Analysis Of Streamflow

1. Introduction

Streamflow is the amount of water flowing at a particular location and a specified time. It is basically the runoff generated from the watershed or catchment whose magnitude are measured at stream gauging sites which are generally outlets. It is measured in the discharge units (L3T-1). Hydrometry is the branch of science which deals with the measurement of flow. The accurate measurement of streamflow is necessary for number of activities such as in-channel structures like bridges, banks, spurs and other purposes. The importance of good quality data is known at the time of developing a model where these are used to forecast streamflow. Mean annual discharge or flow of rivers is an important indicator of global water supply,

Historical Perspective

2.1 Recent and popular methods used for streamflow monitoring

Different methods have been developed over the years for accurate streamflow measurement. All these methods have their own limitations and hence are used taking into consideration the type of installation, cost and precision. Some of the popular, widely used and recent techniques are presented below:

2.1.1 Current Meter

Current meters are used to measure point velocity in the flow direction across various positions of the stream. The rotating element rotates due to the velocity of the stream. The current meter is calibrated initially before using. The stream velocity is calculated by calculating the number of turns of the rotating element. These are expensive but accurate and

For this, he made use of hand-held radars for collecting the surface velocity samples and compared the results with various other methods like ADCP, ADV, rating curves. Dobriyal et al. (2015) reviewed various methods used for streamflow measurement based on adaptability, operational ease and stream size. He also provided the pros and cons of each method. Welber et al. (2016) evaluated the Surface Velocity Radar (SVR) for the stream surface velocity measurement and thereby converted the surface velocity into mean velocity by the use of a proper velocity coefficient depending upon the relative roughness. He also estimated the discharge at various location and compared the results with the conventional techniques.

Barbarossa et al. (2016) developed a global-scale regression model for estimating mean annual stream discharge by taking into five variables which described 90% variation. The model was developed using the mean annual discharge data from 1981 to 2010 from 1885 catchments having area between 2 and 106 km2. He compared the results with that of another