How does USGS measure discharge?
Current Meter One method that has been used for decades by the USGS for measuring discharge is the mechanical current-meter method. In this method, the stream channel cross section is divided into numerous vertical subsections.
What are the requirements for an ideal site for discharge measurement?
An ideal measurement has no more than 5% of the total discharge in any sub-section. Measurements should contain between 25 and 30 sub-sections. The spacing between the verticals should be closer in those parts of the cross section with greater depths and velocities.
How is discharged measured?
A discharge is a measure of the quantity of any fluid flow over unit time. The quantity may be either volume or mass. Thus the water discharge of a tap (faucet) can be measured with a measuring jug and a stopwatch. Here the discharge might be 1 litre per 15 seconds, equivalent to 67 ml/second or 4 litres/minute.
What is stream discharge measuring?
Stream discharge can be measured using (1) volumetric gauging, (2) float gauging, (3) current metering, (4) dilution gauging (constant injection or gulp methods), (5) structural methods, and (6) slope-area methods. The choice of method depends on the characteristics of the stream and on the application.
Which of the following is used to measure discharge?
Venturimeter is a discharge measurement instrument that uses a converging section of pipe to give an increase in the flow velocity and a corresponding pressure drop from which the flowrate can be deduced.
What is the unit for discharge?
The discharge is the volume of water that is transported each second, and the volumes are expressed in litres (l) or in cubic metres (m3) [1 m3 = 1000 l], and the letter Q is commonly used as the symbol for the discharge.
How do you calculate drainage discharge?
To do this, we simply multiply across each row. The runoff, Q, for the roof area in drainage Zone A is: (1.00 x 1.5 x 500) / 96.23 = 7.79 gallons per minute. The runoff for the grass portion of drainage Zone A is: (0.35 x 1.5 x 900) / 96.23 = 4.91 gpm.
Which flow measuring devices are used in discharge measurement and why?
The pitot tube are one the most used (and cheapest) ways to measure fluid flow, especially in air applications like ventilation and HVAC systems, even used in airplanes for speed measurent. The pitot tube measures the fluid flow velocity by converting the kinetic energy of the flow into potential energy.
What is rate of discharge?
The discharge rate is defined as the steady current in amperes (A) that can be taken from a battery of defined capacity (Ah) over a defined period (h). Batteries for CEGB power stations are normally specified for a 10-hour rate.
What is the difference between flow rate and discharge?
Discharge (also called flow rate) The amount of fluid passing a section of a stream in unit time is called the discharge. If v is the mean velocity and A is the cross sectional area, the discharge Q is defined by Q = Av which is known as volume flow rate.
How many methods streamflow can be measured?
1. Direct determination of stream discharge: (a) Area-velocity methods, (b) Dilution techniques, (c) Electromagnetic method, and (d) Ultrasonic method. 2. Indirect determination of streamflow: (a) Hydraulic structures, such as weirs, flumes and gated structures, and (b) Slope-area method.