From cross-section and average speed. 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.
This is one reason for measuring flow - to work out the load of contaminants and sediment the waterway is carrying. Because discharge can have a significant effect on water quality, it is important that it is recorded at the time of sampling and, if possible, during the previous few days.
Top 6 Methods for Estimation of Flood Discharge
- Method # 1. Catchment-Run-Off Method:
- Method # 2. Empirical Formulae:
- Method # 4. Cross Sectional Area and Bed Slope:
- Method # 5. Area of Cross-Section and Velocity as Observed at Bridge Site:
- Method # 6. Available Records:
The discharge is worked out by multiplying the mean velocity with the cross-sectional area • In practice as velocity is not uniform throughout the section due to various resistive forces. The cross-section of river or channel is divided into different parts and the area of each is part is determined.
Design discharge is the maximum flood that any hydraulic cross section allows to pass safely without inundation problems on the channel banks. Figure 7.1 indicates the bank-full level of a flood occurrence in a cross section, Fig.
Stream flow, or discharge, is the volume of water that moves over a designated point over a fixed period of time. It is often expressed as cubic feet per second (ft3/sec). It is important because of its impact on water quality and on the living organisms and habitats in the stream.
For water that is stored or impounded, the acre-foot (af) is how water is measured.
- Cubic feet per second (cfs): * 1 cubic foot = 7.4805 gallons.
- Acre-foot (af): * 1 acre = 43,560 square feet.
- Other conversions: * 1 US gallon = 0.1337 cubic feet = 3.79 liters.
As the rain starts to get heavy, the soil may be saturated, thus there is an increase in surface run off. This causes water to start flowing into the river channel, causing the level of discharge to increase, making the line go up positively.
Q=Vt Q = V t , where V is the volume and t is the elapsed time. The SI unit for flow rate is m3/s, but a number of other units for Q are in common use. For example, the heart of a resting adult pumps blood at a rate of 5.00 liters per minute (L/min).
Laminar flow, type of fluid (gas or liquid) flow in which the fluid travels smoothly or in regular paths, in contrast to turbulent flow, in which the fluid undergoes irregular fluctuations and mixing.
The equation of continuity states that for an incompressible fluid flowing in a tube of varying cross-section, the mass flow rate is the same everywhere in the tube. Generally, the density stays constant and then it's simply the flow rate (Av) that is constant.
However, it's easier to use a handy formula: rate equals distance divided by time: r = d/t.
Introduction. Flow is the volume of fluid that passes in a unit of time. In water resources, flow is often measured in units of cubic feet per second (cfs), cubic meters per second (cms), gallons per minute (gpm), or other various units.
Pipe Diameter (D): The larger the pipe diameter is, the slower the flow velocity will be. Optimal flow rate can be maintained without increasing the velocity, if a larger pipe is specified.
Streamflow is always changingOf course, the main influence on streamflow is precipitation runoff in the watershed. Rainfall causes rivers to rise, and a river can even rise if it only rains very far up in the watershed - remember that water that falls in a watershed will eventually drain by the outflow point.
A stream is a body of water that flows on Earth's surface. The word stream is often used interchangeably with river, though rivers usually describe larger streams. As smaller streams flow downhill, they often merge together to form larger streams. These smaller streams are called tributaries.
A river is a large body of fresh, flowing water.
Upstream and Downstream – Formula
- Upstream = (u−v) km/hr, where “u” is the speed of the boat in still water and “v” is the speed of the stream.
- Downstream = (u+v)Km/hr, where “u” is the speed of the boat in still water and “v” is the speed of the stream.
- Speed of Boat in Still Water = ½ (Downstream Speed + Upstream Speed)
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.
Thus, the terms discharge, streamflow, and runoff represent water with the solids dissolved in it and the sediment mixed with it. Of these terms, discharge is the most comprehensive. The discharge of drainage basins is distinguished as follows: Yield.
How is it calculated? Mean annual flow is obtained by dividing the sum of all the individual daily flows by the number of daily flows recorded for the year. You can also select the average function (=average( ) ) in Excel to the find the mean annual flow.
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.
