licence holder or a person authorised by exemption to generate or supply electricity: (a) shall have regard to the desirability of … protecting sites, buildings and objects of architectural, historical or archaeological interest; and (b) shall do what he reasonably can to mitigate any effects which the proposals would have on … any such flora, fauna, features, sites, buildings or objects.’

2 Nature of the Scheme 2.1. The scheme involves a programme of refurbishment works including:

 Steel tower assessment and ground investigations  Replacement and upgrading of steelwork, tower furniture and fittings  Restringing and replacing conductors  Use of pulling/tensioning equipment at specific locations  Erection of scaffolding for road/rail/powerline crossings  Site compounds  Vehicular access to towers 2.2. The potential for any direct impact on heritage assets is considered to be relatively small, though any heritage assets requiring specific mitigation are detailed below.

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

3 Methodology 3.1. The assessment consisted of a desk-based study of readily available primary and secondary documentary, cartographic, and photographic sources in order to provide a historical framework for any surviving archaeological remains. This included relevant records held at the regional Historic Environment Records (HER) maintained by CPAT and the Gwynedd Archaeological Trust (GAT), Flintshire Archives, Denbighshire Archives, the National Monument Record and the National Library of Wales. The 2m-resolution LiDAR data was accessed for the whole area via the Welsh Government’s Geo-Portal for Wales. Data for designated and registered assets was obtained from the CPAT HER only and checked for the whole route via Cof Cymru - National Historic Assets of Wales.

3.2. The assessment was conducted according to the Chartered Institute for Archaeologists’ (CIfA) Standard and Guidance for Historic Environment Desk-based Assessment (2017).

4 Scope and Guidance 4.1. The cultural heritage is a broad concept that embraces archaeological remains, the built heritage and historic landscapes. Cultural heritage is deemed to include the full range of man-made features that have been imposed on the landscape from the Palaeolithic, more than two hundred and fifty thousand years ago, to the 20th century. Some of these features will be visible as upstanding remains on the ground; others will be buried and only become apparent during ground disturbance. Some will have an archaeological interest and importance; others will be more historical in their origin. Individually all these features are known as heritage assets – as defined for instance, in the Highways Agency’s Design Manual for Roads and Bridges (DMRB).

4.2. Heritage assets include the following designated (statutorily protected) and registered (non-statutorily protected) sites: World Heritage Sites; Scheduled Monuments; Listed Buildings (LBs); Conservation Areas; and Registered Historic Parks and Gardens.

4.3. The legislative framework for the historic environment in Wales was revised by The Historic Environment (Wales) Act 2016. The 2016 Act amended the Ancient Monuments and Archaeological Areas Act 1979 and the Planning (Listed Buildings and Conservation Areas) Act 1990. It extended the definition of scheduled monuments and enhanced their protection, as well as making changes to the process of scheduled monument consent. Changes were also made to the protection of listed buildings. The 2016 Act also provided for a statutory register of historic landscapes, a statutory list of place names, and imposed a statutory duty on Welsh Ministers to compile and maintain Historic Environment Records (HERs).

4.4. Chapter 6 of Planning Policy Wales was revised and re-issued in December 2018. Technical Advice Note 24: The Historic Environment (TAN 24) came into force on 31 May 2017, and replaced previous Welsh Office Circulars 60/96 Planning and the Historic Environment: Archaeology; 61/96 Planning and the Historic Environment: Historic Buildings and Conservation Areas; and 1/98 Planning and the Historic Environment: Directions by the Secretary of State for Wales.

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

4.5. Planning Policy Wales (10th edition, 2018) identifies the desirability of preserving the setting of a World Heritage Site, a nationally important ancient monument (whether scheduled or unscheduled), a listed building, a Conservation Area and a site on the Register of Historic Parks and Gardens in Wales. This desirability will be a material consideration when assessing the potential impact of a development proposal on the historic environment. Recent guidance published by Welsh Government (2017) in Setting of Historic Assets in Wales defines the setting of a historic asset as including ‘the surroundings in which it is understood, experienced and appreciated, embracing present and past relationships to the surrounding landscape. Its extent is not fixed and may change as the asset and its surroundings evolve. Elements of a setting may make a positive, negative or neutral contribution to the significance of an asset. Setting is not itself a historic asset, though land within a setting may contain other historic assets. The importance of setting lies in what it contributes to the significance of a historic asset. The setting of a historic asset can also include less tangible elements. These may include function, sensory perceptions or historical, artistic, literary and scenic associations’.

