Birchall Garden Suburb Green Infrastructure Strategy Part 1
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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 October 2016 2 Birchall Garden Suburb Green Infrastructure Strategy INTRODUCTION BACKGROUND This document has been prepared by David Jarvis Associates Ltd on behalf of A proposal for an extension to Welwyn 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 Welwyn Garden City 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 Panshanger 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 3 David Jarvis Associates Limited Birchall Garden Suburb Green Infrastructure Strategy 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 Hitchin Buntingford ONB Stevenage Knebworth Bishop's Stortford Park Hatfield River Beane River Ash River Rib Forest uton River Stort Hoo KEY Harpenden Ware Sawbridgeworth Strategic link Farmland conservation and Landscape restoration River Lee Welwyn enhancement zone zone Hertford 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/ Hoddesdon 1 Hatfield Harlow creation zone St AlbansEllenbrook Fields Hatfield Broxbourne 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) Cheshunt Epping Potters Bar 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 Aldenham Loughton Country Park management regimes, including storm water management, in order to Enfield Bushey 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 River Mimram 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) October 2016 4 Birchall Garden Suburb Green Infrastructure Strategy 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 Canning Town. 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 HERTINGFORDBURY 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 LETTY GREEN 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.