River Darent Action Plan
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River Darent Action Plan Phase 2 – River Restoration Strategy Nigel Holmes with Eddie Bradbrook, Richard Andrews, Chris Conroy, Ian Humpheryes, Dave Best, Bridget Thorn Where is the Darent? Problems: Historical Groundwater Abstraction Problems: 1976; 1984; 1989-91 Darent Daily Flow at Otford 15 10 Chalk Stream with a difference 5 Flow (cumecs) 0 Jan-87Jan-88Jan-89Jan-90Jan-91Jan-92Jan-93Jan-94Jan-95Jan-96Jan-97Jan-98Jan-99Jan-00Jan-01Jan-02 Date Daily Mean Flow on the River Itchen at Allbrook and Highbridge 25 20 Hydrograph of a Real Chalk stream 15 10 Flow (cumecs) Flow 5 0 01.10.198715.03.198828.08.198810.02.198926.07.198908.01.199023.06.199006.12.199021.05.199103.11.199117.04.199230.09.199215.03.199328.08.199310.02.199426.07.199408.01.199523.06.199506.12.199520.05.199602.11.199617.04.199730.09.199715.03.199828.08.199810.02.199926.07.199908.01.200022.06.200005.12.200020.05.200102.11.2001 - Itchen Abstraction: effects on flow Naturalised flow Actual Flow Abstraction: effects on flow Naturalised Flow Actual Flow Distance down the Darent Historical Channel Degradation Water Quality • Phosphates low – below EN’s SSSI Target • Nitrates OK – within WHO Drinking Water limits • Occasionally high BOD due to ‘weed growth’ in hot summers • Minor point-source small incidents • Silt is a problem • Around 1900 catastrophic pollution ‘killed every living thing in the river’ - previously considered one of finest trout rivers in the country The Darent Action Plan – Water Resources • Two Phases • Phase I (1996) – Reduction of 20 Ml/d from upper catchment & augmentation in low-flow periods in vulnerable lower reaches • Phase II (2005) – Further reductions of 23.5 Ml/d from lower catchment sources • Modelling and other studies to determine an ‘Environmentally Acceptable Flow Regime’ (EAFR) The Darent Action Plan – Reduced Licences Daily licensed abstraction accretion profile. Public water supply abstraction in the Darent Catchment upstream of Dartford in relation to the Darent Action Plan. Reductions in bold type. 200 Pre-Phase 1 (1994-97) quantities /yr Wilmington Current Quantities (2004) /yr 180 Proposed Quantities with phase 2 reductions (2007)/yr Darenth Augmentation Green St 160 Green Stansted Fawkham Ridley 140 Hartley Horton (aggregated) Kirby 120 Hartley (b) 100 Eynsford Kemsing (Honeypot 80 Stream confluence) Lullingstone Cramptons Rd Licenced abstraction (Ml/day) 60 40 Sundridge Oak Lane Westwood Westerham Brasted Dartford 20 Farningham Eynsford Lullingstone 0 -2 4 10 16 22 28 Distance from start of main river (km) The Darent Action Plan – EAFR The Darent Action Plan – Restore flows and augment in extremes The Darent Action Plan – EAFR • At What Cost? – c£75m+!! • Is it Enough (ecologically)? • How do we get best value for money? ………………HAVE A SUSTAINABLE AND ALL-EMBRACING CATCHMENT MANAGEMENT STRATEGY River Darent Restoration Strategy • Builds upon previous plans and actions. • Primarily building on improved flows. • Acknowledges more needed if environmental quality to be restored. • Two parallel studies required to progress a ‘River Restoration Strategy’. River Darent Restoration Strategy – The 2 Studies • Both essential to implement sustainable management and restoration. • Both provide concise outputs. • Outputs include consultation documents enabling the general public, and other project partners/stakeholders, to become involved in the most cost-effective manner. • The focus is the River’s ecology – through consultation this ‘backbone’ will be fleshed out with all interests fully integrated in the future River Restoration Strategy – Study 1 Assess, and report on, the ecological status of the river, its limitations and potential. review of all available ecological data; assess the practices and pressures influencing ecology; consideration of existing environmental responsibilities, and specifically assessments required under the Habitats Regulations (HR) and the Water Framework Directive (WFD). output = ‘River Darent Environmental Appraisal’. Volume 2 ‘Draft River Darent Restoration Strategy; programme of Actions and Measures’ reviews achievements of the Darent Action Plan (WR); assesses how catchment land-use, water resources, flood defences and other activities could be managed in the future in an integrated and sustainable manner; Preparation of a Strategy and Plan that will benefit the ecology of the river and its natural landscape assets, its resources for recreation and amenity, and provide cost-effective and sustainable water use and flood management. ‘Feature Interests’ Approach • Include many key species/habitats of interest/responsibility (e.g. BAP) or of socio- economic importance (e.g. fish) • Can be used as ‘Barometers of health’; • If we get it right for