Experiment No. 3
RAINFALL-RUNOFF CHARACTERISTICS OF A SHORT DURATION SINGLE STORM RAINFALL
Object:- To study the rainfall-runoff characteristics of a short duration single storm rainfall.
Apparatus: Basic hydrology tank and stopwatch.
Experimental Setup/Methodology:
Set the slope of the catchment tank to a slope of about 1/200 (downhill towards the opening).
Using the nozzle control valve set flow rate for the overhead spray nozzles as 14 lit/min. Leaving the valve position unaltered, switch off the pump and allow at least one hour to elapse for the sand bed to drain thoroughly.
Allow rain to fall but cut off rain while hydrograph is still rising and record the recession limb of the hydrograph (< 60% ~ 80% of time of concentration).
Use a stopwatch started (zero time) at commencement of rainfall and read weir discharge as frequently as necessary to show hydrograph form.
Observations:
Rainfall intensity = ______ lit/min = ______ lit/sec;
Storm duration = ____ sec; Runoff step = _____ lit/sec
S. No. | Discharge (lit/sec) | Cumulative Time (sec) | S. No. | Discharge (lit/sec) | Cumulative Time (sec) |
Graphs:
A histogram and hydrograph are plotted from the runoff data of this experiment.
Results: