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Forum david hetherington

  1. 1. Fluvial Geomorphology – From Theory to Practice Dr David Hetherington Ove Arup and Partners, Newcastle upon Tyne, UK. Friday 4th June 2010, Sustainable Cities Forum Universidad Javeriana Bogota Colombia Javeriana, Bogota,
  2. 2. Personal Profile – David Hetherington • BSc Geography • MSc Catchment Dynamics and Management • PhD Remote Sensing and Fluvial Geomorphology • Have worked in Fluvial Geomorphology for 10 years. • Employed for Over Arup and Partners (“ARUP”) for 5 years. y • My work relates to River Restoration, Geomorphological Assessment, Flood Risk Management and Geomatics. • I operate the Arup “Geomorphology” and “Remote Sensing” Communities (appx 80 staff). S i ”C iti ( t ff)
  3. 3. Research Profile • Geomorphological Evolution • U of T Use f Terrestrial LiDAR (Li ht Detection and ti l (Light D t ti d Ranging) in Rivers • Use of Terrestrial LiDAR in Engineering • Fish Habitat • Hydromorphology and Hydraulics • The use of Urban Models for Flood Risk Management M t • Fluvial Geomorphology and River Restoration
  4. 4. Ove Arup and Partners (“ARUP”) • An international multi disciplinary consultancy firm of engineers, scientists and designers (>10,000 staff) i ti t dd i ( 10 000 t ff) • Founded in 1946 by Ove Arup Sydney Opera House was an early project. • Ove was an engineer and philosopher (he died in 1988) • Recent large projects including much of the Beijing Olympics. • Independent and staff owned (trust). • Please visit www arup com www.arup.com
  5. 5. The Key Speech • Ove Arup made the key speech in 1970 to remind Arup staff of how they should operate: key points… points • Work should be interesting and rewarding and be of the best quality p q y possible • All work should have a humanitarian attitude • Work should be honourable with a social conscience • Money is not the main aim • We should be a force of good, and help to shape a better world….
  6. 6. 520 65 105 35 130 GLOBAL WATER SKILLS NETWORK March 2009
  7. 7. Fluvial Geomorphology – What is it? • A river is something of unimaginable wonder . . .
  8. 8. Fluvial Geomorphology – What is it? • An understanding of river behaviour . . . .
  9. 9. Fluvial Geomorphology – What is it? • A complex earth science using elements of Hydraulics, Geology and Physics. • “the study of sediment sources, fluxes and storage within the river catchment and channel over short, medium and longer timescales and of the resultant channel and floodplain morphology” (Newson and Sear 1993). • The study of river form-process interactions and feedbacks over many scales, from the single grain up to the entire catchment catchment. • In Short: An well-qualified Fluvial Geomorphologist understands how rivers behave, and can use this , knowledge to manage them appropriately . . .
  10. 10. Fluvial Geomorphology – Catchment Processes
  11. 11. Fluvial Geomorphology – Catchment Controls • Catchment nature ultimately determines habitat in natural conditions • Diract ( (local) and ) Indirect (Catchment) Anthropogenic changes p g g disrupt natural reactions and responses • Taken from Brierley and Fryirs, 2007 – River styles
  12. 12. Fluvial Geomorphology – Small Scale
  13. 13. Fluvial Geomorphology – Why do we need it? (1) • Rivers are the arteries of the landscape . . . • Freshwater rivers are valuable and only cover around 0.0001% of the Earth’s Surface. (0.0002% of ( total volume of water) – NASA estimate • Natural rivers are physically diverse over short distances supporting unique assemblages • Healthy river systems typically offer better fish stocks, and better quality water to local communities.
  14. 14. Fluvial Geomorphology – Why do we need it? (2) • Healthy meandering systems can help to maintain y g y p aggracultural water table levels. • Upland meandering systems can provide upstream flood storage (reducing flood risk downstream). • Designing with natural geomorphological processes is key k if new engineering schemes are to be sustainable i i h b i bl and environmentally sensitive. • Rivers are important community features and boundaries
  15. 15. Fluvial Geomorphology – Why do we need it? (3) • Rivers are hydraulically and morphologically dynamic in time, making then unique spaces. • Support varied and sometimes rare flora and fauna pp (which has evolved to natural systems) • Damage needs repair • As with most habitats, the quality of the physical space plays a major role in promoting healthy ecology •N t Natural and restored rivers look better and make people l d t d i l k b tt d k l happy!
