This will allow calculations of the response to any input(rainfall). Hydrographs are often affected by factors of soil saturation and the surroundings. The vegetation type and the steepness of the surrounding lands, with the drainage density. Very dry weather, normally creates a crust on river beds and wet winters would increase the discharge. Sand and clay produces a flashy hydrographs but there could be a difference between the two.
In the analysis of the graphs, the bar graph would indicate that the amount of rainfall in the river would cause the river water to rise. We can notice that there is almost a steady flow of water until after a rainstorm. The amount of rainfall is indicated in the bar graph while the rise of water in the river is indicated in the line graph. As the water rises in the river, the height of water is recorded, and the amount of rainfall is computed. Normally the rise of water in a river occurs after a storm rainfall. The discharge is measured at a certain point in a river and is typically time variant. As the line graph is plotted, the part of the hydrograph rises up to its peak and the discharge is seen. The term given to this process in the hydrograph is the rising limb. The decrease of water discharge comes after the rising limb and it is defined as the falling limb. The peak discharge is when water reaches its highest point and there is greatest amount of water in the river. The period of time that is recorded between the peak rainfall and peak discharge is called the lag time. In the study of Cynon River that was performed, a total of 96 hours was consumed. The reading in the river height was taken every hour until the end of the 96th hour. At the end of the 96th hour, a hydrograph was plotted taking into considerations the result of the river height readings. A bar graph was plotted for the rainfall, and a line graph was plotted for the discharge. From the hydrograph, we can see the how the water in the river had risen. The graph showed that the rise of water started on the 44th hour. The peak point was reached on the 56th hour. After the water reached the peak point, it started to fall down. This stage is called the falling limb. It took 40 hours for the water to recede. In all hydrographs, the falling limb always take a longer time to recede, than the rising limb.
In the computations for a channel design and the design load of a pump, we will take into consideration the amount of water needed to satisfy the channel design that will be computed.
Given Data Note: apply the Manning formula to be able to get a suitable
Q = 1.0 m3/s breadth b, of a channel with depth d
n = 0.014
S = 0.0003
d = 0.5
v = R2/3S1/2n where: v = velocity
Q = Av R = Hydraulic Radius
Q = AR2/3S1/2n S = slope
A = bd n = Manning's coefficient
R = Awetted perimeter Q = discharge
A = db
Q = AR2/3S1/2n
R = 0.5b1.0+b
1.0 = 0.5b0.5b1.0 + b2/3(0.0003)1/20.014
1.0(0.014) = 0.5b0.5b1.0+b2/30.00031/2
0.014 = 0.5b 0.5b1.0+b23(0.0171)
0.0140.0171 = 0.5b0.5b1.0+b2/3
0.8187 = 0.5