4.6. The revised Design Manual for Roads and Bridges (DMRB), Volume 11 Section 3 Part 2, HA 208/07 (August 2007) provides a framework for assessments of the historic environment, whether these be for environmental statements or for smaller developments that do not require environmental impact assessments. The approach to the historic environment which it promotes, though designed primarily for road developments, is more generally relevant as a methodology for other types of development and has been adopted here (see Appendix 1).

5 Historical Background 5.1. This section provides a brief summary of the archaeology and history of the study area to enable the findings of the assessment to be placed in a wider context. The AC Line crosses three Registered Historic Landscapes and passes close to a number of important heritage assets.

Prehistoric Era (10,000BC – AD 43) 5.2. There is significant evidence for prehistoric activity across the study area, most notably comprising the remains of a Neolithic chambered tomb near Dolgarrog, which was largely destroyed by flooding in the early 20th century, together with a small number of scheduled Bronze Age burial mounds further to the east. There are also a number of chance finds indicating that prehistoric activity was widespread within the area as a whole.

Roman Period (AD 43 – 410) 5.3. Dolgarrog lies close to the Roman fort at Caerhun, while a Roman road has recently been confirmed along the line of the B5381 to the west of St Asaph. Although direct evidence is scarce, the presence of Roman remains associated with the production of lead at Pentre Ffwrndan, near Flint, indicate that lead is likely to have been extracted on Halkyn Mountain and Holyweel Common during that period.

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Medieval Period (410 - 1500) 5.4. The town of Flint was established as a planned, defended town during the late 13th century, following the construction of a substantial castle there as part of Edward I’s campaigns in Wales. The surrounding area, through which the powerline runs, retains significant evidence for medieval strip fields, the layout of which is preserved by surviving field boundaries. Further to the west the landscape also retains evidence for medieval fields, although these are smaller and more irregular in nature. There are also the earthworks of ridge and furrow cultivation surviving across the area. Another important medieval site is the deserted settlement at Hen Caerwys, which is a scheduled monument.

5.5. Although much of the area is now dominated by agriculture, medieval lead mining on the Flintshire plateau is attested from documentary sources.

Post-Medieval and Modern Periods 5.6. The Quaker Company was instrumental in pioneering lead mining in Flintshire from the late 17th to late 18th centuries, and there is documentary evidence of improvements in technology that allowed deeper shafts to be driven and richer veins to be located. The richest veins were worked intensely throughout the 18th and 19th centuries in the areas now referred to as Halkyn Mountain, Holywell Common and Pen-y-Ball Top.

5.7. The ore field landscape is very distinctive and now forms common land returned to rough pasture. Although most of the standing structures associated with the mining have now been lost, the landscape itself, comprising an extensive myriad of craters and tips of no great size, remains remarkably intact and is particularly apparent from the air. A recent survey in the area has recorded in excess of 250 mine sites and many more individual shafts.

5.8. The decline in the mining industry and the changing fortunes of agriculture are reflected in a number of former house sites which were abandoned in the 19th century and now survive as slight earthworks.

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

6 Baseline Assessment 6.1. The baseline assessment has considered all known heritage assets within a study area which extends for 250m to either side of the AC Line to take account of potential access routes and compounds.

Designated and Registered Assets within 250m of the overhead line 6.2. There are 59 designated assets within 250m of the overhead line, including 37 historic hedgerows.

Table 1: Designated heritage assets within 250m of the overhead line

Designation Number within 250m World Heritage Sites 0 Scheduled Monuments 6 Listed Buildings 33 Registered Historic Parks and 4 Gardens Registered Historic Landscapes 3 Conservation Areas 2 Historic Hedgerows numerous

Scheduled Monuments 6.3. Scheduled Monuments are designated features of national importance. They are protected under the Ancient Monuments and Areas of Archaeological Importance Act, 1979, and their settings are also protected.