  16. 16. Ecology - Fisheries
  17. 17. Fluvial Geomorphology and good quality rivers e s What is considered as being a good quality Geomorphology gy i ? river? and Hydromorphology 1) Suitable physical habitat for native species 2) Suitable water quality to support sensitive native species Ecology Water quality 3) Availibility / introduction of native species
  18. 18. Fluvial Geomorphology and good quality rivers e s What is considered as being a good quality Geomorphology gy i ? river? and Hydromorphology 1) Suitable physical habitat for native species 2) Suitable water quality to support sensitive native species Ecology Water quality 3) Availability / introduction of native species
  19. 19. Fluvial Geomorphology in the UK
  20. 20. Fluvial Geomorphology in the UK
  21. 21. Fluvial Geomorphology in the UK
  22. 22. Fluvial Geomorphology in the UK
  23. 23. Fluvial Geomorphologists • It is a specialist subject that usually requires outside contractors to supply the necessary levels of expertise. From the outset it is important to make clear that like any science, a broad understanding of principles only gets you so far, and a little far knowledge can be a very dangerous thing. Source: (DEFRA) R&D TECHNICAL REPORT FD1914 (DEFRA), FD1914, Applied Fluvial Geomorphology. • It is a profession, and a job of responsibility
  24. 24. Expertise Levels in the UK DEFRA R&D TECHNICAL REPORT FD1914
  25. 25. Legislation and Authorities The Water Framework Directive - Legislation •To protect, and where necessary, restore the structure and function of the aquatic ecosystem •An obligation to return our rivers to their natural hydromorphological state •The aim of achieving “good ecological status” The UK Environment Agency •The UK statutory body responsible for caring for the environment •Powers to prosecute in response to damage to river systems •Promote restoration and habitat creation wherever possible •Have published recent guidance on Ri H bli h d t id River W k Works
  26. 26. The Department for Environment, Food, and Rural Affairs (DEFRA) • Government Department • Conduct research of a national interest • Produce Guidance • With the Environment Agency - C Commissioned a “Guidebook of Applied Fluvial Geomorphology” ( (R&D Technical Report FD1914) in 2003 p ) • By D Sear, M Newson and C Thorne. • Freely Available on line. line • Sets national standards and raised the profile and requirement for Fluvial Geomorphology.
  27. 27. The River Restoration Centre (RRC) • “A national information and advisory centre on all aspects of river restoration and enhancement, and sustainable river management management” • The RRC and an Non-Profit organisation based in Nottingham, UK. • A hub for best-practice and knowledge sharing • Keep databases of projects and outcomes • Offer consultancy services (checking and review) • Work with rivers trusts and local fisheries • Offer promotion and training on River Restoration.
  28. 28. Drivers for Geomorphological Studies and work • Ecology • Fishing • Social (Recreation / Community) • Landscape Improvement • Stability (Land Erosion) • Understanding of impacts of river change • Engineering (allowing for natural processes) • Flood Risk Management • Sediment Management g
  29. 29. From Assessment to Enhancement . . . 1) Asses – Measure/Map/Log evidence of the system 2) Understand – Analyse the Data 3) Identify problems – Reveal key information of quality 4) Prioritise – Use information to plan rehabilitation 5) Restore – Propose sensible, sensitive and sustainable solutions that consider many environmental and social factors.
  30. 30. Geomorphological Assessment • 3 broad levels of approaching investigation and Assessment Small - Immediate • Site Specific Local scale • E g geomorphological impacts of weir removal or E.g. channelisation • Reach Scale • Restoration plans, rivers with special status, sediment management plans, water level management p g plans, fisheries improvements. , p • Catchment scale • Catchment Audits and Management Plans Large – Long Term
  31. 31. Desk Study Information • Old photographs • Ai b Airborne photographs h t h • Old Mapping • Anecdotal evidence • Flow Records • Topographic information • Agency / Government records g y • Geological information
  32. 32. Empirical vs Rational Approaches • Empirical understanding based upon spatial measurements (quantitative) • Requires skills in selecting the correct measurement techniques, methodologies and Processing and analytical methods. • Rational understanding based upon experience- based observations (qualitative) • Requires “hands-on” experience in various river systems to q p y understand how they operate under different conditions, and react to catchment changes. • Most studies use a combination of Empirical and Rational Geomorphological work.
