Changes

[[File:Cistern Size.png|thumb|Schematic diagram of the inputs and outputs to a rainwater harvesting cistern]]

[[File:Cistern Size.png|thumb|Schematic diagram of the inputs and outputs to a rainwater harvesting cistern]]

===Simple===

===Simple===

Five percent of the average annual yield can be estimated:

*Five percent of the average annual yield can be estimated:

<math>Y_{0.05} = A \times C_{vol, A}\times R_{a} \times e \times 0.05</math>

*<math>Y_{0.05} = A \times C_{vol, A}\times R_{a} \times e \times 0.05</math>

*Y_0.05 &#61;  Five percent of the average annual yield (L)

Y_0.05 &#61;  Five percent of the average annual yield (L)

*A &#61;  The catchment area (m²)

A &#61;  The catchment area (m²)

*C_{vol, A} &#61;  The annual runoff coefficient for the catchment

C_{vol, A} &#61;  The annual runoff coefficient for the catchment

*R_a &#61;  The average annual rainfall depth (mm)

R_a &#61;  The average annual rainfall depth (mm)

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

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

 

Filter efficiency (e) can be reasonably estimated as 0.9 pending manufacturer’s information.<br>

Filter efficiency (e) can be reasonably estimated as 0.9 pending manufacturer’s information.<br>