Hydrological assessment of flow in Uma Oya, Sri Lanka

Abstract

A current meter is usually used in river flow measurements. However, if someone is interested in obtaining the temporal variation of a particular river, it may not be the easiest method in the world to use a current meter (i.e. daily) to measure the flow rate. In such events, the stage measurements can be taken and then, they can be converted to the flow rates (USGS, 2014). One can use the stage-discharge relationship to find the corresponding flow rate (Mortuza et al., 2011; Raj and Azeez, 2009; Gupta and Chakrapani, 2005). However, this method still requires some flow measurements to produce the stage-discharge relationship. Therefore, a current meter should be there to measure the velocities and then, to calculate the flow rates. In case of absence of a current meter, one has to think another way of obtaining the flow hydrograph. This paper presents a simple approach in obtaining the flow hydrograph for a river in Sri Lanka: Uma Oya. Uma Oya catchment is being modeled and this study shows some preliminary results. The detailed flow hydrograph for Uma Oya for a longer period is being developed for the frequency analysis. The developed flow hydrograph is being used to model the Uma Oya catchment in Sri Lanka