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| |} | | |} |
| Before you begin you will need to know the following;<br> | | Before you begin you will need to know the following;<br> |
− | * Catchment area (i.e. contributing drainage area), A<sub>c</sub> (m<sup>2) | + | * Catchment area (i.e. contributing drainage area), A<sub>c</sub> (m<sup>2</sup>) |
| * Catchment runoff coefficient, C | | * Catchment runoff coefficient, C |
| * Catchment impervious area, A<sub>i</sub> (m<sup>2) | | * Catchment impervious area, A<sub>i</sub> (m<sup>2) |
| * Design storm intensity, i (mm/h) | | * Design storm intensity, i (mm/h) |
| * Design storm duration, D (h) | | * Design storm duration, D (h) |
− | * Infiltration target for design storm event, I<sub>d</sub> (mm) | + | * Infiltration volume target for the design storm event, V<sub>i</sub> (m<sup>3</sup>), based on average annual water budgets for the catchment for pre- and post-development scenarios and the infiltration volume deficit (pre-development minus post-development infiltration) |
| * Drainage time t (h) to fully drain the active storage of the practice, based on provincial or municipal criteria or average inter-event period for the location | | * Drainage time t (h) to fully drain the active storage of the practice, based on provincial or municipal criteria or average inter-event period for the location |
| * Field infiltration rate of the underlying native soil f<sub>f</sub> (mm/h), median of field measurements or based on interpolation from median grain-size distribution results | | * Field infiltration rate of the underlying native soil f<sub>f</sub> (mm/h), median of field measurements or based on interpolation from median grain-size distribution results |