  33. 33. Empirical Tools – Field mapping • Locating features onto maps or direct into GIS • Handheld GIS has built in GPS technology (How long until we can install GIS on our I-phones?)
  34. 34. Empirical Tools – Surveying and Terrestrial LiDAR
  35. 35. Rational Tools - Experience • Field proforma allowing descriptions and mapping of: • Types of erosion and deposition • Types of sediment Bar Features • Severity of Erosion • Severity of Deposition • Evidence of active and dormant processes • Evidence of Morphological features (Riffles, pools etc) • Hydromorphological units (runs, cascades, riffles, ponded flow etc) ) • Anthropogenic influences (farming, dumping, livestock etc)
  36. 36. Rational Tools - Proforma
  37. 37. Geomorphological Patchiness and Diversity • Patchiness is an expression of the number of different key geomorphological features identified within an individual reach. • Di Diversity i a product of patchiness - th t t l it is d t f t hi the total number of all features within a reach, multiplied by the number of different feature types present within the reach (i.e. patchiness). It is thus a measure of the frequency at which key features q y y occur along a reach.
  38. 38. Assessment of Geomorphological quality • Scales and criteria can be manipulated to suit the p catchment, and to reflect absence or presence of key project features.
  39. 39. GIS analysis
  40. 40. Restoration options
  41. 41. Restoration projects – in channel options Back water channel Log v weirs Flow deflectors/ D’s Ds Flow deflectors/groynes
  42. 42. Catchment Scale – Geomorphological mapping Geomorphological Standard Diversity V.low low Mod High V.high V hi h
  43. 43. Catchment Scale – Ecological mapping V.low low Mod High V.high V hi h Standard diversity for salmonids, lampreys and bullheads (EA technical manual - Hendry & Cragg-Hine, 1997)
  44. 44. Geomorphological – Ecological links Geo Eco Com 40.00 R-Sq = 7.8%; P = 0.037 versity 30.00 Ecolog Standard Div 20.00 gy 10.00 0.00 0.00 0 00 5.00 5 00 10.00 10 00 15.00 15 00 20.00 20 00 25.00 25 00 30.00 30 00 35.00 35 00 40.00 40 00 Geomorphology Standard Diversity
  45. 45. Geomorphological – Ecological links Geo Eco Com R-Sq = 7.8%; P = 0.037 Target for restoration Good Quality y Judgement required
  46. 46. Project Example – River Mease • A Site Specific – Geomorphological Impact assessment of removing a weir
  47. 47. Project Example – River Mease
  48. 48. River Mease - Considerations • Important habitat for Bullhead • Important habitat for Spined Loach • Local regime will change • Local sediment transport potential will change • Local hydraulic diversity will change • Upstream impacts? • Downstream Impacts? • Flood Risk? • Stability
  49. 49. River Mease – Existing Conditions
  50. 50. River Mease – Restoration/mitigation Proposals
  51. 51. River Mease – Anticipated hydraulic habitat
  52. 52. River Mease - Outcomes • Impact assessment reveals opportunities! • Habitat for key species promoted in new layout y p p y • Opportunities found to relocate vegetation • Improved local floodplain connectivity • Upstream hydraulic diversity improved as backwaters are removed • Improved aesthetics • Reduced livestock access • Land-owners appeased
  53. 53. Project Example – Beam Parklands • A reach based assessment to inform landscape improvement for community use
  54. 54. Beam Parklands – Landscape Vision
  55. 55. Beam Parklands - Considerations • No access for fish (downstream sluice) • Urban – high population area, community park • Very Low Morphological or Hydraulic Diversity • Heavily modified system • Currently inaccessible • Very low gradient • Invasive plants • Polluted site • No key species present
  56. 56. Beam Parklands – Restoration Plan
  57. 57. Beam Parklands - Outcomes • Accessible park landscape promoting community involvement and natural play • Two restored rivers with dramatically improved geomorphological, geomorphological hydraulic and ecological diversity. • Pool riffle sequence mimicking natural conditions • Wetland areas • Improved flood storage
  58. 58. Hydromorphology and Hydraulic Diversity • Definition: “The physical characteristics of the shape, the boundaries and the content of a water body” Water Framework Directive Definition • A key part of this “content” is spatio-temporal k t f thi “ t t” i ti t l hydraulic diversity. • Fish plant and invertebrate species undertake Fish, different parts of their life cycles and daily routines in different hydraulic units (Biotopes) – Diversity is key. • It is possible to map these flow unit habitats (Biotopes) visually, b t this comes with many (Bi t ) i ll but thi ith problems.
