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→Planning considerations
==Planning considerations==
==Planning considerations==
===Best cross sections===
[[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.
For a given width and depth, the difference between a triangular and trapzoidal section is small. As shown in the diagrams, under low flow conditions the trapezoidal has greater wetted perimeter, and at higher flows the triangular profile does.
===Check dams===
===Check dams===