Changes

<h3>Best cross sections</h3>

<h3>Best cross sections</h3>

[[File:Best X-section.png|thumb|Both sections a)triangular and, b)trapezoidal, are constrained within ratios of 8:1 H:V]]  

[[File:Best X-section.png|thumb|Both sections a)triangular and, b)trapezoidal, are constrained within ratios of 8:1 H:V]]  

[[File:Sections_perimeters.png|thumb|At lowest flow rates (smallest area) the trapezoidal swale (b) has the greater wetted perimeter, at higher flow rates (greater area) the triangular geometry (a)has a larger wetted perimeter for same area. Both channels modelled using ratios shown in figure above]]

[[File:Sections_perimeters.png|thumb|At lowest flow rates (smallest area) the trapezoidal swale (b) has the greater wetted perimeter; at higher flow rates (greater area) the triangular geometry (a)has a larger wetted perimeter for same area. Both channels modelled using ratios shown in figure above]]

Enhanced swales aim to both reduce the flow rate and retain a portion of the conveyed water. For these purposes the best x-section is that which maximizes the wetted perimeter for a given area.  

Enhanced swales aim to both reduce the flow rate and retain a portion of the conveyed water. For these purposes the best x-section is that which maximizes the wetted perimeter for a given area.