6.4. The assessment has identified six scheduled monuments within the study area.

Fig. 2 Scheduled monuments within the study area.

SM No. Name FL053 Round Barrow 225m SE of Parc y Prysau FL054 Round Barrow 495m SE of Parc y Prysau FL064 Bryn y Cwm Mound & Bailey Castle FL096 Bryn y Cosyn Round Barrows FL162 Hen Caerwys Deserted Village Site FL179 Hafod Wood Moated Site

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Listed Buildings 6.5. These are protected under the Planning (Listed Buildings and Conservation Areas) Act 1990. All listed buildings are nationally important, but are graded in order of significance as Grade I, II* or II. Local planning authorities must have special regard to the desirability of preserving the setting of a listed building regardless of its grade, and it also requires planning proposals to meet the test of determining the extent to which a development affects views to and from a listed building.

6.6. The assessment has identified 33 listed buildings within the study area.

Table 3 Listed buildings within the study area List no Name Grade NGR 86 Cefn-y-Coed Isa II SH 78646 68417 169 Parish Church of St Michael II SH 90685 73546 189 Sirior Goch II SH 92933 73637 Plas Cerrig Farmhouse, including attached 294 former barn and bakehouse II SJ 12835 74763 350 Llwyn-erddyn II* SJ 17601 72636 355 Oakenholt Hall II SJ 26667 71055 521 Oakenholt Farmhouse II SJ 26680 71034 1409 The Rock Chapel II SJ 08185 73742 1442 Southcroft including North Cottage II SJ 02341 73904 1443 Staverton II SJ 02327 73911 Former Coach House,Stables & 1444 Outbuildings to Staverton & Southcroft II SJ 02314 73914 1473 Glan Elwy II SJ 03586 73661 1486 Ysgubor-y-Coed Farmhouse II SJ 04702 73594 1491 Bryn Asaph including Gate House Range II SJ 04155 73316 14880 Gellilyfdy II SJ 14555 73940 15673 Gwyndy Uchaf II SH 88952 73243 15674 Agricultural Range at Gwyndy Uchaf II SH 88920 73230 16409 Leadbrook Hall II SJ 26013 71035 17566 Agricultural Range at Cefn-y-Coed Isa II SH 78686 68389 17570 Pentrefelin and Bwthyn-y-felin II SH 80638 69318 20101 Ffarm II SH 90538 73416 20103 Ty Isa Trofarth II SH 85971 71842

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

20104 Outbuilding at Ty Isa Trofarth II SH 85974 71830 20105 Barn at Ty Isa Trofarth II SH 85999 71832 20106 Agricultural Range at Ty Isa Trofarth II SH 85982 71815 Glascoed Lodge on Bodelwyddan Park 20897 Boundary II SH 99438 74010 24674 Bakehouse at Gellilyfdy II SJ 14552 73909 24675 Stable at Gellilyfdy II SJ 14576 73910 24676 Barn at Gellilyfdy II* SJ 14636 73887 26192 Hafod Farmhouse II SJ 20950 72120 Barn, cart shed and granary at Plas Cerrig 26783 Farm II SJ 12820 74793 26784 Cow shed at Plas Cerrig Farm II SJ 12848 74787 Bryn Celyn Lodge on Bodelwyddan Park 80738 Boundary II SJ 00522 73931

Registered Parks and Gardens 6.7. The Historic Environment (Wales) Act 2016 provides for the creation of a statutory Register of Parks and Gardens of Special Historic Interest in Wales. Parks and gardens are graded using the same categories as listed buildings (i.e. I, II*, II).

6.8. There are four registered parks and gardens within the study area.

Table 4 Registered parks and gardens within the study area Ref no Name Grade C2 Bodelwyddan Castle II C4 Bryngwyn Hall II C35 St Bueno’s College II GD54 Kinmel Park II*

Registered Historic Landscapes 6.9. Some historic landscapes in Wales are considered to be particularly significant and/or well preserved. These have been recorded in a Register of Landscapes of Historic Interest in Wales. Classed as either outstanding or special interest, these have been published in two volumes which form Part 2 of the Register of Landscapes, Parks and Gardens of Special Historic Interest in Wales published in 1998 and 2001. Again this part of the Register is advisory but non-statutory.

