restore
Transcripción
restore
River Restoration Martin Janes ‘Environmental Management of Rivers and Wetlands’ • Complex ‘active’ landscape scale systems with multiple economic & social benefits. • Management needed due to human pressure: 1. Understand the system (is it broken?) 2. Aid recovery (minimal intervention) 3. Reduce detrimental impacts (mitigation & change) 4. Restore the lost/scarce – process:habitat:ecology River systems • Process driven dynamic system – Hydrology input & transport (flow) – Sediment input & transport (erosion & deposition) • Resulting physical & ecological habitat features – Valleys, floodplains, wetlands, & channels – Support wildlife flora & fauna (bugs, fish, humans) • Resilient to change and disturbance (natural) – BUT Modification, over use, taming!, = poor understanding of components and complexity UK River ‘Taming’ • Modified over many centuries. – Domesday Book 1086 • More rapid over the last 100 yrs (industrialization & machinery) Due to: – land clearance/deforestation – milling – navigation – land drainage – flood protection – abstraction – urbanisation, – taming by engineers… • 1998 report indicated 80% of UK rivers have had part of their channel modified. Resulted in: • extensive straightening ‐ – damaged wildlife habitats – reduced value of fisheries – reduced aesthetic appeal • loss of floodplain wetlands ‐ – reduced ability of the floodplain to provide economically viable functions. EU ‐ River management East Europe: Water pollution & Floods South Europe: Water Quan & Floods North Europe: Dams, hydro & e‐flows West Europe: Flood risk & Habitat frag. • Flood ‘Protection’ and ‘Defence’ Channelisation, walls, culverts, pipes – local scale (problem or reach) • Flood ‘Risk Management’ Storage, capacity, and how this affects the river (catchment scale) • Integration ‐ River Basin Management Land (soil) management, sustainable drainage systems, functioning floodplains, integrated planning policies, ecosystem services. Historic management Working with Natural Processes Habitat Enhancement & River Restoration River restoration • Restore river catchment processes • Return physical features & habitat niches • Reconnect isolated habitats • Within the constraints – complexity, land, money, built heritage, perception, ownership , water quality and quantity.... Benefits • • • • • • • Biodiversity Access to wildlife and nature Flood risk management Climate change resilience Sustainable planning and redevelopment Reduced maintenance cost Safety Drivers for change • European Directives – – – – Urban Wastewater treatment Directive (1991) Habitats and Species Directive (1992) Water Framework Directive (WFD) (2000) Floods Directive (2007) • National Poilcy – – – – – Espace de Liberté (France) Room for the River (Netherlands) Making Space for Water (Eng & Wales) Natural Flood Management (Scotland) Env. River Enhancement Prog. (Ireland) • Other global and regional drivers – Climate change (resilience), economy (fishing),.. WF Directive Targeted at Aquatic Ecosystem River Quality; Prevents Further ‘deterioration’; Enhance Aquatic Ecosystem Quality through a program of measures (PoM); Catchment scale river basin planning (RBMP’s); Monitoring of compliance; Penalties for failure; Cyclical Implementation by 2015, 2021, 2027on 6 year ‘cycles’. Restoration of degraded habitats • Good Ecological Status (GES) For all watercourses not impacted severely, or serving an overiding economic/public service • Good (Maximum) Ecological Potential (GEP/MEP)) For all watercourses designated ‘Heavily Modified’, or ‘Artificial’ Best compromise (ecol. vs. needs of society) Monitoring and assessment Multiple objective River Restoration Schemes R. Skerne Darlington In 1994 Urban UK River Restoration Project. £1M demonstration. River Skjern, Denmark Late 60’s Denmark’s largest land drainage scheme, 4000ha wetlands lost. Deepened, straightened, embanked and pump-drained ……………………………………..……………………2004 cost £22M. A sustainable solution. 1997, an environmental ‘U’-turn. Act of Parliament to restore the meandering river and 2200ha of wetands 2004 cost of £25M. Before: Secondary drainage channel Total earth works: 3,000,000 m3 R. Skjern ready to bend again Flood Risk Management Making “Room for the River” in The Netherlands Urban bottleneck City of Arnhem Satellite image 1995 Urban Development Arnhem 1830-2000 1830 2000 Dike relocation of Bakenhof (nearArnhem) The Bakenhof area: Natural ‘playground’ floodplain River Quaggy, Chinbrook Meadows Quaggy ‐ a river released 400m concrete removed Quaggy ‐ for flood storage Historic water meadows restored Quaggy – for education Quaggy ‐ for enjoyment Residents/users: Project improved the park 89% Less anti social behaviour 56% Bayerisches Landesamt für Wasserwirtschaft Restoration of the Isar River in Munich --- flood control, ecology and recreation Urban Re‐development River Colne, Staines, London River Marden Designed to physical forms defined by river processes Include native habitat types to colonise Accessible and visible to users and public • Flood risk…. & Landscape, Habitat, Amenity, Public pride. Simulate form & process in a constrained location Cheong Gye Cheon Restoration Project, Seoul 5.8km, 3 years to completion in 