Physical measures are structures built for soil and water conservation. Some principles should be considered. They should aim to
- increase the time of concentration of runoff, thereby allowing more of it to infiltrate into the soil;
- divide a long slope into several short ones and thereby reducing amount and velocity of surface runoff;
- reduce the velocity of the surface runoff;
- protect against damage due to excessive runoff (Tidemann 1996).
In most systems any physical measure can be built – check dams or contour ditches, for example (see figure) (Heathcote 1998).
Terraces are explained in more detail on the following learning page.