Review of Methods of Measuring Streamflow Using Hydraulic Structures

Abstract

The measurement of streamflow is very critical to hydraulic engineers and hydrologists as it provides vital information for environmental monitoring issues connected to water resources. The objective of this study is to examine various means of measuring streamflow specifically application of hydraulic structures installed across the direction of flow. Weirs are restricted to small rivers where the provision for sufficient head and constriction in the river is acceptable. Sharpcrested weir is easy to construct, and it is commonly used as a flow measuring device in an open channel. Flumes are self-cleaning due to the fact that the flow velocity through a flume is usually high. Traditionally, flume is used in measuring flow in agricultural systems, and it requires low maintenance cost. It has capacity to measure more flow rates than weir. Accurate streamflow measurement using flume is within AE2-5% while that of weir is AE2%. Generally, flumes are employed to determine discharge where weirs are not useful.

Calibración de canales aforadores en sistemas irrigados mediante el procesamiento de imágenes de video y la inferencia bayesiana

“…Sin em-bargo, en la mayoría de los casos la única alternativa viable es emplear técnicas indirectas en las que se miden la velocidad y la geometría de la sección transversal (en ocasiones con sensores costosos) y se estima el caudal como el producto de la velocidad por el área (5) . Un enfoque más práctico emplea la relación teórica de nivel-caudal en secciones de geometría conocida, tales como canales aforadores, vertederos, orificios, que son ampliamente utilizados en sistemas de riego (6) .…”

Forecasting of stage-discharge in a non-perennial river using machine learning with gamma test

“…Different analytical models were used to forecast stage-discharge for monitoring the water resource activities at the basin level, like flood routing, flood mitigation and protection, drought assessment, and optimization of reservoir activities for agriculture, electricity generation, and drinking water supply [ [18] , [19] , [20] , [21] ]. Additionally, the polynomial equations that characterize the stage-discharge relationship fail to effectively forecast the peak values [ [23] , [24] , [25] ]. Usually, the stage-discharge observations are made manually during the day, and flood peaks often strike at night, adding to the discharge uncertainty [ 22 , 23 ].…”

“…Different empirical equations are available for lower discharge, i.e., Manning's. Therefore, simulations are run in a controlled laboratory environment to investigate the impact of their various geometry and hydraulic parameters on flow characteristics [ 25 ].…”

The effect of crump weir

“…With a triangular cross-section, it is referred to as level a V-threesided profile weir. [6] , [7]. This type of wastage was developed in some countries which depend on fish for their livelihood-one of the solutions of fish gathering Fig.…”

“…Under modular flow circumstances, the downstream slope was shallow enough to enable a hydraulic jump to develop on the weir, serving as an inherent energy dissipator and reducing losses under submerged conditions. It is not possible to obtain an exact equation for calculating the discharge passing over the weir because the flow pattern differs from one weir to another, as the flow pattern changes with the discharge [15]; consequently, Eq (1) is the equation for calculating the discharge across Crump Weir [6].…”