6.10. The AC Line crosses three registered historic landscapes.

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Table 5 Registered historic landscapes within the study area Ref no Name HLW (C) 1 Vale of Clwyd HLW (C) 2 Holywell Common & Halkyn Mountain HLW (Gw) 4 Lower Conwy Valley

Conservation Areas 6.11. These are protected under the Planning (Listed Buildings and Conservation Areas) Act 1990. This Act requires local planning authorities to have special regard to the desirability of preserving the setting of a conservation area, and it also requires planning proposals to meet the test of determining the extent to which a development affects views to and from such an area.

6.12. There are two Conservation Areas within the study area:

 Oakenholt Hall  Tremeirchion

Historic Hedgerows 6.13. Historic hedgerows are protected under the Hedgerow Regulations (1997). A hedgerow is deemed important, i.e. historic, if it marks a parish or township boundary which pre-dates AD 1850, incorporates an archaeological feature, is part of or incorporates an archaeological site, marks the boundary of (or is associated with) an estate or manor which pre-dates AD 1600, or forms an integrated part of a pre- parliamentary enclosure.

6.14. The AC Line crosses several areas which retain significant survival of medieval boundaries and associated hedgerows. The most notable area is around Flint, where the pattern of medieval strip fields is largely intact, although significant elements of later, irregular fields survive elsewhere.

Undesignated Assets within 250m of the overhead line 6.15. A total of 931 undesignated assets have been identified within 250m of the overhead line, 545 of which are mine shafts on Halkyn Mountain and Holywell Common, while 64 assets relate to military features at Bodelwyddan. Other potentially significant assets include the site of a Neolithic chambered tomb and a small number of post- medieval house sites.

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

7 Assessment of Impacts 7.1. Towers AC41 and AC42 lie resepectively in the same fields as scheduled monuments FL 42 Bryn Cosyn Round Barrows and FL 053 Round Barrow 225m SE of Parc y Prysau. In addition, although Tower AC58 lies outside the scheduled area of FL 162 Hen Caerwys Deserted Village Site, the scheduled monument does extend into the same field as the tower.

7.2. Twenty-six of the AC Line towers are placed along or close to historic hedgerows which are part of a pre-enclosure landscape, likely to have its origins in the medieval and earlier post-medieval periods. Those historic hedgerows which may be impacted upon by the refurbishment of the line are summarised in Table 3.

7.3. Twelve of the AC Line towers lie in close proximity to undesignated assets, while six assets are close to road crossings which may require the erection of scaffolding as part of the programme of works.

Table 3: Summary of potential direct impacts to heritage assets

Tower Asset Ref Description Value Type of impact designation AC7 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC8 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC14-15 Undesignated PRN 152456 House site Medium Scaffolding AC17 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC18 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC23-24 Undesignated PRN 19573 House site Medium Access AC27 Undesignated PRN 27072 Line of Wat’s Medium Access Dyke 75m S AC28 Undesignated PRN 27069 Line of Wat’s Medium Access Dyke 50m W AC28 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC29 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC35-39 Undesignated Numerous mine Medium Access, ground shafts on Halkyn investigations, Mountain puller/tensioner AC38 Undesignated PRN 152448 Mine shaft and Medium Access, whim circle scaffolding

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

AC40 Undesignated PRN 152447 Mine shaft Medium Access, ground immediately investigations, adjacent to tower puller/tensioner AC41 Undesignated PRN 152454 Mine shaft Medium Access, ground immediately investigations, adjacent to tower puller/tensioner AC41 Scheduled FL 053 Round barrow High Access monument AC42 Scheduled FL 096 Round barrow High Access monument AC44 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC50 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC52 Historic N/A Hedgerow Medium Access hedgerow AC54 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC55 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC56 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC58 Scheduled FL 058 Hen Caerwys High Access monument deserted village AC64 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC65 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC88-89 Undesignated PRN 152441 Farmstead site Medium Access lies between the two towers AC103R Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC103A Historic N/A Hedgerow Medium Access, ground hedgerow; investigations

