Experiment # 4
RAINFALL-RUNOFF CHARACTERISTICS OF LONG STORM IN MULTIPLE STORM RAINFALL
Object: To determine rainfall-runoff characteristics of a long storm in multiple 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).
Switch on the pump and 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 long enough to give a steady runoff value. Switch off pump and record the recession limb of the hydrograph.
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 of 1st storm = ______ lit/min = ______ lit/sec;
Rainfall intensity of 2nd storm = ______ lit/min = ______ lit/sec; Runoff step = 0.01 lit/sec;
Duration of 1st storm = ____ sec; Duration of 2nd storm = ____ sec.
S. No. | Discharge (lit/sec) | Cumulative Time (sec) | S. No. | Discharge (lit/sec) | Cumulative Time (sec) |
Results: