What is the velocity area method?

The velocity-area method is the most common method of estimating river flow. As the term implies, the flow is the product of the average velocity in the cross-section and the cross-sectional area of flow. Strict standard procedures, however, are followed in measuring these parameters as described in the paper.

How do you calculate stream velocity?

Q = AV, where Q is discharge (volume/unit time-e.g. m3/second, also called cumecs), A is the cross-sectional area of the stream (e.g. m2), and V is the average velocity (e.g. m/s). Stream water velocity is typically measured using a current meter.

How do you calculate stream flow rate?

The flow rate of a stream is equal to the flow velocity (speed) multiplied by the cross-sectional area of the flow. The equation Q=AV (Q=discharge rate, A=area, V=velocity) is sometimes known as the discharge equation.

What is the stream flow velocity?

Stream Flow and Sediment Transport. Stream velocity is the speed of the water in the stream. Units are distance per time (e.g., meters per second or feet per second). Stream velocity is greatest in midstream near the surface and is slowest along the stream bed and banks due to friction.

What instrument is used to measure the velocity of a river?

current meter
The most common method used by the USGS for measuring velocity is with a current meter. However, a variety of advanced equipment can also be used to sense stage and measure streamflow. In the simplest method, a current meter turns with the flow of the river or stream.

How do you calculate area of flow?

If the liquid is flowing through a pipe, the area is A = πr2, where r is the radius of the pipe. For a rectangle, the area is A = wh where w is the width, and h is the height. The flow rate can be measured in meters cubed per second (m3/s), or in liters per second (L/s).

What factors affect stream flow?

Mechanisms that cause changes in streamflow

• Runoff from rainfall and snowmelt.
• Evaporation from soil and surface-water bodies.
• Transpiration by vegetation.
• Ground-water discharge from aquifers.
• Ground-water recharge from surface-water bodies.
• Sedimentation of lakes and wetlands.

What is the relationship between velocity and pressure?

Pressure and velocity are inversely proportional to each other. If pressure increases, the velocity decreases to keep the algebraic sum of potential energy, kinetic energy, and pressure constant.

How is the velocity area method used in stream gauging?

STREAM GAUGING: THE VELOCITY AREA METHOD The velocity area method is another way to find flowrate (m3/sec). This method is often used in parts of a river where the flow is relatively laminar and the flow rate is not too high (< 5 m3/s) This method is based on the flowrate equation: = v · A

When do you use the velocity area method?

The velocity area method is another way to find flowrate (m3/sec). This method is often used in parts This method is often used in parts of a river where the flow is relatively laminar and the flow rate is not too high (< 5 m 3 /s)

How is the velocity of water measured in a stream?

Thus, when taking water velocity measurements, it is conventional to measure flow at 0.6 times the total depth, which typically represents the average flow velocity in the stream. This is achieved by attaching the current meter to a height-calibrated rod.

What is the formula to calculate stream flow?

The formula to use when calculating stream flow is: stream flow = velocity x cross sectional area To measure velocity a float (orange peel) will be used to determine how fast the water is