2005. [US$ 280Mil] Multiple benefits River Brent, North London March 2004 May 2005 Concrete 2002 August 1998 Design informed by geomorphology to allow for a ‘semi-natural’ river form with active fluvial process in a constrained urban flood storage and amenity parkland environment July July2003 2009 June 2006 March 2003 Social impact Urban space, Accessibility, Quality of life, Ownership, Social justice. Fisheries and Biodiversity Habitat & ecology • catchment scale – Ecosystem health, repopulation of restored watercourse • Reach scale – Pools & riffles and the life cycle of fish • Meso scale – Individual habitat niches Biodiversity is likely to be greatest in areas of high morphological diversity Witham, Lincolnshire • • • • Defunct weir Fisheries problem Siltation Disrupting natural flow regime • Return free passage • Remove eyesore • Restore natural functions Gravel ‘riffle’ New Forest Mires Some past realignment, but old channels still existing in the woodlands. Restore the natural function of these small systems. Benefits for biodiversity. Mire restoration has been very successful, reducing runoff by infilling the drainage channels. Gravel and clay fill material raising the bed to previous levels [2006] Highland Water. Structure ruined by poor management [2002] London Rivers Action Plan Launched Jan 2009 by the Mayor of London’s Office. To help step up the rate of river restoration throughout the City Target is to restore 15km of river by 2015 Highlighting opportunities and providing practical guidance to local authorities, developers, Non Government Organisations and community groups www.therrc.co.uk/lrap.php SAC River Restoration Plans • England based Protected Areas (Habs Dir) – 47 ‘SSSI rivers’ to favourable condition ‐ 2010. – Protected areas (Habs Dir and WFD) where ‘restoration measures’ have been identified ‐ 2015 – 50 year plan for physical restoration • Remove structures, embankments, interruptions to hydromorphic and ecological processes • Based on walk over survey of morphology & ecology • Long term commitment & for ££ implementation Current Initiatives • Push towards ‘Natural Flood Management’ – Scotland, N. Ireland and England & Wales – POST seminar on Tuesday – NFM in England • Based on ‘working with natural processes’ from the Pitt Review of 2007 flooding – report published Tuesday. • Judicial Review treat in late 2010 – RBMP’s – Defra announce £112M to bring waterbodies to GES (EA £9M pa, NE £6Mpa, CRF £8Mpa – Jan ‘12. • Defra ‘catchment approach’ to water quality – 25 pilot ‘local engagement’ projects ‐ Dec ‘11 Conclusions • River restoration considers the whole river ‘system’; • Multiple, complex interlinkages of biotic and abiotic factors; • Restoration for WHAT? – define targeted measurable objectives for clarity and assessing outcomes; • Planning at the catchment scale is essential to maximise the impact of any site or reach scale works; • River managers working with, not against, the natural system (aiding recovery and WwNP & Room for the River); • Restoring the ability of a river to function naturally (process) has EU policy backing (Habs, WFD and Floods Dir’s); • Large scale demonstration projects can help develop scientific and professional expertise, and give confidence to policy makers and the public. RESTORE: Communicating best practice in river restoration €1.8m, 50% EU LIFE+ 6 Partners, 2010 ‐ 2013 4 Regions, 21 Countries RESTORE common themes Costs and benefits • Long term economic benefits • Costing river restoration • Sourcing funding What do we mean by RR • What is river restoration • How to undertake river restoration Drivers through directives • Contribution to flood risk reduction • Contribution to increased biodiversity • How to meet WFD RR targets • Climate change adaptation • Renewable energy conflicts People and communities • Integrating with urban planning • Social and cultural wellbeing Regional issues and concerns East • Access to funds and information, few networks, promote understanding South • Only little progress outside France, issues of ephemeral rivers, water quality, bioengineering vs RR West • Concept understood, needs evidence, funding, guidance, political & planning buy‐in, public safety. North • Fisheries and hydropower drivers, mixed levels of networks in operation. 3 years ‐ 3 stages • Stage 1 – information collection and collation. What exists as best practice river restoration & implementation and how is this needed by different countries? • Stage 2 – engagement. Building the networks of policy makers, river basin managers and practitioners and forming the information resource. • Stage 3 – Knowledge transfer. Web based database tool for information sharing, long‐term continuation through the European Centre for River Restoration (ECRR). Output ‐ Review of EU Policy Drivers A demand for river restoration tools and methods... • Legislative Drivers: – Habitats, Floods, Water Framework directives – UN BioD Plan, Rural Development Prog., CC Adaptation & Land Use Planning policies. • Supporting Legislation – CAP, Nitrates & Groundwater directives But deterioration of habitats despite these drivers. => Difficulties in overcoming obstacles to implementation for river restoration Barriers and Constraints