Changes

===Simple===

===Simple===

Five percent of the average annual yield can be estimated

Five percent of the average annual yield can be estimated

$$Y_{0.05} = A \times C_{vol, A}\times R_{a} \times e \times 0.05$$

$$Y_{0.05} = A \times C_{vol,A}\times R_{a} \times e \times 0.05$$

where:

where:

{{plainlist|

{{plainlist|

#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 :<math>0.33<Y_{0.05}/D_{0.05}<0.7</math>, the storage volume required can be estimated:

*When Y_0.05/ D_0.05 < 0.33, the storage volume required can be estimated:

<math>V_{S} = A \times C_{vol,E}\times R_{d} \times e</math>

*<strong>V_S &#61; A × C_vol × R_d × e</strong>

*V_S &#61; Storage volume required (L)

*A &#61; The catchment area (m²)

*''V_S'' &#61; Storage volume required (L)

*C_{vol, E} &#61; The design storm runoff coefficient for the catchment

*''A'' &#61; The catchment area (m²)

*R_d &#61; The design storm rainfall depth (mm), and

*''C_vol,E'' &#61; The design storm runoff coefficient for the catchment

*e &#61; The efficiency of the pre-storage filter.}}}}

*''R_d'' &#61; The design storm rainfall depth (mm), and

*''e'' &#61; The efficiency of the pre-storage filter.}}

*Careful catchment selection means that the runoff coefficient, for a rainstorm event (C_{vol, E}) should be 0.9 or greater.

*Careful catchment selection means that the runoff coefficient, for a rainstorm event (C_{vol, E}) should be 0.9 or greater.