Undesignated; PRN 46829 Roman road Medium Undesignated Scaffolding PRN 152439 House site Medium AC112 Historic N/A Hedgerow Medium Access, ground hedgerow investigations

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

AC115 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC128 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC134 Undesignated PRNs House sites Medium Access, 152433-5 puller/tensioner, scaffolding AC135 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC166 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC172 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC174 Historic N/A Hedgerow; Medium Scaffolding; hedgerow; PRN 152461 House site Access Undesignated AC175 Historic N/A Hedgerow Medium Access, ground hedgerow; investigations AC180 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC185 Historic N/A Hedgerow Medium Access, ground hedgerow investigations AC193 Undesignated PRN 1544 Site of Neolithic Medium Ground chambered tomb investigations

8 Mitigation 8.1. A small number of undesignated heritage assets have been identified within the assessment area which could be subject to direct impacts from the proposed work.

8.2. In the light of the assessment above, this section provides a description of the measures adopted to mitigate the identified impacts on heritage assets, together with a consideration of the residual effects of the development on heritage assets.

Mitigation strategy 8.3. Heritage assets represent a non-renewable resource, and should be avoided wherever this is feasible in order to avoid damage or destruction. The purpose of mitigation is to avoid or reduce any adverse impacts that might result from the proposed scheme on the cultural heritage resource. The main strategy for minimising impacts from the scheme is avoidance, through careful planning, design and demarcation of sensitive assets. Where an impact is unavoidable, the reduction of that impact on the heritage asset necessitates detailed consideration of the site 11

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

characteristics and the introduction of specific measures designed to limit the impact. These are addressed in the section that follows.

8.4. The client will be provided with digital data identifying the locations of all heritage assets which should be incorporated into all constraints mapping for the project.

8.5. Table 4 provides detailed mitigation options for those assets for which there may be a direct impact from the proposed refurbishment works.

Mitigation Measures 8.6. At present no details are available regarding the preferred access routes to each of the towers. The location of heritage assets should be taken into account during the planning stage and, if necessary, this assessment should be reviewed to take new information into account. Although none of the scheduled monuments, listed buildings or locally listed buildings will be affected by the proposed refurbishment works, there is the potential for direct impacts from access works. There is also potential for direct impacts to a number of historic hedgerows. Of the numerous undesignated heritage assets within 250m of the overhead line, the majority are unlikely to be impacted by the proposed works, although potential impacts have been identified for 15 heritage assets, the mitigation for which is listed in Table 4.

Types of Identified Impact Access 8.7. Activity There is the potential for direct impacts on three scheduled monuments and a number of undesignated assets through gaining vehicular access to the towers.

8.8. Mitigation The recommended mitigation is avoidance through careful planning. Access routes should be designed to avoid all known heritage assets.

Ground investigations 8.9. Activity A number of towers are located along or close to historic hedgerows which could be affected as a result of ground investigations. There is also the potential for a direct impact to mine shafts during any ground investigations at towers AC40 and AC41 and to buried remains associated with the site of a Neolithic chambered tomb at tower AC193.

8.10. Mitigation A watching brief should be undertaken during any groundworks at towers AC40 and AC41.

Restringing of cables 8.11. Activity There is the potential for direct impacts on a number of undesignated assets through vehicle movement and the positioning of the puller/tensioner equipment and cable drums.

8.12. Mitigation The recommended mitigation is avoidance through careful planning of the works programme and specifically:

 No vehicular access across an asset

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

 No positioning or operation of machinery within the immediate area of an asset  No storage of equipment or materials within the immediate area of an asset

Scaffolding for road crossings etc 8.13. Activity No details are currently available regarding the positioning of scaffolding, although this may have the potential for direct impacts to undesignated heritage assets adjacent to towers AC14, AC15, AC38, AC103A, AC134 and AC174.

