a. Determine the water level in the tap building
High water levels in the tap building tertiary primary or secondary channel can be calculated by the following equation:
P = A + a + b + c + d + e + f + g + h + z
Where:
P = water level in the primary or secondary channel
A = altitude wetland
a = a layer of stagnant water in paddy fields (10 cm)
b = loss of high-energy disaluran quarter to rice (5 cm)
c = high loss of energy in the box for the quarter (5 cm)
d = high energy loss during drainage in irrigation canals
e = high loss of energy in the box for
f = high loss of energy in culvert
g = high loss of energy in the tap building
h = variations in water level
z = high loss of energy in other tertiary buildings
b. Determining the slope of the line in the field,
The slope of the line follows the slope of the land on topographic maps (contour). The best way is to plot the elevation at the point of intersection with a line trace the contour lines
Figure 17. Determining the slope of the line
c. Determining the slope of the land (Lo)
The slope of each segment of the irrigation area can be determined by persanaan:
Where :
RWLu = High water level required in buildings in the upstream tapping
RWLd = High water level required in buildings tapping downstream
H0 = Total high estimate of loss on the building and the channel
L = length of segment