these, everything else should be OK; • They are a basis to monitor – need to know progress being made, and possibly quantified; • Provides feed-back to functions and organisations that their actions have made a difference!! The ‘River Darent Environmental Appraisal’ – Data Review - Reporting • SIMPLE REPORTING FORMAT FOR EASE OF LOCAL INPUT TO DRAFT – What the current status of ‘feature interest’ is considered to be - (e.g. high, good, moderate, poor or bad) – How current status varies from year to year – e.g. upward/downward trends or stability. – The factors considered to be most influential in affecting the present ‘perceived’ status. Integrated Appraisal Approach – Key Factors – Assessing ‘Cause & Effect’ Also consider others – A. e.g. catchment effects Habitat (siltation), factors out of catchment (estuary Quality netting) Etc. C. Feature B. Water Interest Water Quality being Quantity assessed D. Biological Interactions & Responses to Natural Change The Darent Strategy – 1. ‘Feature Interests’ Feature Interest Otter Water vole Salmon Lampreys Bullhead Trout and grayling Other fish communities Invertebrate communities Crayfish Macrophyte community River Habitat The Darent Strategy – approach – 5-scale assessment of status Colour code Natura 2000/EN definitions Water Framework Directive Additional Darent context for SSSIs Status RED: Destroyed/Part Bad (severely degraded Destroyed/At risk Destroyed/Unfavourable and [HMWB]) Declining ORANGE: Unfavourable and Poor (significantly changed Poor condition – has been Maintained from pristine) much better in past YELLOW: Unfavourable and Moderate (moderately Also includes Naturally Recovering changed from pristine) moderate or worse GREEN: Good (slightly departing near-favourable or close to from pristine) maximum potential BLUE: Favourable. High (pristine or near- Healthy and not at risk natural) The Darent Strategy – approach – 5-scale assessment of factors affecting status Score Description of extent of influence on status 5 Probably key influence 4 Major influence 3 Important influence 2 Moderate influence 1 Minor influence Blank or not cited None or not known The Darent Strategy – Standard approach to reporting • Data Sources. • Expert Opinion Sources. • Status between Otford & Dartford. • Basis for Status Category. • Comparison of Present Status with Historical Status. • Key Factors Affecting Status. • Actions. The Darent Strategy – Results of Environmental Status using surrogates Feature Interest Status Otter Unfavourable (no significant change in past 20 years) Water vole Unfavourable and maintained (no significant change in past 20 years) Salmon Naturally Unfavourable?? (no significant change in past 20 years) – May be naturally unfavourable, or historically impacted Lampreys Probably Naturally Unfavourable (no significant change in past 20 years) Bullhead Favourable - Not adequately known - probably recovered in past 10 years Trout and grayling TROUT: Unfavourable (V. slight recovery) GRAYLING: Unfavourable Other fish communities Moderate except in, and after, major drought years Invertebrate communities Unfavourable (recovering) Crayfish Unfavourable (declining [destroyed]) Macrophyte community Near-favourable or close to maximum potential River Habitat Full range from Unfavourable to locally Near-Favourable The Darent Strategy –Factors affecting Ecological status – Matrix Approach Feature Interests/Factors O WV S L B TG O I C M H F Historic changes to channel form and present character 2/2 5 2 2 2/2 2 5 Flood defence management 1/1 2/2 2 2 2 3 3 2 2/2 4 Channel and other fisheries management actions 1/1 1/1 1 1/1 1/1 1/2 1/3 1/1 2/2 1 Siltation of gravels 4 ? 1 3 2 2 2 2 Periodic drying 4 4 4 4 5 5 5 4 5 1 Extreme low flows - 2 4 2 4 4 4 3 3 3 Present general water quality 1 1 1 2 Historic catastrophic pollution ? 4 4 1? ? 2? Estuary quality 2 Alien species – e.g. fish stocking 5 2 5 Catchment/floodplain land-use 3/2 Distant effects (sea/estuary- salmon) 2 Specific effects 5 5 5 5 The Darent Strategy –Factors affecting Ecological status Type of Impacts Historic changes to channel – Severe for Salmon and River Habitat Flood defence management – Moderate for Many things Fisheries management actions – positive or negative for most Siltation of gravels – Fish and invertebrates especially Periodic drying – catastrophic for fish and inverts, and macrophytes?? Extreme regular low flows – bad for everything Present/recent water quality – not an issue Historic catastrophic pollution event – legacy difficult to quantify Alien species – catastrophic for crayfish - Catchment/floodplain Land-use – otter (roads) Outside catchment effects – salmon – probably not an issue Species-specific effects – crayfish, water vole, salmon, native Darent fish The Darent Strategy – Ecological Status and Factors Determines Strategy