8.14. Mitigation The recommended mitigation is avoidance through careful planning of the works programme, specifically:

 No positioning of equipment or materials within the immediate area of an asset  Demarcation where appropriate to ensure avoidance  Watching brief where ground disturbance is unavoidable

Site Compounds and storage of materials 8.15. Activity No details are currently available regarding the positioning of site compounds and storage of material and equipment, although there is the potential for direct impacts on a number of undesignated heritage assets.

8.16. Mitigation The recommended mitigation is avoidance through careful planning of the works programme, specifically:

 No storage of equipment or materials within the immediate area of an asset

Hedgerow Removals 8.17. Activity. Twenty-six of the towers are positioned in close proximity to historic hedgerows (see Table 3), while the AC Line crosses a number of others. The refurbishment scheme has the potential to impact on these hedgerows at all stages of the scheme.

Mitigation. The recommended mitigation is avoidance through careful planning of the works programme, specifically:

 Any hedgerow removals should be checked against the results of this assessment to determine whether an historic hedgerow may be affected.  Avoid removals of historic hedgerows  Permission required to remove sections of historic hedgerow

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Table 4: Specific Mitigation Measures for assets with potential direct impacts

Tower Type Ref Value Type of impact Mitigation Hedgerow N/A Medium Access, ground Preservation in situ investigations AC7 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC8 Permission required to remove House site PRN Medium Scaffolding Avoidance, AC14-15 152456 Preservation in situ Hedgerow N/A Medium Access, ground Preservation in situ investigations AC17 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC18 Permission required to remove House site PRN Medium Access Avoidance, AC23-24 19573 Preservation in situ Line of PRN Medium Access Avoidance, AC27 Wat’s Dyke 27072 Preservation in situ 75m S Line of PRN Medium Access Avoidance, AC28 Wat’s Dyke 27069 Preservation in situ 50m W Hedgerow N/A Medium Access, ground Preservation in situ investigations AC28 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC29 Permission required to remove Numerous Medium Access, ground Avoidance, mine shafts investigations, Preservation in situ AC35-39 on Halkyn puller/tensioner

Mountain Mine shaft PRN Medium Access, Avoidance, and whim 152448 scaffolding Preservation in situ AC38 circle Watching brief during ground disturbance

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Mine shaft PRN Medium Access, ground Avoidance, adjacent to 152447 investigations, Preservation in situ AC40 tower puller/tensioner Watching brief during ground disturbance Mine shaft PRN Medium Access, ground Avoidance, adjacent to 152454 investigations, Preservation in situ AC41 tower puller/tensioner Watching brief during ground disturbance Round FL 053 High Access Avoidance, AC41 barrow Preservation in situ Round FL 096 High Access Avoidance, AC42 barrow Preservation in situ Hedgerow N/A Medium Access, ground Preservation in situ investigations AC44 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC50 Permission required to remove Hedgerow N/A Medium Access Preservation in situ AC52 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC54 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC55 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC56 Permission required to remove Hen FL 058 High Access Avoidance, Caerwys Preservation in situ AC58 deserted village Hedgerow N/A Medium Access, ground Preservation in situ investigations AC64 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ AC65 investigations

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Permission required to remove Farmstead PRN Medium Access Avoidance, site lies 152441 Preservation in situ AC88-89 between the two towers Hedgerow N/A Medium Access, ground Preservation in situ investigations AC103R Permission required to remove Hedgerow; N/A Medium Access, ground Preservation in situ, investigations Permission required

to remove

Roman PRN Medium Preservation in situ AC103A road; 46829 Scaffolding

Avoid ground House site PRN Medium disturbance 152439 Watching brief Hedgerow N/A Medium Access, ground Preservation in situ investigations AC112 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC115 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC128 Permission required to remove House sites PRNs Medium Access, Avoidance, AC134 152433-5 puller/tensioner Preservation in situ scaffolding Hedgerow N/A Medium Access, ground Preservation in situ investigations AC135 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC166 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC172 Permission required to remove Hedgerow; N/A Medium; Scaffolding; Preservation in situ, AC174 Permission required

to remove;

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

House site PRN Medium Access Avoidance, 152461 Preservation in situ Hedgerow N/A Medium Access, ground Preservation in situ investigations AC175 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC180 Permission required to remove Hedgerow N/A Medium Access, ground Preservation in situ investigations AC185 Permission required to remove Site of PRN 1544 Medium Ground Preservation in situ. Neolithic investigations Watching brief during AC193 chambered ground disturbance tomb

8.18. The assessment and recommended mitigation should be reviewed once further details become available regarding access routes, ground investigation, scaffolding positions, pulling locations and site compounds and before the scheme is finalised.

