BIRCHALL GARDEN SUBURB GREEN INFRASTRUCTURE STRATEGY October 2016 Birchall Garden Suburb Green Infrastructure Strategy

Prepared for Tarmac Ltd by David Jarvis Associates Limited, 1 Tennyson Street, Swindon, SN1 5DT

October 2016 Updated December 2016

Maps within this report are based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the controller of Her Majesty’s Sta onary Offi ce ©Crown copyright. Unauthorised reproduc on infringes Crown copyright and may lead to prosecu on or civil proceedings. Reproduced with the permission of the controller of HMSO Licence No: AR189685

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INTRODUCTION BACKGROUND This document has been prepared by David Jarvis Associates Ltd on behalf of A proposal for an extension to Garden City, based on Ebenezer Howard’s Tarmac Trading Ltd. Tarmac is a long-term landowner and steward in Her ordshire Garden City principles, was prepared by David Lock Associates in 2007. The and has been promo ng a sustainable extension to on land at resul ng Visioning Statement and illustra ve masterplan were supplied to WHBC Cole Green and Birchall Farm since 2006. and EHDC to inform their Local Plans. Scope The emerging masterplan has been the subject of a number of public consulta on This report describes the Green Infrastructure (GI) strategy for Birchall Garden events hosted by the Company. These included a Community Planning Weekend Suburb (BGS), a proposed urban extension to Welwyn Garden City, Her ordshire. It held in November 2015 and a public exhibi on in March 2016. The BGS site has includes a descrip on of the exis ng green and blue assets within the BGS site and also been the subject of a wide range of intensive environmental surveys over how they connect to the adjoining urban areas as well as the wider countryside. the past few years; informa on gleaned from this process has been used to guide Reference to emerging local plan GI policy is also made. proposed development and inform a GI strategy for the site. The BGS site extends to some 260 hectares of land south east of Welwyn Garden Planning City as shown on Figure 1. It straddles the boundary between the administra ve The emerging WHBC and EHDC Local Plans will set out the planning framework for areas of Welwyn Ha ield Borough Council (WHBC) and East Herts District Council the period up to 2032 and 2033 respec vely. Proposed alloca ons of 1200 and (EHDC). 1350 dwellings respec vely have been proposed for the BGS site. The provision of GI within and across the Borough and District boundaries forms a key component of emerging Local Plan policy. Green Infrastructure The Her ordshire Strategic Green Infrastructure Plan (incorpora ng the Green Arc area) was produced in 2011 and coincided with the publica on of the Borough and District GI Plans. These provide a high level overview of exis ng GI assets and assess the ability of these to provide mul ple environmental, social and economic func ons. The plans defi ne eleven social and environmental func ons that green infrastructure needs to perform. The func ons were mapped and the results analysed to provide strategic GI proposals. Opportuni es for enhancement and crea on of GI were iden fi ed as well as a number of poten al projects at County, Borough and District level: East Herts District Council County level • Project 2- Woodland Arc; Welwyn Ha ield Borough Council KEY • Project 5 –Mimram Valley Greenspace, including Park; The BGS site boundary • Project 6- Thames Tributaries, River Valleys and Corridors; Other land in control of the applicant

Administrative boundary • Project 9 – Reconnect;

Figure 1 Site loca on plan

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Borough level • Project 2- The Post-Industrial Heritage: promo ng the former rail routes; • Project 3- River Valleys Project - Mimram and Lee; District level • Project 5- Panshanger Park and Mimram Valley Greenspace.

The loca ons of these projects in rela on to the BGS site are reproduced on Figures 2 and 3.

River Quin ONB

Stevenage

Knebworth Bishop's Stortford Park Hatfield River Ash Forest uton Hoo KEY Ware Strategic link Farmland conservation and Landscape restoration River Lee Welwyn enhancement zone zone bourn Heartwood Garden City Panshanger Local link Wetland habitat Heathland/grassland Park Forest Lee and Stort zone creation zone Valley Harlow GI Plan Green infrastructure projects Woodland enhancement/ 1 Hatfield Harlow creation zone St AlbansEllenbrook Fields Hatfield Strategic GI Chalk valleys conservation Country Park Park Woods zone Figure 3 Regional green infrastructure links (Extracts from the Welwyn Ha ield and East Trees Northaw Against Great Wood Pollution Herts green infrastructure plans) Epping Watling Chase Radlett Community Forest Epping The projects: River Roding River Colne Forest tford y • aim to improve the ecological quality of the river corridors and water Borehamwood River Lee Loughton Country Park management regimes, including storm water management, in order to Enfield Weald Country Park contribute to regional and na onal objec ves; Hainault Forest Brentwood Lee Valley outh Oxhey Country Park Regional Park Chigwell • address the fragmenta on of exis ng woodland, the provision of alterna ve greenspaces, new woodlands and buff er plan ng in order to KEY 1. Grand Union Canal, Colne Valley and 6. Thames Tributaries, River Valleys and Existing increase resilience to climate change, protect historic assets and help Regional Park Enhancements Corridors AONB deliver Forestry Commission aspira ons; 2. Woodland Arc 7. Lee Valley Regional Park Lateral Links Lee Valley Existing GI initiatives • iden fy the need for increased access and interpreta on of environmental 3. Mardyke Valley Greenway 8. Chalk Arc assets par cularly with regard to former rail routes, the and 4. Urban GI Heritage (and Urban Greening) 9. Reconnect Panshanger Park; and 5. Mimram Valley Greenspace • aim to reconnect or reinstate public rights of way that have been lost or Figure 2 Regional green infrastructure links (Extract from the Her ordshire Green severed in order to improve the overall green infrastructure network. Infrastructure Plan)

