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... challenges and opportunities, in: Proceedings of the 6th Australian Stream Management. Conference, 'Managing for extremes' (J. R. Grove, I. D. Rutherfurd, ...
Another reason urban streams are stuffed: geomorphic history, challenges and opportunities1 Geoff Vietz1/2, Mike Stewardson1, Chris Walsh2, Tim Fletcher2 1  Department  of  Infrastructure  Engineering,  The  University  of  Melbourne,  Parkville,  3010.  Email  [email protected]   2  Department  of  Resource  Management  and  Geography,  The  University  of  Melbourne,  Parkville,  3010  

Key  Points   • Management  of  the  physical  form  of  urban  streams  has  historically  focused  on  flow  efficiency   and  channel  stability   • Geomorphologic  features  and  functions  that  may  influence  the  ecological  health  of  streams  are   rarely  considered  by  management  approaches   • Protecting  or  reinstating  channel  complexity  and  geomorphic  dynamism  may  assist  in  achieving   urban  stream  health  goals     • The  challenges  associated  with  a  geomorphologically-­‐sensitive  approach  include:  flashy   hydrology,  reduced  sediment  load,  space  limitations,  legacy  impacts,  and  social  and  institutional   perceptions  

Abstract Urbanisation  influences  a  range  of  factors  related  to  stream  health,  including  the  hydrologic  regime  and   water  quality.  There  is  also  a  significant,  but  lesser  known,  impact  on  the  physical  form  and  functioning   of  stream  channels.  Most  urban  geomorphic  research  and  management  have  focused  on  channel   widening  and  deepening  arising  from  a  primary  concern  with  flow  efficiency  and  channel  stability.     However,  changes  in  channel  dimensions  in  themselves  are  unlikely  to  be  primary  drivers  of  change  in   biotic  structure  and  function.  Alongside  efforts  to  address  water  quality  and  hydrologic  stressors  on   stream  biota  and  biological  processes  identifying  geomorphic  attributes,  that  are  known  to  affect  stream   ecological  structure  and  function  in  non-­‐urban  settings,  may  assist  in  achieving  restoration  goals  in   urban  streams  through  both  catchment  and  instream  actions.  This  geomorphologically-­‐sensitive   approach  to  urban  stream  management  requires  a  significantly  greater  understanding  of  the  links   between  urbanisation  and  geomorphic  features  and  functions,  and  recognition  of  the  relevant   constraints  within  the  urban  environment  including:  flashy  hydrology,  reduced  sediment  supply,  limited   space,  legacy  impacts  and  social  and  institutional  perceptions.  

Keywords: urbanisation,  geomorphologic  functioning,  stream  health,  waterway  management   Introduction Healthy  urban  streams  have  been  recognised  as  a  fundamental  prerequisite  to  achieving  sustainable   management  of  our  cities  and  fulfilling  our  imperative  to  maintain  healthy  aquatic  ecosystems  for  future   generations  (United  Nations  General  Assembly,  1987).  There  are  a  number  of  excellent  summaries  on   the  effects  of  urbanisation  on  stream  health  (Walsh  et  al.,  2005a;  Gurnell  et  al.,  2007),  but  these  often   ignore  or  only  briefly  touch  on  geomorphic  impacts.  While  there  is  general  consensus  that  urbanisation                                                                                                                           1

 Vietz, G. J., Stewardson, M. J., Walsh, C. J., Fletcher, T. D., 2012, Another reason urban streams are stuffed: geomorphic history, challenges and opportunities, in: Proceedings of the 6th Australian Stream Management Conference, 'Managing for extremes' (J. R. Grove, I. D. Rutherfurd, eds.), February 6-8, 2012, Canberra, Australia, pp. 110-115.  