9 Sources Published sources Cadw/ICOMOS 1999. Register of Landscapes of Special Historic Interest in Wales: part 1 Parks and Gardens – Powys. Cardiff: Cadw.

Cadw, 2007. Guide to good practice on using the Register of Landscapes of Historic Interest in Wales in the Planning and Development Process. 2nd (revised) Edition. Cardiff: Cadw.

Cadw, 2011. Conservation Principles for the Sustainable Management of the Historic Environment in Wales. Cardiff: Welsh Assembly Government/Cadw.

Cartographic sources

Ordnance Survey Surveyors’ Drawings: 1819 OSD No 309 1821 OSD No 322 1834 OSD No 342 1834 OSD No 343 Tithe Surveys: 1841 Bettws yn Rhos 1847 Caerhun 1849 Caerwys 17

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

1841 Eglwysfach 1840 Flint 1840 Halkyn 1841 Holywell 1839 Llanfair Talhaiarn 1839 Llansantffraid Glan Conwy 1839 Northop 1845 St Asaph townships of Talar, Brynpolyn, Gwenglevryd and Gwerneigron 1845 St Asaph townships of Cilowain, Bodeugan and Rhyllon 1846 St Asaph Meriadog and Gwigfair 1839 St George, township of Meifod 1841 Tremeirchion 1849 Ysceifiog Ordnance Survey 1:2500 1st edition Caernarfonshire: 1889 13.04 and 13.08

Ordnance Survey 1:2500 1st edition Denbighshire: 1872 4.15, 4.16, 5.13 1873 6.07 1874 8.01, 8.02 1875 6.08, 7.01, 7.02, 7.04 1876 7.03

Ordnance Survey 1:2500 1st edition Flintshire: 1870 10.05 1871 4.13, 4.15, 4.16, 5.14, 7.08, 8.02 1872 4.14, 5.13, 5.15, 5.16, 8.04, 9.01 1873 9.07, 9.08 1874 7.04 1875 9.03 1886 9.02

10 Archive deposition Statement 10.1. The project archive has been prepared according to the CPAT Archive Policy and in line with the CIfA Standard and guidance for the creation, compilation, transfer and deposition of archaeological archives guidance (2014). The archive is entirely digital and will be deposited with the regional Historic Environment Record.

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Appendix 1: Methodology for assessing the potential impacts of development on heritage assets General The primary aim of any assessment is to identify the heritage assets within a Development Area in as far as constraints such as varying land-use allow, and to provide a report on them which should enable the reader to understand their historical context, offer guidance on their level of importance, whether national, regional or local, identify the significance of impact that the development might have upon them, and recommend mitigation to limit the impact of the development on them. Impacts and Effects The development may affect a heritage asset in one of several ways: i) Direct Impact: A direct impact upon a heritage asset involves the physical alteration or destruction of the latter as a result of the construction, operation or decommissioning of a development. Direct impacts could include the site clearance, reduction of levels, foundations, services, access roads etc. ii) Indirect Impact: Sometimes known as a secondary impact. An indirect impact arises where the connection between the development and the asset is remote or unpredictable and can affect an asset lying outside the development area. An indirect impact can be physical or visual, and in certain circumstances noise, smell and the like might also be considered under this heading. It should be noted too that in Wales, visual intrusion is normally considered to be indirect, but in England it appears to be classed as a direct impact. More detailed descriptions are offered in Guide to Good Practice on Using the Register of landscapes of Historic Interest in Wales in the Planning and Development Process (Cadw 2007). iii) Cumulative Impact: A cumulative impact may arise from the multiple effects of the same development on a single asset, or the multiple effects of the development and of other developments on an asset. It should be noted that the terms impact and effect are frequently used interchangeably, although there are fine gradations in the meanings of the two words. On occasions these are both used in reports though without explanation.