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EXISTING GREEN INFRASTRUCTURE The methodology used to build on the strategic GI plans and defi ne how the GI projects apply to the BGS site is summarised below: River Mimram • Desktop research to iden fy a study area and the loca on of exis ng GI WE^,E'ZWZ< assets; • Review of environmental surveys carried out over the BGS site; • GI assets mapped using a GIS-based layer system; t>tzE'ZE/dz • Combining the mapping data to provide a base plan of all exis ng assets; ,Zd/E'&KZhZz • Analysis and review against emerging planning policy and site based constraints; and /Z,'ZE • Defi ne a network of green and blue links between the GI assets. >ddz'ZE The study area The study area is shown on Figure 4. It includes the context of east Welwyn, Panshanger Park, the Lee and Mimram valleys and the countryside between Welwyn Garden City and Ha ield. River Lee

Exis ng GI Assets KEY River systems, floodplains and The principal GI assets iden fi ed are: associated habitat • River systems, fl oodplains and associated wildlife habitat; Figure 4 River systems and fl ood plains • Designated ecological sites; River systems and fl oodplains • Ecological interest associated with the BGS site; Welwyn Garden City is bound to the north by the River Mimram, and to the south • General countryside and woodland; by the River Lee as shown on Figure 4. These fl ow east, joining at Her ord, and • Off -road public rights of way; and together with the River Beane, which fl ows from the north through Her ord, con nue as the Lee, travelling south through the Lee Valley Regional Park into • Amenity provision. London where it joins the Thames at .

River Lee fl ood pasture River Mimram

5 David Jarvis Associates Limited Birchall Garden Suburb Green Infrastructure Strategy

TEWINBURY SSSI

W6

B7

R MIM VE RA RI M PANSHANGER PARK A4 B8 B1 M1 W5 P33 BIRCHALL AND HENRY A1 ROLLS AND WOODS BLACKTHORN WOODS WILDLIFE SITE A8 B5 P34 B1 B6 W1 B3 B4 WELWYN GARDEN CITY A2 P1 B2 P2 A5 B9 W3 B2 B8 W2 B15 W3 A3 P6 B16 G1 P5 A7 B14 B11 P3 M2 W4 G2 A6 BIRCH GREEN B10 P4 B12 GREAT CAPTAIN’S AND B17 G3 B18 B20 THE COMMONS HOLWELLPARK WOOD B42 LNR WILDLIFE SITE P7 G4 B13 B19 W7 M6 P8 W9 A9 W8

P10 G5

THE COMMONS M5 M11 P9 WILDLIFE SITE M7 A10 B23 M8 G4 B41 B37 P25 KEY W10 B21 Statutory designated sites P11 B36 P23 B41 G6 P17- P22 B22 B24 RIVER LEE B34 P24 Non Statutory designated sites A15 G10 A11 B43 P12 B38 B39

B35 M9 M4 B44 Figure 5 Designated ecological sites P13 G7 M12 B35 B34 B28 M10 B29 B30 Designated ecological sites G9 G8 B40 A14 The study area contains two statutory designated sites and other non-stututory W12 B29 B27 B33 P14 - P16 G8 M3 designated sites as shown on Figure 5. The statutory sites are Tewinbury Site of B33 W11 P27 B27 B31 A12 B25 KEY Special Scien fi c Interest, which lies on the northern border of the study area, P26 P28 County value B32 B26 adjacent to the River Mimram, and The Commons Local Nature Reserve located on P29 A13 Local value the southern edge of WGC. B26 Low value

Figure 6 Ecological value within the BGS site

Ecological interest associated with the BGS site The BGS site contains ecological interest valued at County, and Local or Parish level. Land of low ecological value is also present, mainly associated with arable farmland and some areas of neutral grassland as shown on Figure 6.