 

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results  in  channel  enlargement,  channel  widening  and  channel  deepening  (e.g.  Booth  and  Jackson,  1997;   Chin,  2006;  Grable  and  Harden,  2006)  there  is  little  evidence  of  impacts  on  instream  features  (e.g.  bars   and  benches)  and  processes  (e.g.  sediment  transport  and  storage).  Though,  some  studies  have   demonstrated  reduced  physical  habitat  in  urban  streams  (Davenport  et  al.,  2001;  Scholz  and  Booth,   2001).  So  whilst  changes  in  mean  channel  geometry  and  physical  habitat  have  been  described,  the   underlying  mechanisms  and  consequences  have  not,  meaning  that  understanding  of  consequences  for   stream  biota  is  very  limited.  In  short,  whilst  there  are  conceptual  models  proposed  to  explain  gross   channel  changes  in  response  to  urbanisation  (e.g.  Chin,  2006),  the  underpinning  mechanisms  for  these   changes  are  not  well  established  and  the  consequences  for  geomorphic  features  or  functions  within   river  channels  are  poorly  described.  Given  the  limited  understanding  of  important  elements  of  physical   form  and  function  in  urban  streams,  it  is  not  surprising  that  little  effort  goes  into  restoring  or  protecting   them.  The  precautionary  principle  is  rarely  applied  to  eco-­‐geomorphic  associations.   We  argue  here  for  the  need  to  move  beyond  the  current  urban  stream  management  approaches  to   consider  geomorphic  form  and  functioning.  We  note,  however,  that  we  must  significantly  improve  our   knowledge  of  the  impacts  of  urbanisation  on  a  range  of  geomorphic  features  and  functions  comprising   healthy  streams.  This  paper  provides  a  précis  of  the  historical  approach  to  the  management  of  urban   stream  physical  form,  in  Australia  and  internationally,  as  background  to  the  current  state  of  knowledge   and  practice.  We  identify  elements  of  geomorphic  management  that  are  likely  to  be  required  if  healthy   streams  are  to  be  achieved,  and  describe  five  main  challenges  to  retaining  or  reinstating  geomorphic   features  associated  with  healthy  urban,  or  peri-­‐urban  streams.  

A focus on flow efficiency and channel stability: pre 2000 Research  into  urbanisation  and  geomorphology  has  almost  solely  focused  on  channel  dimensions  and   bank  stability,  highlighting  two  overarching  physical  form  management  priorities:  flow  efficiency  (i.e.  to   manage  flood  risk)  and  channel  stability  (i.e.  to  understand  rates  of  erosion).  This  approach  has  raised   concerns  over  the  exclusive  focus  on  human  values  (Florsheim  et  al.,  2008).  The  focus  on  flow  efficiency   and  stability  could  be  traced  back  to  the  founding  statement  of  the  institute  of  civil  engineers  in  1830   whose  intention  was  ‘to  harness  the  great  sources  of  power  in  nature  for  the  use  and  convenience  of   man’  (Watson,  1988).  Rivers  were  seen  as  disorganised  systems  that  needed  simplifying  in  order  to   replicate  channels  that  were  better  understood  (northern-­‐hemisphere  channels).  It  appears  that  Wilson   (1946)  was  the  first  to  propose  working  with  rivers  and  natural  processes,  rather  than  ‘man  versus  river’   and  it  was  not  until  the  1960s  that  the  science  of  fluvial  geomorphology  matured  in  the  US  and  later   within  Australia.  In  recent  years,  however,  there  has  been  increasing  recognition  that  stream   engineering  should  be  underpinned  by  an  understanding  of  geomorphology  (Gilvear,  1999).     Unfortunately,  however,  it  appears  that  stream  management  professionals  have  not  moved  beyond  the   ‘big  two’  objectives  of  flow  efficiency  and  channel  stability.  A  recent  study  of  urban  stream  professionals   and  academics,  conducted  for  Melbourne  Water,  revealed  that  the  greatest  driver  for  urban  stream   management  was  considered  to  be  ‘stabilisation/asset  protection’  (noted  by  50%  of  respondents)   (Zavadil,  2009).    The  third  greatest  driver  (23%)  was  ‘flood  mitigation’,  following  ‘recreation/amenity   activities’  (33%).  Despite  the  limited  sample  size  (30  interviews),  the  study  highlights  that  urban  stream   management  priorities  are  still  more  closely  aligned  with  achieving  stability  than  with  ecologically   healthy  streams.    

