If length is measured in feet and time in seconds, Discharge has units of feet
3
/sec or cubic feet per second (cfs). Depth times Width gives the cross-sectional area. The shape of the channel is important because of the reduction in velocity due to friction along the channel margins.
What is river discharge?
Discharge is
the volume of water moving down a stream or river per unit of time
, commonly expressed in cubic feet per second or gallons per day.
How do we determine the total discharge?
Using the depth and width measurements for calculating the area and the velocity measurements, the discharge is computed by the
ADCP using discharge = area x velocity
, similar to the conventional current-meter method.
How will you measure the river discharge with the help of current meter?
In the simplest method, a current meter turns with the flow of the river or stream. The current meter is used to measure
water velocity at predetermined points (subsections) along a marked line
, suspended cableway, or bridge across a river or stream. The depth of the water is also measured at each point.
How is discharge flow rate calculated?
CalcTool: Flow (discharge) rate calculator. 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.
What causes river discharge?
There are several factors that affect stream discharge.
The velocity of the water affects it
; faster water means more passes per second so more discharge. The width and depth of the river also affects it; a larger river at the same speed will have higher discharge.
What are all the different methods of calculation of 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:
Where is discharge greatest in a river?
The base flow is the water that reaches the channel through slow throughflow and permeable rock below the water table. As stormwater enters the drainage basin the discharge rates increase. This is shown in the rising limb. The highest flow in the channel is known as the
peak discharge
.
Where is the highest discharge in a river?
The base flow is the water that reaches the channel through slow throughflow and permeable rock below the water table. As stormwater enters the drainage basin the discharge rates increase. This is shown in the rising limb. The highest flow in the channel is known as the
peak discharge
.
What controls river discharge?
The river’s discharge at that location depends on the rainfall on the catchment or drainage area and the inflow or outflow of groundwater to or from the area, stream modifications such as
dams and irrigation diversions
, as well as evaporation and evapotranspiration from the area’s land and plant surfaces.
What method is best to measure discharge?
Stream gaging
is a technique used to measure the discharge, or the volume of water moving through a channel per unit time, of a stream. The height of water in the stream channel, known as a stage or gage height, can be used to determine the dischage in a stream.
How do you calculate the velocity of a river?
Find the surface water velocity (in m/s)
by dividing the distance from AA to BB
(in this example, 10 m) by the average time (in seconds) and multiply this result by 0.85 (a correction factor) to estimate the average water velocity of the stream. Average water velocity = 0.5 m/s x 0.85 = 0.425 m/s.
Why do we measure discharge?
This is one reason for measuring flow
How much is the discharge of river Krishna?
| Krishna River | • average 2,213 m 3 /s (78,200 cu ft/s) | Discharge | • location Vijayawada (1901–1979 average), max (2009), min (1997) |
|---|
How does weather affect river discharge?
Additional runoff will be compounded by
lower flows and rising temperatures
. More frequent droughts and shifting precipitation patterns lower water levels in rivers, lakes and streams, leaving less water to dilute pollutants.
Is river discharge an output?
River discharge –
the amount of water that passes a given point
, in a given amount of time.
