Environmental Statement volume 4 - Chiltern Evergreen3

Chiltern Line, Oxford - Bicester August 2009Otter and Water Vole Report1.0 Introduction1.1 ERM are producing a Nature Conservation chapter for an Environmental Statement on behalfof Chiltern Railways (CRCL) to assess the upgrade Scheme for the existing railway betweenBicester and Oxford. Duri ng a preli minary assessment of the S cheme water crossing wereidentified as having potential for water voles and otters; therefore water vole and otter surveyswere recommended.1.2 Keystone Environmental Ltd was instructed by ERM to unde rtake an Otter a nd Water Volesurvey of rivers, streams and drains that are crossed by the Chiltern Rail Line between Oxfordand Bicester (grid reference: SP 504063 to SP 594226).Aims and Objectives1.3 The pri mary aim of the otter and water vole su rvey is to inform the Nature Conservationsection of the Environmental Statement.1.4 In order to inform the Environmental Statement a field survey was carried out to ascertain thefollowing:Presence/absence of Water Vole burrowsPresence/absence of Otter holts or potential Otter holtsPresence and distribution of field signs of Water Vole and OtterStatus of resident Water Vole and Otter population if present Development constraintsRequirements to ensure legal complianceSite Characteristics1.5 The Chiltern Line is situated in the Upper Thames river basin, crossing the River Thames andsome of its d istributaries in Oxford and a number of the Thames tributarie s. The main ofthese tributaries is the River Cherwell, plus its main tributary the River Ray and various othersmall tributaries of the River Ray as the line approaches Bicester.1.6 At the southern end of the line lies the urban area of Oxford, with the urban area of Bicester atthe northern end. The area between is characterised mainly by fa rmland, being a mixture ofboth arable and pasture; with the M40 crossing th e Railway line in the centre of the route.The land is generally flat floodpl ain, for the Th ames in the south but towards the north theRiver Ray catchment and the Otmoor basin.1.7 Within Oxford there a re a number of mainly large watercourses that the rail line crosses, sothere is an intense area of survey here, including the Oxford Canal, River Thames, Castle MillStream, Ridd lers Isl and S tream, and Bulstrake Stream. This intensity of water co ursesreduces as the line moves north, with on ly one major river crossing, the River Cherwell, andthen a number of small streams and drains that are crossed by bridges and pipes.Keystone Environmental 1