Considering urban stream geomorphology Managing  urban  streams  for  flood  mitigation  and  stability  is  unlikely  to  result  in  a  healthy  stream   ecosystem.  In  simplistic  terms  we  suggest  there  are  two  geomorphic  attributes  associated  with  streams  

 

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capable  of  supporting  biota:  channel  complexity  (i.e.  physical  form  diversity)  and  geomorphic  dynamism   (i.e.  channel  and  sediment  mobility).  Channel  complexity  –  driving  hydraulic  diversity  -­‐  can  translate  flow   into  an  important  ecological  event  such  as  a  disturbance  (Poff  et  al.,  2010).  It  increases  the  diversity  of   hydraulic  habitat  available  to  species,  particularly  low  velocity  macroinvertebrates  refuge,  and  provides   a  point  from  which  they  may  subsequently  disperse  to  recolonise  the  bed  post-­‐event  (Rice  et  al.,  2010).   The  more  diverse  the  channel  morphology  the  greater  the  resilience  of  the  refuge  habitat  to  a  large   range  of  flows,  and  the  greater  the  diversity  in  flow  depth  and  velocities  (Booker  and  Dunbar,  2004).     Geomorphic  dynamism  refers  to  the  processes  of  erosion,  transport  and  deposition  of  sediments  as  the   stream  mobilises  the  bed  and/or  bank  sediments.  In  particular;  bank  erosion,  mobile  bed  sediments,   geomorphic  features  created  by  transient  sediment  storage  (bars  and  benches)  and  planform  migration   (both  erosional  and  depositional)  are  all  important  dynamic  characteristics  of  natural  geomorphic   functioning.  The  niches  and  diversity  provided  by  bank  erosion  have  been  cited  as  integral  to  the   functioning  of  river  ecosystems  (Florsheim  et  al.,  2008).  In  urban  streams  deposition  tends  to  be  rare   (Grable  &  Harden,  2006)  and  as  such  bars,  benches  and  sediment  deposits  (including  coarse-­‐grained   substrates)  are  by  observation  often  conspicuous  by  their  absence  from  many  urban  streams.     If  you  have  made  it  to  reading  up  to  this  point  you  are  perhaps  pondering  that  there  is  little  hope  for  the   health  of  our  urban  streams,  particularly  their  physical  form  and  functioning.  Some  current  initiatives,   however,  aim  to  enhance  our  understanding  and  improve  management  strategies.  The  Cities  as  Water   Supply  Catchments  project  is  investigating  the  role  geomorphic  form  and  function  play  in  urban  streams   (Wong  et  al.,  2011).  This  is  in  association  with  the  main  project  goals  of  increasing  the  availability  of   water  for  use  in  cities  and  decreasing  stormwater  runoff  to  waterways.    Research  is  being  conducted  to   explicitly  understand  the  link  between  directly  connected  imperviousness  and  geomorphic  features   which  may  assist  in  achieving  ecological  restoration  goals.  In  terms  of  implementation  in  Victoria,   Melbourne  Water  is  developing  a  channel  form  and  function  position  paper.  This  will  outline  a  number   of  principles  for  incorporating  geomorphic  functioning  into  urban  stream  management  including:  the   consideration  of  longitudinal  and  lateral  connectivity,  the  intrinsic  value  of  the  physical  form  of  streams   (particularly  when  rare  or  threatened),  and  the  role  of  planning  in  the  management  of  riparian  lands.   These  activities  are  expanding  the  realm  of  a  physical  form  management  with  a  geomorphologically-­‐ sensitive  approach  more  likely  to  influence  the  health  of  streams  in  the  future.  Relative  to  standard   stream  management  approaches  a  geomorphologically-­‐sensitive  one  needs  to  consider  three  main   attributes:  (1)  the  level  of  channel  complexity,  (2)  the  level  of  acceptable  dynamism  (planform  and   sediment  movement),  and  (3)  the  amount  of  riparian  land  required  to  achieve  these  goals  (Table  1).    

