Changes

{{float right|[[File:Theta.jpg|border|500 px]]}}

{{float right|[[File:Theta.jpg|border|500 px]]}}

===Slope gradient===

===Slope gradient===

Slope gradients are expressed as Y:X where Y is a single unit of rise and X is the corresponding run. It can be calculated by dividing the rise by the run:

Slope gradients are are common form of expression for steeply sloped areas like the sides of [[swales]]. Expressed as Y:X where Y is a single unit of rise and X is the corresponding run. It can be calculated by dividing the rise by the run:

e.g.:<math>\frac{rise}{run}=\frac{4\ m}{12\ m}=\frac{1}{3};we\ say\ the\ slope\ =1:3\ or\ 1\ in\ 3</math>

e.g.:<math>\frac{rise}{run}=\frac{4\ m}{12\ m}=\frac{1}{3};we\ say\ the\ slope\ =1:3\ or\ 1\ in\ 3</math>