The ground water flow component is the sub-surface runoff component contributing to the river discharge from a particular region after the rainfall. If the major portion of runoff water reaches the river as overland flow , a heavy rainfall would result in quick response in the river and the hydrograph shape would be peak. Thus the risk of floods would be higher in this case. While if the major share is through ground water flow the rise in discharge is slower and the repose of the river is slower. Thus the rate at which the flood waters reaches the river body determines the shape of t he hydrograph. The major factors contributing to these situations are characteristics of drainage basin, type and amount of precipitation, land use pattern in a region, impact caused by human intervention, size and shape of drainage basin and major river management measures adopted (Flood hydrograph, n.d.).
The hydrograph for river Cynon is drawn based on the rainfall and river flow depth data (figure 1). The discharge in the river is plotted along y-axis and the time (in hours) along x axis. ...Show more