Challenges and opportunities We  suggest  there  are  five  main  drivers  of  physical  form  degradation  for  urban  streams  discussed  in  the   following  paragraphs.  While  there  may  be  opportunities  to  address  these  challenges  the  solutions  are   not  yet  fully  understood.   Flashy  hydrology:  Changes  to  the  hydrologic  regime  due  to  urbanization  have  been  well  described   (Walsh  et  al.,  2005b;  Gurnell  et  al.,  2007),  and  it  is  the  increased  hydraulic  efficiency  of  the  urban   drainage  system  which  has  been  found  to  account  for  about  70  percent  of  the  increase  in  runoff   magnitude  to  receiving  waters  (Wong  et  al.,  1997).  Increases  in  the  peak  discharge,  and  of  greater   concern,  the  durations  above  erosional  thresholds,  have  been  found  to  be  the  most  damaging  to   physical  form  (Coleman  et  al.,  2005).  Where  possible  the  principle  of  ameliorating  this  driver  of  channel   change  should  focus  on  the  cause  (urban  runoff  to  streams)  as  described  by  Walsh  et  al.  (2005b),  rather   than  treating  the  symptoms  in  streams.  With  a  focus  on  managing  the  urban  water  cycle  in  a  more    

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integrated  and  sustainable  manner,  including  re-­‐use  of  stormwater  (Wong  et  al.,  2011),  it  is  critical  that   geomorphic  considerations  inform  the  design  solutions.  The  tools  for  quantifying  these  components   currently  fall  short  and  better  guidance  on  the  type  of  flow  regime  necessary  to  sustain  the  desired   geomorphology  is  needed.   Table  1.  Approaches  to  managing  streams  and  their  geomorphic  and  ecological  consideration    

Traditional   River   Engineering    

Geomorphologically-­‐ Referenced  River   Engineering  

Natural  Channel  Design    

Geomorphologically-­‐ sensitive  aspirations  

Channel   complexity  

Low  –  hard   engineering  to   reduce   roughness  and   increase   stability  

Medium  –  constructed   features  designed  to   resemble  ‘natural’  stream   with  some  ‘hard’  features   designed  for  low   resistance  

Medium  –  some  variable   cross  sectional  features  with   a  reliance  on  rock   stabilisation  

High  –  stream  controlled   geomorphic  features  such  as   benches,  bars  and  variable   sediment  sizes  which  create   resistance  to  flow  

Allowable   dynamism  

None  

Low  –  no  stream   adjustment,  no  mobile   substrates,  no  erosion   allowed  

Medium  –  limited  stream   adjustment,  limited  mobile   substrate  sediments,  erosion   commonly  addressed  

Riparian   space   required  

Very  low  

Low  –  no  lateral  flow   engagement  or   adjustment    

Medium  –  minimal  lateral   flow  engagement  and  minor   channel  adjustment    

Medium  to  High  –  stream   adjusts  dynamically  within   confined  corridor,  mobile   substrates,  acceptable  rates   of  erosion     Medium  to  High  –   engagement  with  actual  or   ‘internal’  floodplain  to   alleviate  channel  energy,   provide  adjustment  corridor  

