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The first routine measurements of river flow in England began on the Thames and Lea in the 1880s, [2] and in Scotland on the River Garry in 1913. [3] The national gauging station network was established in its current form by the early 1970s and consists of approximately 1500 flow measurement stations supplemented by a variable number of temporary monitoring sites. [2]
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. This is an average measure.
In hydrology, a rating curve is a graph of discharge versus stage for a given point on a stream, usually at gauging stations, where the stream discharge is measured across the stream channel with a flow meter. [1] Numerous measurements of stream discharge are made over a range of stream stages.
For each gaging station, a relation between gage height and streamflow is determined by simultaneous measurements of gage height and streamflow over the natural range of flows (from very low flows to floods). This relation provides the streamflow data from that station. [5]
A stream hydrograph is commonly determining the influence of different hydrologic processes on discharge from the subject catchment. Because the timing, magnitude, and duration of groundwater return flow differs so greatly from that of direct runoff, separating and understanding the influence of these distinct processes is key to analyzing and simulating the likely hydrologic effects of ...
Here, only those rivers whose discharge is more than 2,000 m 3 /s (71,000 cu ft/s) are shown. It can be thought of as a list of the biggest rivers on Earth, measured by a specific metric. For context, the volume of an Olympic-size swimming pool is 2,500 m 3 (88,000 cu ft). The average flow rate at the mouth of the Amazon is sufficient to fill ...
Calculation of the mean flow may often be as simple as the mathematical mean: simply add up the given flow rates and then divide the final figure by the number of initial readings. For example, given two discharges (Q) of 3 m³/s and 5 m³/s, we can use these flow rates Q to calculate the mean flow rate Q mean.
There are two types of area velocity flowmeter: (1) wetted; and (2) non-contact. Wetted area velocity sensors have to be typically mounted on the bottom of a channel or river and use Doppler to measure the velocity of the entrained particles. With depth and a programmed cross-section this can then provide discharge flow measurement.