The Assessment Methodology It is a general tenet in conservation strategies that heritage assets represent a non-renewable resource, and should be avoided wherever this is feasible in order to avoid damage or destruction. All sites can be classified according to a system based on that provided for the assessment of heritage assets in the Design Manual for Roads and Bridges (HA 208/07; Volume 11, Section 3, Part 2), revised in August 2007. The classification of any undesignated asset is based on the collective professional judgement and expertise of the field staff of CPAT using information both from existing records and the field visits to selected assets. 19

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The relative value (importance) of a heritage asset, as given in greater detail in DMRB (2007) is laid out in Table 1. Table 1 Factors for Assessing the Value of Heritage Assets Factors for Assessing the Value of Heritage Assets Very High World Heritage Sites (including those nominated). Assets of acknowledged international importance. Assets that can contribute significantly to acknowledged international research objectives. High Scheduled Monuments (including those proposed). Undesignated monuments of which could potentially be worthy of scheduling. Listed Buildings. Assets that can contribute significantly to acknowledged national research objectives. Medium Conservation Areas. Designated or undesignated assets that contribute to regional research objectives. Low Designated and undesignated assets of local importance. Assets compromised by poor preservation and/or poor survival of contextual associations. Assets of limited value, but with the potential to contribute to local research objectives. Negligible Assets with very little or no surviving heritage interest. Unknown The importance of the resource has not been ascertained.

Factors that need to be considered in assessing the magnitude of the impact are given in Table 2, based on the DMRB (2007), but in modified form, for each historic environment sub-topic (archaeological remains, historic buildings, historic landscapes etc) has its own set of factors, which are set out in great detail in the Design Manual. Table 2 Factors in the Assessment of the Magnitude of Impacts Factors in the Assessment of Magnitude of Direct Impacts Major Change to most or all key heritage elements, such that the resource is totally altered. Moderate Changes to many key heritage elements, such that the resource is clearly modified.

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Minor Changes to key heritage elements, such that the asset is slightly altered or different. Negligible Very minor changes to heritage elements. No No change. Change

The significance of the impact of a development on a particular heritage asset is then established from the matrix (Table 3) also taken from the DMRB (2007). Table 3 Matrix for Assessing the Significance of Direct Impacts of the Proposed Development upon Heritage Assets

Magnitude Value/Sensitivity of Heritage Asset of Impact Very High High Medium Low Negligible Major Very Large Large/ Moderate/ Slight/ Slight Very large Large Moderate Moderate Large/Very Moderate Moderate Slight Neutral/ /Large Large Slight Minor Moderate/ Moderate Slight Neutral/ Neutral/ /Slight Large Slight Slight Negligible Slight Slight Neutral/ Neutral/ Neutral Slight Slight No change Neutral Neutral Neutral Neutral Neutral

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 1 AC Line, Connah’s Quay to Dolgarrog – key to maps 2-15

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 2 Potential impacts to heritage assets, Towers AC6 – AC20A

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 3 Potential impacts to heritage assets, Towers AC21 – AC33

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 4 Potential impacts to heritage assets, Towers AC34 – AC47

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 5 Potential impacts to heritage assets, Towers AC48 – AC60

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 6 Potential impacts to heritage assets, Towers AC61 – AC72

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 7 Potential impacts to heritage assets, Towers AC73 – AC87

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 8 Potential impacts to heritage assets, Towers AC88 – AC100R

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 9 Potential impacts to heritage assets, Towers AC100R88 – AC111

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 10 Potential impacts to heritage assets, Towers AC112 – AC123

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 11 Potential impacts to heritage assets, Towers AC124 – AC136

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 12 Potential impacts to heritage assets, Towers AC136 – AC148

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 13 Potential impacts to heritage assets, Towers AC149 – AC162

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 14 Potential impacts to heritage assets, Towers AC163 – AC177

CPAT Report No 1628 AC Line, Connah’s Quay to Dolgarrog Desk-based Assessment

Fig. 15 Potential impacts to heritage assets, Towers AC177 – AC193