  59. 59. Biotopes (hydraulic habitats) Biotope Types
  60. 60. Mapping Hydraliuc Diversity using terrestrial lidar •The local standard deviation of the data were computed using a 0 2 m radius 0.2 moving window •Data were gridded at 0.04 m so as to capture the smallest biotope unit seen at the study sites •Local standard deviation values at each of the measured biotope locations were then extracted from the grids using the residual function in SURFER™ •Local standard deviation values interrogated at each known biotope location •Statistical properties of each biotope determined Statistical
  61. 61. Biotope signals
  62. 62. Results: Typology validation frequency biotope successfully Unit descriptor classified frequency amalgamated biotope successfully classified Run 0.00 0.90 Glide Glid 0.14 0 14 0.75 0 75 Chute 0.20 0.59 Rapid 0.38 1.00 Riffle 0.25 0.55 Deadwater D d t 0.71 0 71 0.71 0 71 Pool 1.00 1.00
  63. 63. Research outcomes • Different features offer similar surface structure (suggesting similar hydraulics). • Current system for classifying hydraulic units are over-complex. • Rivers present a continuum of hydraulics, rather than defined units (fuzzy boundaries in time and space). • Potential for analysing exiting LiDAR data on larger river systems. y • Methods limited to local and reach scales of investigation (quantifying betterment).
  64. 64. Terrestrial lidar and design
  65. 65. Conclusions – Fluvial Geomorphology • Diagnosing the problems and causes is key to management. • The scale that processes are operating at should determine the scale of the study, and the response. • S ll scale processes/problems = Local studies Small l / bl L l t di • Catchment scale processes/problems = Large studies • Consideration of this early on makes schemes sustainable, sustainable and adds value (in many ways) ways). • It is a serious and complex subject and expertise is required. q
  66. 66. Conclusions – River Restoration • We need to learn from, and correct historical mistakes. • M h existing guidance and project experience. Much i ti id d j t i • Should be based on a sound understanding of the River System System. • Needs to be focused on the drivers. • What conditions to key species require? • Provides multiple direct benefits (and residual benefits e.g. water quality). b fit t lit ) • Often a far more cost effective solution than hard engineering. engineering
  67. 67. River Restoration: Costs • Hard to generalise in terms of economics (projects so diverse!) • S ft V H d (S ft approximately 25-50% cheaper at Soft Vs Hard (Soft i t l 25 50% h t initial outlay) • Cost per m <50% for soft • Engineers vs Bio-engineers (bioengineering groups small with low overheads - 50% in some cases) • Soft then requires monitoring, and maintenance • But has a longer design life because of this g g • Restoration should be part of other schemes. • Additional cost – but great additional benefit • Cost does not reflect “value”
  68. 68. River Restoration: Limitations • A river can never be fully “restored” back to its original state. i i l t t • Sometimes difficult to design for extreme flood events. events • Sometimes restoration has to be done within constraints • Huge potential benefits make the limitations worth working with
  69. 69. Acknowledgements • The project organisers in Bogota! • Arup for supporting my involvement • The below Arup people for contributing and/ helping in various ways towards my attendance and y y presentation at this forum: Patrick Kuhn, Amit Dutta, Dr Sally German, David Wilkes, Prof Mark Fletcher Daniel Newton Daniel House Jane Saul Fletcher, Newton, House, Saul. • Dr David Bradley – APEM aquatic scientists • Research Colleagues • Dr George Heritage – Salford University, UK • Dr David Milan – University of Gloucestershire, UK
  70. 70. Questions? david.hetherington@arup.com (Please stay in touch!) Useful Additional Background Information . . • DEFRA: www.defra.gov.uk (search for “fluvial g g ( geomorphology”) p gy ) • EA fluvial design guide: http://evidence.environment- agency.gov.uk/FCERM/en/FluvialDesignGuide.aspx • River Restoration Centre: www.therrc.co.uk

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