Increasing  geomorphic  &  ecological  consideration  à  

Reduced  sediment  load:  Coarse-­‐grained  sediment  yield  from  an  established  urban  catchment  is  generally   considered  to  decrease  (Bledsloe,  2002;  Gurnell  et  al.,  2007).  Once  the  sediment  supply  is  reduced,  bank   erosion  is  estimated  to  provide  about  two-­‐thirds  of  the  total  sediment  yield  (Trimble,  1997).  The  limited   sediment  supply,  coupled  with  increased  sediment  transport  capacity  (Bledsloe,  2002),  particularly  in   the  naturally  supply-­‐limited  conditions  of  Australia,  significantly  reduce  bedload  sediments  (Figure  1a).   Sediment  supply  reductions  are  the  least  understood  and  potentially  the  greatest  impediments  to  long-­‐ term  recovery,  though  opportunities  exist  in  new  or  peri-­‐urban  developments  where  headwater   sediment  sources  can  be  preserved  and  riparian  land  managed  for  migration.   Limited  riparian  space:  Floodplain  engagement  and  lateral  migration  are  important  both  geomorphically   and  ecologically  (Coleman  et  al.,  2005;  Florsheim  et  al.,  2008),  but  are  reduced  in  urban  catchments.   Floodplain  engagement  is  often  undesirable  in  the  urban  environment,  but  it  is  important  to  recognise   the  geomorphic  implications,  namely,  increased  stream  energy  exerted  within  the  channel.  The  altered   flow  regime  in  combination  with  channel  modifications  are  a  double-­‐edged  sword,  driving  channel   degradation.  The  additional  loss  of  riparian  vegetation,  and  it’s  binding  and  shading  properties,  has   significant  implications  for  the  channel’s  geomorphic  integrity  (Booth,  1991).  Peri-­‐urban  areas  or  new   developments  provide  the  greatest  opportunities  for  larger  riparian  buffers,  or,  in  developed  locations   riparian  space  should  be  vigorously  defended.  The  challenge  is  to  allow  for  the  greatest  amount  of   ‘natural’  (stream  controlled)  adjustment  and  engagement  within  the  often-­‐significant  constraints.  Such   urban  riparian  corridors  may  offer  other  benefits  in  terms  of  aesthetics  improving  urban  livability.   Legacy  impacts:  Urban  stream  degradation  cannot  always  be  entirely  attributed  to  urbanisation  and  it  is   important  to  differentiate  the  relative,  and  often  significant,  role  of  the  prior  land  uses  (Figure  1b).  The   associated  challenges  include:  distinguishing  appropriate  restoration  goals;  distinguishing  natural   reference  conditions;  and  disentangling  impacts  both  temporarally  and  spatially    to  understand  futures    

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responses.  Some  of  the  most  susceptible  stream  types  to  these  issues  are  ephemeral  and  ill-­‐defined   streams  (e.g.  ‘intact  valley  fills’  or  ‘chain-­‐of-­‐ponds’  in  greenfield  sites).  Focusing  management  and   research  efforts  on  relatively  undisturbed  but  rapidly  developing  sites  might  avoid  some  of  these   challenges.     b)  

a)  

 

Figure  1a)  Impact  of  urbanisation  reducing  catchment-­‐derived  sediment  supply  coupled  with  increased   sediment  transport  capacity  leads  to  reduced  bedload  sediment,  and  b)  Legacy  impacts  on  urban  stream   geomorphology.  

 

Social  and  institutional  perceptions:  In  Australia  during  the  mid  1900s  rapid  development  of  cities   involved  major  drainage  works  with  streams  often  piped  or  channelised  (Brown  et  al.,  2009).  While   attitudes  are  rapidly  changing,  suggestions  of  alterations  to  flow  efficiency  or  channel  stability  will  still   face  opposition  within  the  community  and  the  waterway  management  industry.  The  urban   geomorphologist’s  role  is  a  particularly  challenging  endeavor,  being  to  convince  waterway  managers   and  the  community  alike  of  the  benefits  of  a  geomorphologically-­‐sensitive  approach  to  urban  stream   management  (and  the  important  role  of  the  floodplain  in  flood  mitigation):  these  desires  can  co-­‐exist   with  flooding  and  maintenance  management  if  appropriately  understood  and  implemented.  

