In the study catchments the bari terraces slope outwards at between 1 and 10°
(Fig. 3). The most frequent individual slope angle was approximately 5°. As over
65% of terrace slope angles were less than 7°, slope was not thought to be a major
factor influencing water runoff and soil erosion. Terrace widths commonly ranged
from 2 to 10 m and riser heights were commonly up to 2 m, but heights of over 4
m also occurred (Fig. 4). Riser angles are usually above 60°. It is only when the
terrace risers have slumped that the slope angle becomes less than 60°. In general,
outward-sloping terraces are far more common than inward-sloping types in the
Middle Hills. Terraces also tend to slope sideways, either away from a central axis
or as a whole, which facilitates drainage of excess water into adjacent steep tributaries
and natural ravines. Drainage is also commonly aided, in the study area, by
ditches at the bottom of terrace risers. These ditches lead water and associated sediment
into the neighbouring ravines. Farmers indicated that the ditches were needed
in areas of plentiful rain in order to prevent excess water from cascading over several
terraces and causing damaging rills and gullies. Thus, although it has not been invesF