Hydraulic performance of biofilter systems for stormwater management

Figure 7 : K lab deep ini vs. Kf s shallow – white triangle, system with low initial hydraulic conductivity, black
square, systems with high initial hydraulic conductivity
This decrease can be explained by sediment deposition at the surface. However,
final hydraulic conductivities are still relatively high (K fs shallow = 127 mm/h, n=17), and
likely to be adequate to ensure good pollutant removal performance. This observation
may be either because the systems are only partially clogged, or because creation of
macropores is having some effect in creating flow through the media, possibly even at
the surface (for example, at the base of plant stems, where growing, senescence and
even stem movement due to wind, may cause ‘breaking up’ of any clogging layer)
(Figure 8).
K lab deep ini = 241
K fs shallow = 127 mm/h
Figure 8 : Schematic representation of the evolution of the behaviour of biofilters with high initial K
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