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| #A design rainfall depth is to be captured entirely by the RWH system. | | #A design rainfall depth is to be captured entirely by the RWH system. |
| #The average annual demand (D) is greater than the average annual yield (Y) from the catchment. | | #The average annual demand (D) is greater than the average annual yield (Y) from the catchment. |
| When Y<sub>0.05</sub>/ D<sub>0.05</sub> < 0.33, the storage volume required can be estimated: | | |
| <br><strong>V<sub>S</sub> = A × C<sub>vol</sub> × R<sub>d</sub> × e</strong>
| | {{textbox|{{plainlist| |
| <br>V<sub>S</sub> = Storage volume required (L)
| | *When Y<sub>0.05</sub>/ D<sub>0.05</sub> < 0.33, the storage volume required can be estimated: |
| <br>A = The catchment area (m<sup>2</sup>)
| | *<strong>V<sub>S</sub> = A × C<sub>vol</sub> × R<sub>d</sub> × e</strong> |
| <br>C<sub>vol, E</sub> = The design storm runoff coefficient for the catchment
| | *V<sub>S</sub> = Storage volume required (L) |
| <br>R<sub>d</sub> = The design storm rainfall depth (mm), and
| | *A = The catchment area (m<sup>2</sup>) |
| <br>e = The efficiency of the pre-storage filter.
| | *C<sub>vol, E</sub> = The design storm runoff coefficient for the catchment |
| /*Good catchment selection means that the runoff coefficient, for a rainstorm event (C<sub>vol, E</sub>) should be 0.9 or greater. | | *R<sub>d</sub> = The design storm rainfall depth (mm), and |
| | *e = The efficiency of the pre-storage filter.}}}} |
| | |
| | /*Careful catchment selection means that the runoff coefficient, for a rainstorm event (C<sub>vol, E</sub>) should be 0.9 or greater. |
| | | |
| When 0.33 < Y<sub>0.05</sub>/ D<sub>0.05</sub>< 0.7, the total storage required can be estimated by adding Y<sub>0.05</sub>: | | When 0.33 < Y<sub>0.05</sub>/ D<sub>0.05</sub>< 0.7, the total storage required can be estimated by adding Y<sub>0.05</sub>: |