Conclusions Historically  our  management  of  urban  streams,  both  in  Australia  and  internationally,  has  focused  on   flow  efficiency  and  channel  stability,  leading  to  degradation  of  physical  form.  If  we  are  able  address  the   catchment-­‐scale  perturbations  to  hydrology  and  water  quality  (the  former  of  which  has  contributed  to   geomorphic  impacts)  will  ecological  response  be  constrained  by  the  physical  form  and  functioning?  In   addition  to  the  importance  of  improving  our  knowledge  in  this  realm  there  are  a  number  of  challenges   faced  by  a  geomorphologically-­‐sensitive  approach,  including:  flashy  hydrology,  reduced  sediment   supply,  legacy  impacts,  lack  of  riparian  space  and  the  social  and  institutional  perceptions.  These   challenges  also  provide  opportunities  in  the  current  desire  for  more  livable  cities,  particularly  in   Greenfield  developments  as  the  urban  footprints  expand.  A  better  understanding  will,  if  not  reduce  the   risk,  allow  us  to  further  quantify  risks  to  humans  and  infrastructure  resulting  from  greater  consideration   for  the  ecological  and  geomorphic  functioning  of  streams.    

Acknowledgements This  research  is  funded  by  the  Cities  as  Water  Supply  Catchments  program,  which  is  a  collaborative   research  partnership  between  Monash  University,  The  University  of  Melbourne,  The  University  of  

 