Tewinbury SSSI The Commons LNR

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R MIM ,Zd&KZ VE RA RI M R MIM IVE RA R M WE^,E'ZWZ< WE^,E'ZWZ<

t>tzE'ZE/dz t>tzE'ZE/dz A414

,Zd/E'&KZhZz ,Zd/E'&KZhZz

/Z,'ZE /Z,'ZE

>ddz'ZE >ddz'ZE

A414 KEY KEY RIVER LEE

Existing off-road bridleways, cycle RIVER LEE Existing woodland routes and byways Other countryside Existing off-road footpaths Watercourses and Permissive right of way ponds/lakes within Panshanger Park Figure 7 General countryside and woodland Figure 8 Off -road public rights of way

General countryside and woodland Off -road public rights of way The rolling landscape between Welwyn Garden City and Her ord is a rural mixture The study area is quite well served by public rights of way. Some of these are of small se lements, agricultural land, woodlands and copses as shown on Figure severed or restricted by major roads and others, such as the Na onal Cycle Route 7. The area is bisected by the A414 dual carriageway which runs between the (NCR) 61, provide good, extensive off -road access as shown on Figure 8. Rivers Lee and Mimram, passing to the south of Welwyn Garden City and Her ord. Public access along the river corridors is poor and there is li le opportunity to reach the rivers themselves. Public access within Panshanger Park is currently The fragmenta on of woodland habitat is clearly evident notwithstanding the available via a mix of established rights of way and permissive routes. strong links provided by the Lee and Mimram river corridors.

Fragmented woodland groups east of Ha ield Informal path

7 David Jarvis Associates Limited Birchall Garden Suburb Green Infrastructure Strategy

Panshanger Park contains a mosaic of habitats, and

,Zd&KZ approximately 200 R MIM VE RA RI M WE^,E'ZWZ< hectares is now open to the public

t>tzE'ZE/dz

,Zd/E'&KZhZz

/Z,'ZE

>ddz'ZE

Moneyhole Lane Park is a much valued local open space with playing RIVER LEE fi elds, a play area, nature trail and general KEY Recreational facilities recrea on facili es

Figure 9 Amenity provision

Amenity provision Outdoor recrea onal facili es comprise designated areas of Urban Open Land, formal parks, sports facili es, allotments, caravan parks and Panshanger Aerodrome. These are mostly located within the urban areas of Welwyn Garden City and Her ord, the main excep on being Essendon Golf Course to the south of the River Lee. Holwell Hyde Lake. Proposed green Panshanger Park, a 404 hectare site owned by Tarmac, is currently being worked links will improve for gravel. Large areas of the site have been restored and approximately 200 connec ons to hectares are open to the public. The park contains a mosaic of wildlife habitats Moneyhole Lane Park such as lakes, river, woodland and reedbed. Tarmac is working with Herts Wildlife and Panshanger Park Trust and Her ordshire County Council to manage the park.

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PROPOSED GREEN INFRASTRUCTURE • Create a new linear park and green link which would run parallel to the A414, shown on Figures 11, 12 and 13. The link will include a belt of The Lee and Mimram river valley corridors provide the focus for wildlife connec vity deciduous woodland habitat, which will be planted on sensi vely designed within the study area and beyond. The Lee valley corridor is connected directly to bunds. This measure will also provide visual screening to and from the The Commons Wood, The Commons Local Nature Reserve and the BGS site via development and will reduce traffi c noise to proper es within the southern the Ha ield Hyde Brook. New SuDs related connec ons to this network would be por on of the site. provided in the southern part of the BGS site and would also connect to a separate unnamed tributary of the River Mimram, which extends into the BGS site south of Access and rights of way Birchall Lane. New footpaths and bridleways will be created. Apart from providing addi onal access to the countryside, they will link exis ng public rights of way which already The indica ve route of the green corridor, currently depicted in the Strategy Diagrams in the emerging Welwyn Ha ield and East Herts Local Plans, would be realised via a diverse network of access and wildlife links. These would permeate through the site, responding to the complex topography, the species present and the opportuni es that have been iden fi ed to create new habitats along each MONEYHOLE LANE PARK corridor. The BGS GI will link exis ng areas of ecological value adjoining the site such as Panshanger Park in the east and The Commons LNR to the west. The proposals will: PANSHANGER PARK • Develop new parkland in the heart of the development providing a rac ve YWELWYNN GARDEN GARDEN CITY CITY wildlife habitat and ac ve as well as passive recrea on opportuni es; WGC 069 • Develop ecologically diverse sustainable drainage systems around the periphery of the development to accommodate and manage storm water run-off from impermeable areas; • Enhance the overall landscape character of the area through the provision NCR 61 of appropriate plan ng, par cularly woodland, which strengthens and reinforces the local historic landscape character, creates a rac ve gateways to WGC, Ha ield and Her ord, and improves the overall se ng of these urban areas. • Iden fy and protect exis ng habitats of value through the use of ESSE management plans and appropriate public access regimes; NCR 061 THE COMMONS LNR N D

ON H ERT • Create addi onal wildlife habitat links between exis ng sites of ecological INGF ORDBU 0 RY 022 2 value within the site as well as those beyond it, such as The Commons LNR 3 KEY and Panshanger Park and the Lee and Mimram Rivers ; Existing major public rights of way • Create new public rights of way which connect with exis ng routes in order Existing off-road footpaths to provide greater access to the countryside and natural greenspace; Proposed major public rights MILL GREEN of way links • Enhance exis ng points along the A414 where there is access across/under GOLF CLUB Proposed other links Indicative proposed the carriageway for people and wildlife; and development Figure 10 Proposed access and rights of way

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