Drainase is taken from English, ”Drainage” which means channeling,
draining, wasting, or shifting water. This research purposes to analyze the existing
drainage capacity caused by the rainfall runoff, also suggesting
the design of
drainage which is suitable with the local situation.
Rainfall data taken from last ten years at Kranji station, after that it counted
by yearly maximum data method and rainfall plan by Log Pearson type III method.
After that, count the rainf
all intensity by Mononobe method, the discharge of water
channel by rational method, and finding the dimension through Manning method.
There is 24 % channel or 11 channels which is incapacity and 76 % channel
or 35 channels are capable. From the calcula
tion there are 7 dimensions shape square
with different shapes, they are ; 1
st
dimension the channel’s width 0,66 m, and the
height is 1,78 m. The 2
nd
dimension width is 0,50 m and the height is 0,65 m. The 3
rd
width is 0,50 m and the height is 0,50 m.
The 4
th
width is 0,48 m and the height is
0,50 m. The 5
th
width is 0,45 m and the height is 0,50 m. The 6
th
width is 0,45 m
and the height is 0,45. And the last is 0,45 width and the height is 0,40 m.