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Queensland,  AECOM  and  a  large  number  of  industry  partners.  We  thank  James  Grove  for  providing  a   review  of  this  manuscript.   References Bledsloe,  B.  P.  (2002),  Stream  erosion  potential  and  stormwater  management  strategies,  Journal  of  Water   Resources  Planning  and  Management,  128(6),  451-­‐455.   Booker,  D.  J.,  and  M.  J.  Dunbar  (2004),  Application  of  physical  habitat  simulation  (PHABSIM)  modelling  to  modified   urban  river  channels,  River  Research  and  Applications,  20,  167-­‐183.   Booth,  D.  (1991),  Urbanization  and  the  natural  drainage  system  -­‐  Impacts,  solutions,  and  prognoses,  The  Northwest   Environmental  Journal,  7,  93-­‐118.   Booth,  D.  B.,  and  C.  R.  Jackson  (1997),  Urbanization  of  aquatic  systems:  degradation  thresholds,  stormwater   detection,  and  the  limits  of  mitigation,  J.  Am.  Water  Resour.  Assoc.,  33(5),  1077-­‐1090.   Brown,  R.  R.,  N.  Keath,  and  T.  H.  F.  Wong  (2009),  Urban  water  management  in  cities:  historical,  current  and  future   regimes,  Water  Sci.  Technol,  59(5),  847-­‐855.   Chin,  A.  (2006),  Urban  transformation  of  river  landscapes  in  a  global  context,  Geomorphol.,  79,  460-­‐487.   Coleman,  D.,  C.  MacRae,  and  E.  Stein  (2005),  Effect  of  increases  in  peak  flows  and  imperviousness  on  the   morphology  of  Southern  California  Streams,  Southern  California  Coastal  Water  Research  Project,   Westminster,  CA.   Davenport,  A.  J.,  A.  M.  Gurnell,  and  P.  D.  Armitage  (2001),  Classifying  urban  rivers,  Water  Sci.  Technol,  43(9),  147-­‐ 155.   Florsheim,  J.  L.,  J.  F.  Mount,  and  A.  Chin  (2008),  Bank  erosion  as  a  desirable  attribute  of  rivers,  BioScience,  58(6),   519-­‐529.   Gilvear,  D.  J.  (1999),  Fluvial  geomorphology  and  river  engineering:  future  roles  utilizing  a  fluvial  hydrosystems   framework,  Geomorphol.,  31,  229-­‐245.   Grable,  J.  L.,  and  C.  P.  Harden  (2006),  Geomorphic  response  of  an  Appalachian  Valley  and  Ridge  stream  to   ubanization,  Earth  Surf.  Process.  Landf.,  31,  1707-­‐1720.   Gurnell,  A.,  A.  Lee,  and  C.  Souch  (2007),  Urban  rivers:  hydrology,  geomorphology,  ecology  and  opportunities  for   change,  Geography  compass,  1(5),  1118-­‐1137.   Poff,  L.  N.,  B.  D.  Richter,  A.  H.  Arthington,  S.  E.  Bunn,  R.  J.  Naiman,  E.  Kendy,  M.  Acreman,  C.  Apse,  B.  P.  Bledsloe,   M.  C.  Freeman,  J.  Henriksen,  R.  B.  Jacobson,  J.  G.  Kennen,  D.  M.  Merritt,  J.  H.  O'Keefe,  J.  D.  Olden,  K.   Rodgers,  R.  E.  Tharme,  and  A.  Warner  (2010),  The  ecological  limits  of  hydrologic  alteration  (ELOHA):  a  new   framework  for  developing  regional  environmental  flow  standards,  Freshw.  Biol.,  55,  147-­‐170.   Rice,  S.  P.,  J.  Lancaster,  and  P.  Kemp  (2010),  Experimentation  at  the  interface  of  fluvial  geomorphology,  stream   ecology  and  hydraulic  engineering  and  the  development  of  an  effective,  interdisciplinary  river  science,  Earth   Surf.  Process.  Landf.,  35,  64-­‐77.   Scholz,  J.  G.,  and  D.  B.  Booth  (2001),  Monitoring  urban  streams:  Strategies  and  protocols  for  humid-­‐region  lowland   systems,  Environmental  Monitoring  and  Assessment,  71,  143-­‐164.   Trimble,  S.  W.  (1997),  Contribution  of  stream  channel  erosion  to  sediment  yield  from  an  urbanizing  watershed,   Science,  278(5342),  1442-­‐1444.   United  Nations  General  Assembly  (1987),  Report  of  the  World  Commission  on  Environment  and  Development:  Our   Common  Future.   Walsh,  C.  J.,  A.  H.  Roy,  J.  W.  Feminella,  P.  D.  Cottingham,  P.  M.  Groffman,  and  R.  P.  Morgan  (2005a),  The  urban   stream  syndrome:  current  knowledge  and  the  search  for  a  cure,  J.  N.  Am.  Benthol.  Soc.,  24(3),  706-­‐723.   Walsh,  C.  J.,  T.  D.  Fletcher,  and  A.  R.  Ladson  (2005b),  Stream  restoration  in  urban  catchments  through  redesigning   stormwater  systems:  looking  to  the  catchment  to  save  the  stream,  J.  N.  Am.  Benthol.  Soc.,  24(3),  690-­‐705.   Watson,  G.  (1988),  The  Civils  -­‐  the  story  of  Institution  of  Civil  Engineers,  Thomas  Telford  Ltd.   Wilson,  C.  M.  (1946),  River  come  closer  to  my  door!,  The  Scientific  Monthly,  62(2),  117-­‐126.   Wong,  T.  H.  F.,  R.  Allen,  J.  Beringer,  R.  R.  Brown,  V.  Chaudhri,  A.  Deletic,  T.  D.  Fletcher,  W.  Gernjak,  L.  Hodyl,  C.   Jakob,  M.  Reeder,  N.  Tapper,  and  C.  J.  Walsh  (2011),  Blueprint2011  -­‐  Stormwater  Management  in  a  Water   Sensitive  City,  48  pp  pp,  Monash  University,  Clayton,  VIC.   Zavadil,  E.  (2009),  Understanding  how  we  manage  urban  streams,  Report  P109064_R01  by  Alluvium  for  Melbourne   Water,  Melbourne,  Australia.  

   

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