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The foundation for the Little Stringybark Creek Project was a research project run through the Cooperative Research Centre (CRC) for Freshwater Ecology, Project D210: Urbanization and Stream Function. Partly funded by the Melbourne Water Corporation, this project studied 16 independent catchments east of Melbourne to understand what drives their ecological and water quality. It found that that conventionally piped stormwater drainage systems are the primary degrading impact of waterways in urban catchments, including:
  • P, DOC and EC (Hatt et al. 2005)
  • Benthic algal biomass (Taylor et al. 2004)
  • Macroinvertebrate assemblages (Walsh 2004)
  • Diatom assemblages (Newall & Walsh 2005)
  • Labile leaf breakdown (Imberger et al. 2008)
  • Denitrifier assemblages (Perryman et al. 2011)

Project D210 resulted in a quantitative model of instream ecological response to ‘effective imperviousness’ (EI), the proportion of a catchment covered by impervious surfaces with direct, piped connection to the stream. This model identified that degradation from urban runoff occurs at very low levels of EI (around 0.5%), with streams typically substantially degraded once there is 2% or more of connected impervious areas. The work suggests that to achieve instream ecological condition similar to other similar eastern Melbourne streams with no catchment urbanization, connected impervious area should be kept as far below 2% as possible.

Project D210 led to a new research question posed by Walsh et al. (2005):

Could catchment-scale stormwater retention restore the hydrology, water quality & ecological structure and function of a degraded urban stream?



Hatt, B.E., Fletcher, T.D., Walsh, C.J., Taylor, S.L., 2004, The influence of urban density and drainage infrastructure on the concentrations and loads of pollutants in small streams, Environmental Management, vol 34, issue 1, Springer-Verlag New York, New York NY USA, pp. 112-124.

Imberger, S. J., Walsh, C. J., and Grace, M. R. (2008). More microbial activity, not abrasive flow or shredder abundance, accelerates breakdown of labile leaf litter in urban streams. Journal of the North American Benthological Society 27, 549–561. 

Newall, P., and Walsh, C. J. (2005). Response of epilithic diatom assemblages to urbanization influences. Hydrobiologia 532, 53–67.

Perryman, S.E., Rees, G.N., Walsh, C. J., and Grace, M. R. (2011). Urban stormwater runoff drives denitrifying community composition through changes in sediment texture and carbon content. Microbial Ecology 61, 932–940.

Taylor, S. L., Roberts, S. C., Walsh, C. J., and Hatt, B. E. (2004). Catchment urbanization and increased benthic algal biomass in streams: linking mechanisms to management. Freshwater Biology 49, 835–851.

Walsh, C. J. (2004). Protection of in-stream biota from urban impacts: to minimize catchment imperviousness or to improve drainage design? Marine and Freshwater Research 55, 317–326.

Walsh, C. J., T. D. Fletcher, and A. R. Ladson. 2005. Stream restoration in urban catchments through re-designing stormwater systems: looking to the catchment to save the stream. Journal of the North American Benthological Society 24:690–705.

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